# Patent

## Title
Zoom lens system, imaging device and camera

## Abstract

A zoom lens system, in order from an object side to an image side, comprising a first lens unit of positive power, a second lens unit of negative power, a third lens unit of positive power, and a fourth lens unit of positive power, wherein the first lens unit is composed of three or fewer lens elements, wherein the second lens unit is composed of three lens elements, wherein in zooming, the first to the fourth lens units are moved individually along an optical axis such that air spaces should vary, so that variable magnification is achieved, and wherein the conditions are satisfied: tan 2ωW×m2W≦−1.78, tan 2ωW×|fG2|/fG1≧1.25, ωW≧37 and fT/fW≧10 (m2W is a lateral magnification of the second lens unit at a wide-angle limit, fG1 and fG2 are composite focal lengths of the first and the second lens units, ωW is a half view angle at a wide-angle limit, and fT and fW are focal lengths of the entire system respectively at a telephoto limit and at a wide-angle limit), an imaging device and a camera are provided.

## Background
CROSS-REFERENCE TO RELATED APPLICATION
This application is based on application Nos. 2009-002554, 2009-002555 and 2009-002556 filed in Japan on Jan. 8, 2009, the contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a zoom lens system, an imaging device and a camera. In particular, the present invention relates to: a high-performance zoom lens system having a small size and still having a wide view angle at a wide-angle limit as well as a high zooming ratio; an imaging device employing this zoom lens system; and a compact and thin camera employing this imaging device.
2. Description of the Background Art
Remarkably strong requirements of size reduction and performance improvement are present in digital still cameras and digital video cameras (simply referred to as digital cameras, hereinafter) provided with an image sensor for performing photoelectric conversion. In particular, from a convenience point of view, digital cameras are strongly requested that employ a zoom lens system having a high zooming ratio and still covering a wide focal-length range from a wide angle condition to a highly telephoto condition. On the other hand, in recent years, zoom lens systems are also desired that have a wide angle range where the photographing field is large.
As zoom lens systems having a high zooming ratio as described above, in conventional art, various kinds of zoom lens systems having a four-unit construction of positive, negative, positive and positive have been proposed that, in order from the object side to the image side, comprise: a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power.
Japanese Laid-Open Patent Publication No. H07-005361 discloses a zoom lens having the above-mentioned four-unit construction of positive, negative, positive and positive, wherein at the time of magnification change from a wide-angle limit to a telephoto limit, the first lens unit and the third lens unit are displaced to the object side relatively in a telephoto limit position than in a wide-angle limit position, the second lens unit is displaced to the image side relatively in a telephoto limit position than in a wide-angle limit position, and the fourth lens unit is moved along the optical axis, and wherein the ratio of the focal lengths of the entire system and the first lens unit and the image formation magnification of the second lens unit are set forth.
Japanese Laid-Open Patent Publication No. H07-020381 discloses a zoom lens having the above-mentioned four-unit construction of positive, negative, positive and positive, wherein at the time of magnification change from a wide-angle limit to a telephoto limit, the first lens unit moves monotonically to the object side, the second lens unit moves monotonically to the image side, the third lens unit moves such as to be located on the object side relatively at a wide-angle limit than at a telephoto limit, and the fourth lens unit moves such that in an infinite in-focus condition, the axial air space with the third lens unit should be larger at a telephoto limit than at a wide-angle limit, and wherein the ratio of the focal lengths of the third and the fourth lens units, the air space between the third and the fourth lens units, and the composite focal lengths of the first to the third lens units are set forth.
Japanese Laid-Open Patent Publication No. 2006-133632 discloses a zoom lens having the above-mentioned four-unit construction of positive, negative, positive and positive, wherein at the time of magnification change from a wide-angle limit to a telephoto limit, the intervals of the individual units are changed and the first lens unit moves to the object side relatively at a telephoto limit than at a wide-angle limit, and wherein the focal length of the first lens unit and the values of lateral magnification of the second lens unit at a telephoto limit and a wide-angle limit are set forth.
Japanese Laid-Open Patent Publication No. 2007-003554 discloses a zoom lens having the above-mentioned four-unit construction of positive, negative, positive and positive, wherein at least the first and the third lens units are moved at the time of magnification change and the first lens unit is moved to the object side at the time of magnification change from a wide-angle limit to a telephoto limit, and wherein the amount of relative movement of the second lens unit in magnification change from a wide-angle limit to a telephoto limit and the focal lengths of the first and the third lens units are set forth.
Japanese Laid-Open Patent Publication No. 2007-010695 discloses a zoom lens having the above-mentioned four-unit construction of positive, negative, positive and positive, wherein at least the first lens unit is moved in magnification change from a wide-angle limit to a telephoto limit, and wherein the focal length of the first lens unit and the average refractive index to the d-line of all lenses in the second lens unit are set forth.
Japanese Laid-Open Patent Publication No. 2008-026837 discloses a zoom lens having the above-mentioned four-unit construction of positive, negative, positive and positive, wherein at the time of magnification change from a wide-angle limit to a telephoto limit, the interval between the first lens unit and the second lens unit increases and the interval between the second lens unit and the third lens unit decreases, and wherein the refractive index, the Abbe number, and the anomalous dispersion property are set forth at least for one positive lens in the third lens unit.
Each zoom lens disclosed in the above-mentioned patent documents has a sufficiently reduced size that permits application to a thin and compact digital camera and still has a high zooming ratio of approximately 10 or greater. Nevertheless, each zoom lens has an insufficient view angle at a wide-angle limit, and hence does not satisfy a requested level in recent years.
SUMMARY OF THE INVENTION
An object of the present invention is to provide: a high-performance zoom lens system having a small size and still having a wide view angle at a wide-angle limit as well as a high zooming ratio; an imaging device employing this zoom lens system; and a compact and thin camera employing this imaging device.
(I) The novel concepts disclosed herein were achieved in order to solve the foregoing problems in the conventional art, and herein is disclosed:
a zoom lens system, in order from an object side to an image side, comprising a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
the first lens unit is composed of three or fewer lens elements, wherein
the second lens unit is composed of three lens elements, wherein
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
the following conditions (5), (6), (a-2) and (b) are satisfied:

tan 2ωW×m2W≦−1.78  (5)

tan 2ωW×|fG2|/fG1≧1.25  (6)

ωW≧37  (a-2)

fT/fW≧10  (b)

where,
m2W is a lateral magnification of the second lens unit at a wide-angle limit in an infinity in-focus condition,
fG1 is a composite focal length of the first lens unit,
fG2 is a composite focal length of the second lens unit,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.
The novel concepts disclosed herein were achieved in order to solve the foregoing problems in the conventional art, and herein is disclosed:
an imaging device capable of outputting an optical image of an object as an electric image signal, comprising:
a zoom lens system that forms the optical image of the object; and
an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
in the zoom lens system,
the zoom lens system, in order from an object side to an image side, comprises a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
the first lens unit is composed of three or fewer lens elements, wherein
the second lens unit is composed of three lens elements, wherein
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
the following conditions (5), (6), (a-2) and (b) are satisfied:

tan 2ωW×m2W≦−1.78  (5)

tan 2ωW×|fG2|/fG1≧1.25  (6)

ωW≧37  (a-2)

fT/fW≧10  (b)

where,
m2W is a lateral magnification of the second lens unit at a wide-angle limit in an infinity in-focus condition,
fG1 is a composite focal length of the first lens unit,
fG2 is a composite focal length of the second lens unit,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.
The novel concepts disclosed herein were achieved in order to solve the foregoing problems in the conventional art, and herein is disclosed:
a camera for converting an optical image of an object into an electric image signal and then performing at least one of displaying and storing of the converted image signal, comprising
an imaging device including a zoom lens system that forms the optical image of the object and an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
in the zoom lens system,
the zoom lens system, in order from an object side to an image side, comprises a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
the first lens unit is composed of three or fewer lens elements, wherein
the second lens unit is composed of three lens elements, wherein
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
the following conditions (5), (6), (a-2) and (b) are satisfied:

tan 2ωW×m2W≦−1.78  (5)

tan 2ωW×|fG2|/fG1≧1.25  (6)

ωW≧37  (a-2)

fT/fW≧10  (b)

where,
m2W is a lateral magnification of the second lens unit at a wide-angle limit in an infinity in-focus condition,
fG1 is a composite focal length of the first lens unit,
fG2 is a composite focal length of the second lens unit,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.
(II) The novel concepts disclosed herein were achieved in order to solve the foregoing problems in the conventional art, and herein is disclosed:
a zoom lens system, in order from an object side to an image side, comprising a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
the first lens unit is composed of three or fewer lens elements, wherein
the second lens unit is composed of three lens elements, wherein
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
the following conditions (7), (8), (a-2) and (b) are satisfied:

−3.12≦TG1/fW≦−2.36  (7)

1.26≦TG2/fW≦1.78  (8)

ωW≧37  (a-2)

fT/fW≧10  (b)

where,
TG1 is an amount of axial movement of the first lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
TG2 is an amount of axial movement of the second lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.
The novel concepts disclosed herein were achieved in order to solve the foregoing problems in the conventional art, and herein is disclosed:
an imaging device capable of outputting an optical image of an object as an electric image signal, comprising:
a zoom lens system that forms the optical image of the object; and
an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
in the zoom lens system,
the zoom lens system, in order from an object side to an image side, comprises a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
the first lens unit is composed of three or fewer lens elements, wherein
the second lens unit is composed of three lens elements, wherein
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
the following conditions (7), (8), (a-2) and (b) are satisfied:

−3.12≦TG1/fW≦−2.36  (7)

1.26≦TG2/fW≦1.78  (8)

ωW≧37  (a-2)

fT/fW≧10  (b)

where,
TG1 is an amount of axial movement of the first lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
TG2 is an amount of axial movement of the second lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.
The novel concepts disclosed herein were achieved in order to solve the foregoing problems in the conventional art, and herein is disclosed:
a camera for converting an optical image of an object into an electric image signal and then performing at least one of displaying and storing of the converted image signal, comprising
an imaging device including a zoom lens system that forms the optical image of the object and an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
in the zoom lens system,
the zoom lens system, in order from an object side to an image side, comprises a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
the first lens unit is composed of three or fewer lens elements, wherein
the second lens unit is composed of three lens elements, wherein
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
the following conditions (7), (8), (a-2) and (b) are satisfied:

−3.12≦TG1/fW≦−2.36  (7)

1.26≦TG2/fW≦1.78  (8)

ωW≧37  (a-2)

fT/fW≧10  (b)

where,
TG1 is an amount of axial movement of the first lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
TG2 is an amount of axial movement of the second lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.
(III) The novel concepts disclosed herein were achieved in order to solve the foregoing problems in the conventional art, and herein is disclosed:
a zoom lens system, in order from an object side to an image side, comprising a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
the first lens unit is composed of three or fewer lens elements, wherein
the second lens unit is composed of three lens elements, wherein
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
the following conditions (9), (a-2) and (b) are satisfied:

0.64≦fG4/fG1≦0.82  (9)

ωW≧37  (a-2)

fT/fW≧10  (b)

where,
fG1 is a composite focal length of the first lens unit,
fG4 is a composite focal length of the fourth lens unit,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.
The novel concepts disclosed herein were achieved in order to solve the foregoing problems in the conventional art, and herein is disclosed:
an imaging device capable of outputting an optical image of an object as an electric image signal, comprising:
a zoom lens system that forms the optical image of the object; and
an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
in the zoom lens system,
the zoom lens system, in order from an object side to an image side, comprises a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
the first lens unit is composed of three or fewer lens elements, wherein
the second lens unit is composed of three lens elements, wherein
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
the following conditions (9), (a-2) and (b) are satisfied:

0.64≦fG4/fG1≦0.82  (9)

ωW≧37  (a-2)

fT/fW≧10  (b)

where,
fG1 is a composite focal length of the first lens unit,
fG4 is a composite focal length of the fourth lens unit,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.
The novel concepts disclosed herein were achieved in order to solve the foregoing problems in the conventional art, and herein is disclosed:
a camera for converting an optical image of an object into an electric image signal and then performing at least one of displaying and storing of the converted image signal, comprising
an imaging device including a zoom lens system that forms the optical image of the object and an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
in the zoom lens system,
the zoom lens system, in order from an object side to an image side, comprises a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
the first lens unit is composed of three or fewer lens elements, wherein
the second lens unit is composed of three lens elements, wherein
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
the following conditions (9), (a-2) and (b) are satisfied:

0.64≦fG4/fG1≦0.82  (9)

ωW≧37  (a-2)

fT/fW≧10  (b)

where,
fG1 is a composite focal length of the first lens unit,
fG4 is a composite focal length of the fourth lens unit,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.
The present invention realizes: a high-performance zoom lens system having a small size and still having a wide view angle at a wide-angle limit as well as a high zooming ratio; an imaging device employing this zoom lens system; and a compact and thin camera employing this imaging device.



BRIEF DESCRIPTION OF THE DRAWINGS
This and other objects and features of this invention will become clear from the following description, taken in conjunction with the preferred embodiments with reference to the accompanied drawings in which:
FIG. 1 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment I-1 (Example I-1);
FIG. 2 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example I-1;
FIG. 3 is a lateral aberration diagram of a zoom lens system according to Example I-1 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state;
FIG. 4 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment I-2 (Example I-2);
FIG. 5 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example I-2;
FIG. 6 is a lateral aberration diagram of a zoom lens system according to Example I-2 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state;
FIG. 7 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment I-3 (Example I-3);
FIG. 8 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example I-3;
FIG. 9 is a lateral aberration diagram of a zoom lens system according to Example I-3 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state;
FIG. 10 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment I-4 (Example I-4);
FIG. 11 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example I-4;
FIG. 12 is a lateral aberration diagram of a zoom lens system according to Example I-4 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state;
FIG. 13 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment I-5 (Example I-5);
FIG. 14 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example I-5;
FIG. 15 is a lateral aberration diagram of a zoom lens system according to Example I-5 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state;
FIG. 16 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment I-6 (Example I-6);
FIG. 17 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example I-6;
FIG. 18 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment I-7 (Example I-7);
FIG. 19 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example I-7;
FIG. 20 is a lateral aberration diagram of a zoom lens system according to Example I-7 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state;
FIG. 21 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment I-8 (Example I-8);
FIG. 22 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example I-8;
FIG. 23 is a lateral aberration diagram of a zoom lens system according to Example I-8 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state;
FIG. 24 is a schematic construction diagram of a digital still camera according to Embodiment I-9;
FIG. 25 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment II-1 (Example II-1);
FIG. 26 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example II-1;
FIG. 27 is a lateral aberration diagram of a zoom lens system according to Example II-1 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state;
FIG. 28 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment II-2 (Example II-2);
FIG. 29 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example II-2;
FIG. 30 is a lateral aberration diagram of a zoom lens system according to Example II-2 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state;
FIG. 31 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment II-3 (Example II-3);
FIG. 32 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example II-3;
FIG. 33 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment II-4 (Example II-4);
FIG. 34 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example II-4;
FIG. 35 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment II-5 (Example II-5);
FIG. 36 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example II-5;
FIG. 37 is a lateral aberration diagram of a zoom lens system according to Example II-5 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state;
FIG. 38 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment II-6 (Example II-6);
FIG. 39 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example II-6;
FIG. 40 is a lateral aberration diagram of a zoom lens system according to Example II-6 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state;
FIG. 41 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment II-7 (Example II-7);
FIG. 42 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example II-7;
FIG. 43 is a lateral aberration diagram of a zoom lens system according to Example II-7 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state;
FIG. 44 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment II-8 (Example II-8);
FIG. 45 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example II-8;
FIG. 46 is a lateral aberration diagram of a zoom lens system according to Example II-8 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state;
FIG. 47 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment II-9 (Example II-9);
FIG. 48 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example II-9;
FIG. 49 is a lateral aberration diagram of a zoom lens system according to Example II-9 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state;
FIG. 50 is a schematic construction diagram of a digital still camera according to Embodiment II-10;
FIG. 51 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment III-1 (Example III-1);
FIG. 52 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example III-1;
FIG. 53 is a lateral aberration diagram of a zoom lens system according to Example III-1 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state;
FIG. 54 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment III-2 (Example III-2);
FIG. 55 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example III-2;
FIG. 56 is a lateral aberration diagram of a zoom lens system according to Example III-2 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state;
FIG. 57 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment III-3 (Example III-3);
FIG. 58 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example III-3;
FIG. 59 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment III-4 (Example III-4);
FIG. 60 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example III-4;
FIG. 61 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment III-5 (Example III-5);
FIG. 62 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example III-5;
FIG. 63 is a lateral aberration diagram of a zoom lens system according to Example III-5 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state;
FIG. 64 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment III-6 (Example III-6);
FIG. 65 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example III-6;
FIG. 66 is a lateral aberration diagram of a zoom lens system according to Example III-6 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state;
FIG. 67 is a lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment III-7 (Example III-7);
FIG. 68 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example III-7;
FIG. 69 is a lateral aberration diagram of a zoom lens system according to Example III-7 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state; and
FIG. 70 is a schematic construction diagram of a digital still camera according to Embodiment III-8.



