# Patent

## Title
Zoom lens system, imaging device and camera

## Abstract

A high-performance zoom lens system which is compact and has a wide view angle at a wide-angle limit and a high zooming ratio in a balanced manner, 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 at most two lens elements, the second lens unit is composed of two lens elements, the third lens unit is composed of three lens elements, in order from the object side to the image side, including an object side lens element having positive optical power, a lens element having negative optical power, and an image side lens element having positive optical power, and the conditions: −2.0<f2/fW<−1.1, fT/fW>6.0 and ωW≧30 (f2: a composite focal length of the second lens unit, fT: a focal length of the entire system at a telephoto limit, fW: a focal length of the entire system at a wide-angle limit, ωW: a half view angle at a wide-angle limit) are satisfied; an imaging device; and a camera are provided.

## Background
TECHNICAL FIELD
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 which is compact and has a wide view angle at a wide-angle limit and a high zooming ratio in a balanced manner; an imaging device employing the zoom lens system; and a thin and compact camera employing the imaging device.
BACKGROUND ART
There are extremely strong demands for size reduction and performance improvement in digital still cameras and digital video cameras (simply referred to as digital cameras, hereinafter) having 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 and zoom lens systems having a wide angle range as described above, various kinds of zoom lenses having a four-unit construction of positive, negative, positive and positive have conventionally been proposed, which each comprises, in order from the object side to the image side, 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. 2008-146016 discloses a zoom lens having the above-mentioned four-unit construction of positive, negative, positive and positive, in which at the time of magnification change from a wide-angle limit to a telephoto limit, at least a first lens unit, a second lens unit, and a third lens unit are moved and thereby the intervals between the respective lens units are changed, the second lens unit is composed of at most three lenses, and the relation between the ratio of the values of lateral magnification of the second lens unit at a telephoto limit and a wide-angle limit and the ratio of the values of lateral magnification of the third lens unit at a telephoto limit and a wide-angle limit is set forth.
Japanese Laid-Open Patent Publication No. 2008-122880 discloses a zoom lens having the above-mentioned four-unit construction of positive, negative, positive and positive, and having a zooming ratio of 3 to 12, in which a second lens unit is composed of at most three lenses, a bi-concave negative lens is arranged on the most object side in the second lens unit, and the shape factor of the bi-concave negative lens is set forth.
Japanese Laid-Open Patent Publication No. 2008-122879 discloses a zoom lens having the above-mentioned four-unit construction of positive, negative, positive and positive, in which a first lens unit is composed of a negative lens and a positive lens, and the shape factor of the positive lens is set forth.
Japanese Laid-Open Patent Publication No. 2008-052116 discloses a zoom lens having the above-mentioned four-unit construction of positive, negative, positive and positive, in which a first lens unit is composed of a positive lens and a negative lens, a second lens unit is composed of, in order from the object side, a negative lens and a positive lens, and a refractive index and an Abbe number of the negative lens in the second lens unit are set forth.
Japanese Laid-Open Patent Publication No. 2008-052113 discloses a zoom lens having the above-mentioned four-unit construction of positive, negative, positive and positive, and having a zooming ratio of 3.8 to 10, in which a second lens unit includes a bi-concave negative lens on the most object side, the entire second lens unit is composed of at most two negative lenses and a positive lens, and the shape factor of the bi-concave negative lens is set forth.
Japanese Laid-Open Patent Publication No. 2008-052110 discloses a zoom lens having the above-mentioned four-unit construction of positive, negative, positive and positive, in which a second lens unit is composed of, in order from the object side, a negative lens and a positive lens, and a refractive index and an Abbe number of the positive lens are set forth.
Japanese Laid-Open Patent Publication No. 2007-328178 discloses a zoom lens having the above-mentioned four-unit construction of positive, negative, positive and positive, in which a first lens unit is composed of, in order from the object side, a negative lens and a positive lens, a second lens unit is composed of, in order from the object side, a negative lens and a positive lens, a third lens unit is composed of at most three lenses including a positive lens and a negative lens, and a fourth lens unit is composed of a positive lens.
Japanese Laid-Open Patent Publication No. 2007-256452 discloses a zoom lens having the above-mentioned four-unit construction of positive, negative, positive and positive, in which a third lens unit is composed of, in order from the object side, a first positive lens, a second bi-concave negative lens, and a third negative lens, and at the time of magnification change, the interval between a first lens unit and a second lens unit is greater and the interval between the second lens unit and the third lens unit is smaller at a telephoto limit than at a wide-angle limit.
Japanese Laid-Open Patent Publication No. 2007-240747 discloses a zoom lens having the above-mentioned four-unit construction of positive, negative, positive and positive, in which a first lens unit is composed of, in order from the object side, two lenses, i.e., a negative lens and a positive lens; a second lens unit is composed of, in order from the object side, two lenses, i.e., a negative lens and a positive lens; a third lens unit is composed of, in order from the object side, three lenses, i.e., a positive lens, a positive lens, and a negative lens; a fourth lens unit is composed of a positive lens; at the time of magnification change, the interval between the first lens unit and the second lens unit is greater at a telephoto limit than at a wide-angle limit, and the third lens unit is located closer to the object side so that the interval between the third lens unit and the second lens unit decreases; a brightness diaphragm, which moves in the direction along the optical axis at the time of magnification change, is arranged between the second lens unit and the third lens unit; and the brightness diaphragm is located closer to the object side at a telephoto limit than at a wide-angle limit.
Japanese Laid-Open Patent Publication No. 2007-171371 discloses a zoom lens having the above-mentioned four-unit construction of positive, negative, positive and positive, in which a first lens unit is located closer to the object side at a telephoto limit than at a wide-angle limit; the interval between the first lens unit and a second lens unit is greater, the interval between the second lens unit and a third lens unit is smaller, and the interval between the third lens unit and a fourth lens unit is greater at a telephoto limit than at a wide-angle limit; the first lens unit is composed of a negative lens and a positive lens; the second lens unit is composed of, in order from the object side to the image side, a negative lens and a positive lens; and the ratio between the focal length of the negative lens in the second lens unit or the focal length of the second lens unit, and the focal length of the entire lens system at a wide-angle limit is set forth.
Japanese Laid-Open Patent Publication No. 2008-172321 discloses an imaging device comprising: a zoom lens which includes the above-mentioned four-unit construction of positive, negative, positive and positive, and performs zooming from a wide-angle limit to a telephoto limit with the intervals between a plurality of lens units being varied; an image sensor; and an image recovery unit, in which the relations among the maximum length of the zoom lens along the optical axis from its most-object-side refractive surface to its imaging surface, the focal lengths of the entire system at a wide-angle limit and a telephoto limit, the minimum F-number at a telephoto limit, and the half of the diagonal length of an effective imaging range on the imaging surface, are set forth.
CITATION LIST
Patent Literature


    [PTL 1] Japanese Laid-Open Patent Publication No. 2008-146016
    [PTL 2] Japanese Laid-Open Patent Publication No. 2008-122880
    [PTL 3] Japanese Laid-Open Patent Publication No. 2008-122879
    [PTL 4] Japanese Laid-Open Patent Publication No. 2008-052116
    [PTL 5] Japanese Laid-Open Patent Publication No. 2008-052113
    [PTL 6] Japanese Laid-Open Patent Publication No. 2008-052110
    [PTL 7] Japanese Laid-Open Patent Publication No. 2007-328178
    [PTL 8] Japanese Laid-Open Patent Publication No. 2007-256452
    [PTL 9] Japanese Laid-Open Patent Publication No. 2007-240747
    [PTL 10] Japanese Laid-Open Patent Publication No. 2007-171371
    [PTL 11] Japanese Laid-Open Patent Publication No. 2008-172321


SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
Each of the zoom lenses disclosed in the respective patent literatures is miniaturized to such an extent that it can be applied to a thin and compact digital camera, but cannot meet the recent demands in terms of achieving a good balance between the view angle at a wide-angle limit and the zooming ratio.
The object of the present invention is to provide: a high-performance zoom lens system which is compact and has a wide view angle at a wide-angle limit and a high zooming ratio in a balanced manner; an imaging device employing the zoom lens system; and a thin and compact camera employing the imaging device.
Solution to the Problems
(I) One of the above-described objects is achieved by the following zoom lens system. That is, the present invention relates to:
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 at most two lens elements,
the second lens unit is composed of two lens elements,
the third lens unit is composed of three lens elements, in order from the object side to the image side, including an object side lens element having positive optical power, a lens element having negative optical power, and an image side lens element having positive optical power, and
the following conditions (2-2), (b-1) and (a-2) are satisfied:

−2.0<f2/fW<−1.1  (2-2)

fT/fW>6.0  (b-1)

ωW≧30  (a-2)

where,
f2 is a composite focal length of the second lens unit,
fT is a focal length of the entire system at a telephoto limit,
fW is a focal length of the entire system at a wide-angle limit, and
ωW is a half view angle (°) at a wide-angle limit.
One of the above-described objects is achieved by the following imaging device. That is, the present invention relates to:
an imaging device capable of outputting an optical image of an object as an electric image signal, comprising:
a zoom lens system that forms an 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
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 at most two lens elements,
the second lens unit is composed of two lens elements,
the third lens unit is composed of three lens elements, in order from the object side to the image side, including an object side lens element having positive optical power, a lens element having negative optical power, and an image side lens element having positive optical power, and
the following conditions (2-2), (b-1) and (a-2) are satisfied:

−2.0<f2/fW<−1.1  (2-2)

fT/fW>6.0  (b-1)

ωW≧30  (a-2)

where,
f2 is a composite focal length of the second lens unit,
fT is a focal length of the entire system at a telephoto limit,
fW is a focal length of the entire system at a wide-angle limit, and
ωW is a half view angle (°) at a wide-angle limit.
One of the above-described objects is achieved by the following camera. That is, the present invention relates to:
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
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 at most two lens elements,
the second lens unit is composed of two lens elements,
the third lens unit is composed of three lens elements, in order from the object side to the image side, including an object side lens element having positive optical power, a lens element having negative optical power, and an image side lens element having positive optical power, and
the following conditions (2-2), (b-1) and (a-2) are satisfied:

−2.0<f2/fW<−1.1  (2-2)

fT/fW>6.0  (b-1)

ωW≧30  (a-2)

where,
f2 is a composite focal length of the second lens unit,
fT is a focal length of the entire system at a telephoto limit,
fW is a focal length of the entire system at a wide-angle limit, and
ωW is a half view angle (°) at a wide-angle limit.
(II) One of the above-described objects is achieved by the following zoom lens system. That is, the present invention relates to:
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 at most two lens elements,
the second lens unit is composed of two lens elements,
the third lens unit is composed of three lens elements, in order from the object side to the image side, including an object side lens element having positive optical power, a lens element having negative optical power, and an image side lens element having positive optical power, and
the following conditions (3-2), (b-1) and (a-2) are satisfied:

1.1<(β2T/β2W)/(β3T/β3W)<5.2  (3-2)

fT/fW>6.0  (b-1)

ωW≧30  (a-2)

where,
β2T is a lateral magnification of the second lens unit at a telephoto limit,
β2W is a lateral magnification of the second lens unit at a wide-angle limit,
β3T is a lateral magnification of the third lens unit at a telephoto limit,
β3W is a lateral magnification of the third lens unit at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit,
fW is a focal length of the entire system at a wide-angle limit, and
ωW is a half view angle (°) at a wide-angle limit.
One of the above-described objects is achieved by the following imaging device. That is, the present invention relates to:
an imaging device capable of outputting an optical image of an object as an electric image signal, comprising:
a zoom lens system that forms an 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
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 at most two lens elements,
the second lens unit is composed of two lens elements,
the third lens unit is composed of three lens elements, in order from the object side to the image side, including an object side lens element having positive optical power, a lens element having negative optical power, and an image side lens element having positive optical power, and
the following conditions (3-2), (b-1) and (a-2) are satisfied:

1.1<(β2T/β2W)/(β3T/β3W)<5.2  (3-2)

fT/fW>6.0  (b-1)

ωW≧30  (a-2)

where,
β2T is a lateral magnification of the second lens unit at a telephoto limit,
β2W is a lateral magnification of the second lens unit at a wide-angle limit,
β3T is a lateral magnification of the third lens unit at a telephoto limit,
β3W is a lateral magnification of the third lens unit at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit,
fW is a focal length of the entire system at a wide-angle limit, and
ωW is a half view angle (°) at a wide-angle limit.
One of the above-described objects is achieved by the following camera. That is, the present invention relates to:
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
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 at most two lens elements,
the second lens unit is composed of two lens elements,
the third lens unit is composed of three lens elements, in order from the object side to the image side, including an object side lens element having positive optical power, a lens element having negative optical power, and an image side lens element having positive optical power, and
the following conditions (3-2), (b-1) and (a-2) are satisfied:

1.1<(β2T/β2W)/(β3T/β3W)<5.2  (3-2)

fT/fW>6.0  (b-1)

ωW≧30  (a-2)

where,
β2T is a lateral magnification of the second lens unit at a telephoto limit,
β2W is a lateral magnification of the second lens unit at a wide-angle limit,
β3T is a lateral magnification of the third lens unit at a telephoto limit,
β3W is a lateral magnification of the third lens unit at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit,
fW is a focal length of the entire system at a wide-angle limit, and
ωW is a half view angle (°) at a wide-angle limit.
(III) One of the above-described objects is achieved by the following zoom lens system. That is, the present invention relates to:
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 at most two lens elements,
the second lens unit is composed of two lens elements,
the third lens unit is composed of three lens elements, in order from the object side to the image side, including an object side lens element having positive optical power, a lens element having negative optical power, and an image side lens element having positive optical power, and
the following conditions (4-2), (b-1) and (a-2) are satisfied:

0.9<M1/M3<3.0  (4-2)

fT/fW>6.0  (b-1)

ωW≧30  (a-2)

where,
M1 is an amount of movement of the first lens unit in the direction along the optical axis during zooming from a wide-angle limit to a telephoto limit (movement from the image side to the object side is positive),
M3 is an amount of movement of the third lens unit in the direction along the optical axis during zooming from a wide-angle limit to a telephoto limit (movement from the image side to the object side is positive),
fT is a focal length of the entire system at a telephoto limit,
fW is a focal length of the entire system at a wide-angle limit, and
ωW is a half view angle (°) at a wide-angle limit.
One of the above-described objects is achieved by the following imaging device. That is, the present invention relates to:
an imaging device capable of outputting an optical image of an object as an electric image signal, comprising:
a zoom lens system that forms an 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
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 at most two lens elements,
the second lens unit is composed of two lens elements,
the third lens unit is composed of three lens elements, in order from the object side to the image side, including an object side lens element having positive optical power, a lens element having negative optical power, and an image side lens element having positive optical power, and
the following conditions (4-2), (b-1) and (a-2) are satisfied:

0.9<M1/M3<3.0  (4-2)

fT/fW>6.0  (b-1)

ωW≧30  (a-2)

where,
M1 is an amount of movement of the first lens unit in the direction along the optical axis during zooming from a wide-angle limit to a telephoto limit (movement from the image side to the object side is positive),
M3 is an amount of movement of the third lens unit in the direction along the optical axis during zooming from a wide-angle limit to a telephoto limit (movement from the image side to the object side is positive),
fT is a focal length of the entire system at a telephoto limit,
fW is a focal length of the entire system at a wide-angle limit, and
ωW is a half view angle (°) at a wide-angle limit.
One of the above-described objects is achieved by the following camera. That is, the present invention relates to:
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
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 at most two lens elements,
the second lens unit is composed of two lens elements,
the third lens unit is composed of three lens elements, in order from the object side to the image side, including an object side lens element having positive optical power, a lens element having negative optical power, and an image side lens element having positive optical power, and
the following conditions (4-2), (b-1) and (a-2) are satisfied:

0.9<M1/M3<3.0  (4-2)

fT/fW>6.0  (b-1)

ωW≧30  (a-2)

where,
M1 is an amount of movement of the first lens unit in the direction along the optical axis during zooming from a wide-angle limit to a telephoto limit (movement from the image side to the object side is positive),
M3 is an amount of movement of the third lens unit in the direction along the optical axis during zooming from a wide-angle limit to a telephoto limit (movement from the image side to the object side is positive),
fT is a focal length of the entire system at a telephoto limit,
fW is a focal length of the entire system at a wide-angle limit, and
ωW is a half view angle (°) at a wide-angle limit.
Effects of the Invention
According to the present invention, it is possible to provide: a high-performance zoom lens system which is compact and has a wide view angle at a wide-angle limit and a high zooming ratio in a balanced manner; an imaging device employing the zoom lens system; and a thin and compact camera employing the imaging device.