DESCRIPTION OF THE PREFERRED EMBODIMENTS
(Embodiments I-1 to I-8)
FIGS. 1, 4, 7, 10, 13, 16, 18 and 21 are lens arrangement diagrams of zoom lens systems according to Embodiments I-1 to 1-8, respectively.
Each of FIGS. 1, 4, 7, 10, 13, 16, 18 and 21 shows a zoom lens system in an infinity in-focus condition. In each Fig., part (a) shows a lens configuration at a wide-angle limit (in the minimum focal length condition: focal length fW), part (b) shows a lens configuration at a middle position (in an intermediate focal length condition: focal length fM=√{square root over ( )}(fW*fT)), and part (c) shows a lens configuration at a telephoto limit (in the maximum focal length condition: focal length fT). Further, in each Fig., an arrow of straight or curved line provided between part (a) and part (b) indicates the movement of each lens unit from a wide-angle limit through a middle position to a telephoto limit. Moreover, in each Fig., an arrow imparted to a lens unit indicates focusing from an infinity in-focus condition to a close-object in-focus condition. That is, the arrow indicates the moving direction at the time of focusing from an infinity in-focus condition to a close-object in-focus condition.
The zoom lens system according to each embodiment, in order from the object side to the image side, comprises a first lens unit G1 having positive optical power, a second lens unit G2 having negative optical power, a third lens unit G3 having positive optical power, and a fourth lens unit G4 having positive optical power. Then, in zooming, the individual lens units move in a direction along the optical axis such that intervals between the lens units, that is, the interval between the first lens unit G1 and the second lens unit G2, the interval between the second lens unit G2 and the third lens unit G3, and the interval between the third lens unit G3 and the fourth lens unit G4 should all vary. In the zoom lens system according to each embodiment, since these lens units are arranged in the desired optical power configuration, high optical performance is obtained and still size reduction is achieved in the entire lens system.
Further, in FIGS. 1, 4, 7, 10, 13, 16, 18 and 21, an asterisk “*” imparted to a particular surface indicates that the surface is aspheric. In each Fig., symbol (+) or (−) imparted to the symbol of each lens unit corresponds to the sign of the optical power of the lens unit. In each Fig., the straight line located on the most right-hand side indicates the position of the image surface S. On the object side relative to the image surface S (that is, between the image surface S and the most image side lens surface of the fourth lens unit G4), a plane parallel plate P such as an optical low-pass filter and a face plate of an image sensor is provided.
Further, in FIGS. 1, 4, 7, 10, 13, 16, 18 and 21, an aperture diaphragm A is provided on the most object side of the third lens unit G3. Then, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the aperture diaphragm A moves along the optical axis integrally with the third lens unit G3.
As shown in FIG. 1, in the zoom lens system according to Embodiment I-1, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment I-1, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
In the zoom lens system according to Embodiment I-1, the third lens unit G3, in order from the object side to the image side, comprises: a positive meniscus seventh lens element L7 with the convex surface facing the object side; a positive meniscus eighth lens element L8 with the convex surface facing the object side; and a negative meniscus ninth lens element L9 with the convex surface facing the object side. Among these, the eighth lens element L8 and the ninth lens element L9 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 17 indicates the cement layer between the eighth lens element L8 and the ninth lens element L9. Further, the eighth lens element L8 has an aspheric object side surface.
Further, in the zoom lens system according to Embodiment I-1, the fourth lens unit G4 comprises solely a bi-convex tenth lens element L10. The tenth lens element L10 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment I-1, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the tenth lens element L10).
In the zoom lens system according to Embodiment I-1, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 4, in the zoom lens system according to Embodiment I-2, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment I-2, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
In the zoom lens system according to Embodiment I-2, the third lens unit G3, in order from the object side to the image side, comprises: a positive meniscus seventh lens element L7 with the convex surface facing the object side; a positive meniscus eighth lens element L8 with the convex surface facing the object side; and a negative meniscus ninth lens element L9 with the convex surface facing the object side. Among these, the eighth lens element L8 and the ninth lens element L9 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 17 indicates the cement layer between the eighth lens element L8 and the ninth lens element L9. Further, the eighth lens element L8 has an aspheric object side surface.
Further, in the zoom lens system according to Embodiment I-2, the fourth lens unit G4 comprises solely a bi-convex tenth lens element L10. The tenth lens element L10 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment I-2, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the tenth lens element L10).
In the zoom lens system according to Embodiment I-2, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 7, in the zoom lens system according to Embodiment I-3, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment I-3, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
In the zoom lens system according to Embodiment I-3, the third lens unit G3, in order from the object side to the image side, comprises: a positive meniscus seventh lens element L7 with the convex surface facing the object side; a positive meniscus eighth lens element L8 with the convex surface facing the object side; and a negative meniscus ninth lens element L9 with the convex surface facing the object side. Among these, the eighth lens element L8 and the ninth lens element L9 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 17 indicates the cement layer between the eighth lens element L8 and the ninth lens element L9. Further, the eighth lens element L8 has an aspheric object side surface.
Further, in the zoom lens system according to Embodiment I-3, the fourth lens unit G4 comprises solely a bi-convex tenth lens element L10. The tenth lens element L10 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment I-3, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the tenth lens element L10).
In the zoom lens system according to Embodiment I-3, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 10, in the zoom lens system according to Embodiment I-4, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment I-4, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
In the zoom lens system according to Embodiment I-4, the third lens unit G3, in order from the object side to the image side, comprises: a positive meniscus seventh lens element L7 with the convex surface facing the object side; a positive meniscus eighth lens element L8 with the convex surface facing the object side; and a negative meniscus ninth lens element L9 with the convex surface facing the object side. Among these, the eighth lens element L8 and the ninth lens element L9 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 17 indicates the cement layer between the eighth lens element L8 and the ninth lens element L9. Further, the eighth lens element L8 has an aspheric object side surface.
Further, in the zoom lens system according to Embodiment I-4, the fourth lens unit G4 comprises solely a bi-convex tenth lens element L10. The tenth lens element L10 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment I-4, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the tenth lens element L10).
In the zoom lens system according to Embodiment I-4, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 13, in the zoom lens system according to Embodiment I-5, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment I-5, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
In the zoom lens system according to Embodiment I-5, the third lens unit G3, in order from the object side to the image side, comprises: a positive meniscus seventh lens element L7 with the convex surface facing the object side; a positive meniscus eighth lens element L8 with the convex surface facing the object side; and a negative meniscus ninth lens element L9 with the convex surface facing the object side. Among these, the eighth lens element L8 and the ninth lens element L9 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 17 indicates the cement layer between the eighth lens element L8 and the ninth lens element L9. Further, the eighth lens element L8 has an aspheric object side surface.
Further, in the zoom lens system according to Embodiment I-5, the fourth lens unit G4 comprises solely a bi-convex tenth lens element L10. The tenth lens element L10 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment I-5, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the tenth lens element L10).
In the zoom lens system according to Embodiment I-5, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 16, in the zoom lens system according to Embodiment I-6, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment I-6, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
Further, in the zoom lens system according to Embodiment I-6, the third lens unit G3, in order from the object side to the image side, comprises: a bi-convex seventh lens element L7; a negative meniscus eighth lens element L8 with the convex surface facing the object side; and a positive meniscus ninth lens element L9 with the convex surface facing the object side. Among these, the seventh lens element L7 has two aspheric surfaces.
Further, in the zoom lens system according to Embodiment I-6, the fourth lens unit G4 comprises solely a bi-convex tenth lens element L10. The tenth lens element L10 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment I-6, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the tenth lens element L10).
In the zoom lens system according to Embodiment I-6, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 18, in the zoom lens system according to Embodiment I-7, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment I-7, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
In the zoom lens system according to Embodiment I-7, the third lens unit G3, in order from the object side to the image side, comprises: a positive meniscus seventh lens element L7 with the convex surface facing the object side; a positive meniscus eighth lens element L8 with the convex surface facing the object side; and a negative meniscus ninth lens element L9 with the convex surface facing the object side. Among these, the eighth lens element L8 and the ninth lens element L9 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 17 indicates the cement layer between the eighth lens element L8 and the ninth lens element L9. Further, the eighth lens element L8 has an aspheric object side surface.
Further, in the zoom lens system according to Embodiment I-7, the fourth lens unit G4 comprises solely a bi-convex tenth lens element L10. The tenth lens element L10 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment I-7, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the tenth lens element L10).
In the zoom lens system according to Embodiment I-7, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 21, in the zoom lens system according to Embodiment I-8, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; and a bi-convex second lens element L2. The first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2. Further, the second lens element L2 has an aspheric image side surface.
In the zoom lens system according to Embodiment I-8, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus third lens element L3 with the convex surface facing the object side; a bi-concave fourth lens element L4; and a positive meniscus fifth lens element L5 with the convex surface facing the object side.
Further, in the zoom lens system according to Embodiment I-8, the third lens unit G3, in order from the object side to the image side, comprises: a bi-convex sixth lens element L6; a bi-convex seventh lens element L7; and a bi-concave eighth lens element L8. Among these, the seventh lens element L7 and the eighth lens element L8 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 15 indicates the cement layer between the seventh lens element L7 and the eighth lens element L8. Further, the seventh lens element L7 has an aspheric object side surface.
Moreover, in the zoom lens system according to Embodiment I-8, the fourth lens unit G4 comprises solely a positive meniscus ninth lens element L9 with the convex surface facing the object side. The ninth lens element L9 has an aspheric object side surface.
Here, in the zoom lens system according to Embodiment I-8, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the ninth lens element L9).
In the zoom lens system according to Embodiment I-8, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
In the zoom lens system according to Embodiments I-1 to I-8, the first lens unit G1 is composed of three or two lens elements while the second lens unit G2 is composed of three lens elements. Thus, the lens system has a short overall length.
In the zoom lens system according to Embodiments I-1 to I-7, the first lens unit G1, in order from the object side to the image side, comprises a negative meniscus lens element L1 with the convex surface facing the object side, a positive meniscus lens element L2 with the convex surface facing the object side, and a positive meniscus lens element L3 with the convex surface facing the object side. Further, among these, the negative meniscus lens element L1 and the positive meniscus lens element L2 are cemented with each other so that a cemented lens element is formed. This realizes a compact lens system. Further, in the zoom lens system according to Embodiment I-8, the first lens unit G1, in order from the object side to the image side, comprises a negative meniscus first lens element L1 with the convex surface facing the object side, and a bi-convex second lens element L2. Then, the first lens elements L1 and the second lens element L2 are cemented with each other so that a cemented lens element is formed. This realizes a compact lens system. In the zoom lens system according to Embodiments I-1 to I-8, such a configuration permits satisfactory compensation of chromatic aberration.
In the zoom lens system according to Embodiments I-1 to I-7, each surface of the three lens elements constituting the first lens unit G1 and the three lens elements constituting the second lens unit G2 has a positive radius of curvature except for the object side surface of the fifth lens element L5 arranged in the center of the second lens unit G2. Thus, in a state that a compact lens system is realized, compensation of curvature of field is achieved.
In the zoom lens system according to Embodiments I-1 to I-8, the third lens unit G3 includes at least one lens element having negative optical power and having a concave image side surface. This permits satisfactory compensation of spherical aberration, coma aberration and chromatic aberration.
In the zoom lens system according to Embodiments I-1 to I-5 and I-7, the third lens unit G3, in order from the object side to the image side, comprises a seventh lens element L7 having positive optical power, an eighth lens element L8 having an aspheric object side surface and having positive optical power, and a ninth lens element L9 having negative optical power. Further, the eighth lens element L8 serving as a positive lens element on the image side and the ninth lens element L9 are cemented with each other so that a cemented lens element is formed. This permits remarkably satisfactory compensation of spherical aberration, coma aberration and chromatic aberration. Further, in the zoom lens system according to Embodiment I-8, the third lens unit G3, in order from the object side to the image side, comprises a sixth lens element L6 having positive optical power, a seventh lens element L7 having an aspheric object side surface and having positive optical power, and an eighth lens element L8 having negative optical power. Furthermore, the seventh lens element L7 serving as a positive lens element on the image side and the eighth lens element L8 are cemented with each other so that a cemented lens element is formed. This permits remarkably satisfactory compensation of spherical aberration, coma aberration and chromatic aberration.
In the zoom lens system according to Embodiments I-1 to I-8, the fourth lens unit G4 also is composed of one lens element, and this lens element has positive optical power. This realizes a lens system having a short overall length. Further, at the time of focusing change from an infinite-distance object to a short-distance object, as shown in each Fig., the fourth lens unit G4 is drawn out to the object side so that rapid focusing is achieved easily. Further, in the zoom lens system according to Embodiments I-1 to I-7, the one lens element constituting the fourth lens unit G4 has two aspheric surfaces. This permits satisfactory compensation of curvature of off-axial field over the range from a wide-angle limit to a telephoto limit.
Further, in the zoom lens system according to Embodiments I-1 to I-8, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1, the second lens unit G2, the third lens unit G3 and the fourth lens unit G4 are moved individually along the optical axis so that zooming is achieved. Then, any lens unit among the first lens unit G1, the second lens unit G2, the third lens unit G3 and the fourth lens unit G4, or alternatively a sub lens unit consisting of a part of a lens unit is moved in a direction perpendicular to the optical axis so that image point movement caused by vibration of the entire system is compensated, that is, image blur caused by hand blurring, vibration and the like can be compensated optically.
When image point movement caused by vibration of the entire system is to be compensated, for example, the third lens unit G3 is moved in a direction perpendicular to the optical axis, so that image blur is compensated in a state that size increase in the entire zoom lens system is suppressed and a compact construction is realized and that excellent imaging characteristics such as small decentering coma aberration and decentering astigmatism are satisfied.
Here, in a case that a lens unit is composed of a plurality of lens elements, the above-mentioned sub lens unit consisting of a part of a lens unit indicates any one lens element or alternatively a plurality of adjacent lens elements among the plurality of lens elements.
(Embodiments II-1 to II-9)
FIGS. 25, 28, 31, 33, 35, 38, 41, 44 and 47 are lens arrangement diagrams of zoom lens systems according to Embodiments II-1 to II-9, respectively.
Each of FIGS. 25, 28, 31, 33, 35, 38, 41, 44 and 47 shows a zoom lens system in an infinity in-focus condition. In each Fig., part (a) shows a lens configuration at a wide-angle limit (in the minimum focal length condition: focal length fW), part (b) shows a lens configuration at a middle position (in an intermediate focal length condition: focal length fM=√{square root over ( )}(fW*fT)), and part (c) shows a lens configuration at a telephoto limit (in the maximum focal length condition: focal length fT). Further, in each Fig., an arrow of straight or curved line provided between part (a) and part (b) indicates the movement of each lens unit from a wide-angle limit through a middle position to a telephoto limit. Moreover, in each Fig., an arrow imparted to a lens unit indicates focusing from an infinity in-focus condition to a close-object in-focus condition. That is, the arrow indicates the moving direction at the time of focusing from an infinity in-focus condition to a close-object in-focus condition.
The zoom lens system according to each embodiment, in order from the object side to the image side, comprises a first lens unit G1 having positive optical power, a second lens unit G2 having negative optical power, a third lens unit G3 having positive optical power, and a fourth lens unit G4 having positive optical power. Then, in zooming, the individual lens units move in a direction along the optical axis such that intervals between the lens units, that is, the interval between the first lens unit G1 and the second lens unit G2, the interval between the second lens unit G2 and the third lens unit G3, and the interval between the third lens unit G3 and the fourth lens unit G4 should all vary. In the zoom lens system according to each embodiment, since these lens units are arranged in the desired optical power configuration, high optical performance is obtained and still size reduction is achieved in the entire lens system.
Further, in FIGS. 25, 28, 31, 33, 35, 38, 41, 44 and 47, an asterisk “*” imparted to a particular surface indicates that the surface is aspheric. In each Fig., symbol (+) or (−) imparted to the symbol of each lens unit corresponds to the sign of the optical power of the lens unit. In each Fig., the straight line located on the most right-hand side indicates the position of the image surface S. On the object side relative to the image surface S (that is, between the image surface S and the most image side lens surface of the fourth lens unit G4), a plane parallel plate P such as an optical low-pass filter and a face plate of an image sensor is provided.
Further, in FIGS. 25, 28, 31, 33, 35, 38, 41, 44 and 47, an aperture diaphragm A is provided on the most object side of the third lens unit G3. Then, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the aperture diaphragm A moves along the optical axis integrally with the third lens unit G3.
As shown in FIG. 25, in the zoom lens system according to Embodiment II-1, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment II-1, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
In the zoom lens system according to Embodiment II-1, the third lens unit G3, in order from the object side to the image side, comprises: a positive meniscus seventh lens element L7 with the convex surface facing the object side; a positive meniscus eighth lens element L8 with the convex surface facing the object side; and a negative meniscus ninth lens element L9 with the convex surface facing the object side. Among these, the eighth lens element L8 and the ninth lens element L9 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 17 indicates the cement layer between the eighth lens element L8 and the ninth lens element L9. Further, the eighth lens element L8 has an aspheric object side surface.
Further, in the zoom lens system according to Embodiment II-1, the fourth lens unit G4 comprises solely a bi-convex tenth lens element L10. The tenth lens element L10 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment II-1, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the tenth lens element L10).
In the zoom lens system according to Embodiment II-1, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 28, in the zoom lens system according to Embodiment II-2, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment II-2, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
In the zoom lens system according to Embodiment II-2, the third lens unit G3, in order from the object side to the image side, comprises: a positive meniscus seventh lens element L7 with the convex surface facing the object side; a positive meniscus eighth lens element L8 with the convex surface facing the object side; and a negative meniscus ninth lens element L9 with the convex surface facing the object side. Among these, the eighth lens element L8 and the ninth lens element L9 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 17 indicates the cement layer between the eighth lens element L8 and the ninth lens element L9. Further, the eighth lens element L8 has an aspheric object side surface.
Further, in the zoom lens system according to Embodiment II-2, the fourth lens unit G4 comprises solely a bi-convex tenth lens element L10. The tenth lens element L10 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment II-2, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the tenth lens element L10).
In the zoom lens system according to Embodiment II-2, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 31, in the zoom lens system according to Embodiment II-3, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment II-3, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
Further, in the zoom lens system according to Embodiment II-3, the third lens unit G3, in order from the object side to the image side, comprises: a bi-convex seventh lens element L7; a negative meniscus eighth lens element L8 with the convex surface facing the object side; and a positive meniscus ninth lens element L9 with the convex surface facing the object side. Among these, the seventh lens element L7 has two aspheric surfaces.
Further, in the zoom lens system according to Embodiment II-3, the fourth lens unit G4 comprises solely a bi-convex tenth lens element L10. The tenth lens element L10 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment II-3, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the tenth lens element L10).
In the zoom lens system according to Embodiment II-3, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 33, in the zoom lens system according to Embodiment II-4, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment II-4, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
Further, in the zoom lens system according to Embodiment II-4, the third lens unit G3, in order from the object side to the image side, comprises: a bi-convex seventh lens element L7; and a negative meniscus eighth lens element L8 with the convex surface facing the object side. Among these, the seventh lens element L7 has two aspheric surfaces.
Further, in the zoom lens system according to Embodiment II-4, the fourth lens unit G4 comprises solely a bi-convex ninth lens element L9. The ninth lens element L9 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment II-4, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the ninth lens element L9).
In the zoom lens system according to Embodiment II-4, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 35, in the zoom lens system according to Embodiment II-5, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment II-5, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
In the zoom lens system according to Embodiment II-5, the third lens unit G3, in order from the object side to the image side, comprises: a bi-convex seventh lens element L7; a negative meniscus eighth lens element L8 with the convex surface facing the image side; and a negative meniscus ninth lens element L9 with the convex surface facing the object side. Among these, the seventh lens element L7 and the eighth lens element L8 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 15 indicates the cement layer between the seventh lens element L7 and the eighth lens element L8. Further, each of the seventh lens element L7 and the ninth lens element L9 has an aspheric object side surface.
Further, in the zoom lens system according to Embodiment II-5, the fourth lens unit G4 comprises solely a bi-convex tenth lens element L10. The tenth lens element L10 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment II-5, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the tenth lens element L10).
In the zoom lens system according to Embodiment II-5, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 38, in the zoom lens system according to Embodiment II-6, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment II-6, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
In the zoom lens system according to Embodiment II-6, the third lens unit G3, in order from the object side to the image side, comprises: a positive meniscus seventh lens element L7 with the convex surface facing the object side; a positive meniscus eighth lens element L8 with the convex surface facing the object side; and a negative meniscus ninth lens element L9 with the convex surface facing the object side. Among these, the eighth lens element L8 and the ninth lens element L9 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 17 indicates the cement layer between the eighth lens element L8 and the ninth lens element L9. Further, the eighth lens element L8 has an aspheric object side surface.
Further, in the zoom lens system according to Embodiment II-6, the fourth lens unit G4 comprises solely a bi-convex tenth lens element L10. The tenth lens element L10 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment II-6, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the tenth lens element L10).
In the zoom lens system according to Embodiment II-6, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 41, in the zoom lens system according to Embodiment II-7, the first lens unit G1, in order from the object side to the image side, comprises a negative meniscus first lens element L1 with the convex surface facing the object side and a planer-convex second lens element L2 with the convex surface facing the object side. The first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2. Further, the second lens element L2 has an aspheric image side surface.
In the zoom lens system according to Embodiment II-7, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus third lens element L3 with the convex surface facing the object side; a bi-concave fourth lens element L4; and a positive meniscus fifth lens element L5 with the convex surface facing the object side. Among these, the fourth lens element L4 and the fifth lens element L5 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 8 indicates the cement layer between the fourth lens element L4 and the fifth lens element L5. Further, the fifth lens element L5 has an aspheric image side surface.
Further, in the zoom lens system according to Embodiment II-7, the third lens unit G3, in order from the object side to the image side, comprises: a bi-convex sixth lens element L6; a bi-convex seventh lens element L7; a bi-concave eighth lens element L8; and a bi-convex ninth lens element L9. Among these, the seventh lens element L7 and the eighth lens element L8 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 15 indicates the cement layer between the seventh lens element L7 and the eighth lens element L8. Further, the seventh lens element L7 has an aspheric object side surface.
Moreover, in the zoom lens system according to Embodiment II-7, the fourth lens unit G4 comprises solely a positive meniscus tenth lens element L10 with the convex surface facing the object side. The tenth lens element L10 has an aspheric object side surface.
Here, in the zoom lens system according to Embodiment II-7, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the tenth lens element L10).
In the zoom lens system according to Embodiment II-7, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 44, in the zoom lens system according to Embodiment II-8, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; and a planer-convex second lens element L2 with the convex surface facing the object side. The first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2. Further, the second lens element L2 has an aspheric image side surface.
In the zoom lens system according to Embodiment II-8, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus third lens element L3 with the convex surface facing the object side; a bi-concave fourth lens element L4; and a positive meniscus fifth lens element L5 with the convex surface facing the object side.
Further, in the zoom lens system according to Embodiment II-8, the third lens unit G3, in order from the object side to the image side, comprises: a bi-convex sixth lens element L6; a bi-convex seventh lens element L7; and a bi-concave eighth lens element L8. Among these, the seventh lens element L7 and the eighth lens element L8 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 15 indicates the cement layer between the seventh lens element L7 and the eighth lens element L8. Further, the seventh lens element L7 has an aspheric object side surface.
Moreover, in the zoom lens system according to Embodiment II-8, the fourth lens unit G4 comprises solely a positive meniscus ninth lens element L9 with the convex surface facing the object side. The ninth lens element L9 has an aspheric object side surface.
Here, in the zoom lens system according to Embodiment II-8, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the ninth lens element L9).
In the zoom lens system according to Embodiment II-8, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 47, in the zoom lens system according to Embodiment II-9, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; and a bi-convex second lens element L2. The first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2. Further, the second lens element L2 has an aspheric image side surface.
In the zoom lens system according to Embodiment II-9, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus third lens element L3 with the convex surface facing the object side; a bi-concave fourth lens element L4; and a positive meniscus fifth lens element L5 with the convex surface facing the object side.
Further, in the zoom lens system according to Embodiment II-9, the third lens unit G3, in order from the object side to the image side, comprises: a bi-convex sixth lens element L6; a bi-convex seventh lens element L7; and a bi-concave eighth lens element L8. Among these, the seventh lens element L7 and the eighth lens element L8 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 15 indicates the cement layer between the seventh lens element L7 and the eighth lens element L8. Further, the seventh lens element L7 has an aspheric object side surface.
Moreover, in the zoom lens system according to Embodiment II-9, the fourth lens unit G4 comprises solely a positive meniscus ninth lens element L9 with the convex surface facing the object side. The ninth lens element L9 has an aspheric object side surface.
Here, in the zoom lens system according to Embodiment II-9, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the ninth lens element L9).
In the zoom lens system according to Embodiment II-9, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
In the zoom lens system according to Embodiments II-1 to II-9, the first lens unit G1 is composed of three or two lens elements while the second lens unit G2 is composed of three lens elements. Thus, the lens system has a short overall length.
In the zoom lens system according to Embodiments II-1 to II-6, the first lens unit G1, in order from the object side to the image side, comprises a negative meniscus lens element L1 with the convex surface facing the object side, a positive meniscus lens element L2 with the convex surface facing the object side, and a positive meniscus lens element L3 with the convex surface facing the object side. Further, among these, the negative meniscus lens element L1 and the positive meniscus lens element L2 are cemented with each other so that a cemented lens element is formed. This realizes a compact lens system. Further, in the zoom lens system according to Embodiments II-7 to II-9, the first lens unit G1, in order from the object side to the image side, comprises a negative meniscus first lens element L1 with the convex surface facing the object side, and a planer-convex second lens element L2 with the convex surface facing the object side or a bi-convex second lens element L2. Then, the first lens elements L1 and the second lens element L2 are cemented with each other so that a cemented lens element is formed. This realizes a compact lens system. In the zoom lens system according to Embodiments II-1 to II-9, such a configuration permits satisfactory compensation of chromatic aberration.
In the zoom lens system according to Embodiments II-1 to II-8, each surface of the three or two lens elements constituting the first lens unit G1 and the three lens elements constituting the second lens unit G2 has a positive radius of curvature except for the object side surface of the fifth lens element L5 or the object side surface of the fourth lens element L4 arranged in the center of the second lens unit G2. Thus, in a state that a compact lens system is realized, compensation of curvature of field is achieved.
In the zoom lens system according to Embodiments II-1 to II-9, the third lens unit G3 includes at least one lens element having negative optical power and having a concave image side surface. This permits satisfactory compensation of spherical aberration, coma aberration and chromatic aberration.
In the zoom lens system according to Embodiments II-1, II-2 and II-6, the third lens unit G3, in order from the object side to the image side, comprises a seventh lens element L7 having positive optical power, an eighth lens element L8 having an aspheric object side surface and having positive optical power, and a ninth lens element L9 having negative optical power. Further, the eighth lens element L8 serving as a positive lens element on the image side and the ninth lens element L9 are cemented with each other so that a cemented lens element is formed. This permits remarkably satisfactory compensation of spherical aberration, coma aberration and chromatic aberration. Further, in the zoom lens system according to Embodiments II-7 to II-9, the third lens unit G3, in order from the object side to the image side, includes a sixth lens element L6 having positive optical power, a seventh lens element L7 having an aspheric object side surface and having positive optical power, and an eighth lens element L8 having negative optical power. Furthermore, the seventh lens element L7 serving as a positive lens element located at the second position on the object side and the eighth lens element L8 are cemented with each other so that a cemented lens element is formed. This permits remarkably satisfactory compensation of spherical aberration, coma aberration and chromatic aberration.
In the zoom lens system according to Embodiments II-1 to II-9, the fourth lens unit G4 also is composed of one lens element, and this lens element has positive optical power. This realizes a lens system having a short overall length. Further, at the time of focusing change from an infinite-distance object to a short-distance object, as shown in each Fig., the fourth lens unit G4 is drawn out to the object side so that rapid focusing is achieved easily. Further, in the zoom lens system according to Embodiments II-1 to II-6, the one lens element constituting the fourth lens unit G4 has two aspheric surfaces. This permits satisfactory compensation of curvature of off-axial field over the range from a wide-angle limit to a telephoto limit.
Further, in the zoom lens system according to Embodiments II-1 to II-9, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1, the second lens unit G2, the third lens unit G3 and the fourth lens unit G4 are moved individually along the optical axis so that zooming is achieved. Then, any lens unit among the first lens unit G1, the second lens unit G2, the third lens unit G3 and the fourth lens unit G4, or alternatively a sub lens unit consisting of a part of a lens unit is moved in a direction perpendicular to the optical axis so that image point movement caused by vibration of the entire system is compensated, that is, image blur caused by hand blurring, vibration and the like can be compensated optically.
When image point movement caused by vibration of the entire system is to be compensated, for example, the third lens unit G3 is moved in a direction perpendicular to the optical axis, so that image blur is compensated in a state that size increase in the entire zoom lens system is suppressed and a compact construction is realized and that excellent imaging characteristics such as small decentering coma aberration and decentering astigmatism are satisfied.
Here, in a case that a lens unit is composed of a plurality of lens elements, the above-mentioned sub lens unit consisting of a part of a lens unit indicates any one lens element or alternatively a plurality of adjacent lens elements among the plurality of lens elements.
(Embodiments III-1 to III-7)
FIGS. 51, 54, 57, 59, 61, 64 and 67 are lens arrangement diagrams of zoom lens systems according to Embodiments III-1 to III-7, respectively.
Each of FIGS. 51, 54, 57, 59, 61, 64 and 67 shows a zoom lens system in an infinity in-focus condition. In each Fig., part (a) shows a lens configuration at a wide-angle limit (in the minimum focal length condition: focal length fW), part (b) shows a lens configuration at a middle position (in an intermediate focal length condition: focal length fM=√{square root over ( )}(fW*fT)), and part (c) shows a lens configuration at a telephoto limit (in the maximum focal length condition: focal length fT). Further, in each Fig., an arrow of straight or curved line provided between part (a) and part (b) indicates the movement of each lens unit from a wide-angle limit through a middle position to a telephoto limit. Moreover, in each Fig., an arrow imparted to a lens unit indicates focusing from an infinity in-focus condition to a close-object in-focus condition. That is, the arrow indicates the moving direction at the time of focusing from an infinity in-focus condition to a close-object in-focus condition.
The zoom lens system according to each embodiment, in order from the object side to the image side, comprises a first lens unit G1 having positive optical power, a second lens unit G2 having negative optical power, a third lens unit G3 having positive optical power, and a fourth lens unit G4 having positive optical power. Then, in zooming, the individual lens units move in a direction along the optical axis such that intervals between the lens units, that is, the interval between the first lens unit G1 and the second lens unit G2, the interval between the second lens unit G2 and the third lens unit G3, and the interval between the third lens unit G3 and the fourth lens unit G4 should all vary. In the zoom lens system according to each embodiment, since these lens units are arranged in the desired optical power configuration, high optical performance is obtained and still size reduction is achieved in the entire lens system.
Further, in FIGS. 51, 54, 57, 59, 61, 64 and 67, an asterisk “*” imparted to a particular surface indicates that the surface is aspheric. In each Fig., symbol (+) or (−) imparted to the symbol of each lens unit corresponds to the sign of the optical power of the lens unit. In each Fig., the straight line located on the most right-hand side indicates the position of the image surface S. On the object side relative to the image surface S (that is, between the image surface S and the most image side lens surface of the fourth lens unit G4), a plane parallel plate P such as an optical low-pass filter and a face plate of an image sensor is provided.
Further, in FIGS. 51, 54, 57, 59, 61, 64 and 67, an aperture diaphragm A is provided on the most object side of the third lens unit G3. Then, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the aperture diaphragm A moves along the optical axis integrally with the third lens unit G3.
As shown in FIG. 51, in the zoom lens system according to Embodiment III-1, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment III-1, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
In the zoom lens system according to Embodiment III-1, the third lens unit G3, in order from the object side to the image side, comprises: a positive meniscus seventh lens element L7 with the convex surface facing the object side; a positive meniscus eighth lens element L8 with the convex surface facing the object side; and a negative meniscus ninth lens element L9 with the convex surface facing the object side. Among these, the eighth lens element L8 and the ninth lens element L9 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 17 indicates the cement layer between the eighth lens element L8 and the ninth lens element L9. Further, the eighth lens element L8 has an aspheric object side surface.
Further, in the zoom lens system according to Embodiment III-1, the fourth lens unit G4 comprises solely a bi-convex tenth lens element L10. The tenth lens element L10 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment III-1, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the tenth lens element L10).
In the zoom lens system according to Embodiment III-1, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 54, in the zoom lens system according to Embodiment III-2, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment III-2, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
In the zoom lens system according to Embodiment III-2, the third lens unit G3, in order from the object side to the image side, comprises: a positive meniscus seventh lens element L7 with the convex surface facing the object side; a positive meniscus eighth lens element L8 with the convex surface facing the object side; and a negative meniscus ninth lens element L9 with the convex surface facing the object side. Among these, the eighth lens element L8 and the ninth lens element L9 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 17 indicates the cement layer between the eighth lens element L8 and the ninth lens element L9. Further, the eighth lens element L8 has an aspheric object side surface.
Further, in the zoom lens system according to Embodiment III-2, the fourth lens unit G4 comprises solely a bi-convex tenth lens element L10. The tenth lens element L10 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment III-2, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the tenth lens element L10).
In the zoom lens system according to Embodiment III-2, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 57, in the zoom lens system according to Embodiment III-3, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment III-3, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
Further, in the zoom lens system according to Embodiment III-3, the third lens unit G3, in order from the object side to the image side, comprises: a bi-convex seventh lens element L7; a negative meniscus eighth lens element L8 with the convex surface facing the object side; and a positive meniscus ninth lens element L9 with the convex surface facing the object side. Among these, the seventh lens element L7 has two aspheric surfaces.
Further, in the zoom lens system according to Embodiment III-3, the fourth lens unit G4 comprises solely a bi-convex tenth lens element L10. The tenth lens element L10 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment III-3, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the tenth lens element L10).
In the zoom lens system according to Embodiment III-3, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 59, in the zoom lens system according to Embodiment III-4, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment III-4, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
Further, in the zoom lens system according to Embodiment III-4, the third lens unit G3, in order from the object side to the image side, comprises: a bi-convex seventh lens element L7; and a negative meniscus eighth lens element L8 with the convex surface facing the object side. Among these, the seventh lens element L7 has two aspheric surfaces.
Further, in the zoom lens system according to Embodiment III-4, the fourth lens unit G4 comprises solely a bi-convex ninth lens element L9. The ninth lens element L9 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment III-4, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the ninth lens element L9).
In the zoom lens system according to Embodiment III-4, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 61, in the zoom lens system according to Embodiment III-5, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment III-5, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
In the zoom lens system according to Embodiment III-5, the third lens unit G3, in order from the object side to the image side, comprises: a bi-convex seventh lens element L7; a negative meniscus eighth lens element L8 with the convex surface facing the image side; and a negative meniscus ninth lens element L9 with the convex surface facing the object side. Among these, the seventh lens element L7 and the eighth lens element L8 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 15 indicates the cement layer between the seventh lens element L7 and the eighth lens element L8. Further, each of the seventh lens element L7 and the ninth lens element L9 has an aspheric object side surface.
Further, in the zoom lens system according to Embodiment III-5, the fourth lens unit G4 comprises solely a bi-convex tenth lens element L10. The tenth lens element L10 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment III-5, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the tenth lens element L10).
In the zoom lens system according to Embodiment III-5, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 64, in the zoom lens system according to Embodiment III-6, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; a positive meniscus second lens element L2 with the convex surface facing the object side; and a positive meniscus third lens element L3 with the convex surface facing the object side. Among these, the first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2.
In the zoom lens system according to Embodiment III-6, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus fourth lens element L4 with the convex surface facing the object side; a bi-concave fifth lens element L5; and a positive meniscus sixth lens element L6 with the convex surface facing the object side.
In the zoom lens system according to Embodiment III-6, the third lens unit G3, in order from the object side to the image side, comprises: a positive meniscus seventh lens element L7 with the convex surface facing the object side; a positive meniscus eighth lens element L8 with the convex surface facing the object side; and a negative meniscus ninth lens element L9 with the convex surface facing the object side. Among these, the eighth lens element L8 and the ninth lens element L9 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 17 indicates the cement layer between the eighth lens element L8 and the ninth lens element L9. Further, the eighth lens element L8 has an aspheric object side surface.
Further, in the zoom lens system according to Embodiment III-6, the fourth lens unit G4 comprises solely a bi-convex tenth lens element L10. The tenth lens element L10 has two aspheric surfaces.
Here, in the zoom lens system according to Embodiment III-6, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the tenth lens element L10).
In the zoom lens system according to Embodiment III-6, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
As shown in FIG. 67, in the zoom lens system according to Embodiment III-7, the first lens unit G1, in order from the object side to the image side, comprises: a negative meniscus first lens element L1 with the convex surface facing the object side; and a bi-convex second lens element L2. The first lens element L1 and the second lens element L2 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 2 indicates the cement layer between the first lens element L1 and the second lens element L2. Further, the second lens element L2 has an aspheric image side surface.
In the zoom lens system according to Embodiment III-7, the second lens unit G2, in order from the object side to the image side, comprises: a negative meniscus third lens element L3 with the convex surface facing the object side; a bi-concave fourth lens element L4; and a positive meniscus fifth lens element L5 with the convex surface facing the object side.
Further, in the zoom lens system according to Embodiment III-7, the third lens unit G3, in order from the object side to the image side, comprises: a bi-convex sixth lens element L6; a bi-convex seventh lens element L7; and a bi-concave eighth lens element L8. Among these, the seventh lens element L7 and the eighth lens element L8 are cemented with each other. In the surface data in the corresponding numerical example described later, surface number 15 indicates the cement layer between the seventh lens element L7 and the eighth lens element L8. Further, the seventh lens element L7 has an aspheric object side surface.
Moreover, in the zoom lens system according to Embodiment III-7, the fourth lens unit G4 comprises solely a positive meniscus ninth lens element L9 with the convex surface facing the object side. The ninth lens element L9 has an aspheric object side surface.
Here, in the zoom lens system according to Embodiment III-7, a plane parallel plate P is provided on the object side relative to the image surface S (between the image surface S and the ninth lens element L9).
In the zoom lens system according to Embodiment III-7, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1 and the third lens unit G3 move to the object side. Further, the second lens unit G2 moves to the image side, while the fourth lens unit G4 moves to the image side with locus of a convex to the object side. That is, in zooming, the individual lens units are moved along the optical axis such that the interval between the first lens unit G1 and the second lens unit G2 should increase, that the interval between the second lens unit G2 and the third lens unit G3 should decrease, and that the interval between the third lens unit G3 and the fourth lens unit G4 should increase.
In the zoom lens system according to Embodiments III-1 to III-7, the first lens unit G1 is composed of three or two lens elements while the second lens unit G2 is composed of three lens elements. Thus, the lens system has a short overall length.
In the zoom lens system according to Embodiments III-1 to III-6, the first lens unit G1, in order from the object side to the image side, comprises a negative meniscus lens element L1 with the convex surface facing the object side, a positive meniscus lens element L2 with the convex surface facing the object side, and a positive meniscus lens element L3 with the convex surface facing the object side. Further, among these, the negative meniscus lens element L1 and the positive meniscus lens element L2 are cemented with each other so that a cemented lens element is formed. This realizes a compact lens system. Further, in the zoom lens system according to Embodiment III-7, the first lens unit G1, in order from the object side to the image side, comprises a negative meniscus first lens element L1 with the convex surface facing the object side, and a bi-convex second lens element L2. Then, the first lens elements L1 and the second lens element L2 are cemented with each other so that a cemented lens element is formed. This realizes a compact lens system. In the zoom lens system according to Embodiments III-1 to III-7, such a configuration permits satisfactory compensation of chromatic aberration.
In the zoom lens system according to Embodiments III-1 to III-6, each surface of the three lens elements constituting the first lens unit G1 and the three lens elements constituting the second lens unit G2 has a positive radius of curvature except for the object side surface of the fifth lens element L5 arranged in the center of the second lens unit G2. Thus, in a state that a compact lens system is realized, compensation of curvature of field is achieved.
In the zoom lens system according to Embodiments III-1 to III-7, the third lens unit G3 includes at least one lens element having negative optical power and having a concave image side surface. This permits satisfactory compensation of spherical aberration, coma aberration and chromatic aberration.
In the zoom lens system according to Embodiments III-1, III-2 and III-6, the third lens unit G3, in order from the object side to the image side, comprises a seventh lens element L7 having positive optical power, an eighth lens element L8 having an aspheric object side surface and having positive optical power, and a ninth lens element L9 having negative optical power. Further, the eighth lens element L8 serving as a positive lens element on the image side and the ninth lens element L9 are cemented with each other so that a cemented lens element is formed. This permits remarkably satisfactory compensation of spherical aberration, coma aberration and chromatic aberration. Further, in the zoom lens system according to Embodiment III-7, the third lens unit G3, in order from the object side to the image side, comprises a sixth lens element L6 having positive optical power, a seventh lens element L7 having an aspheric object side surface and having positive optical power, and an eighth lens element L8 having negative optical power. Furthermore, the seventh lens element L7 serving as a positive lens element on the image side and the eighth lens element L8 are cemented with each other so that a cemented lens element is formed. This permits remarkably satisfactory compensation of spherical aberration, coma aberration and chromatic aberration.
In the zoom lens system according to Embodiments III-1 to III-7, the fourth lens unit G4 also is composed of one lens element, and this lens element has positive optical power. This realizes a lens system having a short overall length. Further, at the time of focusing change from an infinite-distance object to a short-distance object, as shown in each Fig., the fourth lens unit G4 is drawn out to the object side so that rapid focusing is achieved easily. Further, in the zoom lens system according to Embodiments III-1 to III-6, the one lens element constituting the fourth lens unit G4 has two aspheric surfaces. This permits satisfactory compensation of curvature of off-axial field over the range from a wide-angle limit to a telephoto limit.
Further, in the zoom lens system according to Embodiments III-1 to III-7, in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit G1, the second lens unit G2, the third lens unit G3 and the fourth lens unit G4 are moved individually along the optical axis so that zooming is achieved. Then, any lens unit among the first lens unit G1, the second lens unit G2, the third lens unit G3 and the fourth lens unit G4, or alternatively a sub lens unit consisting of a part of a lens unit is moved in a direction perpendicular to the optical axis so that image point movement caused by vibration of the entire system is compensated, that is, image blur caused by hand blurring, vibration and the like can be compensated optically.
When image point movement caused by vibration of the entire system is to be compensated, for example, the third lens unit G3 is moved in a direction perpendicular to the optical axis, so that image blur is compensated in a state that size increase in the entire zoom lens system is suppressed and a compact construction is realized and that excellent imaging characteristics such as small decentering coma aberration and decentering astigmatism are satisfied.
Here, in a case that a lens unit is composed of a plurality of lens elements, the above-mentioned sub lens unit consisting of a part of a lens unit indicates any one lens element or alternatively a plurality of adjacent lens elements among the plurality of lens elements.
The following description is given for conditions preferred to be satisfied by a zoom lens system like the zoom lens system according to Embodiments I-1 to I-8, a zoom lens system like the zoom lens system according to Embodiments II-1 to II-9, and a zoom lens system like the zoom lens system according to Embodiments III-1 to III-7. Here, a plurality of preferable conditions are set forth for the zoom lens system according to each embodiment. A construction that satisfies all the plural conditions is most desirable for the zoom lens system. However, when an individual condition is satisfied, a zoom lens system having the corresponding effect is obtained.
In a zoom lens system like the zoom lens system according to Embodiments I-1 to I-8, in order from the object side to the image side, comprising a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein the first lens unit is composed of three or fewer lens elements, and wherein the second lens unit is composed of three lens elements (this lens configuration is referred to as basic configuration I of the embodiment, hereinafter), the following conditions (5), (6), (a-2) and (b) are satisfied.