BRIEF DESCRIPTION OF THE DRAWINGS
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 lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment I-3 (Example I-3).
FIG. 7 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example I-3.
FIG. 8 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. 9 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. 10 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example I-4.
FIG. 11 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. 12 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example I-5.
FIG. 13 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. 14 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example I-6.
FIG. 15 is a schematic construction diagram of a digital still camera according to Embodiment I-7.
FIG. 16 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. 17 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example II-1.
FIG. 18 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. 19 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example II-2.
FIG. 20 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. 21 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. 22 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example II-3.
FIG. 23 is a lateral aberration diagram of a zoom lens system according to Example II-3 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 lens arrangement diagram showing an infinity in-focus condition of a zoom lens system according to Embodiment II-4 (Example II-4).
FIG. 25 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example II-4.
FIG. 26 is a lateral aberration diagram of a zoom lens system according to Example II-4 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state.
FIG. 27 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. 28 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example II-5.
FIG. 29 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. 30 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. 31 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example II-6.
FIG. 32 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. 33 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example II-7.
FIG. 34 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. 35 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example II-8.
FIG. 36 is a schematic construction diagram of a digital still camera according to Embodiment II-9.
FIG. 37 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. 38 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example III-1.
FIG. 39 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. 40 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example III-2.
FIG. 41 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. 42 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. 43 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example III-3.
FIG. 44 is a lateral aberration diagram of a zoom lens system according to Example III-3 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state.
FIG. 45 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. 46 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example III-4.
FIG. 47 is a lateral aberration diagram of a zoom lens system according to Example III-4 at a telephoto limit in a basic state where image blur compensation is not performed and in a blur compensation state.
FIG. 48 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. 49 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example III-5.
FIG. 50 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. 51 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. 52 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example III-6.
FIG. 53 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. 54 is a longitudinal aberration diagram of an infinity in-focus condition of a zoom lens system according to Example III-7.
FIG. 55 is a schematic construction diagram of a digital still camera according to Embodiment III-8.