tan 2ωW×m2W≦−1.78  (5)

tan 2ωW×|fG2|/fG1≧1.25  (6)

ωW≧37  (a-2)

fT/fW≧10  (b)

where,
m2W is a lateral magnification of the second lens unit at a wide-angle limit in an infinity in-focus condition,
fG1 is a composite focal length of the first lens unit,
fG2 is a composite focal length of the second lens unit,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.
The condition (5) sets forth the relation between the view angle and the magnification of the second lens unit. When the condition (5) is not satisfied, compensation of curvature of field becomes difficult.
When the following condition (5)′ is satisfied, the above-mentioned effect is achieved more successfully.

−6.00≦tan 2ωW×m2W  (5)′

The condition (6) sets forth the relation between the view angle and the focal lengths of the first lens unit and the second lens unit. When the condition (6) is not satisfied, compensation of spherical aberration and curvature of field becomes difficult.
When the following condition (6)′ is satisfied, the above-mentioned effect is achieved more successfully.

5.00≧tan 2ωW×|fG2|/fG1  (6)′

In a zoom lens system like the zoom lens system according to Embodiments II-1 to II-9, in order from the object side to the image side, comprising a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein the first lens unit is composed of three or fewer lens elements, and wherein the second lens unit is composed of three lens elements (this lens configuration is referred to as basic configuration II of the embodiment, hereinafter), the following conditions (7), (8), (a-2) and (b) are satisfied.

−3.12≦TG1/fW≦−2.36  (7)

1.26≦TG2/fW≦1.78  (8)

ωW≧37  (a-2)

fT/fW≧10  (b)

where,
TG1 is an amount of axial movement of the first lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
TG2 is an amount of axial movement of the second lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
ωw is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.
The condition (7) sets forth the ratio between the amount of axial movement of the first lens unit and the focal length of the entire system at a wide-angle limit. When the value goes below the lower limit of the condition (7), the focal length of the first lens unit is excessively short, and hence compensation of spherical aberration and curvature of field becomes difficult. In contrast, when the value exceeds the upper limit of the condition (7), the amount of movement of the first lens unit is excessively large, and hence compactness is difficult to be realized.
Here, when at least one of the following conditions (7)′ and (7)′′ is satisfied, the above-mentioned effect is achieved more successfully.

−2.94≦TG1/fW  (7)′

TG1/fW≦−2.46  (7)′′

The condition (8) sets forth the ratio between the amount of axial movement of the second lens unit and the focal length of the entire system at a wide-angle limit. When the value goes below the lower limit of the condition (8), the focal length of the second lens unit is excessively short, and hence compensation of curvature of field becomes difficult. In contrast, when the value exceeds the upper limit of the condition (8), the amount of movement of the second lens unit is excessively large, and hence compactness is difficult to be realized.
Here, when at least one of the following conditions (8)′ and (8)′′ is satisfied, the above-mentioned effect is achieved more successfully.

1.32≦TG2/fW  (8)′

TG2/fW≦1.74  (8)′′

In a zoom lens system like the zoom lens system according to Embodiments III-1 to III-7, in order from the object side to the image side, comprising a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein the first lens unit is composed of three or fewer lens elements, and wherein the second lens unit is composed of three lens elements (this lens configuration is referred to as basic configuration III of the embodiment, hereinafter), the following conditions (9), (a-2) and (b) are satisfied.

0.64≦fG4/fG1≦0.82  (9)

ωW≦37  (a-2)

fT/fW≧10  (b)

where,
fG1 is a composite focal length of the first lens unit,
fG4 is a composite focal length of the fourth lens unit,
ωw is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.
The condition (9) sets forth the ratio of the focal lengths of the first lens unit and the fourth lens unit. When the value goes below the lower limit of the condition (9), the refractive power of the first lens unit is excessively strong, and hence compensation of curvature of field generated in the first lens unit becomes difficult. In contrast, when the value exceeds the upper limit of the condition (9), the refractive power of the fourth lens unit is excessively strong. This causes difficulty in ensuring a necessity lens back. Further, when the refractive power of the first lens unit is excessively weak, a larger outer diameter becomes necessary in the first lens unit in order that the wide-angle property should be achieved. This causes difficulty in realizing compactness.
Here, when at least one of the following conditions (9)′ and (9)′′ is satisfied, the above-mentioned effect is achieved more successfully.

0.68≦fG4/fG1  (9)′

fG4/fG1≦0.72  (9)′′

In a zoom lens system having the basic configuration I like the zoom lens system according to Embodiments I-1 to I-8, in a zoom lens system having the basic configuration II like the zoom lens system according to Embodiments II-1 to II-9, and in a zoom lens system having the basic configuration III like the zoom lens system according to Embodiments III-1 to III-7, it is preferable that the following condition (10) is satisfied.

4.00≦m2T/m2W≦8.00  (10)

where,
m2T is a lateral magnification of the second lens unit at a telephoto limit in an infinity in-focus condition, and
m2W is a lateral magnification of the second lens unit at a wide-angle limit in an infinity in-focus condition.
The condition (10) sets forth magnification change in the second lens unit, and substantially optimizes a variable magnification load to the second lens unit during zooming. When the value falls outside the range of the condition (10), the variable magnification load to the second lens unit becomes inappropriate. This can cause difficulty in constructing a compact zoom lens system having satisfactory optical performance.
Here, when at least one of the following conditions (10)′ and (10)′′ is satisfied, the above-mentioned effect is achieved more successfully.

4.50≦m2T/m2W  (10)′

m2T/m2W≦6.00  (10)′′

In a zoom lens system having the basic configuration I like the zoom lens system according to Embodiments I-1 to I-8, in a zoom lens system having the basic configuration II like the zoom lens system according to Embodiments II-1 to II-9, and in a zoom lens system having the basic configuration III like the zoom lens system according to Embodiments III-1 to III-7, it is preferable that the following condition (11) is satisfied.

1.00≦LT/fT≦2.00  (11)

where,
LT is an overall length of lens system at a telephoto limit (a distance from the most object side surface of the first lens unit to the image surface), and
fT is a focal length of the entire system at a telephoto limit.
The condition (11) sets forth the overall length of the zoom lens system at a telephoto limit. When the value goes below the lower limit of the condition (11), the refractive power of each lens unit is excessively strong. Thus, various kinds of aberration of each lens unit increases, and hence causes a possibility that aberration compensation becomes difficult. In contrast, when the value exceeds the upper limit of the condition (11), the refractive power of each lens unit is weak. Thus, in order that a high variable magnification ratio should be achieved, a larger amount of movement is necessary in each lens unit. Thus, a possibility arises that compactness is difficult to be realized.
Here, when at least one of the following conditions (11)′ and (11)′′ is satisfied, the above-mentioned effect is achieved more successfully.

1.10≦LT/fT  (11)′

LT/fT≦1.37  (11)′′

In a zoom lens system having the basic configuration I like the zoom lens system according to Embodiments I-1 to I-8, in a zoom lens system having the basic configuration II like the zoom lens system according to Embodiments II-1 to II-9, and in a zoom lens system having the basic configuration III like the zoom lens system according to Embodiments III-1 to III-7, it is preferable that the following condition (12) is satisfied.

1.00≦fT/fG1≦2.00  (12)

where,
fG1 is a composite focal length of the first lens unit, and
fT is a focal length of the entire system at a telephoto limit.
The condition (12) sets forth a suitable focal length of the first lens unit. When the value goes below the lower limit of the condition (12), the refractive power of the first lens unit is weak. Thus, in order that a high variable magnification ratio should be achieved, a larger amount of movement is necessary in the second lens unit. Thus, a possibility arises that compactness is difficult to be realized. In contrast, when the value exceeds the upper limit of the condition (12), the refractive power of the first lens unit is excessively strong. This causes an increase in various kinds of aberration, and hence causes a possibility that compensation of axial chromatic aberration becomes difficult especially at a telephoto limit.
Here, when at least one of the following conditions (12)′ and (12)′′ is satisfied, the above-mentioned effect is achieved more successfully.

1.40≦fT/fG1  (12)′

fT/fG1≦1.70  (12)′′

In a zoom lens system having the basic configuration I like the zoom lens system according to Embodiments I-1 to I-8, in a zoom lens system having the basic configuration II like the zoom lens system according to Embodiments II-1 to II-9, and in a zoom lens system having the basic configuration III like the zoom lens system according to Embodiments III-1 to III-7, it is preferable that the following condition (13) is satisfied.

1.00≦LW/fG1≦2.00  (13)

where,
LW is an overall length of lens system at a wide-angle limit (a distance from the most object side surface of the first lens unit to the image surface), and
fG1 is a composite focal length of the first lens unit.
The condition (13) sets forth the ratio between the overall length of the zoom lens system at a wide-angle limit and the focal length of the first lens unit. When the value goes below the lower limit of the condition (13), the refractive power of the first lens unit is excessively weak, and hence the refractive power of the second lens unit becomes weak. This causes an increase in the necessary amount of movement of the second lens unit. As a result, the position of the first lens unit at a wide-angle limit is relatively located to the object side. This causes an increase in the necessary outer diameter of the first lens unit for achieving the wide-angle property. Thus, a possibility arises that compactness is difficult to be realized. In contrast, when the value exceeds the upper limit of the condition (13), the refractive power of the first lens unit is excessively strong. Thus, a possibility arises that compensation of curvature of field becomes difficult especially at a wide-angle limit.
Here, when at least one of the following conditions (13)′ and (13)′′ is satisfied, the above-mentioned effect is achieved more successfully.

1.30≦LW/fG1  (13)′

LW/fG1≦1.50  (13)′′

In a zoom lens system having the basic configuration I like the zoom lens system according to Embodiments I-1 to I-8, in a zoom lens system having the basic configuration II like the zoom lens system according to Embodiments II-1 to II-9, and in a zoom lens system having the basic configuration III like the zoom lens system according to Embodiments III-1 to III-7, it is preferable that the following condition (14) is satisfied.

1.50≦LT/fG1≦2.00  (14)

where,
LT is an overall length of lens system at a telephoto limit (a distance from the most object side surface of the first lens unit to the image surface), and
fG1 is a composite focal length of the first lens unit.
The condition (14) sets forth the ratio between the overall length of the zoom lens system at a telephoto limit and the focal length of the first lens unit. When the value goes below the lower limit of the condition (14), the refractive power of the first lens unit is weak. Thus, in order that a high variable magnification ratio should be achieved, a larger amount of movement is necessary in the second lens unit. Thus, a possibility arises that compactness is difficult to be realized. In contrast, when the value exceeds the upper limit of the condition (14), the refractive power of the first lens unit is excessively strong. This causes an increase in various kinds of aberration, and hence causes a possibility that compensation of axial chromatic aberration becomes difficult especially at a telephoto limit.
Here, when at least one of the following conditions (14)′ and (14)′′ is satisfied, the above-mentioned effect is achieved more successfully.

1.60≦LT/fG1  (14)′

LT/fG1≦1.80  (14)′′

In a zoom lens system having the basic configuration I like the zoom lens system according to Embodiments I-1 to I-8, in a zoom lens system having the basic configuration II like the zoom lens system according to Embodiments II-1 to II-9, and in a zoom lens system having the basic configuration III like the zoom lens system according to Embodiments III-1 to III-7, it is preferable that the following condition (15) is satisfied.

4.50≦fG1/|fG2|≦7.00  (15)

where,
fG1 is a composite focal length of the first lens unit, and
fG2 is a composite focal length of the second lens unit.
The condition (15) sets forth the ratio of the focal lengths of the first lens unit and the second lens unit. When the value goes below the lower limit of the condition (15), the focal length of the first lens unit becomes excessively small relatively. This causes difficulty in maintaining the variable magnification function of the second lens unit, and hence can cause difficulty in constructing a zoom lens system having a zooming ratio of 10 or greater in a state that satisfactory optical performance is obtained. In contrast, when the value exceeds the upper limit of the condition (15), the focal length of the second lens unit becomes excessively small relatively. This can cause difficulty in compensating aberration generated in the second lens unit.
Here, when at least one of the following conditions (15)′ and (15)′′ is satisfied, the above-mentioned effect is achieved more successfully.