EMBODIMENTS OF THE INVENTION
Embodiments I-1 to I-6
FIGS. 1, 4, 6, 9, 11 and 13 are lens arrangement diagrams of zoom lens systems according to Embodiments I-1 to I-6, respectively.
Each of FIGS. 1, 4, 6, 9, 11 and 13 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=√(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 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 and the second lens unit, the interval between the second lens unit and the third lens unit, and the interval between the third lens unit and the fourth lens unit 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 maintained and still size reduction is achieved in the entire lens system.
Further, in FIGS. 1, 4, 6, 9, 11 and 13, 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 equivalent to an optical low-pass filter or a face plate of an image sensor is provided.
Further, in FIGS. 1, 4, 6, 9, 11 and 13, an aperture diaphragm A is provided on the most object side in the third lens unit G3. 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; and a positive meniscus 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 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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. Further, the fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment I-1, the fourth lens unit G4 comprises solely a bi-convex eighth lens element L8. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side with locus of a convex to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
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; and a positive meniscus 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 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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. The fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment I-2, the fourth lens unit G4 comprises solely a positive meniscus eighth lens element L8 with the convex surface facing the object side. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side with locus of a convex to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
As shown in FIG. 6, 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; and a positive meniscus 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. Further, the second lens element L2 has an aspheric image side surface.
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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. Further, the fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment I-3, the fourth lens unit G4 comprises solely a bi-convex eighth lens element L8. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
As shown in FIG. 9, 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; and a positive meniscus 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. Further, the second lens element L2 has an aspheric image side surface.
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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. Further, the fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment I-4, the fourth lens unit G4 comprises solely a bi-convex eighth lens element L8. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
As shown in FIG. 11, 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; and a positive meniscus 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 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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. Further, the fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment I-5, the fourth lens unit G4 comprises solely a bi-convex eighth lens element L8. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side with locus of a convex to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
As shown in FIG. 13, 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; and a positive meniscus 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 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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 positive meniscus fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. Further, the fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment I-6, the fourth lens unit G4 comprises solely a bi-convex eighth lens element L8. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side with locus of a convex to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
In the zoom lens systems according to Embodiments I-1 to I-6, the first lens unit G1 comprises two lens elements, the second lens unit G2 comprises two lens elements, and the third lens unit G3 comprises three lens elements. Thus, the lens system has a short overall optical length (overall length of lens system).
In the zoom lens systems according to Embodiments I-1 to I-6, the first lens unit G1, in order from the object side to the image side, is composed of the negative meniscus lens element L1 with the convex surface facing the object side, and the positive lens element L2. These two lens elements are cemented with each other to constitute a cemented lens element. Thus, a compact lens system is realized. Further, such a construction permits favorable compensation of chromatic aberration.
In the zoom lens systems according to Embodiments I-1 to I-6, in the second lens unit G2, the third lens element L3, which is an object side lens element, has an aspheric surface. Therefore, aberrations, particularly distortion at a wide-angle limit, can be compensated more favorably. Further, in the third lens unit G3, the fifth lens element L5, which is an object side positive lens element, has an aspheric surface. Therefore, aberrations, particularly spherical aberration, can be compensated more favorably.
In the zoom lens systems according to Embodiments I-1 to I-6, the third lens unit G3 is composed of three lens elements, i.e., in order from the object side to the image side, the fifth lens element L5 having positive optical power, the sixth lens element L6 having negative optical power, and the seventh lens element L7 having positive optical power. The fifth lens element L5, which is an object side positive lens element, and the sixth lens element L6 are cemented with each other to constitute a cemented lens element. Therefore, axial aberration, which occurs in the positive lens element, is compensated in the negative lens element, and thus excellent optical performance is achieved with a small number of lens elements.
In the zoom lens systems according to Embodiments I-1 to I-6, the fourth lens unit G4 is composed of a single lens element, and the lens element has positive optical power. Thus, the lens system has a short overall optical length (overall length of lens system). Further, at the time of focusing from an infinite-distance object to a close-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 systems according to Embodiments I-1 to I-6, 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. Thus, image blur is compensated in a state that size increase in the entire zoom lens system is suppressed to realize a compact construction and that excellent imaging characteristics such as small decentering coma aberration and small decentering astigmatism are maintained.
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-8
FIGS. 16, 18, 21, 24, 27, 30, 32 and 34 are lens arrangement diagrams of zoom lens systems according to Embodiments II-1 to II-8, respectively.
Each of FIGS. 16, 18, 21, 24, 27, 30, 32 and 34 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=√(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 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 and the second lens unit, the interval between the second lens unit and the third lens unit, and the interval between the third lens unit and the fourth lens unit 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 maintained and still size reduction is achieved in the entire lens system.
Further, in FIGS. 16, 18, 21, 24, 27, 30, 32 and 34, 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 equivalent to an optical low-pass filter or a face plate of an image sensor is provided.
Further, in FIGS. 16, 18, 21, 24, 27, 30, 32 and 34, an aperture diaphragm A is provided on the most object side in the third lens unit G3. 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. 16, 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; and a positive meniscus 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 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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a positive meniscus seventh lens element L7 with the convex surface facing the object side. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. Further, the fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment II-1, the fourth lens unit G4 comprises solely a bi-convex eighth lens element L8. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side with locus of a convex to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
As shown in FIG. 18, 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; and a positive meniscus 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 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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. Further, the fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment II-2, the fourth lens unit G4 comprises solely a bi-convex eighth lens element L8. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side with locus of a convex to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
As shown in FIG. 21, 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; and a positive meniscus 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 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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 positive meniscus fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. Further, the fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment II-3, the fourth lens unit G4 comprises solely a bi-convex eighth lens element L8. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side with locus of a convex to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
As shown in FIG. 24, 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; and a positive meniscus 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. Further, the second lens element L2 has an aspheric image side surface.
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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 positive meniscus fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. The fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment II-4, the fourth lens unit G4 comprises solely a positive meniscus eighth lens element L8 with the convex surface facing the object side. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
As shown in FIG. 27, 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; and a positive meniscus 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. Further, the second lens element L2 has an aspheric image side surface.
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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 positive meniscus fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. Further, the fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment II-5, the fourth lens unit G4 comprises solely a bi-convex eighth lens element L8. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
As shown in FIG. 30, 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; and a positive meniscus 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. Further, the second lens element L2 has an aspheric image side surface.
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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. Further, the fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment II-6, the fourth lens unit G4 comprises solely a bi-convex eighth lens element L8. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
As shown in FIG. 32, 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 positive meniscus 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 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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 positive meniscus fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. Further, the fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment II-7, the fourth lens unit G4 comprises solely a bi-convex eighth lens element L8. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side with locus of a convex to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
As shown in FIG. 34, 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 positive meniscus 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 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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 positive meniscus fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. Further, the fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment II-8, the fourth lens unit G4 comprises solely a bi-convex eighth lens element L8. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side with locus of a convex to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
In the zoom lens systems according to Embodiments II-1 to II-8, the first lens unit G1 comprises two lens elements, the second lens unit G2 comprises two lens elements, and the third lens unit G3 comprises three lens elements. Thus, the lens system has a short overall optical length (overall length of lens system).
In the zoom lens systems according to Embodiments II-1 to II-8, the first lens unit G1, in order from the object side to the image side, is composed of the negative meniscus lens element L1 with the convex surface facing the object side, and the positive lens element L2. These two lens elements are cemented with each other to constitute a cemented lens element. Thus, a compact lens system is realized. Further, such a construction permits favorable compensation of chromatic aberration.
In the zoom lens systems according to Embodiments II-1 to II-8, in the second lens unit G2, the third lens element L3, which is an object side lens element, has an aspheric surface. Therefore, aberrations, particularly distortion at a wide-angle limit, can be compensated more favorably. Further, in the third lens unit G3, the fifth lens element L5, which is an object side positive lens element, has an aspheric surface. Therefore, aberrations, particularly spherical aberration, can be compensated more favorably.
In the zoom lens systems according to Embodiments II-1 to II-8, the third lens unit G3 is composed of three lens elements, i.e., in order from the object side to the image side, the fifth lens element L5 having positive optical power, the sixth lens element L6 having negative optical power, and the seventh lens element L7 having positive optical power. The fifth lens element L5, which is an object side positive lens element, and the sixth lens element L6 are cemented with each other to constitute a cemented lens element. Therefore, axial aberration, which occurs in the positive lens element, is compensated in the negative lens element, and thus excellent optical performance is achieved with a small number of lens elements.
In the zoom lens systems according to Embodiments II-1 to II-8, the fourth lens unit G4 is composed of a single lens element, and the lens element has positive optical power. Thus, the lens system has a short overall optical length (overall length of lens system). Further, at the time of focusing from an infinite-distance object to a close-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 systems according to Embodiments II-1 to II-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. Thus, image blur is compensated in a state that size increase in the entire zoom lens system is suppressed to realize a compact construction and that excellent imaging characteristics such as small decentering coma aberration and small decentering astigmatism are maintained.
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. 37, 39, 42, 45, 48, 51 and 53 are lens arrangement diagrams of zoom lens systems according to Embodiments III-1 to III-7, respectively.
Each of FIGS. 37, 39, 42, 45, 48, 51 and 53 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=√(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 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 and the second lens unit, the interval between the second lens unit and the third lens unit, and the interval between the third lens unit and the fourth lens unit 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 maintained and still size reduction is achieved in the entire lens system.
Further, in FIGS. 37, 39, 42, 45, 48, 51 and 53, 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 equivalent to an optical low-pass filter or a face plate of an image sensor is provided.
Further, in FIGS. 37, 39, 42, 45, 48, 51 and 53, an aperture diaphragm A is provided on the most object side in the third lens unit G3. 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. 37, 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; and a positive meniscus 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 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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. Further, the fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment III-1, the fourth lens unit G4 comprises solely a bi-convex eighth lens element L8. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side with locus of a convex to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
As shown in FIG. 39, 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; and a positive meniscus 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 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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. Further, the fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment III-2, the fourth lens unit G4 comprises solely a bi-convex eighth lens element L8. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side with locus of a convex to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
As shown in FIG. 42, 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; and a positive meniscus 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 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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 positive meniscus fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. The fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment III-3, the fourth lens unit G4 comprises solely a bi-convex eighth lens element L8. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side with locus of a convex to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
As shown in FIG. 45, 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; and a positive meniscus 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. Further, the second lens element L2 has an aspheric image side surface.
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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 positive meniscus fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. The fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment III-4, the fourth lens unit G4 comprises solely a positive meniscus eighth lens element L8 with the convex surface facing the object side. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
As shown in FIG. 48, 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; and a positive meniscus 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. Further, the second lens element L2 has an aspheric image side surface.
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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 positive meniscus fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. Further, the fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment III-5, the fourth lens unit G4 comprises solely a bi-convex eighth lens element L8. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
As shown in FIG. 51, 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; and a positive meniscus 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 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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. Further, the fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment III-6, the fourth lens unit G4 comprises solely a bi-convex eighth lens element L8. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side with locus of a convex to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
As shown in FIG. 53, 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 positive meniscus 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 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 bi-concave third lens element L3; and a positive meniscus fourth lens element L4 with the convex surface facing the object side. The third lens element L3 has two aspheric surfaces.
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 positive meniscus fifth lens element L5 with the convex surface facing the object side; a negative meniscus sixth lens element L6 with the convex surface facing the object side; and a bi-convex seventh lens element L7. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented with each other. Further, the fifth lens element L5 has an aspheric object side surface.
In the zoom lens system according to Embodiment III-7, the fourth lens unit G4 comprises solely a bi-convex eighth lens element L8. The eighth lens element L8 has an aspheric object side surface.
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 eighth lens element L8).
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, the second lens unit G2 moves to the image side with locus of a convex to the image side, and 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 move along the optical axis such that the interval between the second lens unit G2 and the third lens unit G3 should decrease.
In the zoom lens systems according to Embodiments III-1 to III-7, the first lens unit G1 comprises two lens elements, the second lens unit G2 comprises two lens elements, and the third lens unit G3 comprises three lens elements. Thus, the lens system has a short overall optical length (overall length of lens system).
In the zoom lens systems according to Embodiments III-1 to III-7, the first lens unit G1, in order from the object side to the image side, is composed of the negative meniscus lens element L1 with the convex surface facing the object side, and the positive lens element L2. These two lens elements are cemented with each other to constitute a cemented lens element. Thus, a compact lens system is realized. Further, such a construction permits favorable compensation of chromatic aberration.
In the zoom lens systems according to Embodiments III-1 to III-7, in the second lens unit G2, the third lens element L3, which is an object side lens element, has an aspheric surface. Therefore, aberrations, particularly distortion at a wide-angle limit, can be compensated more favorably. Further, in the third lens unit G3, the fifth lens element L5, which is an object side positive lens element, has an aspheric surface. Therefore, aberrations, particularly spherical aberration, can be compensated more favorably.
In the zoom lens systems according to Embodiments III-1 to III-7, the third lens unit G3 is composed of three lens elements, i.e., in order from the object side to the image side, the fifth lens element L5 having positive optical power, the sixth lens element L6 having negative optical power, and the seventh lens element L7 having positive optical power. The fifth lens element L5, which is an object side positive lens element, and the sixth lens element L6 are cemented with each other to constitute a cemented lens element. Therefore, axial aberration, which occurs in the positive lens element, is compensated in the negative lens element, and thus excellent optical performance is achieved with a small number of lens elements.
In the zoom lens systems according to Embodiments III-1 to III-7, the fourth lens unit G4 is composed of a single lens element, and the lens element has positive optical power. Thus, the lens system has a short overall optical length (overall length of lens system). Further, at the time of focusing from an infinite-distance object to a close-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 systems 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. Thus, image blur is compensated in a state that size increase in the entire zoom lens system is suppressed to realize a compact construction and that excellent imaging characteristics such as small decentering coma aberration and small decentering astigmatism are maintained.
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 systems according to Embodiments I-1 to I-6, II-1 to II-8 and 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 systems according to Embodiments I-1 to I-6, 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 at most two lens elements, the second lens unit is composed of two lens elements, and the third lens unit is composed of three lens elements, in order from the object side to the image side, including an object side lens element having positive optical power, a lens element having negative optical power, and an image side lens element having positive optical power (this lens configuration is referred to as basic configuration I of the embodiments, hereinafter), the following conditions (2-2), (b-1) and (a-2) are satisfied.