5.00≦fG1/|fG2|  (15)′

fG1/|fG2|≦6.00  (15)′′

Each lens unit constituting the zoom lens system according to Embodiments I-1 to I-8, the zoom lens system according to Embodiments II-1 to II-9 and the zoom lens system according to Embodiments III-1 to III-7 is composed exclusively of refractive type lens elements that deflect the incident light by refraction (that is, lens elements of a type in which deflection is achieved at the interface between media each having a distinct refractive index). However, the present invention is not limited to this. For example, the lens units may employ diffractive type lens elements that deflect the incident light by diffraction; refractive-diffractive hybrid type lens elements that deflect the incident light by a combination of diffraction and refraction; or gradient index type lens elements that deflect the incident light by distribution of refractive index in the medium. In particular, in refractive-diffractive hybrid type lens elements, when a diffraction structure is formed in the interface between media having mutually different refractive indices, wavelength dependence in the diffraction efficiency is improved. Thus, such a configuration is preferable.
Moreover, in each embodiment, a configuration has been described that on the object side relative to the image surface S (that is, between the image surface S and the most image side lens surface of the fourth lens unit G4), a plane parallel plate P such as an optical low-pass filter and a face plate of an image sensor is provided. This low-pass filter may be: a birefringent type low-pass filter made of, for example, a crystal whose predetermined crystal orientation is adjusted; or a phase type low-pass filter that achieves required characteristics of optical cut-off frequency by diffraction.
(Embodiment I-9)
FIG. 24 is a schematic construction diagram of a digital still camera according to Embodiment I-9. In FIG. 24, the digital still camera comprises: an imaging device having a zoom lens system 1 and an image sensor 2 composed of a CCD; a liquid crystal display monitor 3; and a body 4. The employed zoom lens system 1 is a zoom lens system according to Embodiment I-7. In FIG. 24, the zoom lens system 1 comprises a first lens unit G1, a second lens unit G2, an aperture diaphragm A, a third lens unit G3 and a fourth lens unit G4. In the body 4, the zoom lens system 1 is arranged on the front side, while the image sensor 2 is arranged on the rear side of the zoom lens system 1. On the rear side of the body 4, the liquid crystal display monitor 3 is arranged, while an optical image of a photographic object generated by the zoom lens system 1 is formed on an image surface S.
The lens barrel comprises a main barrel 5, a moving barrel 6 and a cylindrical cam 7. When the cylindrical cam 7 is rotated, the first lens unit G1, the second lens unit G2, the aperture diaphragm A, the third lens unit G3 and the fourth lens unit G4 move to predetermined positions relative to the image sensor 2, so that zooming from a wide-angle limit to a telephoto limit is achieved. The fourth lens unit G4 is movable in an optical axis direction by a motor for focus adjustment.
As such, when the zoom lens system according to Embodiment I-7 is employed in a digital still camera, a small digital still camera is obtained that has a high resolution and high capability of compensating the curvature of field and that has a short overall length of lens system at the time of non-use. Here, in the digital still camera shown in FIG. 24, any one of the zoom lens systems according to Embodiments I-1 to I-6 and I-8 may be employed in place of the zoom lens system according to Embodiment I-7. Further, the optical system of the digital still camera shown in FIG. 24 is applicable also to a digital video camera for moving images. In this case, moving images with high resolution can be acquired in addition to still images.
Here, the digital still camera according to the present Embodiment I-9 has been described for a case that the employed zoom lens system 1 is a zoom lens system according to Embodiments I-1 to I-8. However, in these zoom lens systems, the entire zooming range need not be used. That is, in accordance with a desired zooming range, a range where satisfactory optical performance is obtained may exclusively be used. Then, the zoom lens system may be used as one having a lower magnification than the zoom lens system described in Embodiments I-1 to I-8.
Further, Embodiment I-9 has been described for a case that the zoom lens system is applied to a lens barrel of so-called barrel retraction construction. However, the present invention is not limited to this. For example, the zoom lens system may be applied to a lens barrel of so-called bending construction where a prism having an internal reflective surface or a front surface reflective mirror is arranged at an arbitrary position within the first lens unit G1 or the like. Further, in Embodiment I-9, the zoom lens system may be applied to a so-called sliding lens barrel in which a part of the lens units constituting the zoom lens system like the entirety of the second lens unit G2, the entirety of the third lens unit G3, or alternatively a part of the second lens unit G2 or the third lens unit G3 is caused to escape from the optical axis at the time of retraction.
Further, an imaging device comprising a zoom lens system according to Embodiments I-1 to I-8 described above and an image sensor such as a CCD or a CMOS may be applied to a mobile telephone, a PDA (Personal Digital Assistance), a surveillance camera in a surveillance system, a Web camera, a vehicle-mounted camera or the like.
(Embodiment II-10)
FIG. 50 is a schematic construction diagram of a digital still camera according to Embodiment II-10. In FIG. 50, the digital still camera comprises: an imaging device having a zoom lens system 1 and an image sensor 2 composed of a CCD; a liquid crystal display monitor 3; and a body 4. The employed zoom lens system 1 is a zoom lens system according to Embodiment II-6. In FIG. 50, the zoom lens system 1 comprises a first lens unit G1, a second lens unit G2, an aperture diaphragm A, a third lens unit G3 and a fourth lens unit G4. In the body 4, the zoom lens system 1 is arranged on the front side, while the image sensor 2 is arranged on the rear side of the zoom lens system 1. On the rear side of the body 4, the liquid crystal display monitor 3 is arranged, while an optical image of a photographic object generated by the zoom lens system 1 is formed on an image surface S.
The lens barrel comprises a main barrel 5, a moving barrel 6 and a cylindrical cam 7. When the cylindrical cam 7 is rotated, the first lens unit G1, the second lens unit G2, the aperture diaphragm A, the third lens unit G3 and the fourth lens unit G4 move to predetermined positions relative to the image sensor 2, so that zooming from a wide-angle limit to a telephoto limit is achieved. The fourth lens unit G4 is movable in an optical axis direction by a motor for focus adjustment.
As such, when the zoom lens system according to Embodiment II-6 is employed in a digital still camera, a small digital still camera is obtained that has a high resolution and high capability of compensating the curvature of field and that has a short overall length of lens system at the time of non-use. Here, in the digital still camera shown in FIG. 50, any one of the zoom lens systems according to Embodiments II-1 to II-5 and II-7 to II-9 may be employed in place of the zoom lens system according to Embodiment II-6. Further, the optical system of the digital still camera shown in FIG. 50 is applicable also to a digital video camera for moving images. In this case, moving images with high resolution can be acquired in addition to still images.
Here, the digital still camera according to the present Embodiment II-10 has been described for a case that the employed zoom lens system 1 is a zoom lens system according to Embodiments II-1 to II-9. However, in these zoom lens systems, the entire zooming range need not be used. That is, in accordance with a desired zooming range, a range where satisfactory optical performance is obtained may exclusively be used. Then, the zoom lens system may be used as one having a lower magnification than the zoom lens system described in Embodiments II-1 to II-9.
Further, Embodiment II-10 has been described for a case that the zoom lens system is applied to a lens barrel of so-called barrel retraction construction. However, the present invention is not limited to this. For example, the zoom lens system may be applied to a lens barrel of so-called bending construction where a prism having an internal reflective surface or a front surface reflective mirror is arranged at an arbitrary position within the first lens unit G1 or the like. Further, in Embodiment II-10, the zoom lens system may be applied to a so-called sliding lens barrel in which a part of the lens units constituting the zoom lens system like the entirety of the second lens unit G2, the entirety of the third lens unit G3, or alternatively a part of the second lens unit G2 or the third lens unit G3 is caused to escape from the optical axis at the time of retraction.
Further, an imaging device comprising a zoom lens system according to Embodiments II-1 to II-9 described above and an image sensor such as a CCD or a CMOS may be applied to a mobile telephone, a PDA (Personal Digital Assistance), a surveillance camera in a surveillance system, a Web camera, a vehicle-mounted camera or the like.
(Embodiment III-8)
FIG. 70 is a schematic construction diagram of a digital still camera according to Embodiment III-8. In FIG. 70, the digital still camera comprises: an imaging device having a zoom lens system 1 and an image sensor 2 composed of a CCD; a liquid crystal display monitor 3; and a body 4. The employed zoom lens system 1 is a zoom lens system according to Embodiment III-6. In FIG. 70, the zoom lens system 1 comprises a first lens unit G1, a second lens unit G2, an aperture diaphragm A, a third lens unit G3 and a fourth lens unit G4. In the body 4, the zoom lens system 1 is arranged on the front side, while the image sensor 2 is arranged on the rear side of the zoom lens system 1. On the rear side of the body 4, the liquid crystal display monitor 3 is arranged, while an optical image of a photographic object generated by the zoom lens system 1 is formed on an image surface S.
The lens barrel comprises a main barrel 5, a moving barrel 6 and a cylindrical cam 7. When the cylindrical cam 7 is rotated, the first lens unit G1, the second lens unit G2, the aperture diaphragm A, the third lens unit G3 and the fourth lens unit G4 move to predetermined positions relative to the image sensor 2, so that zooming from a wide-angle limit to a telephoto limit is achieved. The fourth lens unit G4 is movable in an optical axis direction by a motor for focus adjustment.
As such, when the zoom lens system according to Embodiment III-6 is employed in a digital still camera, a small digital still camera is obtained that has a high resolution and high capability of compensating the curvature of field and that has a short overall length of lens system at the time of non-use. Here, in the digital still camera shown in FIG. 70, any one of the zoom lens systems according to Embodiments III-1 to III-5 and III-7 may be employed in place of the zoom lens system according to Embodiment III-6. Further, the optical system of the digital still camera shown in FIG. 70 is applicable also to a digital video camera for moving images. In this case, moving images with high resolution can be acquired in addition to still images.
Here, the digital still camera according to the present Embodiment III-8 has been described for a case that the employed zoom lens system 1 is a zoom lens system according to Embodiments III-1 to III-7. However, in these zoom lens systems, the entire zooming range need not be used. That is, in accordance with a desired zooming range, a range where satisfactory optical performance is obtained may exclusively be used. Then, the zoom lens system may be used as one having a lower magnification than the zoom lens system described in Embodiments III-1 to III-7.
Further, Embodiment III-8 has been described for a case that the zoom lens system is applied to a lens barrel of so-called barrel retraction construction. However, the present invention is not limited to this. For example, the zoom lens system may be applied to a lens barrel of so-called bending construction where a prism having an internal reflective surface or a front surface reflective mirror is arranged at an arbitrary position within the first lens unit G1 or the like. Further, in Embodiment III-8, the zoom lens system may be applied to a so-called sliding lens barrel in which a part of the lens units constituting the zoom lens system like the entirety of the second lens unit G2, the entirety of the third lens unit G3, or alternatively a part of the second lens unit G2 or the third lens unit G3 is caused to escape from the optical axis at the time of retraction.
Further, an imaging device comprising a zoom lens system according to Embodiments III-1 to III-7 described above and an image sensor such as a CCD or a CMOS may be applied to a mobile telephone, a PDA (Personal Digital Assistance), a surveillance camera in a surveillance system, a Web camera, a vehicle-mounted camera or the like.
Numerical embodiments are described below in which the zoom lens systems according to Embodiments I-1 to I-8, the zoom lens systems according to Embodiments II-1 to II-9 and the zoom lens systems according to Embodiments III-1 to III-7 are implemented respectively. In the numerical examples, the units of the length in the tables are all “mm”, while the units of the view angle are all “°”. Moreover, in the numerical examples, r is the radius of curvature, d is the axial distance, nd is the refractive index to the d-line, and vd is the Abbe number to the d-line. In the numerical examples, the surfaces marked with * are aspheric surfaces, and the aspheric surface configuration is defined by the following expression.




  Z
  =
  
    
      
        
          h
          2
        
        /
        r
      
      
        1
        +
        
          
            1
            -
            
              
                (
                
                  1
                  +
                  κ
                
                )
              
              ⁢
              
                
                  (
                  
                    h
                    /
                    r
                  
                  )
                
                2
              
            
          
        
      
    
    +
    
      A
      ⁢
      
        
      
      ⁢
      4
      ⁢
      
        h
        4
      
    
    +
    
      A
      ⁢
      
        
      
      ⁢
      6
      ⁢
      
        h
        6
      
    
    +
    
      A
      ⁢
      
        
      
      ⁢
      8
      ⁢
      
        h
        8
      
    
    +
    
      A
      ⁢
      
        
      
      ⁢
      10
      ⁢
      
        h
        10
      
    
    +
    
      A
      ⁢
      
        
      
      ⁢
      12
      ⁢
      
        
      
      ⁢
      
        h
        12
      
    
    +
    
      A
      ⁢
      
        
      
      ⁢
      14
      ⁢
      
        
      
      ⁢
      
        h
        14
      
    
    +
    
      A
      ⁢
      
        
      
      ⁢
      16
      ⁢
      
        
      
      ⁢
      
        h
        16
      
    
  




Here, κ is the conic constant, A4, A6, A8, A10, A12, A14 and A16 are a fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order and sixteenth-order aspherical coefficients, respectively.
FIGS. 2, 5, 8, 11, 14, 17, 19 and 22 are longitudinal aberration diagrams of the zoom lens systems according to Embodiments I-1 to I-8, respectively.
FIGS. 26, 29, 32, 34, 36, 39, 42, 45 and 48 are longitudinal aberration diagrams of the zoom lens systems according to Embodiments II-1 to II-9, respectively.
FIGS. 52, 55, 58, 60, 62, 65 and 68 are longitudinal aberration diagrams of the zoom lens systems according to Embodiments III-1 to III-7, respectively.
In each longitudinal aberration diagram, part (a) shows the aberration at a wide-angle limit, part (b) shows the aberration at a middle position, and part (c) shows the aberration at a telephoto limit. Each longitudinal aberration diagram, in order from the left-hand side, shows the spherical aberration (SA (mm)), the astigmatism (AST (mm)) and the distortion (DIS (%)). In each spherical aberration diagram, the vertical axis indicates the F-number (in each Fig., indicated as F), and the solid line, the short dash line and the long dash line indicate the characteristics to the d-line, the F-line and the C-line, respectively. In each astigmatism diagram, the vertical axis indicates the image height (in each Fig., indicated as H), and the solid line and the dash line indicate the characteristics to the sagittal plane (in each Fig., indicated as “s”) and the meridional plane (in each Fig., indicated as “m”), respectively. In each distortion diagram, the vertical axis indicates the image height (in each Fig., indicated as H).
FIGS. 3, 6, 9, 12, 15, 20 and 23 are lateral aberration diagrams of the zoom lens systems at a telephoto limit according to Embodiments I-1, I-2, I-3, I-4, I-5, I-7 and I-8, respectively.
FIGS. 27, 30, 37, 40, 43, 46 and 49 are lateral aberration diagrams of the zoom lens systems at a telephoto limit according to Embodiments II-1, II-2, II-5, II-6, II-7, II-8 and II-9, respectively.
FIGS. 53, 56, 63, 66 and 69 are lateral aberration diagrams of the zoom lens systems at a telephoto limit according to Embodiments III-1, III-2, III-5, III-6 and III-7, respectively.
In each lateral aberration diagram, the aberration diagrams in the upper three parts correspond to a basic state where image blur compensation is not performed at a telephoto limit, while the aberration diagrams in the lower three parts correspond to an image blur compensation state where the entire third lens unit G3 is moved by a predetermined amount in a direction perpendicular to the optical axis at a telephoto limit. Among the lateral aberration diagrams of a basic state, the upper part shows the lateral aberration at an image point of 70% of the maximum image height, the middle part shows the lateral aberration at the axial image point, and the lower part shows the lateral aberration at an image point of −70% of the maximum image height. Among the lateral aberration diagrams of an image blur compensation state, the upper part shows the lateral aberration at an image point of 70% of the maximum image height, the middle part shows the lateral aberration at the axial image point, and the lower part shows the lateral aberration at an image point of −70% of the maximum image height. In each lateral aberration diagram, the horizontal axis indicates the distance from the principal ray on the pupil surface, and the solid line, the short dash line and the long dash line indicate the characteristics to the d-line, the F-line and the C-line, respectively. In each lateral aberration diagram, the meridional plane is adopted as the plane containing the optical axis of the first lens unit G1 and the optical axis of the third lens unit G3.
Here, in the zoom lens system according to each example, the amount of movement of the third lens unit G3 in a direction perpendicular to the optical axis in an image blur compensation state at a telephoto limit is as follows.













Amount of movement (mm)












Example
I-
II-
III-







1
0.135
0.135
0.135



2
0.135
0.142
0.139



3
0.137
—
—



4
0.144
—
—



5
0.142
0.135
0.135



6
—
0.135
0.135



7
0.135
0.182
0.115



8
0.115
0.107
—



9
—
0.115
—










Here, when the shooting distance is infinity, at a telephoto limit, the amount of image decentering in a case that the zoom lens system inclines by 0.3° is equal to the amount of image decentering in a case that the entire third lens unit G3 displaces in parallel by each of the above-mentioned values in a direction perpendicular to the optical axis.
As seen from the lateral aberration diagrams, satisfactory symmetry is obtained in the lateral aberration at the axial image point. Further, when the lateral aberration at the +70% image point and the lateral aberration at the −70% image point are compared with each other in a basic state, all have a small degree of curvature and almost the same inclination in the aberration curve. Thus, decentering coma aberration and decentering astigmatism are small. This indicates that sufficient imaging performance is obtained even in an image blur compensation state. Further, when the image blur compensation angle of a zoom lens system is the same, the amount of parallel translation required for image blur compensation decreases with decreasing focal length of the entire zoom lens system. Thus, at arbitrary zoom positions, sufficient image blur compensation can be performed for image blur compensation angles up to 0.3° without degrading the imaging characteristics.
Numerical Example I-1
The zoom lens system of Numerical Example I-1 corresponds to Embodiment I-1 shown in FIG. 1. Table I-1 shows the surface data of the zoom lens system of Numerical Example I-1. Table I-2 shows the aspherical data. Table I-3 shows various data.







TABLE I-1







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
28.99500
0.75000
1.84666
23.8


 2
19.06100
0.01000
1.56732
42.8


 3
19.06100
2.84700
1.49700
81.6


 4
106.49800
0.15000


 5
19.93700
2.17900
1.72916
54.7


 6
66.38300
Variable


 7
46.75800
0.40000
1.88300
40.8


 8
5.20400
2.92000


 9
−27.85600
0.40000
1.78590
43.9


10
12.36700
0.47500


11
10.23200
1.34100
1.94595
18.0


12
48.88200
Variable


13 (Diaphragm)
∞
0.30000


14
4.29700
1.76700
1.49700
81.6


15
8241.75900
1.15600


16*
8.40200
1.39900
1.80359
40.8


17
50.50600
0.01000
1.56732
42.8


18
50.50600
0.40000
1.84666
23.8


19
5.31000
Variable


20*
11.71400
1.57800
1.51788
70.1


21*
−1903.05100
variable


22
∞
0.78000
1.51680
64.2


23
∞
(BF)


Image surface
∞
















TABLE I-2





(Aspherical data)

















Surface No. 16



K = −2.28822E−01, A4 = −1.79052E−03, A6 = −2.03953E−04,



A8 = 6.65739E−05 A10 = −2.75026E−05, A12 = 5.38981E−06,



A14 = −5.53822E−07, A16 = 2.31265E−08



Surface No. 20



K = 0.00000E+00, A4 = −7.84816E−04, A6 = 6.11566E−05,



A8 = −8.70671E−06 A10 = 2.07853E−07, A12 = 1.30642E−08,



A14 = −4.95350E−10, A16 = 9.73908E−14



Surface No. 21



K = 0.00000E+00, A4 = −9.08686E−04, A6 = 7.99050E−05,



A8 = −1.33973E−05 A10 = 7.26054E−07, A12 = −1.80771E−08,



A14 = 3.95939E−10, A16 = −6.83275E−12

















TABLE I-3





(Various data)







Zooming ratio 11.03046













Wide-angle
Middle
Telephoto




limit
position
limit







Focal length
4.3007
13.8388
47.4383



F-number
3.27846
4.28177
5.08881



View angle
42.8104
14.6240
4.2606



Image height
3.5000
3.6000
3.6000



Overall length
43.0950
45.9352
54.8315



of lens system



BF
0.87558
0.86948
0.86672



d6
0.3050
8.7502
18.1095



d12
15.2180
4.9127
1.2400



d19
4.1289
3.9787
12.8898



d21
3.7055
8.5621
2.8635



Entrance pupil
11.6301
31.3439
103.4648



position



Exit pupil
−14.9503
−19.5021
−54.6732



position



Front principal
14.7621
35.7817
110.3846



points position



Back principal
38.7943
32.0963
7.3932



points position











Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−68.0664


2
3
46.2134


3
5
38.3211


4
7
−6.6617


5
9
−10.8504


6
11
13.4533


7
14
8.6498


8
16
12.3591


9
18
−7.0371


10
20
22.4871










Zoom lens unit data















Overall
Front
Back



Initial

length
principal
principal


Lens
surface
Focal
of lens
points
points


unit
No.
length
unit
position
position





1
1
31.38739
5.93600
1.01427
3.21201


2
7
−5.93817
5.53600
0.35694
1.34712


3
13
10.09342
5.03200
−2.42725
0.43524


4
20
22.48708
1.57800
0.00636
0.54446










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.26914
−0.43605
−1.39433


3
13
−0.69983
−1.97584
−1.41639


4
20
0.72745
0.51175
0.76529









Numerical Example I-2
The zoom lens system of Numerical Example I-2 corresponds to Embodiment I-2 shown in FIG. 4. Table I-4 shows the surface data of the zoom lens system of Numerical Example I-2. Table I-5 shows the aspherical data. Table I-6 shows various data.







TABLE I-4







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
28.99700
0.75000
1.84666
23.8


 2
19.09100
0.01000
1.56732
42.8


 3
19.09100
2.84700
1.49700
81.6


 4
103.92400
0.15000


 5
19.82600
2.17900
1.72916
54.7


 6
64.92800
Variable


 7
44.87200
0.40000
1.88300
40.8


 8
5.18700
2.92000


 9
−29.21100
0.40000
1.78590
43.9


10
12.37500
0.47500


11
10.24000
1.34100
1.94595
18.0


12
47.83600
Variable


13 (Diaphragm)
∞
0.30000


14
4.30100
1.76700
1.49700
81.6


15
8241.75900
1.15600


16*
8.43200
1.39900
1.80359
40.8


17
47.76900
0.01000
1.56732
42.8


18
47.76900
0.40000
1.84666
23.8


19
5.30000
Variable


20*
11.73300
1.57800
1.51788
70.1


21*
−1903.05100
Variable


22
∞
0.78000
1.51680
64.2


23
∞
(BF)


Image surface
∞
















TABLE I-5





(Aspherical data)

















Surface No. 16



K = −1.08120E−01, A4 = −1.77933E−03, A6 = −2.10910E−04,



A8 = 6.71009E−05 A10 = −2.73694E−05, A12 = 5.38864E−06,



A14 = −5.55377E−07, A16 = 2.30717E−08



Surface No. 20



K = 0.00000E+00, A4 = −7.73857E−04, A6 = 6.08786E−05,



A8 = −8.73181E−06 A10 = 2.05548E−07, A12 = 1.29957E−08,



A14 = −4.94747E−10, A16 = 4.24877E−13



Surface No. 21



K = 0.00000E+00, A4 = −9.05532E−04, A6 = 7.99808E−05,



A8 = −1.34302E−05 A10 = 7.25546E−07, A12 = −1.80811E−08,



A14 = 3.94130E−10, A16 = −6.65585E−12

















TABLE I-6





(Various data)







Zooming ratio 11.02792













Wide-angle
Middle
Telephoto




limit
position
limit







Focal length
4.3008
13.7797
47.4286



F-number
3.25999
4.27060
5.07866



View angle
42.8274
14.6883
4.2641



Image height
3.5000
3.6000
3.6000



Overall length
43.0322
45.9106
54.8663



of lens system



BF
0.88584
0.88510
0.87609



d6
0.3050
8.7502
18.1561



d12
15.2479
4.9989
1.2400



d19
3.8106
3.8386
12.8035



d21
3.9209
8.5758
2.9286



Entrance pupil
11.6669
31.3764
103.4955



position



Exit pupil
−14.5144
−19.2244
−53.6397



position



Front principal
14.7666
35.7138
109.6613



points position



Back principal
38.7315
32.1309
7.4377



points position











Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−68.3779


2
3
46.5386


3
5
38.3610


4
7
−6.6736


5
9
−11.0140


6
11
13.5388


7
14
8.6579


8
16
12.5433


9
18
−7.0716


10
20
22.5233










Zoom lens unit data















Overall
Front
Back



Initial

length
principal
principal


Lens
surface
Focal
of lens
points
points


unit
No.
length
unit
position
position





1
1
31.49755
5.93600
0.99755
3.19687


2
7
−5.98535
5.53600
0.34887
1.33719


3
13
10.15073
5.03200
−2.46007
0.41501


4
20
22.52334
1.57800
0.00637
0.54447










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.27060
−0.43772
−1.40235


3
13
−0.70292
−1.95501
−1.40848


4
20
0.71787
0.51123
0.76236









Numerical Example I-3
The zoom lens system of Numerical Example I-3 corresponds to Embodiment I-3 shown in FIG. 7. Table I-7 shows the surface data of the zoom lens system of Numerical Example I-3. Table I-8 shows the aspherical data. Table I-9 shows various data.