−2.0<f2/fW<−1.1  (2-2)

fT/fW>6.0  (b-1)

ωW≧30  (a-2)

where,
f2 is a composite focal length of the second lens unit,
fT is a focal length of the entire system at a telephoto limit,
fW is a focal length of the entire system at a wide-angle limit, and
ωW is a half view angle (°) at a wide-angle limit.
The condition (2-2) sets forth a suitable focal length of the second lens unit. When the value exceeds the upper limit of the condition (2-2), the focal length of the second lens unit becomes excessively long, and the amount of movement of the second lens unit increases in zooming, which might result in difficulty in achieving a compact zoom lens system having a zooming ratio exceeding 6.0. On the other hand, when the value goes below the lower limit of the condition (2-2), the focal length of the second lens unit becomes excessively short, which might result in difficulty in compensating variation in aberration caused by movement of the second lens unit.
When at least one of the following conditions (2-2)′ and (2-2)′′ is satisfied, the above-mentioned effect is achieved more successfully.

−1.7<f2/fW  (2-2)′

f2/fW<−1.5  (2-2)′′

In a zoom lens system having the basic configuration I like the zoom lens systems according to Embodiments I-1 to I-6, it is preferable that the following condition (3-2) is satisfied.

1.1<(β2T/β2W)/(β3T/β3W)<5.2  (3-2)

where,
β2T is a lateral magnification of the second lens unit at a telephoto limit,
β2W is a lateral magnification of the second lens unit at a wide-angle limit,
β3T is a lateral magnification of the third lens unit at a telephoto limit, and
β3W is a lateral magnification of the third lens unit at a wide-angle limit.
The condition (3-2) sets forth the ratio between lateral magnification change in the second lens unit and lateral magnification change in the third lens unit. When the value exceeds the upper limit of the condition (3-2), variable magnification load to the second lens unit becomes excessively great, which might result in difficulty in suppressing occurrence of aberration due to increase in the power, particularly, occurrence of abaxial aberration such as curvature of field at a telephoto limit or magnification chromatic aberration. On the other hand, when the value goes below the lower limit of the condition (3-2), it might be difficult to suppress increase in the size of the lens system due to increase in the amount of movement of the third lens unit, and occurrence of aberration due to increase in the power of the third lens unit, particularly, occurrence of axial aberration such as spherical aberration at a telephoto limit.
When at least one of the following conditions (3-2)′ and (3-2)′′ is satisfied, the above-mentioned effect is achieved more successfully.

1.5<(β2T/β2W)/(β3T/β3W)  (3-2)′

(β2T/β2W)/(β3T/β3W)<4.5  (3-2)′′

In a zoom lens system having the basic configuration I like the zoom lens systems according to Embodiments I-1 to I-6, it is preferable that the following condition (4-2) is satisfied.

0.9<M1/M3<3.0  (4-2)

where,
M1 is an amount of movement of the first lens unit in the direction along the optical axis during zooming from a wide-angle limit to a telephoto limit (movement from the image side to the object side is positive), and
M3 is an amount of movement of the third lens unit in the direction along the optical axis during zooming from a wide-angle limit to a telephoto limit (movement from the image side to the object side is positive).
The condition (4-2) sets forth the ratio between the amount of movement of the first lens unit in the direction along the optical axis and the amount of movement of the third lens unit in the direction along the optical axis. When the value exceeds the upper limit of the condition (4-2), the amount of movement of the first lens unit increases and then, the overall optical length increases. As a result, a lens barrel at the time of retraction increases in size, which might result in difficulty in achieving a compact zoom lens system. On the other hand, when the value goes below the lower limit of the condition (4-2), the amount of movement of the third lens unit becomes excessively great, which might result in difficulty in compensating curvature of field or magnification chromatic aberration.
When at least one of the following conditions (4-2)′ and (4-2)′′ is satisfied, the above-mentioned effect is achieved more successfully.

1.1<M1/M3  (4-2)′

M1/M3<2.8  (4-2)′′

In a zoom lens system like the zoom lens systems according to Embodiments II-1 to II-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 at most two lens elements, the second lens unit is composed of two lens elements, and the third lens unit is composed of three lens elements, in order from the object side to the image side, including an object side lens element having positive optical power, a lens element having negative optical power, and an image side lens element having positive optical power (this lens configuration is referred to as basic configuration II of the embodiments, hereinafter), the following conditions (3-2), (b-1) and (a-2) are satisfied.

1.1<(β2T/β2W)/(β3T/β3W)<5.2  (3-2)

fT/fW>6.0  (b-1)

ωW≧30  (a-2)

where,
β2T is a lateral magnification of the second lens unit at a telephoto limit,
β2W is a lateral magnification of the second lens unit at a wide-angle limit,
β3T is a lateral magnification of the third lens unit at a telephoto limit,
β3W is a lateral magnification of the third lens unit at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit,
fW is a focal length of the entire system at a wide-angle limit, and
ωW is a half view angle (°) at a wide-angle limit.
The condition (3-2) sets forth the ratio between lateral magnification change in the second lens unit and lateral magnification change in the third lens unit. When the value exceeds the upper limit of the condition (3-2), variable magnification load to the second lens unit becomes excessively great, which might result in difficulty in suppressing occurrence of aberration due to increase in the power, particularly, occurrence of abaxial aberration such as curvature of field at a telephoto limit or magnification chromatic aberration. On the other hand, when the value goes below the lower limit of the condition (3-2), it might be difficult to suppress increase in the size of the lens system due to increase in the amount of movement of the third lens unit, and occurrence of aberration due to increase in the power of the third lens unit, particularly, occurrence of axial aberration such as spherical aberration at a telephoto limit.
When at least one of the following conditions (3-2)′ and (3-2)′′ is satisfied, the above-mentioned effect is achieved more successfully.

1.5<(β2T/β2W)/(β3T/β3W)  (3-2)′

(β2T/β2W)/(β3T/β3W)<4.5  (3-2)′′

In a zoom lens system having the basic configuration II like the zoom lens systems according to Embodiments II-1 to II-8, it is preferable that the following condition (2-2) is satisfied.

−2.0<f2/fW<−1.1  (2-2)

where,
f2 is a composite focal length of the second lens unit, and
fW is a focal length of the entire system at a wide-angle limit.
The condition (2-2) sets forth a suitable focal length of the second lens unit. When the value exceeds the upper limit of the condition (2-2), the focal length of the second lens unit becomes excessively long, and the amount of movement of the second lens unit increases in zooming, which might result in difficulty in achieving a compact zoom lens system having a zooming ratio exceeding 6.0. On the other hand, when the value goes below the lower limit of the condition (2-2), the focal length of the second lens unit becomes excessively short, which might result in difficulty in compensating variation in aberration caused by movement of the second lens unit.
When at least one of the following conditions (2-2)′ and (2-2)′′ is satisfied, the above-mentioned effect is achieved more successfully.

−1.7<f2/fW  (2-2)′

f2/fW<−1.5  (2-2)′′

In a zoom lens system having the basic configuration II like the zoom lens systems according to Embodiments II-1 to II-8, it is preferable that the following condition (4-2) is satisfied.

0.9<M1/M3<3.0  (4-2)

where,
M1 is an amount of movement of the first lens unit in the direction along the optical axis during zooming from a wide-angle limit to a telephoto limit (movement from the image side to the object side is positive), and
M3 is an amount of movement of the third lens unit in the direction along the optical axis during zooming from a wide-angle limit to a telephoto limit (movement from the image side to the object side is positive).
The condition (4-2) sets forth the ratio between the amount of movement of the first lens unit in the direction along the optical axis and the amount of movement of the third lens unit in the direction along the optical axis. When the value exceeds the upper limit of the condition (4-2), the amount of movement of the first lens unit increases and then, the overall optical length increases. As a result, a lens barrel at the time of retraction increases in size, which might result in difficulty in achieving a compact zoom lens system. On the other hand, when the value goes below the lower limit of the condition (4-2), the amount of movement of the third lens unit becomes excessively great, which might result in difficulty in compensating curvature of field or magnification chromatic aberration.
When at least one of the following conditions (4-2)′ and (4-2)′′ is satisfied, the above-mentioned effect is achieved more successfully.