TABLE I-7







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
28.95300
0.75000
1.84666
23.8


 2
19.07400
0.01000
1.56732
42.8


 3
19.07400
2.84700
1.49700
81.6


 4
102.59900
0.15000


 5
19.75500
2.17900
1.72916
54.7


 6
63.58500
Variable


 7
41.65600
0.40000
1.88300
40.8


 8
5.19900
2.92000


 9
−29.77800
0.40000
1.78590
43.9


10
12.49200
0.47500


11
10.24000
1.33100
1.94595
18.0


12
46.29800
Variable


13 (Diaphragm)
∞
0.30000


14
4.30400
1.76700
1.49700
81.6


15
8241.75900
1.15600


16*
8.55800
1.39900
1.80359
40.8


17
46.55400
0.01000
1.56732
42.8


18
46.55400
0.40000
1.84666
23.8


19
5.32600
Variable


20*
11.65500
1.57800
1.51788
70.1


21*
−1903.05100
Variable


22
∞
0.78000
1.51680
64.2


23
∞
(BF)


Image surface
∞
















TABLE I-8





(Aspherical data)

















Surface No. 16



K = −8.53000E−02, A4 = −1.79943E−03, A6 = −1.98982E−04,



A8 = 6.52382E−05 A10 = −2.72130E−05, A12 = 5.37007E−06,



A14 = −5.53606E−07, A16 = 2.29509E−08



Surface No. 20



K = 0.00000E+00, A4 = −6.55021E−04, A6 = 6.29639E−05,



A8 = −8.78772E−06 A10 = 2.06133E−07, A12 = 1.31011E−08,



A14 = −4.97108E−10, A16 = −5.00067E−13



Surface No. 21



K = 0.00000E+00, A4 = −7.19117E−04, A6 = 8.06908E−05,



A8 = −1.39557E−05 A10 = 7.59747E−07, A12 = −1.68506E−08,



A14 = 1.71944E−10, A16 = −5.16658E−13

















TABLE I-9





(Various data)







Zooming ratio 11.03447













Wide-angle
Middle
Telephoto




limit
position
limit







Focal length
4.3028
13.8628
47.4786



F-number
3.25644
4.28046
5.09375



View angle
41.6709
14.5348
4.2566



Image height
3.4000
3.6000
3.6000



Overall length
43.2052
45.3720
54.8214



of lens system



BF
0.88493
0.87830
0.87516



d6
0.3128
8.5714
18.1623



d12
15.4915
4.8361
1.2400



d19
3.6304
3.2810
12.8380



d21
4.0336
8.9532
2.8539



Entrance pupil
11.7985
30.6568
102.9723



position



Exit pupil
−14.2987
−18.5579
−54.6467



position



Front principal
14.8820
34.6320
109.8503



points position



Back principal
38.9025
31.5092
7.3427



points position











Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−68.4065


2
3
46.6152


3
5
38.4970


4
7
−6.7623


5
9
−11.1513


6
11
13.6543


7
14
8.6639


8
16
12.8378


9
18
−7.1350


10
20
22.3745










Zoom lens unit data















Overall
Front
Back



Initial

length
principal
principal


Lens
surface
Focal
of lens
points
points


unit
No.
length
unit
position
position





1
1
31.61710
5.93600
0.97969
3.18057


2
7
−6.07545
5.52600
0.34993
1.33482


3
13
10.23904
5.03200
−2.49736
0.38786


4
20
22.37451
1.57800
0.00633
0.54443










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.27462
−0.43819
−1.42149


3
13
−0.69700
−2.03619
−1.38245


4
20
0.71100
0.49142
0.76416









Numerical Example I-4
The zoom lens system of Numerical Example I-4 corresponds to Embodiment I-4 shown in FIG. 10. Table I-10 shows the surface data of the zoom lens system of Numerical Example I-4. Table I-11 shows the aspherical data. Table I-12 shows various data.







TABLE I-10







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
29.96700
0.75000
1.84666
23.8


 2
19.76100
0.01000
1.56732
42.8


 3
19.76100
2.87000
1.49700
81.6


 4
113.14300
0.15000


 5
20.52300
2.17200
1.72916
54.7


 6
66.07200
Variable


 7
42.98400
0.40000
1.88300
40.8


 8
5.24000
2.87300


 9
−26.74300
0.40000
1.72916
54.7


10
11.79700
0.41400


11
9.87600
1.61100
1.92286
20.9


12
49.90000
Variable


13 (Diaphragm)
∞
0.30000


14
4.35100
1.71500
1.49700
81.6


15
8241.75900
1.15600


16*
8.17800
1.39900
1.80359
40.8


17
26.89800
0.01000
1.56732
42.8


18
26.89800
0.40000
1.84666
23.8


19
5.12800
Variable


20*
11.58100
1.57800
1.51835
70.3


21*
−1903.05100
Variable


22
∞
0.78000
1.51680
64.2


23
∞
(BF)


Image surface
∞
















TABLE I-11





(Aspherical data)

















Surface No. 16



K = 2.48612E−01, A4 = −1.72469E−03, A6 = −2.47114E−04,



A8 = 8.90838E−05 A10 = −3.12229E−05, A12 = 5.32264E−06,



A14 = −4.63452E−07, A16 = 1.59112E−08



Surface No. 20



K = 0.00000E+00, A4 = −8.09583E−04, A6 = 7.87583E−05,



A8 = −9.48222E−06 A10 = 1.69233E−07, A12 = 1.30664E−08,



A14 = −4.30331E−10, A16 = 0.00000E+00



Surface No. 21



K = 0.00000E+00, A4 = −8.68096E−04, A6 = 8.93558E−05,



A8 = −1.40719E−05 A10 = 7.56809E−07, A12 = −2.21847E−08,



A14 = 3.91923E−10, A16 = 0.00000E+00

















TABLE I-12





(Various data)







Zooming ratio 11.19473













Wide-angle
Middle
Telephoto




limit
position
limit







Focal length
4.3435
13.8635
48.6242



F-number
3.32176
4.29281
5.09761



View angle
42.1252
14.5274
4.1532



Image height
3.4800
3.6000
3.6000



Overall length
43.6261
46.0995
55.1687



of lens system



BF
0.88520
0.87910
0.88176



d6
0.3325
9.1692
18.9873



d12
15.6779
5.0320
1.0000



d19
3.7027
3.3848
12.5529



d21
4.0398
8.6464
2.7587



Entrance pupil
11.8828
32.3910
107.5476



position



Exit pupil
−14.3910
−18.3900
−52.0024



position



Front principal
14.9913
36.2802
111.4645



points position



Back principal
39.2826
32.2360
6.5445



points position











Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−70.9202


2
3
47.6882


3
5
40.0231


4
7
−6.7919


5
9
−11.1776


6
11
13.0893


7
14
8.7586


8
16
14.1515


9
18
−7.5470


10
20
22.2132










Zoom lens unit data















Overall
Front
Back



Initial

length
principal
principal


Lens
surface
Focal
of lens
points
points


unit
No.
length
unit
position
position





1
1
32.51235
5.95200
1.00008
3.20471


2
7
−6.24486
5.69800
0.31767
1.42601


3
13
10.34842
4.98000
−2.56327
0.32969


4
20
22.21316
1.57800
0.00629
0.54471










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.27306
−0.44500
−1.48150


3
13
−0.69043
−1.91066
−1.31711


4
20
0.70862
0.50151
0.76645









Numerical Example I-5
The zoom lens system of Numerical Example I-5 corresponds to Embodiment I-5 shown in FIG. 13. Table I-13 shows the surface data of the zoom lens system of Numerical Example I-5. Table I-14 shows the aspherical data. Table I-15 shows various data.







TABLE I-13







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
30.54000
0.75000
1.84666
23.8


 2
19.97400
0.01000
1.56732
42.8


 3
19.97400
2.87000
1.49700
81.6


 4
119.50600
0.15000


 5
20.80800
2.17200
1.72916
54.7


 6
68.56200
Variable


 7
41.49100
0.40000
1.88300
40.8


 8
5.16400
2.91600


 9
−28.12500
0.40000
1.77250
49.6


10
11.42600
0.28600


11
9.47800
1.61100
1.92286
20.9


12
67.30800
Variable


13 (Diaphragm)
∞
0.30000


14
4.35700
1.71500
1.49700
81.6


15
8241.75900
1.15600


16*
7.96700
1.39900
1.80359
40.8


17
29.75200
0.01000
1.56732
42.8


18
29.75200
0.40000
1.84666
23.8


19
5.06400
Variable


20*
11.61900
1.57800
1.51835
70.3


21*
−1903.05100
Variable


22
∞
0.78000
1.51680
64.2


23
∞
(BF)


Image surface
∞
















TABLE I-14





(Aspherical data)

















Surface No. 16



K = 1.39021E−02, A4 = −1.64228E−03, A6 = −2.91551E−04,



A8 = 1.15748E−04 A10 = −3.67628E−05, A12 = 5.42614E−06,



A14 = −3.77856E−07, A16 = 9.18243E−09



Surface No. 20



K = 0.00000E+00, A4 = −8.71053E−04, A6 = 8.45133E−05,



A8 = −9.60026E−06 A10 = 1.40515E−07, A12 = 1.12552E−08,



A14 = −2.70338E−10, A16 = 0.00000E+00



Surface No. 21



K = 0.00000E+00, A4 = −9.33492E−04, A6 = 9.55308E−05,



A8 = −1.40865E−05 A10 = 6.99833E−07, A12 = −2.23769E−08,



A14 = 5.21314E−10, A16 = 0.00000E+00

















TABLE I-15





(Various data)







Zooming ratio 11.22733













Wide-angle
Middle
Telephoto




limit
position
limit







Focal length
4.3008
13.8502
48.2860



F-number
3.29451
4.30437
5.08373



View angle
42.3554
14.5254
4.1813



Image height
3.5000
3.6000
3.6000



Overall length
43.5390
46.0641
55.1007



of lens system



BF
0.88366
0.87555
0.87318



d6
0.3270
9.1087
19.1281



d12
15.8063
5.0015
1.0000



d19
3.7135
3.6945
12.5209



d21
3.9055
8.4808
2.6755



Entrance pupil
11.8346
31.7799
106.5530



position



Exit pupil
−14.2580
−18.7963
−51.2354



position



Front principal
14.9138
35.8787
110.0952



points position



Back principal
39.2382
32.2138
6.8147



points position











Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−70.4825


2
3
47.7970


3
5
40.2004


4
7
−6.7143


5
9
−10.4718


6
11
11.7958


7
14
8.7707


8
16
13.1634


9
18
−7.2619


10
20
22.2856










Zoom lens unit data















Overall
Front
Back



Initial

length
principal
principal


Lens
surface
Focal
of lens
points
points


unit
No.
length
unit
position
position





1
1
32.73986
5.95200
1.03540
3.23820


2
7
−6.27895
5.61300
0.30084
1.41358


3
13
10.26409
4.98000
−2.53886
0.35305


4
20
22.28560
1.57800
0.00631
0.54473










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.27159
−0.43794
−1.45407


3
13
−0.67585
−1.89141
−1.31499


4
20
0.71566
0.51072
0.77132









Numerical Example I-6
The zoom lens system of Numerical Example I-6 corresponds to Embodiment I-6 shown in FIG. 16. Table I-16 shows the surface data of the zoom lens system of Numerical Example I-6. Table I-17 shows the aspherical data. Table I-18 shows various data.







TABLE I-16







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
28.83400
0.75000
1.84666
23.8


 2
19.10600
0.01000
1.56732
42.8


 3
19.10600
2.85000
1.49700
81.6


 4
101.86400
0.15000


 5
20.12000
2.17900
1.72916
54.7


 6
67.88000
Variable


 7
48.57300
0.40000
1.88300
40.8


 8
5.25800
2.88300


 9
−30.09700
0.40000
1.78590
43.9


10
11.97200
0.46400


11
10.02000
1.38900
1.94595
18.0


12
45.19300
Variable


13 (Diaphragm)
∞
0.30000


14*
4.07200
1.85400
1.51835
70.3


15*
−14.78000
1.10600


16
10.46100
0.40000
1.80518
25.5


17
3.45300
0.45000


18
4.62900
1.00100
1.60342
38.0


19
7.26800
Variable


20*
12.44300
1.57700
1.51835
70.3


21*
−178.17400
Variable


22
∞
0.78000
1.51680
64.2


23
∞
(BF)


Image surface
∞
















TABLE I-17





(Aspherical data)

















Surface No. 14



K = 0.00000E+00, A4 = −8.24968E−04, A6 = −1.09073E−06,



A8 = 2.17711E−05 A10 = −5.02279E−06, A12 = 2.35314E−07,



A14 = 1.63202E−07, A16 = −1.54658E−08



Surface No. 15



K = 0.00000E+00, A4 = 1.49679E−03, A6 = 1.31240E−04,



A8 = 1.46070E−06 A10 = −1.18079E−06, A12 = −9.13721E−08,



A14 = 2.62896E−07, A16 = −2.45633E−08



Surface No. 20



K = 0.00000E+00, A4 = −7.69541E−04, A6 = 7.69065E−05,



A8 = −1.40933E−05 A10 = 9.19495E−07, A12 = −1.81967E−08,



A14 = −1.78801E−09, A16 = 7.53515E−11



Surface No. 21



K = 0.00000E+00, A4 = −7.47072E−04, A6 = 4.18687E−05,



A8 = −9.53545E−06 A10 = 6.77844E−07, A12 = −2.96255E−08,



A14 = 8.03400E−11, A16 = 2.04568E−11

















TABLE I-18





(Various data)







Zooming ratio 11.02588













Wide-angle
Middle
Telephoto




limit
position
limit







Focal length
4.2986
13.8551
47.3961



F-number
3.28208
4.24530
5.13352



View angle
42.0251
14.6001
4.2709



Image height
3.4000
3.6000
3.6000



Overall length
43.1677
45.8742
54.8407



of lens system



BF
0.87410
0.86181
0.87475



d6
0.3050
8.8771
18.0441



d12
15.5017
5.0021
1.2400



d19
3.8901
3.6860
12.7948



d21
3.6538
8.5042
2.9441



Entrance pupil
11.7092
31.8814
101.3999



position



Exit pupil
−15.4282
−19.8509
−59.3792



position



Front principal
14.8744
36.4685
111.5140



points position



Back principal
38.8691
32.0191
7.4446



points position











Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−69.3377


2
3
46.7831


3
5
38.4775


4
7
−6.7066


5
9
−10.8530


6
11
13.3538


7
14
6.3728


8
16
−6.5687


9
18
18.4881


10
20
22.5016










Zoom lens unit data















Overall
Front
Back



Initial

length
principal
principal


Lens
surface
Focal
of lens
points
points


unit
No.
length
unit
position
position





1
1
31.49909
5.93900
1.00554
3.20336


2
7
−5.98151
5.53600
0.36288
1.39105


3
13
10.16322
5.11100
−2.32440
0.11796


4
20
22.50158
1.57700
0.06799
0.60342










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.27048
−0.44170
−1.36721


3
13
−0.68864
−1.92377
−1.44020


4
20
0.73265
0.51764
0.76416









Numerical Example I-7
The zoom lens system of Numerical Example I-7 corresponds to Embodiment I-7 shown in FIG. 18. Table I-19 shows the surface data of the zoom lens system of Numerical Example I-7. Table I-20 shows the aspherical data. Table I-21 shows various data.







TABLE I-19







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
31.60900
0.75700
1.92286
20.9


 2
22.12900
0.01000
1.56732
42.8


 3
22.12900
2.85800
1.49700
81.6


 4
221.46700
0.14400


 5
19.82900
2.17900
1.72916
54.7


 6
56.23800
Variable


 7
44.93500
0.40100
1.88300
40.8


 8
5.19000
2.94100


 9
−28.98600
0.39900
1.78590
43.9


10
12.33500
0.47500


11
10.20700
1.34300
1.94595
18.0


12
47.99500
Variable


13 (Diaphragm)
∞
0.30000


14
4.30200
1.77300
1.49700
81.6


15
6803.89600
1.15900


16*
8.43500
1.39700
1.80359
40.8


17
49.88900
0.01000
1.56732
42.8


18
49.88900
0.39800
1.84666
23.8


19
5.29900
Variable


20*
11.72100
1.58000
1.51835
70.3


21*
−1629.06500
Variable


22
∞
0.78000
1.51680
64.2


23
∞
(BF)


Image surface
∞
















TABLE I-20





(Aspherical data)

















Surface No. 16



K = −1.26014E−01, A4 = −1.78233E−03, A6 = −2.10674E−04,



A8 = 6.69814E−05 A10 = −2.74048E−05, A12 = 5.39168E−06,



A14 = −5.55222E−07, A16 = 2.30211E−08



Surface No. 20



K = 0.00000E+00, A4 = −7.75064E−04, A6 = 6.14125E−05,



A8 = −8.73167E−06 A10 = 2.05005E−07, A12 = 1.29818E−08,



A14 = −4.93909E−10, A16 = 6.87949E−13



Surface No. 21



K = 0.00000E+00, A4 = −9.03803E−04, A6 = 7.96172E−05,



A8 = −1.34273E−05 A10 = 7.25544E−07, A12 = −1.80856E−08,



A14 = 3.95732E−10, A16 = −6.69981E−12

















TABLE I-21





(Various data)







Zooming ratio 11.02287













Wide-angle
Middle
Telephoto




limit
position
limit







Focal length
4.3008
13.8156
47.4068



F-number
3.26165
4.24209
5.08129



View angle
42.5203
14.6148
4.2714



Image height
3.5000
3.6000
3.6000



Overall length
43.1633
45.9912
54.9059



of lens system



BF
0.88315
0.88011
0.86611



d6
0.3402
8.9311
18.1547



d12
15.2947
5.0260
1.2415



d19
3.8356
3.6957
12.7992



d21
3.9057
8.5543
2.9404



Entrance pupil
11.7233
32.1123
103.6880



position



Exit pupil
−14.5669
−18.9414
−53.9620



position



Front principal
14.8268
36.2985
110.1048



points position



Back principal
38.8626
32.1757
7.4991



points position











Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−83.1380


2
3
49.2339


3
5
40.9708


4
7
−6.6768


5
9
−10.9635


6
11
13.4721


7
14
8.6607


8
16
12.4456


9
18
−7.0312


10
20
22.4580










Zoom lens unit data















Overall
Front
Back



Initial

length
principal
principal


Lens
surface
Focal
of lens
points
points


unit
No.
length
unit
position
position





1
1
31.49407
5.94800
0.97373
3.20547


2
7
−5.98650
5.55900
0.35026
1.33891


3
13
10.16527
5.03700
−2.46799
0.41145


4
20
22.45799
1.58000
0.00744
0.54649










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.27119
−0.44398
−1.40526


3
13
−0.70146
−1.93358
−1.40649


4
20
0.71785
0.51099
0.76159









Numerical Example I-8
The zoom lens system of Numerical Example I-8 corresponds to Embodiment I-8 shown in FIG. 21. Table I-22 shows the surface data of the zoom lens system of Numerical Example I-8. Table I-23 shows the aspherical data. Table I-24 shows various data.







TABLE I-22







(Surface data)

















Effective


Surface number
r
d
nd
vd
diameter





Object surface
∞






 1
19.77840
0.75000
1.85139
23.6
9.867


 2
15.05080
0.01000
1.56732
42.8
9.046


 3
15.05080
4.55170
1.58913
61.2
9.044


 4*
−2009.86870
Variable


8.687


 5
52.22170
0.40000
1.95534
29.4
6.224


 6
5.68140
3.07420


4.550


 7
−23.91140
0.40000
1.72668
53.6
4.494


 8
14.22890
0.15000


4.447


 9
10.89020
1.62340
1.94595
18.0
4.541


10
165.48490
Variable


4.456


11 (Diaphragm)
∞
0.30000


2.205


12
4.18710
2.65790
1.49171
69.9


13
−22.46530
0.20000


14*
6.60790
1.54420
1.71418
29.7
2.712


15
−18.34560
0.01000
1.56732
42.8


16
−18.34560
0.40000
2.00080
24.4


17
4.72980
Variable


1.753


18*
9.76620
1.36180
1.51760
63.5
3.622


19
23.45330
Variable


3.603


20
∞
0.78000
1.51680
64.2


21
∞
(BF)


Image surface
∞
















TABLE I-23





(Aspherical data)

















Surface No. 4



K = 0.00000E+00, A4 = 6.68914E−06, A6 = −9.93410E−10,



A8 = −8.29880E−11 A10 = 4.79336E−13, A12 = 0.00000E+00



Surface No. 14



K = −1.97925E+00, A4 = −1.09715E−03, A6 = −1.81257E−04,



A8 = 5.09203E−07 A10 = −1.71341E−06, A12 = 0.00000E+00



Surface No. 18



K = 0.00000E+00, A4 = −3.54076E−04, A6 = 7.33046E−05,



A8 = −1.00180E−05 A10 = 6.97991E−07, A12 = −1.86608E−08

















TABLE I-24





(Various data)







Zooming ratio 11.44412













Wide-angle
Middle
Telephoto




limit
position
limit







Focal length
4.5865
14.9965
52.4889



F-number
3.44725
4.69828
5.62110



View angle
41.0129
14.5052
4.2129



Image height
3.5100
3.9300
3.9300



Overall length
45.8634
47.8820
59.0016



of lens system



BF
0.91651
0.88175
0.87169



d4
0.3000
9.8706
21.5407



d10
18.5253
6.1613
1.0000



d17
5.3803
3.7677
11.8523



d19
2.5281
8.9874
5.5237



Entrance pupil
11.8960
32.6328
107.7666



position



Exit pupil
−13.4686
−17.4274
−31.0462



position



Front principal
15.0202
35.3461
73.9375



points position



Back principal
41.2769
32.8854
6.5127



points position











Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−79.7777


2
3
25.3788


3
5
−6.7011


4
7
−12.2219


5
9
12.2609


6
12
7.4217


7
14
6.9824


8
16
−3.7250


9
18
31.2703










Zoom lens unit data















Overall
Front
Back



Initial

length
principal
principal


Lens
surface
Focal
of lens
points
points


unit
No.
length
unit
position
position





1
1
38.18058
5.31170
−0.23227
1.80477


2
5
−6.86331
5.64760
0.11084
1.15898


3
11
10.27017
5.11210
−3.64054
0.23351


4
18
31.27028
1.36180
−0.61927
−0.12535










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
5
−0.25049
−0.38495
−1.11439


3
11
−0.58070
−1.64465
−1.68650


4
18
0.82584
0.62039
0.73148









The following Table I-25 shows the corresponding values to the individual conditions in the zoom lens systems of the numerical examples.







TABLE I-25







(Corresponding values to conditions)









Example

















Condition
I-1
I-2
I-3
I-4
I-5
I-6
I-7
I-8



















 (5)
tan2ωW × m2W
−3.514
−3.561
−2.352
−2.712
−2.934
−2.596
−3.125
−1.788


 (6)
tan2ωW × |fG2|/fG1
2.470
2.501
1.646
1.908
2.072
1.822
2.191
1.283


(a-2)
ωW
42.81
42.83
41.67
42.13
42.36
42.03
42.52
41.01


(b)
fT/fW
11.03
11.03
11.03
11.19
11.23
11.03
11.02
11.44


(10)
m2T/m2W
5.181
5.182
5.177
5.425
5.354
5.054
5.182
4.449


(11)
LT/fT
1.156
1.157
1.155
1.135
1.141
1.157
1.158
1.124


(12)
fT/fG1
1.511
1.506
1.502
1.496
1.475
1.505
1.505
1.375


(13)
LW/fG1
1.373
1.366
1.367
1.342
1.330
1.370
1.371
1.201


(14)
LT/fG1
1.747
1.742
1.734
1.697
1.683
1.741
1.743
1.545


(15)
fG1/|fG2|
5.286
5.262
5.204
5.206
5.214
5.266
5.261
5.563









Numerical Example II-1
The zoom lens system of Numerical Example II-1 corresponds to Embodiment II-1 shown in FIG. 25. Table II-1 shows the surface data of the zoom lens system of Numerical Example II-1. Table II-2 shows the aspherical data. Table II-3 shows various data.







TABLE II-1







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
28.99500
0.75000
1.84666
23.8


 2
19.08700
0.01000
1.56732
42.8


 3
19.08700
2.84700
1.49700
81.6


 4
103.92400
0.15000


 5
19.82600
2.17900
1.72916
54.7


 6
64.93200
Variable


 7
44.87700
0.40000
1.88300
40.8


 8
5.18600
2.92000


 9
−29.16200
0.40000
1.78590
43.9


10
12.33600
0.47500


11
10.21400
1.34100
1.94595
18.0


12
47.83400
Variable


13 (Diaphragm)
∞
0.30000


14
4.30100
1.76700
1.49700
81.6


15
8241.75900
1.15600


16*
8.43400
1.39900
1.80359
40.8


17
47.78600
0.01000
1.56732
42.8


18
47.78600
0.40000
1.84666
23.8


19
5.30000
Variable


20*
11.73300
1.57800
1.51788
70.1


21*
−1903.05100
Variable


22
∞
0.78000
1.51680
64.2


23
∞
(BF)


Image surface
∞
















TABLE II-2





(Aspherical data)

















Surface No. 16



K = −1.08120E−01, A4 = −1.77815E−03, A6 = −2.10683E−04,



A8 = 6.70181E−05 A10 = −2.73725E−05, A12 = 5.38765E−06,



A14 = −5.55279E−07, A16 = 2.30717E−08



Surface No. 20



K = 0.00000E+00, A4 = −7.73195E−04, A6 = 6.10146E−05,



A8 = −8.73485E−06 A10 = 2.05233E−07, A12 = 1.29977E−08,



A14 = −4.93132E−10, A16 = 4.24886E−13



Surface No. 21



K = 0.00000E+00, A4 = −9.05532E−04, A6 = 7.99808E−05,



A8 = −1.34302E−05 A10 = 7.25546E−07, A12 = −1.80811E−08,



A14 = 3.94130E−10, A16 = −6.65586E−12

















TABLE II-3





(Various data)







Zooming ratio 11.02510













Wide-angle
Middle
Telephoto




limit
position
limit







Focal length
4.3006
13.7819
47.4146



F-number
3.26027
4.27212
5.07918



View angle
42.8331
14.6873
4.2674



Image height
3.5000
3.6000
3.6000



Overall length
43.0332
45.9184
54.8755



of lens system



BF
0.88682
0.88842
0.88365



d6
0.3050
8.7502
18.1561



d12
15.2479
4.9989
1.2400



d19
3.8073
3.8429
12.7973



d21
3.9242
8.5760
2.9364



Entrance pupil
11.6651
31.3726
103.4747



position



Exit pupil
−14.5110
−19.2329
−53.5837



position



Front principal
14.7645
35.7147
109.6143



points position



Back principal
38.7326
32.1365
7.4609



points position











Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−68.3446


2
3
46.5267


3
5
38.3600


4
7
−6.6721


5
9
−10.9840


6
11
13.4954


7
14
8.6579


8
16
12.5461


9
18
−7.0713


10
20
22.5233










Zoom lens unit data















Overall
Front
Back



Initial

length
principal
principal


Lens
surface
Focal
of lens
points
points


unit
No.
length
unit
position
position





1
1
31.49864
5.93600
0.99762
3.19693


2
7
−5.98512
5.53600
0.34799
1.33545


3
13
10.15272
5.03200
−2.46124
0.41427


4
20
22.52334
1.57800
0.00637
0.54447










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.27056
−0.43763
−1.40155


3
13
−0.70315
−1.95626
−1.41007


4
20
0.71768
0.51108
0.76168









Numerical Example II-2
The zoom lens system of Numerical Example II-2 corresponds to Embodiment II-2 shown in FIG. 28. Table II-4 shows the surface data of the zoom lens system of Numerical Example II-2. Table II-5 shows the aspherical data. Table II-6 shows various data.







TABLE II-4







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
30.54400
0.75000
1.84666
23.8


 2
19.97400
0.01000
1.56732
42.8


 3
19.97400
2.87000
1.49700
81.6


 4
119.41300
0.15000


 5
20.78100
2.17200
1.72916
54.7


 6
68.25600
Variable


 7
41.23000
0.40000
1.88300
40.8


 8
5.16000
2.91700


 9
−28.35400
0.40000
1.77250
49.6


10
11.39200
0.28600


11
9.45200
1.61100
1.92286
20.9


12
65.98200
Variable


13 (Diaphragm)
∞
0.30000


14
4.35700
1.71500
1.49700
81.6


15
8241.75900
1.15600


16*
7.96500
1.39900
1.80359
40.8


17
29.72600
0.01000
1.56732
42.8


18
29.72600
0.40000
1.84666
23.8


19
5.06400
Variable


20*
11.62400
1.57800
1.51835
70.3


21*
−1903.05100
Variable


22
∞
0.78000
1.51680
64.2


23
∞
(BF)


Image surface
∞
















TABLE II-5





(Aspherical data)

















Surface No. 16



K = 1.39341E−02, A4 = −1.64227E−03, A6 = −2.91556E−04,



A8 = 1.15858E−04 A10 = −3.67861E−05, A12 = 5.42493E−06,



A14 = −3.77635E−07, A16 = 9.18775E−09



Surface No. 20



K = 0.00000E+00, A4 = −8.69167E−04, A6 = 8.47786E−05,



A8 = −9.59803E−06 A10 = 1.40175E−07, A12 = 1.12463E−08,



A14 = −2.70390E−10, A16 = 0.00000E+00



Surface No. 21



K = 0.00000E+00, A4 = −9.30204E−04, A6 = 9.56087E−05,



A8 = −1.40798E−05 A10 = 6.99942E−07, A12 = −2.23827E−08,



A14 = 5.20712E−10, A16 = 0.00000E+00

















TABLE II-6





(Various data)







Zooming ratio 11.22248













Wide-angle
Middle
Telephoto




limit
position
limit







Focal length
4.3010
13.8474
48.2674



F-number
3.29469
4.30198
5.08146



View angle
42.3477
14.5267
4.1832



Image height
3.5000
3.6000
3.6000



Overall length
43.5388
46.0391
55.0983



of lens system



BF
0.88401
0.87645
0.87539



d6
0.3248
9.1089
19.1293



d12
15.8067
4.9971
1.0000



d19
3.7184
3.6596
12.5064



d21
3.9009
8.4930
2.6832



Entrance pupil
11.8334
31.7811
106.5538



position



Exit pupil
−14.2616
−18.7397
−51.0622



position



Front principal
14.9130
35.8533
109.9646



points position



Back principal
39.2379
32.1916
6.8309



points position











Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−70.4642


2
3
47.8040


3
5
40.1995


4
7
−6.7146


5
9
−10.4742


6
11
11.7933


7
14
8.7707


8
16
13.1627


9
18
−7.2633


10 
20
22.2951










Zoom lens unit data
















Front




Initial

Overall
principal


Lens
surface
Focal
length of
points
Back principal


unit
No.
length
lens unit
position
points position





1
1
32.74603
5.95200
1.03339
3.23646


2
7
−6.27842
5.61400
0.30252
1.41714


3
13
10.26172
4.98000
−2.53747
0.35393


4
20
22.29513
1.57800
0.00631
0.54473










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.27150
−0.43781
−1.45325


3
13
−0.67567
−1.89263
−1.31556


4
20
0.71597
0.51034
0.77098









Numerical Example II-3
The zoom lens system of Numerical Example II-3 corresponds to Embodiment II-3 shown in FIG. 31 . Table II-7 shows the surface data of the zoom lens system of Numerical Example II-3. Table II-8 shows the aspherical data. Table II-9 shows various data.







TABLE II-7







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
28.83400
0.75000
1.84666
23.8


 2
19.10600
0.01000
1.56732
42.8


 3
19.10600
2.85000
1.49700
81.6


 4
101.86400
0.15000


 5
20.12000
2.17900
1.72916
54.7


 6
67.88000
Variable


 7
48.57300
0.40000
1.88300
40.8


 8
5.25800
2.88300


 9
−30.09700
0.40000
1.78590
43.9


10
11.97200
0.46400


11
10.02000
1.38900
1.94595
18.0


12
45.19300
Variable


13 (Diaphragm)
∞
0.30000


14*
4.07200
1.85400
1.51835
70.3


15*
−14.78000
1.10600


16
10.46100
0.40000
1.80518
25.5


17
3.45300
0.45000


18
4.62900
1.00100
1.60342
38.0


19
7.26800
Variable


20*
12.44300
1.57700
1.51835
70.3


21*
−178.17400
Variable


22
∞
0.78000
1.51680
64.2


23
∞
(BF)


Image surface
∞
















TABLE II-8





(Aspherical data)

















Surface No. 14



K = 0.00000E+00, A4 = −8.24968E−04, A6 = −1.09073E−06,



A8 = 2.17711E−05 A10 = −5.02279E−06, A12 = 2.35314E−07,



A14 = 1.63202E−07, A16 = −1.54658E−08



Surface No. 15



K = 0.00000E+00, A4 = 1.49679E−03, A6 = 1.31240E−04,



A8 = 1.46070E−06 A10 = −1.18079E−06, A12 = −9.13721E−08,



A14 = 2.62896E−07, A16 = −2.45633E−08



Surface No. 20



K = 0.00000E+00, A4 = −7.69541E−04, A6 = 7.69065E−05,



A8 = −1.40933E−05 A10 = 9.19495E−07, A12 = −1.81967E−08,



A14 = −1.78801E−09, A16 = 7.53515E−11



Surface No. 21



K = 0.00000E+00, A4 = −7.47072E−04, A6 = 4.18687E−05,



A8 = −9.53545E−06 A10 = 6.77844E−07, A12 = −2.96255E−08,



A14 = 8.03400E−11, A16 = 2.04568E−11

















TABLE II-9





(Various data)







Zooming ratio 11.02588













Wide-angle
Middle
Telephoto




limit
position
limit







Focal length
4.2986
13.8551
47.3961



F-number
3.28208
4.24530
5.13352



View angle
42.0251
14.6001
4.2709



Image height
3.4000
3.6000
3.6000



Overall length
43.1677
45.8742
54.8407



of lens system



BF
0.87410
0.86181
0.87475



d6
0.3050
8.8771
18.0441



d12
15.5017
5.0021
1.2400



d19
3.8901
3.6860
12.7948



d21
3.6538
8.5042
2.9441



Entrance pupil
11.7092
31.8814
101.3999



position



Exit pupil
−15.4282
−19.8509
−59.3792



position



Front principal
14.8744
36.4685
111.5140



points position



Back principal
38.8691
32.0191
7.4446



points position











Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−69.3377


2
3
46.7831


3
5
38.4775


4
7
−6.7066


5
9
−10.8530


6
11
13.3538


7
14
6.3728


8
16
−6.5687


9
18
18.4881


10 
20
22.5016










Zoom lens unit data
















Front




Initial

Overall
principal


Lens
surface
Focal
length of
points
Back principal


unit
No.
length
lens unit
position
points position





1
1
31.49909
5.93900
1.00554
3.20336


2
7
−5.98151
5.53600
0.36288
1.39105


3
13
10.16322
5.11100
−2.32440
0.11796


4
20
22.50158
1.57700
0.06799
0.60342










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.27048
−0.44170
−1.36721


3
13
−0.68864
−1.92377
−1.44020


4
20
0.73265
0.51764
0.76416









Numerical Example II-4
The zoom lens system of Numerical Example II-4 corresponds to Embodiment II-4 shown in FIG. 33. Table II-10 shows the surface data of the zoom lens system of Numerical Example II-4. Table II-11 shows the aspherical data. Table II-12 shows various data.







TABLE II-10







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
30.82100
0.75000
1.84666
23.8


 2
19.80200
0.01000
1.56732
42.8


 3
19.80200
2.84100
1.49700
81.6


 4
132.37900
0.15000


 5
19.70800
2.19000
1.72916
54.7


 6
63.77100
Variable


 7
46.49600
0.40000
1.88300
40.8


 8
5.15900
2.99000


 9
−26.75700
0.40000
1.78590
43.9


10
13.20600
0.40800


11
10.12700
1.34000
1.94595
18.0


12
46.54600
Variable


13 (Diaphragm)
∞
0.30000


14*
4.69000
2.11400
1.51835
70.3


15*
−14.23800
1.13000


16
6.94600
0.91900
1.94595
18.0


17
3.99000
Variable


18*
11.88000
1.57700
1.51835
70.3


19*
−613.12200
Variable


20
∞
0.78000
1.51680
64.2


21
∞
(BF)


Image surface
∞
















TABLE II-11





(Aspherical data)

















Surface No. 14



K = 0.00000E+00, A4 = −6.98798E−04, A6 = −3.07231E−05,



A8 = 4.14892E−05 A10 = −7.19360E−06, A12 = 8.33698E−08,



A14 = 1.67474E−07, A16 = −1.49651E−08



Surface No. 15



K = 0.00000E+00, A4 = 1.02954E−03, A6 = 2.16803E−04,



A8 = −3.21361E−05 A10 = 3.94649E−06, A12 = 2.58926E−07,



A14 = −6.31197E−09, A16 = −3.45461E−09



Surface No. 18



K = 0.00000E+00, A4 = −2.31301E−04, A6 = −3.30169E−05,



A8 = −5.02139E−06 A10 = 7.52561E−07, A12 = −5.25403E−08,



A14 = 2.01872E−09, A16 = −4.40237E−11



Surface No. 19



K = 0.00000E+00, A4 = −5.07083E−04, A6 = 2.66686E−05,



A8 = −1.42819E−05 A10 = 1.13449E−06, A12 = −2.14192E−08,



A14 = −1.36032E−09, A16 = 4.60748E−11

















TABLE II-12





(Various data)







Zooming ratio 11.02420













Wide-angle
Middle
Telephoto




limit
position
limit







Focal length
4.2999
13.8718
47.4034



F-number
3.31040
4.20958
4.99163



View angle
41.5250
14.5528
4.2738



Image height
3.3500
3.6000
3.6000



Overall length
43.3831
45.7414
54.4466



of lens system



BF
0.87136
0.88634
0.87037



d6
0.3050
9.1454
18.3495



d12
15.6017
5.0041
1.2400



d17
4.8012
3.7877
12.7923



d19
3.5048
8.6189
2.8954



Entrance pupil
11.6412
32.7101
105.6893



position



Exit pupil
−15.5987
−18.6607
−51.0614



position



Front principal
14.8185
36.7376
109.8228



points position



Back principal
39.0831
31.8696
7.0432



points position











Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−67.5261


2
3
46.4623


3
5
38.3143


4
7
−6.6017


5
9
−11.2015


6
11
13.4422


7
14
7.0758


8
16
−11.6760


9
18
22.5026










Zoom lens unit data
















Front






Overall
principal


Lens
Initial
Focal
length of
points
Back principal


unit
surface No.
length
lens unit
position
points position





1
1
31.49935
5.94100
1.07105
3.27435


2
7
−5.98100
5.53800
0.35015
1.35673


3
13
10.16664
4.46300
−2.41163
0.14756


4
18
22.50262
1.57700
0.01976
0.55724










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.26946
−0.44781
−1.44049


3
13
−0.68706
−1.93046
−1.36656


4
18
0.73736
0.50942
0.76448









Numerical Example II-5
The zoom lens system of Numerical Example II-5 corresponds to Embodiment II-5 shown in FIG. 35. Table II-13 shows the surface data of the zoom lens system of Numerical Example II-5. Table II-14 shows the aspherical data. Table II-15 shows various data.







TABLE II-13







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
29.29600
0.75000
1.84666
23.8


 2
19.18900
0.01000
1.56732
42.8


 3
19.18900
2.85700
1.49700
81.6


 4
108.03300
0.15000


 5
20.45300
2.17600
1.72916
54.7


 6
72.91900
Variable


 7
51.45000
0.40000
1.88300
40.8


 8
5.22500
2.88000


 9
−33.13900
0.40000
1.78590
43.9


10
11.81100
0.46700


11
9.75900
1.38900
1.94595
18.0


12
40.80000
Variable


13 (Diaphragm)
∞
0.30000


14*
4.91700
1.83400
1.60602
57.4


15
−12.30000
0.01000
1.56732
42.8


16
−12.30000
0.74400
1.84666
23.8


17
−20.45800
1.34000


18*
10.29900
0.80300
1.99540
20.7


19
5.31600
Variable


20*
11.88800
1.57700
1.51835
70.3


21*
−586.41400
Variable


22
∞
0.78000
1.51680
64.2


23
∞
(BF)


Image surface
∞
















TABLE II-14





(Aspherical data)

















Surface No. 14



K = 0.00000E+00, A4 = −4.87214E−04, A6 = −3.67232E−05,



A8 = 1.22587E−05 A10 = −2.94245E−06, A12 = 3.29255E−07,



A14 = −9.71641E−09, A16 = −7.68082E−10



Surface No. 18



K = 0.00000E+00, A4 = −1.16235E−03, A6 = −7.02341E−05,



A8 = 8.26548E−07 A10 = −1.03094E−06, A12 = 2.73287E−07,



A14 = −5.65024E−08, A16 = 5.26646E−09



Surface No. 20



K = 0.00000E+00, A4 = −5.35774E−04, A6 = 3.02823E−05,



A8 = −9.38385E−06 A10 = 5.44017E−07, A12 = 4.39358E−09,



A14 = −1.41360E−09, A16 = 2.98041E−11



Surface No. 21



K = 0.00000E+00, A4 = −6.64748E−04, A6 = 3.66417E−05,



A8 = −1.31889E−05 A10 = 1.02733E−06, A12 = −2.21503E−08,



A14 = −8.57851E−10, A16 = 3.13948E−11

















TABLE II-15





(Various data)







Zooming ratio 11.03744













Wide-angle
Middle
Telephoto




limit
position
limit







Focal length
4.2998
13.8577
47.4583



F-number
3.26307
4.22605
5.06442



View angle
42.8635
14.5180
4.2583



Image height
3.5000
3.6000
3.6000



Overall length
43.1100
46.0464
54.9041



of lens system



BF
0.87367
0.86814
0.86731



d6
0.3050
9.0407
18.2431



d12
15.2547
5.0015
1.2400



d19
3.9267
3.7030
12.8393



d21
3.8829
8.5661
2.8474



Entrance pupil
11.6152
32.2976
103.7219



position



Exit pupil
−14.7562
−18.9976
−54.3396



position



Front principal
14.7321
36.4886
110.3829



points position



Back principal
38.8102
32.1888
7.4458



points position











Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−68.0081


2
3
46.4531


3
5
38.3148


4
7
−6.6130


5
9
−11.0366


6
11
13.2714


7
14
6.0392


8
16
−38.0210


9
18
−12.0029


10 
20
22.4989










Zoom lens unit data
















Front






Overall
principal


Lens
Initial
Focal
length of
points
Back principal


unit
surface No.
length
lens unit
position
points position





1
1
31.50001
5.94300
1.06957
3.26401


2
7
−5.99110
5.53600
0.33757
1.36227


3
13
10.15425
5.03100
−2.41145
0.42952


4
20
22.49886
1.57700
0.02066
0.55809










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.27002
−0.44538
−1.40992


3
13
−0.70167
−1.92719
−1.39365


4
20
0.72044
0.51254
0.76675









Numerical Example II-6
The zoom lens system of Numerical Example II-6 corresponds to Embodiment II-6 shown in FIG. 38. Table II-16 shows the surface data of the zoom lens system of Numerical Example II-6. Table II-17 shows the aspherical data. Table II-18 shows various data.







TABLE II-16







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
31.60900
0.75700
1.92286
20.9


 2
22.12900
0.01000
1.56732
42.8


 3
22.12900
2.85800
1.49700
81.6


 4
221.46700
0.14400


 5
19.82900
2.17900
1.72916
54.7


 6
56.23800
Variable


 7
44.93500
0.40100
1.88300
40.8


 8
5.19000
2.94100


 9
−28.98600
0.39900
1.78590
43.9


10
12.33500
0.47500


11
10.20700
1.34300
1.94595
18.0


12
47.99500
Variable


13 (Diaphragm)
∞
0.30000


14
4.30200
1.77300
1.49700
81.6


15
6803.89600
1.15900


16*
8.43500
1.39700
1.80359
40.8


17
49.88900
0.01000
1.56732
42.8


18
49.88900
0.39800
1.84666
23.8


19
5.29900
Variable


20*
11.72100
1.58000
1.51835
70.3


21*
−1629.06500
Variable


22
∞
0.78000
1.51680
64.2


23
∞
(BF)


Image surface
∞
















TABLE II-17





(Aspherical data)

















Surface No. 16



K = −1.26014E−01, A4 = −1.78233E−03, A6 = −2.10674E−04,



A8 = 6.69814E−05 A10 = −2.74048E−05, A12 = 5.39168E−06,



A14 = −5.55222E−07, A16 = 2.30211E−08



Surface No. 20



K = 0.00000E+00, A4 = −7.75064E−04, A6 = 6.14125E−05,



A8 = −8.73167E−06 A10 = 2.05005E−07, A12 = 1.29818E−08,



A14 = −4.93909E−10, A16 = 6.87949E−13



Surface No. 21



K = 0.00000E+00, A4 = −9.03803E−04, A6 = 7.96172E−05,



A8 = −1.34273E−05 A10 = 7.25544E−07, A12 = −1.80856E−08,



A14 = 3.95732E−10, A16 = −6.69981E−12

















TABLE II-18





(Various data)







Zooming ratio 11.02287













Wide-angle
Middle
Telephoto




limit
position
limit







Focal length
4.3008
13.8156
47.4068



F-number
3.26165
4.24209
5.08129



View angle
42.5203
14.6148
4.2714



Image height
3.5000
3.6000
3.6000



Overall length
43.1633
45.9912
54.9059



of lens system



BF
0.88315
0.88011
0.86611



d6
0.3402
8.9311
18.1547



d12
15.2947
5.0260
1.2415



d19
3.8356
3.6957
12.7992



d21
3.9057
8.5543
2.9404



Entrance pupil
11.7233
32.1123
103.6880



position



Exit pupil
−14.5669
−18.9414
−53.9620



position



Front principal
14.8268
36.2985
110.1048



points position



Back principal
38.8626
32.1757
7.4991



points position











Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−83.1380


2
3
49.2339


3
5
40.9708


4
7
−6.6768


5
9
−10.9635


6
11
13.4721


7
14
8.6607


8
16
12.4456


9
18
−7.0312


10 
20
22.4580










Zoom lens unit data
















Front






Overall
principal


Lens
Initial
Focal
length of
points
Back principal


unit
surface No.
length
lens unit
position
points position





1
1
31.49407
5.94800
0.97373
3.20547


2
7
−5.98650
5.55900
0.35026
1.33891


3
13
10.16527
5.03700
−2.46799
0.41145


4
20
22.45799
1.58000
0.00744
0.54649










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.27119
−0.44398
−1.40526


3
13
−0.70146
−1.93358
−1.40649


4
20
0.71785
0.51099
0.76159









Numerical Example II-7
The zoom lens system of Numerical Example II-7 corresponds to Embodiment II-7 shown in FIG. 41. Table II-19 shows the surface data of the zoom lens system of Numerical Example II-7. Table II-20 shows the aspherical data. Table II-21 shows various data.







TABLE II-19







(Surface data)

















Effective


Surface number
r
d
nd
vd
diameter





Object surface
∞






 1
20.98290
0.75000
1.80518
25.5
9.839


 2
13.88780
0.01000
1.56732
42.8
8.842


 3
13.88780
4.37500
1.66550
55.3
8.838


 4*
∞
Variable


8.324


 5
84.91200
0.40000
1.90366
31.3
6.341


 6
5.39320
3.24050


4.587


 7
−28.22190
0.40000
1.62299
58.1
4.575


 8
9.79740
0.01000
1.56732
42.8
4.652


 9
9.79740
2.15110
2.00170
20.6
4.653


 10*
98.54000
Variable


4.584


11
∞
0.30000


2.295


(Diaphragm)


12
4.60320
2.50820
1.48749
70.4


13
−27.47690
0.20000


 14*
6.60560
1.74010
1.68398
31.2
3.144


15
−15.56150
0.01000
1.56732
42.8


16
−15.56150
0.40000
2.00069
25.5


17
4.84080
0.40000


1.850


18
33.57380
0.80000
1.62004
36.3


19
−45.87960
Variable


1.850


 20*
10.44000
1.30510
1.51443
63.6
3.708


21
19.71820
Variable


3.675


22
∞
0.78000
1.51680
64.2


23
∞
(BF)


Image surface
∞
















TABLE II-20





(Aspherical data)

















Surface No. 4



K = 0.00000E+00, A4 = 5.44859E−06, A6 = −3.16138E−09,



A8 = −4.46348E−11 A10 = 1.30269E−13



Surface No. 10



K = 0.00000E+00, A4 = −1.36503E−04, A6 = −7.12314E−07,



A8 = −3.65563E−08 A10 = −2.35003E−09



Surface No. 14



K = −1.18891E+00, A4 = −7.28073E−04, A6 = −9.31333E−05,



A8 = 7.94547E−07 A10 = −7.01384E−07



Surface No. 20



K = 0.00000E+00, A4 = −1.01241E−04, A6 = 7.25117E−06,



A8 = −1.67079E−07 A10 = 0.00000E+00

















TABLE II-21





(Various data)







Zooming ratio 11.20139













Wide-angle
Middle
Telephoto




limit
position
limit







Focal length
4.6499
14.9976
52.0854



F-number
3.40109
4.57355
5.84643



View angle
40.6107
14.4180
4.2309



Image height
3.5100
3.9300
3.9300



Overall length
47.6917
49.7109
59.0505



of lens system



BF
0.96082
0.94475
0.87062



d4
0.3000
9.4768
18.9347



d10
18.9756
6.8855
1.0000



d19
4.6225
4.0673
13.9922



d21
3.0528
8.5565
4.4730



Entrance pupil
11.7392
33.0254
90.7706



position



Exit pupil
−13.7800
−18.4896
−33.9713



position



Front principal
14.9223
36.4493
64.9930



points position



Back principal
43.0418
34.7132
6.9651



points position











Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−53.5331


2
3
20.8681


3
5
−6.3882


4
7
−11.6268


5
9
10.7304


6
12
8.3004


7
14
7.0030


8
16
−3.6538


9
18
31.3881


10 
20
41.1632










Zoom lens unit data
















Front






Overall
principal


Lens
Initial
Focal
length of
points
Back principal


unit
surface No.
length
lens unit
position
points position





1
1
35.11856
5.13500
−0.14515
1.94345


2
5
−6.80610
6.20160
0.10086
1.48861


3
11
10.66323
6.35830
−2.91266
0.74640


4
20
41.16318
1.30510
−0.92547
−0.44285










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
5
−0.27533
−0.43788
−1.11844


3
11
−0.56741
−1.36551
−1.62662


4
20
0.84754
0.71422
0.81523









Numerical Example II-8
The zoom lens system of Numerical Example II-8 corresponds to Embodiment II-8 shown in FIG. 44. Table II-22 shows the surface data of the zoom lens system of Numerical Example II-8. Table II-23 shows the aspherical data. Table II-24 shows various data.