1.1<M1/M3  (4-2)′

M1/M3<2.8  (4-2)′′

In a zoom lens system like the zoom lens systems 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 at most two lens elements, the second lens unit is composed of two lens elements, and the third lens unit is composed of three lens elements, in order from the object side to the image side, including an object side lens element having positive optical power, a lens element having negative optical power, and an image side lens element having positive optical power (this lens configuration is referred to as basic configuration III of the embodiments, hereinafter), the following conditions (4-2), (b-1) and (a-2) are satisfied.

0.9<M1/M3<3.0  (4-2)

fT/fW>6.0  (b-1)

ωW≧30  (a-2)

where,
M1 is an amount of movement of the first lens unit in the direction along the optical axis during zooming from a wide-angle limit to a telephoto limit (movement from the image side to the object side is positive),
M3 is an amount of movement of the third lens unit in the direction along the optical axis during zooming from a wide-angle limit to a telephoto limit (movement from the image side to the object side is positive),
fT is a focal length of the entire system at a telephoto limit,
fW is a focal length of the entire system at a wide-angle limit, and
ωW is a half view angle (°) at a wide-angle limit.
The condition (4-2) sets forth the ratio between the amount of movement of the first lens unit in the direction along the optical axis and the amount of movement of the third lens unit in the direction along the optical axis. When the value exceeds the upper limit of the condition (4-2), the amount of movement of the first lens unit increases and then, the overall optical length increases. As a result, a lens barrel at the time of retraction increases in size, which might result in difficulty in achieving a compact zoom lens system. On the other hand, when the value goes below the lower limit of the condition (4-2), the amount of movement of the third lens unit becomes excessively great, which might result in difficulty in compensating curvature of field or magnification chromatic aberration.
When at least one of the following conditions (4-2)′ and (4-2)′′ is satisfied, the above-mentioned effect is achieved more successfully.

1.1<M1/M3  (4-2)′

M1/M3<2.8  (4-2)′′

In a zoom lens system having the basic configuration III like the zoom lens systems according to Embodiments III-1 to III-7, it is preferable that the following condition (2-2) is satisfied.

−2.0<f2/fW<−1.1  (2-2)

where,
f2 is a composite focal length of the second lens unit, and
fW is a focal length of the entire system at a wide-angle limit.
The condition (2-2) sets forth a suitable focal length of the second lens unit. When the value exceeds the upper limit of the condition (2-2), the focal length of the second lens unit becomes excessively long, and the amount of movement of the second lens unit increases in zooming, which might result in difficulty in achieving a compact zoom lens system having a zooming ratio exceeding 6.0. On the other hand, when the value goes below the lower limit of the condition (2-2), the focal length of the second lens unit becomes excessively short, which might result in difficulty in compensating variation in aberration caused by movement of the second lens unit.
When at least one of the following conditions (2-2)′ and (2-2)′′ is satisfied, the above-mentioned effect is achieved more successfully.

−1.7<f2/fW  (2-2)′

f2/fW<−1.5  (2-2)′′

In a zoom lens system having the basic configuration III like the zoom lens systems according to Embodiments III-1 to III-7, it is preferable that the following condition (3-2) is satisfied.

1.1<(β2T/β2W)/(β3T/β3W)<5.2  (3-2)

where,

β2T is a lateral magnification of the second lens unit at a telephoto limit,
β2W is a lateral magnification of the second lens unit at a wide-angle limit,
β3T is a lateral magnification of the third lens unit at a telephoto limit, and
β3W is a lateral magnification of the third lens unit at a wide-angle limit.
The condition (3-2) sets forth the ratio between lateral magnification change in the second lens unit and lateral magnification change in the third lens unit. When the value exceeds the upper limit of the condition (3-2), variable magnification load to the second lens unit becomes excessively great, which might result in difficulty in suppressing occurrence of aberration due to increase in the power, particularly, occurrence of abaxial aberration such as curvature of field at a telephoto limit or magnification chromatic aberration. On the other hand, when the value goes below the lower limit of the condition (3-2), it might be difficult to suppress increase in the size of the lens system due to increase in the amount of movement of the third lens unit, and occurrence of aberration due to increase in the power of the third lens unit, particularly, occurrence of axial aberration such as spherical aberration at a telephoto limit.
When at least one of the following conditions (3-2)′ and (3-2)′′ is satisfied, the above-mentioned effect is achieved more successfully.

1.5<(β2T/β2W)/(β3T/β3W)  (3-2)′

(β2T/β2W)/(β3T/β3W)<4.5  (3-2)′′

In a zoom lens system having the basic configuration I like the zoom lens systems according to Embodiments I-1 to I-6, in which the second lens unit includes a lens element having positive optical power, and in a zoom lens system having the basic configuration II like the zoom lens systems according to Embodiments II-1 to II-8, in which the second lens unit includes a lens element having positive optical power, and in a zoom lens system having the basic configuration III like the zoom lens systems according to Embodiments III-1 to III-7, in which the second lens unit includes a lens element having positive optical power, it is preferable that the following condition (5) is satisfied.

1.88<nd2p<2.20  (5)

where,
nd2p is a refractive index to the d-line of the lens element having positive optical power, which is included in the second lens unit.
The condition (5) sets forth the refractive index of the lens element having positive optical power, which is included in the second lens unit. When the value exceeds the upper limit of the condition (5), it might be difficult to realize mass production of the lens material. On the other hand, when the value goes below the lower limit of the condition (5), it might be difficult to compensate curvature of field and distortion at a wide-angle limit, and coma aberration in the entire zooming range from a wide-angle limit to a telephoto limit.
When at least one of the following conditions (5)′ and (5)′′ is satisfied, the above-mentioned effect is achieved more successfully.

1.90<nd2p  (5)′

nd2p<2.15  (5)′′

In a zoom lens system having the basic configuration I like the zoom lens systems according to Embodiments I-1 to I-6, in which the second lens unit includes a lens element having negative optical power, and in a zoom lens system having the basic configuration II like the zoom lens systems according to Embodiments II-1 to II-8, in which the second lens unit includes a lens element having negative optical power, and in a zoom lens system having the basic configuration III like the zoom lens systems according to Embodiments III-1 to III-7, in which the second lens unit includes a lens element having negative optical power, it is preferable that the following condition (6) is satisfied.

0.35<(r2na+r2nb)/(r2na−r2nb)<1.20  (6)

where,
r2na is a radius of curvature of an object side surface of the lens element having negative optical power, which is included in the second lens unit, and
r2nb is a radius of curvature of an image side surface of the lens element having negative optical power, which is included in the second lens unit.
The condition (6) sets forth the shape factor of the lens element having negative optical power, which is included in the second lens unit. When the value exceeds the upper limit of the condition (6), it might be difficult to compensate curvature of field and distortion at a wide-angle limit. On the other hand, when the value goes below the lower limit of the condition (6), it might be difficult to compensate coma aberration in the entire zooming range from a wide-angle limit to a telephoto limit.
When at least one of the following conditions (6)′ and (6)′′ is satisfied, the above-mentioned effect is achieved more successfully.

0.60<(r2na+r2nb)/(r2na−r2nb)  (6)′

(r2na+r2nb)/(r2na−r2nb)<0.90  (6)′′

In a zoom lens system having the basic configuration I like the zoom lens systems according to Embodiments I-1 to I-6, in which the second lens is composed of two lens elements, i.e., in order from the object side to the image side, a lens element having negative optical power and a lens element having positive optical power, and in a zoom lens system having the basic configuration II like the zoom lens systems according to Embodiments II-1 to II-8, in which the second lens unit is composed of two lens elements, i.e., in order from the object side to the image side, a lens element having negative optical power and a lens element having positive optical power, and in a zoom lens system having the basic configuration III like the zoom lens systems according to Embodiments III-1 to III-7, in which the second lens unit is composed of two lens elements, i.e., in order from the object side to the image side, a lens element having negative optical power and a lens element having positive optical power, it is preferable that the following condition (7) is satisfied.

−8.5<(r2nb+r2pa)/(r2nb−r2pa)<−3.5  (7)

where,
r2nb is a radius of curvature of an image side surface of the lens element having negative optical power, which is included in the second lens unit, and
r2pa is a radius of curvature of an object side surface of the lens element having positive optical power, which is included in the second lens unit.
The condition (7) sets forth the shape factor of an air lens between the two lens elements constituting the second lens unit. When the value exceeds the upper limit of the condition (7), it might be difficult to compensate curvature of field and distortion at a wide-angle limit. On the other hand, when the value goes below the lower limit of the condition (7), it might be difficult to compensate coma aberration in the entire zooming range from a wide-angle limit to a telephoto limit.
When at least one of the following conditions (7)′ and (7)′′ is satisfied, the above-mentioned effect is achieved more successfully.

−8.0<(r2nb+r2pa)/(r2nb−r2pa)  (7)′

(r2nb+r2pa)/(r2nb−r2pa)<−5.2  (7)′′

In a zoom lens system having the basic configuration I like the zoom lens systems according to Embodiments I-1 to I-6, in which the first lens unit includes a lens element having positive optical power, and in a zoom lens system having the basic configuration II like the zoom lens systems according to Embodiments II-1 to II-8, in which the first lens unit includes a lens element having positive optical power, and in a zoom lens system having the basic configuration III like the zoom lens systems according to Embodiments III-1 to III-7, in which the first lens unit includes a lens element having positive optical power, it is preferable that the following condition (8) is satisfied.

−1.80<(r1pa+r1pb)/(r1pa−r1pb)<0.00  (8)

where,
r1pa is a radius of curvature of an object side surface of the lens element having positive optical power, which is included in the first lens unit, and
r1pb is a radius of curvature of an image side surface of the lens element having positive optical power, which is included in the first lens unit.
The condition (8) sets forth the shape factor of the lens element having positive optical power, which is included in the first lens unit. When the value exceeds the upper limit of the condition (8), it might be difficult to compensate coma aberration at a telephoto limit. On the other hand, when the value goes below the lower limit of the condition (8), it might be difficult to compensate curvature of field at a wide-angle limit.
When at least one of the following conditions (8)′ and (8)′′ is satisfied, the above-mentioned effect is achieved more successfully.

−1.47<(r1pa+r1pb)/(r1pa−r1pb)  (8)′

(r1pa+r1pb)/(r1pa−r1pb)<−1.20  (8)′′

In a zoom lens system having the basic configuration I like the zoom lens systems according to Embodiments I-1 to I-6, and in a zoom lens system having the basic configuration II like the zoom lens systems according to Embodiments II-1 to II-8, and in a zoom lens system having the basic configuration III like the zoom lens systems according to Embodiments III-1 to III-7, it is preferable that the following condition (9) is satisfied.

1.87<f3/fW<3.00  (9)

where,
f3 is a composite focal length of the third lens unit, and
fW is a focal length of the entire system at a wide-angle limit.
The condition (9) sets forth a suitable focal length of the third lens unit. When the value exceeds the upper limit of the condition (9), the focal length of the third lens unit becomes excessively long, which might result in difficulty in achieving a compact zoom lens system. Further, when the value exceeds the upper limit of the condition (9), the amount of movement of, for example, the third lens unit becomes excessively great when the third lens unit is moved in a direction perpendicular to the optical axis for blur compensation. Such a situation is not desirable. On the other hand, when the value goes below the lower limit of the condition (9), the focal length of the third lens unit becomes excessively short. Then, the aberration compensation capability of the third lens unit becomes excessively high, and compensation of various aberrations is not well-balanced, which might result in difficulty in achieving a compact zoom lens system.
When at least one of the following conditions (9)′ and (9)′′ is satisfied, the above-mentioned effect is achieved more successfully.

1.90<f3/fW  (9)′

f3/fW<2.06  (9)′′

In a zoom lens system having the basic configuration I like the zoom lens systems according to Embodiments I-1 to I-6, and in a zoom lens system having the basic configuration II like the zoom lens systems according to Embodiments II-1 to II-8, and in a zoom lens system having the basic configuration III like the zoom lens systems according to Embodiments III-1 to III-7, it is preferable that the following condition (10) is satisfied.

0.5<f3IL/f3<1.5  (10)

where,
f3IL is a focal length of the image side lens element having positive optical power, which is included in the third lens unit, and
f3 is a composite focal length of the third lens unit.
The condition (10) sets forth a suitable focal length of the image side lens element having positive optical power, which is included in the third lens unit. When the value exceeds the upper limit of the condition (10), it might be difficult to compensate spherical aberration and coma aberration in a balanced manner by other lens elements, although the overall optical length can be reduced. On the other hand, when the value goes below the lower limit of the condition (10), it might be difficult to reduce the overall optical length, although spherical aberration and coma aberration can be compensated in a balanced manner by other lens elements.
When at least one of the following conditions (10)′ and (10)′′ is satisfied, the above-mentioned effect is achieved more successfully.

1.0<f3IL/f3  (10)′

f3IL/f3<1.3  (10)′′

In a zoom lens system having the basic configuration I like the zoom lens systems according to Embodiments I-1 to I-6, and in a zoom lens system having the basic configuration II like the zoom lens systems according to Embodiments II-1 to II-8, and in a zoom lens system having the basic configuration III like the zoom lens systems according to Embodiments III-1 to III-7, it is preferable that the following condition (11) is satisfied.

−1.00<f3n/f3<−0.25  (11)

where,
f3n is a focal length of the lens element having negative optical power, which is included in the third lens unit, and
f3 is a composite focal length of the third lens unit.
The condition (11) sets forth a suitable focal length of the lens element having negative optical power, which is included in the third lens unit. When the value exceeds the upper limit of the condition (11), it might be difficult to compensate spherical aberration and coma aberration in a balanced manner by other lens elements, although the overall optical length can be reduced. On the other hand, when the value goes below the lower limit of the condition (11), it might be difficult to reduce the overall optical length, although spherical aberration and coma aberration can be compensated in a balanced manner by other lens elements.
When at least one of the following conditions (11)′ and (11)′′ is satisfied, the above-mentioned effect is achieved more successfully.

−0.68<f3n/f3  (11)′

f3n/f3<−0.46  (11)′′

Each of the lens units constituting the zoom lens system according to any of Embodiments I-1 to I-6, II-1 to II-8 and 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 the 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-7
FIG. 15 is a schematic construction diagram of a digital still camera according to Embodiment I-7. In FIG. 15, 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-1. In FIG. 15, 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, and 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, and an optical image of a photographic object generated by the zoom lens system 1 is formed on an image surface S.
A 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 and 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.
In this way, when the zoom lens system according to Embodiment I-1 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. 15, any one of the zoom lens systems according to Embodiments I-2 to I-6 may be employed in place of the zoom lens system according to Embodiment I-1. Further, the optical system of the digital still camera shown in FIG. 15 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 Embodiment I-7 has been described for a case that the employed zoom lens system 1 is a zoom lens system according to any of Embodiments I-1 to I-6. 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 systems described in Embodiments I-1 to I-6.
Further, Embodiment I-7 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 minor is arranged at an arbitrary position within the first lens unit G1 or the like. Further, in Embodiment I-7, 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 any of Embodiments I-1 to I-6 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-9
FIG. 36 is a schematic construction diagram of a digital still camera according to Embodiment II-9. In FIG. 36, 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-1. In FIG. 36, 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, and 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, and an optical image of a photographic object generated by the zoom lens system 1 is formed on an image surface S.
A 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 and 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.
In this way, when the zoom lens system according to Embodiment II-1 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. 36, any one of the zoom lens systems according to Embodiments II-2 to II-8 may be employed in place of the zoom lens system according to Embodiment II-1. Further, the optical system of the digital still camera shown in FIG. 36 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 Embodiment II-9 has been described for a case that the employed zoom lens system 1 is a zoom lens system according to any of Embodiments II-1 to II-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 systems described in Embodiments II-1 to II-8.
Further, Embodiment II-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 minor is arranged at an arbitrary position within the first lens unit G1 or the like. Further, in Embodiment II-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 any of Embodiments II-1 to II-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 III-8
FIG. 55 is a schematic construction diagram of a digital still camera according to Embodiment III-8. In FIG. 55, 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-1. In FIG. 55, 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, and 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, and an optical image of a photographic object generated by the zoom lens system 1 is formed on an image surface S.
A 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 and 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.
In this way, when the zoom lens system according to Embodiment III-1 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. 55, any one of the zoom lens systems according to Embodiments III-2 to III-7 may be employed in place of the zoom lens system according to Embodiment III-1. Further, the optical system of the digital still camera shown in FIG. 55 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 Embodiment III-8 has been described for a case that the employed zoom lens system 1 is a zoom lens system according to any of 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 systems 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 minor 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 any of 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 examples are described below in which the zoom lens systems according to Embodiments I-1 to I-6, II-1 to II-8 and III-1 to III-7 are implemented. Here, in the numerical examples, the units of length are all “mm”, while the units of 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 aspherical surfaces, and the aspherical 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
      
    
  




Here, κ is the conic constant, A4, A6, A8 and A10 are a fourth-order, sixth-order, eighth-order and tenth-order aspherical coefficients, respectively.