TABLE II-22







(Surface data)

















Effective


Surface number
r
d
nd
vd
diameter





Object surface
∞






 1
19.74460
0.75000
1.80518
25.5
9.867


 2
14.42530
0.01000
1.56732
42.8
9.046


 3
14.42530
4.58060
1.58842
61.4
9.044


 4*
∞
Variable


8.687


 5
51.45680
0.40000
1.90366
31.3
6.224


 6
5.56270
3.12720


4.550


 7
−25.07760
0.40000
1.72916
54.7
4.494


 8
14.27150
0.16660


4.447


 9
10.68100
1.55340
1.94595
18.0
4.541


10
75.93340
Variable


4.456


11
∞
0.30000


2.205


(Diaphragm)


12
4.01800
2.44330
1.48749
70.4


13
−21.09430
0.20000


 14*
6.14200
1.23530
1.68398
31.2
2.594


15
−42.70560
0.01000
1.56732
42.8


16
−42.70560
0.40000
2.00069
25.5


17
4.55800
Variable


1.753


 18*
10.12120
1.31660
1.52500
70.3
3.622


19
21.51830
Variable


3.603


20
∞
0.78000
1.51680
64.2


21
∞
(BF)


Image surface
∞
















TABLE II-23





(Aspherical data)

















Surface No. 4



K = 0.00000E+00, A4 = 6.17753E−06, A6 = −1.49369E−09,



A8 = −8.29862E−11 A10 = 4.82705E−13, A12 = 0.00000E+00



Surface No. 14



K = −2.06747E+00, A4 = −1.16941E−03, A6 = −2.34186E−04,



A8 = −6.87246E−08 A10 = −2.18647E−06, A12 = 0.00000E+00



Surface No. 18



K = 0.00000E+00, A4 = −3.08123E−04, A6 = 6.64049E−05,



A8 = −9.04968E−06 A10 = 6.32666E−07, A12 = −1.69826E−08

















TABLE II-24





(Various data)







Zooming ratio 11.40034













Wide-angle
Middle
Telephoto




limit
position
limit







Focal length
4.6049
14.9993
52.4971



F-number
3.42225
4.69287
5.64395



View angle
40.9010
14.5275
4.2181



Image height
3.5100
3.9300
3.9300



Overall length
45.3684
47.6360
59.0317



of lens system



BF
0.93231
0.89902
0.90205



d4
0.3000
9.7009
21.5121



d10
18.1817
6.0382
1.0000



d17
5.7814
4.2306
12.6513



d19
2.5000
9.0943
5.2933



Entrance pupil
12.0254
32.1580
106.5866



position



Exit pupil
−13.5292
−17.8075
−30.6943



position



Front principal
15.1639
35.1306
71.8603



points position



Back principal
40.7635
32.6367
6.5347



points position











Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−70.9634


2
3
24.5155


3
5
−6.9306


4
7
−12.4205


5
9
12.9893


6
12
7.1515


7
14
7.9322


8
16
−4.0982


9
18
35.0062










Zoom lens unit data
















Front






Overall
principal


Lens
Initial
Focal
length of
points
Back principal


unit
surface No.
length
lens unit
position
points position





1
1
38.45052
5.34060
−0.23969
1.79936


2
5
−6.80173
5.64720
0.23455
1.32483


3
11
10.18755
4.58860
−3.11748
0.11964


4
18
35.00621
1.31660
−0.73737
−0.25109










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
5
−0.24668
−0.37430
−1.06930


3
11
−0.57626
−1.59102
−1.67223


4
18
0.84248
0.65505
0.76355









Numerical Example II-9
The zoom lens system of Numerical Example II-9 corresponds to Embodiment II-9 shown in FIG. 47. Table II-25 shows the surface data of the zoom lens system of Numerical Example II-9. Table II-26 shows the aspherical data. Table II-27 shows various data.







TABLE II-25







(Surface data)

















Effective


Surface number
r
d
nd
vd
diameter





Object surface
∞






 1
19.77840
0.75000
1.85139
23.6
9.867


 2
15.05080
0.01000
1.56732
42.8
9.046


 3
15.05080
4.55170
1.58913
61.2
9.044


 4*
−2009.86870
Variable


8.687


 5
52.22170
0.40000
1.95534
29.4
6.224


 6
5.68140
3.07420


4.550


 7
−23.91140
0.40000
1.72668
53.6
4.494


 8
14.22890
0.15000


4.447


 9
10.89020
1.62340
1.94595
18.0
4.541


10
165.48490
Variable


4.456


11
∞
0.30000


2.205


(Diaphragm)


12
4.18710
2.65790
1.49171
69.9


13
−22.46530
0.20000


 14*
6.60790
1.54420
1.71418
29.7
2.712


15
−18.34560
0.01000
1.56732
42.8


16
−18.34560
0.40000
2.00080
24.4


17
4.72980
Variable


1.753


 18*
9.76620
1.36180
1.51760
63.5
3.622


19
23.45330
Variable


3.603


20
∞
0.78000
1.51680
64.2


21
∞
(BF)


Image surface
∞
















TABLE II-26





(Aspherical data)

















Surface No. 4



K = 0.00000E+00, A4 = 6.68914E−06, A6 = −9.93410E−10,



A8 = −8.29880E−11 A10 = 4.79336E−13, A12 = 0.00000E+00



Surface No. 14



K = −1.97925E+00, A4 = −1.09715E−03, A6 = −1.81257E−04,



A8 = 5.09203E−07 A10 = −1.71341E−06, A12 = 0.00000E+00



Surface No. 18



K = 0.00000E+00, A4 = −3.54076E−04, A6 = 7.33046E−05,



A8 = −1.00180E−05 A10 = 6.97991E−07, A12 = −1.86608E−08

















TABLE II-27





(Various data)







Zooming ratio 11.44412













Wide-angle
Middle
Telephoto




limit
position
limit







Focal length
4.5865
14.9965
52.4889



F-number
3.44725
4.69828
5.62110



View angle
41.0129
14.5052
4.2129



Image height
3.5100
3.9300
3.9300



Overall length
45.8634
47.8820
59.0016



of lens system



BF
0.91651
0.88175
0.87169



d4
0.3000
9.8706
21.5407



d10
18.5253
6.1613
1.0000



d17
5.3803
3.7677
11.8523



d19
2.5281
8.9874
5.5237



Entrance pupil
11.8960
32.6328
107.7666



position



Exit pupil
−13.4686
−17.4274
−31.0462



position



Front principal
15.0202
35.3461
73.9375



points position



Back principal
41.2769
32.8854
6.5127



points position











Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−79.7777


2
3
25.3788


3
5
−6.7011


4
7
−12.2219


5
9
12.2609


6
12
7.4217


7
14
6.9824


8
16
−3.7250


9
18
31.2703










Zoom lens unit data
















Front






Overall
principal


Lens
Initial
Focal
length of
points
Back principal


unit
surface No.
length
lens unit
position
points position





1
1
38.18058
5.31170
−0.23227
1.80477


2
5
−6.86331
5.64760
0.11084
1.15898


3
11
10.27017
5.11210
−3.64054
0.23351


4
18
31.27028
1.36180
−0.61927
−0.12535










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
5
−0.25049
−0.38495
−1.11439


3
11
−0.58070
−1.64465
−1.68650


4
18
0.82584
0.62039
0.73148









The following Table II-28 shows the corresponding values to the individual conditions in the zoom lens systems of the numerical examples.







TABLE II-28







(Corresponding values to conditions)









Example
















Condition
II-1
II-2
II-3
II-4
II-5
II-6
II-7
II-8
II-9




















 (7)
TG1/fW
−2.754
−2.690
−2.715
−2.573
−2.744
−2.734
−2.442
−2.974
−2.874


 (8)
TG2/fW
1.396
1.682
1.411
1.623
1.427
1.408
1.566
1.633
1.757


(a-2)
ωW
42.83
42.35
42.03
41.53
42.86
42.52
40.60
40.90
41.01


(b)
fT/fW
11.03
11.22
11.03
11.02
11.04
11.02
11.20
11.40
11.44


(10)
m2T/m2W
5.179
5.353
5.054
5.345
5.222
5.182
4.062
4.337
4.449


(11)
LT/fT
1.157
1.142
1.157
1.149
1.157
1.158
1.134
1.124
1.124


(12)
fT/fG1
1.505
1.474
1.505
1.505
1.507
1.505
1.483
1.365
1.375


(13)
LW/fG1
1.366
1.330
1.370
1.377
1.369
1.371
1.358
1.180
1.201


(14)
LT/fG1
1.742
1.683
1.741
1.729
1.743
1.743
1.681
1.535
1.545


(15)
fG1/|fG2|
5.263
5.216
5.266
5.267
5.258
5.261
5.160
5.653
5.563









Numerical Example III-1
The zoom lens system of Numerical Example III-1 corresponds to Embodiment III-1 shown in FIG. 51. Table III-1 shows the surface data of the zoom lens system of Numerical Example III-1. Table III-2 shows the aspherical data. Table III-3 shows various data.







TABLE III-1







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
28.99500
0.75000
1.84666
23.8


 2
19.06100
0.01000
1.56732
42.8


 3
19.06100
2.84700
1.49700
81.6


 4
106.49800
0.15000


 5
19.93700
2.17900
1.72916
54.7


 6
66.38300
Variable


 7
46.75800
0.40000
1.88300
40.8


 8
5.20400
2.92000


 9
−27.85600
0.40000
1.78590
43.9


10
12.36700
0.47500


11
10.23200
1.34100
1.94595
18.0


12
48.88200
Variable


13 (Diaphragm)
∞
0.30000


14
4.29700
1.76700
1.49700
81.6


15
8241.75900
1.15600


16*
8.40200
1.39900
1.80359
40.8


17
50.50600
0.01000
1.56732
42.8


18
50.50600
0.40000
1.84666
23.8


19
5.31000
Variable


20*
11.71400
1.57800
1.51788
70.1


21*
−1903.05100
variable


22
∞
0.78000
1.51680
64.2


23
∞
(BF)


Image surface
∞
















TABLE III-2





(Aspherical data)

















Surface No. 16



K = −2.28822E−01, A4 = −1.79052E−03, A6 = −2.03953E−04,



A8 = 6.65739E−05 A10 = −2.75026E−05, A12 = 5.38981E−06,



A14 = −5.53822E−07, A16 = 2.31265E−08



Surface No. 20



K = 0.00000E+00, A4 = −7.84816E−04, A6 = 6.11566E−05,



A8 = −8.70671E−06 A10 = 2.07853E−07, A12 = 1.30642E−08,



A14 = −4.95350E−10, A16 = 9.73908E−14



Surface No. 21



K = 0.00000E+00, A4 = −9.08686E−04, A6 = 7.99050E−05,



A8 = −1.33973E−05 A10 = 7.26054E−07, A12 = −1.80771E−08,



A14 = 3.95939E−10, A16 = −6.83275E−12

















TABLE III-3





(Various data)







Zooming ratio 11.03046











Wide-angle
Middle
Telephoto



limit
position
limit





Focal length
4.3007
13.8388
47.4383


F-number
3.27846
4.28177
5.08881


View angle
42.8104
14.6240
4.2606


Image height
3.5000
3.6000
3.6000


Overall length
43.0950
45.9352
54.8315


of lens system


BF
0.87558
0.86948
0.86672


d6
0.3050
8.7502
18.1095


d12
15.2180
4.9127
1.2400


d19
4.1289
3.9787
12.8898


d21
3.7055
8.5621
2.8635


Entrance pupil
11.6301
31.3439
103.4648


position


Exit pupil
−14.9503
−19.5021
−54.6732


position


Front principal
14.7621
35.7817
110.3846


points position


Back principal
38.7943
32.0963
7.3932


points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−68.0664


2
3
46.2134


3
5
38.3211


4
7
−6.6617


5
9
−10.8504


6
11
13.4533


7
14
8.6498


8
16
12.3591


9
18
−7.0371


10 
20
22.4871










Zoom lens unit data















Overall





Initial

length


Lens
surface
Focal
of lens
Front principal
Back principal


unit
No.
length
unit
points position
points position





1
1
31.38739
5.93600
1.01427
3.21201


2
7
−5.93817
5.53600
0.35694
1.34712


3
13
10.09342
5.03200
−2.42725
0.43524


4
20
22.48708
1.57800
0.00636
0.54446










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.26914
−0.43605
−1.39433


3
13
−0.69983
−1.97584
−1.41639


4
20
0.72745
0.51175
0.76529









Numerical Example III-2
The zoom lens system of Numerical Example III-2 corresponds to Embodiment III-2 shown in FIG. 54. Table III-4 shows the surface data of the zoom lens system of Numerical Example III-2. Table III-5 shows the aspherical data. Table III-6 shows various data.







TABLE III-4







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
30.04800
0.75000
1.84666
23.8


 2
19.79100
0.01000
1.56732
42.8


 3
19.79100
2.87000
1.49700
81.6


 4
110.53100
0.15000


 5
20.53300
2.17200
1.72916
54.7


 6
66.95400
Variable


 7
42.41000
0.40000
1.88300
40.8


 8
5.23200
2.92000


 9
−26.60600
0.40000
1.72916
54.7


10
11.77400
0.41400


11
9.85000
1.52500
1.92286
20.9


12
49.89900
Variable


13 (Diaphragm)
∞
0.30000


14
4.34100
1.71500
1.49700
81.6


15
8241.75900
1.15600


16*
8.13300
1.39900
1.80359
40.8


17
29.64300
0.01000
1.56732
42.8


18
29.64300
0.40000
1.84666
23.8


19
5.13200
Variable


20*
11.58600
1.57800
1.51835
70.3


21*
−1903.05100
Variable


22
∞
0.78000
1.51680
64.2


23
∞
(BF)


Image surface
∞
















TABLE III-5





(Aspherical data)

















Surface No. 16



K = 1.78419E−01, A4 = −1.74423E−03, A6 = −2.43524E−04,



A8 = 8.84289E−05 A10 = −3.13851E−05, A12 = 5.33759E−06,



A14 = −4.60617E−07, A16 = 1.56777E−08



Surface No. 20



K = 0.00000E+00, A4 = −7.66562E−04, A6 = 7.82061E−05,



A8 = −9.47410E−06 A10 = 1.69202E−07, A12 = 1.30492E−08,



A14 = −4.30772E−10, A16 = 0.00000E+00



Surface No. 21



K = 0.00000E+00, A4 = −8.32096E−04, A6 = 9.10521E−05,



A8 = −1.41343E−05 A10 = 7.49749E−07, A12 = −2.21508E−08,



A14 = 4.12406E−10, A16 = 0.00000E+00

















TABLE III-6





(Various data)







Zooming ratio 11.01481











Wide-angle
Middle
Telephoto



limit
position
limit





Focal length
4.3066
13.8459
47.4361


F-number
3.30024
4.29885
5.09193


View angle
42.3363
14.5427
4.2584


Image height
3.4800
3.6000
3.6000


Overall length
43.5229
45.7546
55.0476


of lens system


BF
0.87881
0.87324
0.87433


d6
0.3224
8.9809
18.8488


d12
15.7053
4.8375
1.0000


d19
3.7902
3.4857
12.4922


d21
3.8772
8.6283
2.8833


Entrance pupil
11.8589
31.5019
104.5924


position


Exit pupil
−14.4027
−18.5649
−51.5094


position


Front principal
14.9518
35.4853
109.0727


points position


Back principal
39.2163
31.9088
7.6115


points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−70.8535


2
3
48.0023


3
5
39.8296


4
7
−6.7934


5
9
−11.1448


6
11
13.0598


7
14
8.7385


8
16
13.5548


9
18
−7.3858


10 
20
22.2227










Zoom lens unit data















Overall





Initial

length


Lens
surface
Focal
of lens
Front principal
Back principal


unit
No.
length
unit
points position
points position





1
1
32.54769
5.95200
1.00942
3.21326


2
7
−6.24827
5.65900
0.31566
1.37601


3
13
10.26521
4.98000
−2.52584
0.35485


4
20
22.22269
1.57800
0.00629
0.54471










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.27258
−0.43804
−1.42128


3
13
−0.67763
−1.93147
−1.34700


4
20
0.71635
0.50280
0.76127









Numerical Example III-3
The zoom lens system of Numerical Example III-3 corresponds to Embodiment III-3 shown in FIG. 57. Table III-7 shows the surface data of the zoom lens system of Numerical Example III-3. Table III-8 shows the aspherical data. Table III-9 shows various data.







TABLE III-7







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
28.83400
0.75000
1.84666
23.8


 2
19.10600
0.01000
1.56732
42.8


 3
19.10600
2.85000
1.49700
81.6


 4
101.86400
0.15000


 5
20.12000
2.17900
1.72916
54.7


 6
67.88000
Variable


 7
48.57300
0.40000
1.88300
40.8


 8
5.25800
2.88300


 9
−30.09700
0.40000
1.78590
43.9


10
11.97200
0.46400


11
10.02000
1.38900
1.94595
18.0


12
45.19300
Variable


13 (Diaphragm)
∞
0.30000


14*
4.07200
1.85400
1.51835
70.3


15*
−14.78000
1.10600


16
10.46100
0.40000
1.80518
25.5


17
3.45300
0.45000


18
4.62900
1.00100
1.60342
38.0


19
7.26800
Variable


20*
12.44300
1.57700
1.51835
70.3


21*
−178.17400
Variable


22
∞
0.78000
1.51680
64.2


23
∞
(BF)


Image surface
∞
















TABLE III-8





(Aspherical data)

















Surface No. 14



K = 0.00000E+00, A4 = −8.24968E−04, A6 = −1.09073E−06,



A8 = 2.17711E−05 A10 = −5.02279E−06, A12 = 2.35314E−07,



A14 = 1.63202E−07, A16 = −1.54658E−08



Surface No. 15



K = 0.00000E+00, A4 = 1.49679E−03, A6 = 1.31240E−04,



A8 = 1.46070E−06 A10 = −1.18079E−06, A12 = −9.13721E−08,



A14 = 2.62896E−07, A16 = −2.45633E−08



Surface No. 20



K = 0.00000E+00, A4 = −7.69541E−04, A6 = 7.69065E−05,



A8 = −1.40933E−05 A10 = 9.19495E−07, A12 = −1.81967E−08,



A14 = −1.78801E−09, A16 = 7.53515E−11



Surface No. 21



K = 0.00000E+00, A4 = −7.47072E−04, A6 = 4.18687E−05,



A8 = −9.53545E−06 A10 = 6.77844E−07, A12 = −2.96255E−08,



A14 = 8.03400E−11, A16 = 2.04568E−11

















TABLE III-9





(Various data)







Zooming ratio 11.02588











Wide-angle
Middle
Telephoto



limit
position
limit





Focal length
4.2986
13.8551
47.3961


F-number
3.28208
4.24530
5.13352


View angle
42.0251
14.6001
4.2709


Image height
3.4000
3.6000
3.6000


Overall length
43.1677
45.8742
54.8407


of lens system


BF
0.87410
0.86181
0.87475


d6
0.3050
8.8771
18.0441


d12
15.5017
5.0021
1.2400


d19
3.8901
3.6860
12.7948


d21
3.6538
8.5042
2.9441


Entrance pupil
11.7092
31.8814
101.3999


position


Exit pupil
−15.4282
−19.8509
−59.3792


position


Front principal
14.8744
36.4685
111.5140


points position


Back principal
38.8691
32.0191
7.4446


points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−69.3377


2
3
46.7831


3
5
38.4775


4
7
−6.7066


5
9
−10.8530


6
11
13.3538


7
14
6.3728


8
16
−6.5687


9
18
18.4881


10 
20
22.5016










Zoom lens unit data















Overall





Initial

length


Lens
surface
Focal
of lens
Front principal
Back principal


unit
No.
length
unit
points position
points position





1
1
31.49909
5.93900
1.00554
3.20336


2
7
−5.98151
5.53600
0.36288
1.39105


3
13
10.16322
5.11100
−2.32440
0.11796


4
20
22.50158
1.57700
0.06799
0.60342










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.27048
−0.44170
−1.36721


3
13
−0.68864
−1.92377
−1.44020


4
20
0.73265
0.51764
0.76416









Numerical Example III-4
The zoom lens system of Numerical Example III-4 corresponds to Embodiment III-4 shown in FIG. 59. Table III-10 shows the surface data of the zoom lens system of Numerical Example III-4. Table III-11 shows the aspherical data. Table III-12 shows various data.







TABLE III-10







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
30.82100
0.75000
1.84666
23.8


 2
19.80200
0.01000
1.56732
42.8


 3
19.80200
2.84100
1.49700
81.6


 4
132.37900
0.15000


 5
19.70800
2.19000
1.72916
54.7


 6
63.77100
Variable


 7
46.49600
0.40000
1.88300
40.8


 8
5.15900
2.99000


 9
−26.75700
0.40000
1.78590
43.9


10
13.20600
0.40800


11
10.12700
1.34000
1.94595
18.0


12
46.54600
Variable


13 (Diaphragm)
∞
0.30000


14*
4.69000
2.11400
1.51835
70.3


15*
−14.23800
1.13000


16
6.94600
0.91900
1.94595
18.0


17
3.99000
Variable


18*
11.88000
1.57700
1.51835
70.3


19*
−613.12200
Variable


20
∞
0.78000
1.51680
64.2


21
∞
(BF)


Image surface
∞
















TABLE III-11





(Aspherical data)

















Surface No. 14



K = 0.00000E+00, A4 = −6.98798E−04, A6 = −3.07231E−05,



A8 = 4.14892E−05 A10 = −7.19360E−06, A12 = 8.33698E−08,



A14 = 1.67474E−07, A16 = −1.49651E−08



Surface No. 15



K = 0.00000E+00, A4 = 1.02954E−03, A6 = 2.16803E−04,



A8 = −3.21361E−05 A10 = 3.94649E−06, A12 = 2.58926E−07,



A14 = −6.31197E−09, A16 = −3.45461E−09



Surface No. 18



K = 0.00000E+00, A4 = −2.31301E−04, A6 = −3.30169E−05,



A8 = −5.02139E−06 A10 = 7.52561E−07, A12 = −5.25403E−08,



A14 = 2.01872E−09, A16 = −4.40237E−11



Surface No. 19



K = 0.00000E+00, A4 = −5.07083E−04, A6 = 2.66686E−05,



A8 = −1.42819E−05 A10 = 1.13449E−06, A12 = −2.14192E−08,



A14 = −1.36032E−09, A16 = 4.60748E−11

















TABLE III-12





(Various data)







Zooming ratio 11.02420











Wide-angle
Middle
Telephoto



limit
position
limit





Focal length
4.2999
13.8718
47.4034


F-number
3.31040
4.20958
4.99163


View angle
41.5250
14.5528
4.2738


Image height
3.3500
3.6000
3.6000


Overall length
43.3831
45.7414
54.4466


of lens system


BF
0.87136
0.88634
0.87037


d6
0.3050
9.1454
18.3495


d12
15.6017
5.0041
1.2400


d17
4.8012
3.7877
12.7923


d19
3.5048
8.6189
2.8954


Entrance pupil
11.6412
32.7101
105.6893


position


Exit pupil
−15.5987
−18.6607
−51.0614


position


Front principal
14.8185
36.7376
109.8228


points position


Back principal
39.0831
31.8696
7.0432


points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−67.5261


2
3
46.4623


3
5
38.3143


4
7
−6.6017


5
9
−11.2015


6
11
13.4422


7
14
7.0758


8
16
−11.6760


9
18
22.5026










Zoom lens unit data















Overall





Initial

length


Lens
surface
Focal
of lens
Front principal
Back principal


unit
No.
length
unit
points position
points position





1
1
31.49935
5.94100
1.07105
3.27435


2
7
−5.98100
5.53800
0.35015
1.35673


3
13
10.16664
4.46300
−2.41163
0.14756


4
18
22.50262
1.57700
0.01976
0.55724










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.26946
−0.44781
−1.44049


3
13
−0.68706
−1.93046
−1.36656


4
18
0.73736
0.50942
0.76448









Numerical Example III-5
The zoom lens system of Numerical Example III-5 corresponds to Embodiment III-5 shown in FIG. 61. Table III-13 shows the surface data of the zoom lens system of Numerical Example III-5. Table III-14 shows the aspherical data. Table III-15 shows various data.







TABLE III-13







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
29.29600
0.75000
1.84666
23.8


 2
19.18900
0.01000
1.56732
42.8


 3
19.18900
2.85700
1.49700
81.6


 4
108.03300
0.15000


 5
20.45300
2.17600
1.72916
54.7


 6
72.91900
Variable


 7
51.45000
0.40000
1.88300
40.8


 8
5.22500
2.88000


 9
−33.13900
0.40000
1.78590
43.9


10
11.81100
0.46700


11
9.75900
1.38900
1.94595
18.0


12
40.80000
Variable


13 (Diaphragm)
∞
0.30000


14*
4.91700
1.83400
1.60602
57.4


15
−12.30000
0.01000
1.56732
42.8


16
−12.30000
0.74400
1.84666
23.8


17
−20.45800
1.34000


18*
10.29900
0.80300
1.99540
20.7


19
5.31600
Variable


20*
11.88800
1.57700
1.51835
70.3


21*
−586.41400
Variable


22
∞
0.78000
1.51680
64.2


23
∞
(BF)


Image surface
∞
















TABLE III-14





(Aspherical data)

















Surface No. 14



K = 0.00000E+00, A4 = −4.87214E−04, A6 = −3.67232E−05,



A8 = 1.22587E−05 A10 = −2.94245E−06, A12 = 3.29255E−07,



A14 = −9.71641E−09, A16 = −7.68082E−10



Surface No. 18



K = 0.00000E+00, A4 = −1.16235E−03, A6 = −7.02341E−05,



A8 = 8.26548E−07 A10 = −1.03094E−06, A12 = 2.73287E−07,



A14 = −5.65024E−08, A16 = 5.26646E−09



Surface No. 20



K = 0.00000E+00, A4 = −5.35774E−04, A6 = 3.02823E−05,



A8 = −9.38385E−06 A10 = 5.44017E−07, A12 = 4.39358E−09,



A14 = −1.41360E−09, A16 = 2.98041E−11



Surface No. 21



K = 0.00000E+00, A4 = −6.64748E−04, A6 = 3.66417E−05,



A8 = −1.31889E−05 A10 = 1.02733E−06, A12 = −2.21503E−08,



A14 = −8.57851E−10, A16 = 3.13948E−11

















TABLE III-15





(Various data)







Zooming ratio 11.03744











Wide-angle
Middle
Telephoto



limit
position
limit





Focal length
4.2998
13.8577
47.4583


F-number
3.26307
4.22605
5.06442


View angle
42.8635
14.5180
4.2583


Image height
3.5000
3.6000
3.6000


Overall length
43.1100
46.0464
54.9041


of lens system


BF
0.87367
0.86814
0.86731


d6
0.3050
9.0407
18.2431


d12
15.2547
5.0015
1.2400


d19
3.9267
3.7030
12.8393


d21
3.8829
8.5661
2.8474


Entrance pupil
11.6152
32.2976
103.7219


position


Exit pupil
−14.7562
−18.9976
−54.3396


position


Front principal
14.7321
36.4886
110.3829


points position


Back principal
38.8102
32.1888
7.4458


points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−68.0081


2
3
46.4531


3
5
38.3148


4
7
−6.6130


5
9
−11.0366


6
11
13.2714


7
14
6.0392


8
16
−38.0210


9
18
−12.0029


10 
20
22.4989










Zoom lens unit data















Overall





Initial

length


Lens
surface
Focal
of lens
Front principal
Back principal


unit
No.
length
unit
points position
points position





1
1
31.50001
5.94300
1.06957
3.26401


2
7
−5.99110
5.53600
0.33757
1.36227


3
13
10.15425
5.03100
−2.41145
0.42952


4
20
22.49886
1.57700
0.02066
0.55809










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.27002
−0.44538
−1.40992


3
13
−0.70167
−1.92719
−1.39365


4
20
0.72044
0.51254
0.76675









Numerical Example III-6
The zoom lens system of Numerical Example III-6 corresponds to Embodiment III-6 shown in FIG. 64. Table III-16 shows the surface data of the zoom lens system of Numerical Example III-6. Table III-17 shows the aspherical data. Table III-18 shows various data.







TABLE III-16







(Surface data)











Surface number
r
d
nd
vd





Object surface
∞





 1
31.60900
0.75700
1.92286
20.9


 2
22.12900
0.01000
1.56732
42.8


 3
22.12900
2.85800
1.49700
81.6


 4
221.46700
0.14400


 5
19.82900
2.17900
1.72916
54.7


 6
56.23800
Variable


 7
44.93500
0.40100
1.88300
40.8


 8
5.19000
2.94100


 9
−28.98600
0.39900
1.78590
43.9


10
12.33500
0.47500


11
10.20700
1.34300
1.94595
18.0


12
47.99500
Variable


13 (Diaphragm)
∞
0.30000


14
4.30200
1.77300
1.49700
81.6


15
6803.89600
1.15900


16*
8.43500
1.39700
1.80359
40.8


17
49.88900
0.01000
1.56732
42.8


18
49.88900
0.39800
1.84666
23.8


19
5.29900
Variable


20*
11.72100
1.58000
1.51835
70.3


21*
−1629.06500
Variable


22
∞
0.78000
1.51680
64.2


23
∞
(BF)


Image surface
∞
















TABLE III-17





(Aspherical data)

















Surface No. 16



K = −1.26014E−01, A4 = −1.78233E−03, A6 = −2.10674E−04,



A8 = 6.69814E−05 A10 = −2.74048E−05, A12 = 5.39168E−06,



A14 = −5.55222E−07, A16 = 2.30211E−08



Surface No. 20



K = 0.00000E+00, A4 = −7.75064E−04, A6 = 6.14125E−05,



A8 = −8.73167E−06 A10 = 2.05005E−07, A12 = 1.29818E−08,



A14 = −4.93909E−10, A16 = 6.87949E−13



Surface No. 21



K = 0.00000E+00, A4 = −9.03803E−04, A6 = 7.96172E−05,



A8 = −1.34273E−05 A10 = 7.25544E−07, A12 = −1.80856E−08,



A14 = 3.95732E−10, A16 = −6.69981E−12

















TABLE III-18





(Various data)







Zooming ratio 11.02287











Wide-angle
Middle
Telephoto



limit
position
limit





Focal length
4.3008
13.8156
47.4068


F-number
3.26165
4.24209
5.08129


View angle
42.5203
14.6148
4.2714


Image height
3.5000
3.6000
3.6000


Overall length
43.1633
45.9912
54.9059


of lens system


BF
0.88315
0.88011
0.86611


d6
0.3402
8.9311
18.1547


d12
15.2947
5.0260
1.2415


d19
3.8356
3.6957
12.7992


d21
3.9057
8.5543
2.9404


Entrance pupil
11.7233
32.1123
103.6880


position


Exit pupil
−14.5669
−18.9414
−53.9620


position


Front principal
14.8268
36.2985
110.1048


points position


Back principal
38.8626
32.1757
7.4991


points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−83.1380


2
3
49.2339


3
5
40.9708


4
7
−6.6768


5
9
−10.9635


6
11
13.4721


7
14
8.6607


8
16
12.4456


9
18
−7.0312


10 
20
22.4580










Zoom lens unit data















Overall





Initial

length


Lens
surface
Focal
of lens
Front principal
Back principal


unit
No.
length
unit
points position
points position





1
1
31.49407
5.94800
0.97373
3.20547


2
7
−5.98650
5.55900
0.35026
1.33891


3
13
10.16527
5.03700
−2.46799
0.41145


4
20
22.45799
1.58000
0.00744
0.54649










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
7
−0.27119
−0.44398
−1.40526


3
13
−0.70146
−1.93358
−1.40649


4
20
0.71785
0.51099
0.76159









Numerical Example III-7
The zoom lens system of Numerical Example III-7 corresponds to Embodiment III-7 shown in FIG. 67. Table III-19 shows the surface data of the zoom lens system of Numerical Example III-7. Table III-20 shows the aspherical data. Table III-21 shows various data.







TABLE III-19







(Surface data)

















Effective


Surface number
r
d
nd
vd
diameter





Object surface
∞






 1
19.77840
0.75000
1.85139
23.6
9.867


 2
15.05080
0.01000
1.56732
42.8
9.046


 3
15.05080
4.55170
1.58913
61.2
9.044


 4*
−2009.86870
Variable


8.687


 5
52.22170
0.40000
1.95534
29.4
6.224


 6
5.68140
3.07420


4.550


 7
−23.91140
0.40000
1.72668
53.6
4.494


 8
14.22890
0.15000


4.447


 9
10.89020
1.62340
1.94595
18.0
4.541


10
165.48490
Variable


4.456


11 (Diaphragm)
∞
0.30000


2.205


12
4.18710
2.65790
1.49171
69.9


13
−22.46530
0.20000


14*
6.60790
1.54420
1.71418
29.7
2.712


15
−18.34560
0.01000
1.56732
42.8


16
−18.34560
0.40000
2.00080
24.4


17
4.72980
Variable


1.753


18*
9.76620
1.36180
1.51760
63.5
3.622


19
23.45330
Variable


3.603


20
∞
0.78000
1.51680
64.2


21
∞
(BF)


Image surface
∞
















TABLE III-20





(Aspherical data)

















Surface No. 4



K = 0.00000E+00, A4 = 6.68914E−06, A6 = −9.93410E−10,



A8 = −8.29880E−11 A10 = 4.79336E−13, A12 = 0.00000E+00



Surface No. 14



K = −1.97925E+00, A4 = −1.09715E−03, A6 = −1.81257E−04,



A8 = 5.09203E−07 A10 = −1.71341E−06, A12 = 0.00000E+00



Surface No. 18



K = 0.00000E+00, A4 = −3.54076E−04, A6 = 7.33046E−05,



A8 = −1.00180E−05 A10 = 6.97991E−07, A12 = −1.86608E−08

















TABLE III-21





(Various data)







Zooming ratio 11.44412











Wide-angle
Middle
Telephoto



limit
position
limit





Focal length
4.5865
14.9965
52.4889


F-number
3.44725
4.69828
5.62110


View angle
41.0129
14.5052
4.2129


Image height
3.5100
3.9300
3.9300


Overall length
45.8634
47.8820
59.0016


of lens system


BF
0.91651
0.88175
0.87169


d4
0.3000
9.8706
21.5407


d10
18.5253
6.1613
1.0000


d17
5.3803
3.7677
11.8523


d19
2.5281
8.9874
5.5237


Entrance pupil
11.8960
32.6328
107.7666


position


Exit pupil
−13.4686
−17.4274
−31.0462


position


Front principal
15.0202
35.3461
73.9375


points position


Back principal
41.2769
32.8854
6.5127


points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−79.7777


2
3
25.3788


3
5
−6.7011


4
7
−12.2219


5
9
12.2609


6
12
7.4217


7
14
6.9824


8
16
−3.7250


9
18
31.2703










Zoom lens unit data















Overall





Initial

length


Lens
surface
Focal
of lens
Front principal
Back principal


unit
No.
length
unit
points position
points position





1
1
38.18058
5.31170
−0.23227
1.80477


2
5
−6.86331
5.64760
0.11084
1.15898


3
11
10.27017
5.11210
−3.64054
0.23351


4
18
31.27028
1.36180
−0.61927
−0.12535










Magnification of zoom lens unit











Lens
Initial
Wide-angle
Middle
Telephoto


unit
surface No.
limit
position
limit





1
1
0.00000
0.00000
0.00000


2
5
−0.25049
−0.38495
−1.11439


3
11
−0.58070
−1.64465
−1.68650


4
18
0.82584
0.62039
0.73148









The following Table III-22 shows the corresponding values to the individual conditions in the zoom lens systems of the numerical examples.







TABLE III-22







(Corresponding values to conditions)









Example














Condition
III-1
III-2
III-3
III-4
III-5
III-6
III-7


















 (9)
fG4/fG1
0.716
0.683
0.714
0.714
0.714
0.713
0.819


(a-2)
ωW
42.81
42.34
42.03
41.53
42.86
42.52
41.01


(b)
fT/fW
11.03
11.01
11.03
11.02
11.04
11.02
11.44


(10)
m2T/m2W
5.181
5.214
5.054
5.345
5.222
5.182
4.449


(11)
LT/fT
1.156
1.160
1.157
1.149
1.157
1.158
1.124


(12)
fT/fG1
1.511
1.457
1.505
1.505
1.507
1.505
1.375


(13)
LW/fG1
1.373
1.337
1.370
1.377
1.369
1.371
1.201


(14)
LT/fG1
1.747
1.691
1.741
1.729
1.743
1.743
1.545


(15)
fG1/|fG2|
5.286
5.209
5.266
5.267
5.258
5.261
5.563









The zoom lens system according to the present invention is applicable to a digital input device such as a digital camera, a mobile telephone, a PDA (Personal Digital Assistance), a surveillance camera in a surveillance system, a Web camera or a vehicle-mounted camera. In particular, the zoom lens system according to the present invention is suitable for a photographing optical system where high image quality is required like in a digital camera.
Although the present invention has been fully described by way of example with reference to the accompanying drawings, it is to be understood that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modification depart from the scope of the present invention, they should be construed as being included therein.

## Claims

1. A zoom lens system, in order from an object side to an image side, comprising a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
the first lens unit is composed of three or fewer lens elements, wherein
the second lens unit is composed of three lens elements, wherein
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
the following conditions (5), (6), (a-2) and (b) are satisfied:


tan 2ωW×m2W≦−1.78  (5)



tan 2ωW×|fG2|/fG1≧1.25  (6)



ωW≧37  (a-2)



fT/fW≧10  (b)


where,
m2W is a lateral magnification of the second lens unit at a wide-angle limit in an infinity in-focus condition,
fG1 is a composite focal length of the first lens unit,
fG2 is a composite focal length of the second lens unit,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.

2. The zoom lens system as claimed in claim 1, satisfying the following condition (10):


4.00≦m2T/m2W≦8.00  (10)

where,
m2T is a lateral magnification of the second lens unit at a telephoto limit in an infinity in-focus condition, and
m2W is a lateral magnification of the second lens unit at a wide-angle limit in an infinity in-focus condition.

3. The zoom lens system as claimed in claim 1, satisfying the following condition (11):


1.00≦LT/fT≦2.00  (11)

where,
LT is an overall length of lens system at a telephoto limit (a distance from the most object side surface of the first lens unit to the image surface), and
fT is a focal length of the entire system at a telephoto limit.

4. The zoom lens system as claimed in claim 1, satisfying the following condition (12):


1.00≦fT/fG1≦2.00  (12)

where,
fG1 is a composite focal length of the first lens unit, and
fT is a focal length of the entire system at a telephoto limit.

5. The zoom lens system as claimed in claim 1, satisfying the following condition (13):


1.00≦LW/fG1≦2.00  (13)

where,
LW is an overall length of lens system at a wide-angle limit (a distance from the most object side surface of the first lens unit to the image surface), and
fG1 is a composite focal length of the first lens unit.

6. The zoom lens system as claimed in claim 1, satisfying the following condition (14):


1.50≦LT/fG1≦2.00  (14)

where,
LT is an overall length of lens system at a telephoto limit (a distance from the most object side surface of the first lens unit to the image surface), and
fG1 is a composite focal length of the first lens unit.

7. The zoom lens system as claimed in claim 1, satisfying the following condition (15):


4.50≦fG1/|fG2|≦7.00  (15)

where,
fG1 is a composite focal length of the first lens unit, and
fG2 is a composite focal length of the second lens unit.

8. The zoom lens system as claimed in claim 1, wherein among the three or fewer lens elements constituting the first lens unit and the three lens elements constituting the second lens unit, only the object side surface of the lens element arranged in the center of the second lens unit has a negative radius of curvature.

9. The zoom lens system as claimed in claim 1, wherein the third lens unit is composed of three lens elements.

10. The zoom lens system as claimed in claim 9, wherein the third lens unit includes a lens element having positive optical power and located on the most object side.

11. The zoom lens system as claimed in claim 9, wherein the third lens unit includes at least one lens element having negative optical power and having a concave image side surface.

12. The zoom lens system as claimed in claim 1, wherein the fourth lens unit is composed of one lens element having positive optical power.

13. An imaging device capable of outputting an optical image of an object as an electric image signal, comprising:
a zoom lens system that forms the optical image of the object; and
an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
in the zoom lens system,
the zoom lens system, in order from an object side to an image side, comprises a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
the first lens unit is composed of three or fewer lens elements, wherein
the second lens unit is composed of three lens elements, wherein
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
the following conditions (5), (6), (a-2) and (b) are satisfied:


tan 2ωW×m2W≦−1.78  (5)



tan 2ωW×|fG2|/fG1≧1.25  (6)



ωW≧37  (a-2)



fT/fW≧10  (b)


where,
m2W is a lateral magnification of the second lens unit at a wide-angle limit in an infinity in-focus condition,
fG1 is a composite focal length of the first lens unit,
fG2 is a composite focal length of the second lens unit,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.

14. A camera for converting an optical image of an object into an electric image signal and then performing at least one of displaying and storing of the converted image signal, comprising
an imaging device including a zoom lens system that forms the optical image of the object and an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
in the zoom lens system,
the zoom lens system, in order from an object side to an image side, comprises a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
the first lens unit is composed of three or fewer lens elements, wherein
the second lens unit is composed of three lens elements, wherein
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
the following conditions (5), (6), (a-2) and (b) are satisfied:


tan 2ωW×m2W≧−1.78  (5)



tan 2ωW×|fG2|/fG1≧1.25  (6)



ωW≧37  (a-2)



fT/fW≧10   (b)


where,
M2W is a lateral magnification of the second lens unit at a wide-angle limit in an infinity in-focus condition,
fG1 is a composite focal length of the first lens unit,
fG2 is a composite focal length of the second lens unit,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.

15. A zoom lens system, in order from an object side to an image side, comprising a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
the first lens unit is composed of three or fewer lens elements, wherein
the second lens unit is composed of three lens elements, wherein
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
the following conditions (7), (8), (a-2) and (b) are satisfied:


−3.12≦TG1/fW≦−2.36  (7)



1.26≦TG2/fW≦1.78  (8)



ωW≧37  (a-2)



fT/fW≧10  (b)


where,
TG1 is an amount of axial movement of the first lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
TG2 is an amount of axial movement of the second lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.

16. The zoom lens system as claimed in claim 15, satisfying the following condition (10):


4.00≦m2T/m2W≦8.00  (10)

where,
m2T is a lateral magnification of the second lens unit at a telephoto limit in an infinity in-focus condition, and
m2W is a lateral magnification of the second lens unit at a wide-angle limit in an infinity in-focus condition.

17. The zoom lens system as claimed in claim 15, satisfying the following condition (11):


1.00≦LT/fT≦2.00  (11)

where,
LT is an overall length of lens system at a telephoto limit (a distance from the most object side surface of the first lens unit to the image surface), and
fT is a focal length of the entire system at a telephoto limit.

18. The zoom lens system as claimed in claim 15, satisfying the following condition (12):


1.00≦fT/fG1≦2.00  (12)

where,
fG1 is a composite focal length of the first lens unit, and
fT is a focal length of the entire system at a telephoto limit.

19. The zoom lens system as claimed in claim 15, satisfying the following condition (13):


1.00≦LW/fG1≦2.00  (13)

where,
LW is an overall length of lens system at a wide-angle limit (a distance from the most object side surface of the first lens unit to the image surface), and
fG1 is a composite focal length of the first lens unit.

20. The zoom lens system as claimed in claim 15, satisfying the following condition (14):


1.50≦LT/fG1≦2.00  (14)

where,
LT is an overall length of lens system at a telephoto limit (a distance from the most object side surface of the first lens unit to the image surface), and
fG1 is a composite focal length of the first lens unit.

21. The zoom lens system as claimed in claim 15, satisfying the following condition (15):


4.50≦fG1/|fG2|≦7.00  (15)

where,
fG1 is a composite focal length of the first lens unit, and
fG2 is a composite focal length of the second lens unit.

22. The zoom lens system as claimed in claim 15, wherein among the three or fewer lens elements constituting the first lens unit and the three lens elements constituting the second lens unit, only the object side surface of the lens element arranged in the center of the second lens unit has a negative radius of curvature.

23. The zoom lens system as claimed in claim 15, wherein the third lens unit is composed of two or three lens elements.

24. The zoom lens system as claimed in claim 23, wherein the third lens unit includes a lens element having positive optical power and located on the most object side.

25. The zoom lens system as claimed in claim 23, wherein the third lens unit includes at least one lens element having negative optical power and having a concave image side surface.

26. The zoom lens system as claimed in claim 15, wherein the fourth lens unit is composed of one lens element having positive optical power.

27. An imaging device capable of outputting an optical image of an object as an electric image signal, comprising:
a zoom lens system that forms the optical image of the object; and
an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
in the zoom lens system,
the zoom lens system, in order from an object side to an image side, comprises a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
the first lens unit is composed of three or fewer lens elements, wherein
the second lens unit is composed of three lens elements, wherein
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
the following conditions (7), (8), (a-2) and (b) are satisfied:


−3.12≦TG1/fW≦−2.36  (7)



1.26≦TG2/fW≦1.78  (8)



ωW≧37  (a-2)



fT/fW≧10  (b)


where,
TG1 is an amount of axial movement of the first lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
TG2 is an amount of axial movement of the second lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.

28. A camera for converting an optical image of an object into an electric image signal and then performing at least one of displaying and storing of the converted image signal, comprising
an imaging device including a zoom lens system that forms the optical image of the object and an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
in the zoom lens system,
the zoom lens system, in order from an object side to an image side, comprises a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
the first lens unit is composed of three or fewer lens elements, wherein
the second lens unit is composed of three lens elements, wherein
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
the following conditions (7), (8), (a-2) and (b) are satisfied:


−3.12≦TG1/fW≦−2.36  (7)



1.26≦TG2/fW≦1.78  (8)



ωW≧37  (a-2)



fT/fw≧10  (b)


where,
TG1 is an amount of axial movement of the first lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
TG2 is an amount of axial movement of the second lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.

29. A zoom lens system, in order from an object side to an image side, comprising a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
the first lens unit is composed of three or fewer lens elements, wherein
the second lens unit is composed of three lens elements, wherein
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
the following conditions (9), (a-2) and (b) are satisfied:


0.64≦fG4/fG1≦0.82  (9)



ωW≧37  (a-2)



fT/fW≧10  (b)


where,
fG1 is a composite focal length of the first lens unit,
fG4 is a composite focal length of the fourth lens unit,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.

30. The zoom lens system as claimed in claim 29, satisfying the following condition (10):


4.00≦m2T/m2W≦8.00  (10)

where,
m2T is a lateral magnification of the second lens unit at a telephoto limit in an infinity in-focus condition, and
m2W is a lateral magnification of the second lens unit at a wide-angle limit in an infinity in-focus condition.

31. The zoom lens system as claimed in claim 29, satisfying the following condition (11):


1.00≦LT/fT≦2.00  (11)

where,
LT is an overall length of lens system at a telephoto limit (a distance from the most object side surface of the first lens unit to the image surface), and
fT is a focal length of the entire system at a telephoto limit.

32. The zoom lens system as claimed in claim 29, satisfying the following condition (12):


1.00≦fT/fG1≦2.00  (12)

where,
fG1 is a composite focal length of the first lens unit, and
fT is a focal length of the entire system at a telephoto limit.

33. The zoom lens system as claimed in claim 29, satisfying the following condition (13):


1.00≦LW/fG1≦2.00  (13)

where,
LW is an overall length of lens system at a wide-angle limit (a distance from the most object side surface of the first lens unit to the image surface), and
fG1 is a composite focal length of the first lens unit.

34. The zoom lens system as claimed in claim 29, satisfying the following condition (14):


1.50≦LT/fG1≦2.00  (14)

where,
LT is an overall length of lens system at a telephoto limit (a distance from the most object side surface of the first lens unit to the image surface), and
fG1 is a composite focal length of the first lens unit.

35. The zoom lens system as claimed in claim 29, satisfying the following condition (15):


4.50≦fG1/|fG2|≦7.00  (15)

where,
fG1 is a composite focal length of the first lens unit, and
fG2 is a composite focal length of the second lens unit.

36. The zoom lens system as claimed in claim 29, wherein among the three or fewer lens elements constituting the first lens unit and the three lens elements constituting the second lens unit, only the object side surface of the lens element arranged in the center of the second lens unit has a negative radius of curvature.

37. The zoom lens system as claimed in claim 29, wherein the third lens unit is composed of two or three lens elements.

38. The zoom lens system as claimed in claim 37, wherein the third lens unit includes a lens element having positive optical power and located on the most object side.

39. The zoom lens system as claimed in claim 37, wherein the third lens unit includes at least one lens element having negative optical power and having a concave image side surface.

40. The zoom lens system as claimed in claim 29, wherein the fourth lens unit is composed of one lens element having positive optical power.

41. An imaging device capable of outputting an optical image of an object as an electric image signal, comprising:
a zoom lens system that forms the optical image of the object; and
an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
in the zoom lens system,
the zoom lens system, in order from an object side to an image side, comprises a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
the first lens unit is composed of three or fewer lens elements, wherein
the second lens unit is composed of three lens elements, wherein
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
the following conditions (9), (a-2) and (b) are satisfied:


0.64≦fG4/fG1≦0.82  (9)



ωW≧37  (a-2)



fT/fW≧10  (b)


where,
fG1 is a composite focal length of the first lens unit,
fG4 is a composite focal length of the fourth lens unit,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.

42. A camera for converting an optical image of an object into an electric image signal and then performing at least one of displaying and storing of the converted image signal, comprising
an imaging device including a zoom lens system that forms the optical image of the object and an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
in the zoom lens system,
the zoom lens system, in order from an object side to an image side, comprises a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
the first lens unit is composed of three or fewer lens elements, wherein
the second lens unit is composed of three lens elements, wherein
in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
the following conditions (9), (a-2) and (b) are satisfied:


0.64≦fG4/fG1≦0.82  (9)



ωW≧37  (a-2)



fT/fW≧10  (b)


where,
fG1 is a composite focal length of the first lens unit,
fG4 is a composite focal length of the fourth lens unit,
ωW is a half view angle (°) at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit, and
fW is a focal length of the entire system at a wide-angle limit.