FIGS. 2, 5, 7, 10, 12 and 14 are longitudinal aberration diagrams of the zoom lens systems according to Embodiments I-1 to I-6, respectively.
FIGS. 17, 19, 22, 25, 28, 31, 33 and 35 are longitudinal aberration diagrams of the zoom lens systems according to Embodiments II-1 to II-8, respectively.
FIGS. 38, 40, 43, 46, 49, 52 and 54 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 and 8 are lateral aberration diagrams of the zoom lens systems at a telephoto limit according to Embodiments I-1 and I-3, respectively.
FIGS. 20, 23, 26 and 29 are lateral aberration diagrams of the zoom lens systems at a telephoto limit according to Embodiments II-2, II-3, II-4 and II-5, respectively.
FIGS. 41, 44, 47 and 50 are lateral aberration diagrams of the zoom lens systems at a telephoto limit according to Embodiments III-2, III-3, III-4 and III-5, 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 entirety of the 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 the image blur compensation state at a telephoto limit is as follows.














Amount of movement 



Example
(mm)


















I-1
0.122



I-3
0.162



II-2
0.122



II-3
0.129



II-4
0.164



II-5
0.162



III-2
0.129



III-3
0.132



III-4
0.164



III-5
0.162









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 entirety of the 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 the 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 the 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
22.20034
0.80000 
1.92286
20.9


 2
16.29755
3.20000
1.72916 
54.7


 3
139.18600
Variable




 4*
−59.14503
1.10000
1.85976
40.6


 5*
5.94383
1.39250




 6
8.10158 
1.70000
1.94595 
18.0


 7
14.57504
Variable




 8
∞ 
0.00000




(Diaphragm)






 9*
4.39479
2.50000
1.85135 
40.1


10
9.90230 
0.40000
1.92286
20.9


11
3.68214 
0.50000




12
10.58272
1.50000
1.77250 
49.6


13
−59.81446
Variable




 14*
14.64296
1.80000 
1.62299
58.1


15
−81.51573
Variable




16
∞ 
1.00000
1.51680 
64.2


17
∞ 
(BF)




Image surface
∞ 



















TABLE I-2





(Aspherical data)







Surface No. 4


K = 0.00000E+00, A4 = 1.61461E−04, A6 = −3.32899E−06, 


A8 = 4.44142E−08 A10 = −2.25656E−10


Surface No. 5


K = −2.51025E+00, A4 = 1.41935E−03, A6 = −1.36992E−05, 


A8 = 1.83402E−07 A10 = 1.40309E−09


Surface No. 9


K = −4.30638E−01, A4 = 1.17618E−04, A6 = 2.71101E−05, 


A8 = −5.66873E−06 A10 = 6.02589E−07


Surface No. 14


K = 0.00000E+00, A4 = 5.90546E−05, A6 = 6.41505E−06, 


A8 = −3.18335E−07 A10 = 6.30964E−09
















TABLE I-3





(Various data)

















Zooming ratio
6.54203















Wide-angle limit
Middle position
Telephoto limit





Focal length
6.1188
12.9779
40.0295


F-number
3.23953
3.96695
5.67089


View angle
34.8313
16.7900
5.3897


Image height
3.8300
3.8300
3.8300


Overall length of lens system
41.5545
37.1082
52.5801


BF
0.50591
0.51794
0.52121


d3
0.6000
4.2068
17.3105


d7
16.5610
4.8693
1.0000


 d13
2.3036
3.1689
16.2175


 d15
5.6914
8.4528
1.6384


Entrance pupil position
13.4247
15.7784
54.0064


Exit pupil position
−14.4333 
−18.8833 
−435.0709


Front principal points position
17.0374
20.0751
90.3573


Back principal points position
35.4356
24.1303
12.5506










Single lens data









Lens element
Initial surface number
Focal length





1
1
−71.0393


2
2
25.0404


3
4
−6.2333


4
6
17.1001


5
9
7.6785


6
10
−6.5541


7
12
11.7490


8
14
20.0692










Zoom lens unit data












Lens
Initial
Focal
Overall length
Front principal
Back principal


unit
surface No.
length
of lens unit
points position
points position





1
1
39.94948
4.00000
−0.67384
1.09928


2
4
−10.25874
4.19250
0.24741
1.66395


3
8
12.13874
4.90000
−2.11245
0.31040


4
14
20.06917
1.80000
0.17011
0.85302










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
4
−0.39544
−0.45929
−1.11120


3
8
−0.63375
−1.49544
−1.11002


4
14
0.61117
0.47297
0.81236









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
22.98440
0.80000
2.00170
20.6



 2
17.06934
3.00000
1.80420
46.5



 3
88.78142
Variable





 4*
−221.40520
1.00000
1.85976
40.6



 5*
5.56527
1.39220





 6
8.04492
1.70000
2.00170
20.6



 7
14.35270
Variable





 8
∞
0.00000





(Diaphragm)







 9*
4.58023
2.50000
1.77377
47.2



10
13.17091
0.40000
1.84666
23.8



11
3.98157
0.50000





12
11.32115
1.50000
1.80420
46.5



13
−172.13620
Variable





 14*
15.84590
1.80000
1.80420
46.5



15
696.20750
Variable





16
∞
1.00000
1.51680
64.2



17
∞
(BF)





Image surface
∞

















TABLE I-5





(Aspherical data)







Surface No. 4


K = 0.00000E+00, A4 = −7.92798E−05, A6 = 1.31994E−06,


A8 = 0.00000E+00 A10 = 0.00000E+00


Surface No. 5


K = −1.64472E+00, A4 = 8.04967E−04, A6 = −4.09967E−06,


A8 = 9.96207E−08 A10 = 3.79729E−09


Surface No. 9


K = −3.85474E−01, A4 = 7.27041E−05, A6 = 1.43854E−05,


A8 = −3.37492E−06 A10 = 3.29500E−07


Surface No. 14


K = 0.00000E+00, A4 = 4.52987E−05, A6 = 3.58657E−07,


A8 = 0.00000E+00 A10 = 0.00000E+00
















TABLE I-6





(Various data)







Zooming ratio 6.54358













Wide-angle
Middle
Telephoto




limit
position
limit






Focal length
6.7963
17.3331
44.4720



F-number
3.43627
3.88419
5.87738



View angle
32.0601
12.5864
4.8709



Image height
3.8300
3.8300
3.8300



Overall length
44.4426
45.4138
57.7571



of lens system






BF
0.49855
0.53779
0.50695



d3
0.5000
11.3199
18.7857



d7
17.5535
5.3040
1.4500



d13
3.9343
3.8667
18.8854



d15
6.3640
8.7933
2.5369



Entrance pupil
13.4475
33.8815
59.9670



position






Exit pupil
−18.1536
−20.4311
278.7394



position






Front principal
17.7674
36.8869
111.5473



points position






Back principal
37.6463
28.0807
13.2851



points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−71.0212


2
2
25.7964


3
4
−6.3015


4
6
16.1025


5
9
8.0531


6
10
−6.8775


7
12
13.2571


8
14
20.1391










Zoom lens unit data
















Front
Back



Initial

Overall
principal
principal


Lens
surface
Focal
length of
points
points


unit
No.
length
lens unit
position
position





1
1
42.02118
3.80000
−0.98229
0.81730


2
4
−10.85227
4.09220
0.21956
1.61285


3
8
13.70595
4.90000
−2.18526
0.19508


4
14
20.13910
1.80000
−0.02321
0.78029










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
4
−0.39511
−0.65191
−1.18204


3
8
−0.71083
−1.39583
−1.16962


4
14
0.57587
0.45330
0.76549









Numerical Example I-3
The zoom lens system of Numerical Example I-3 corresponds to Embodiment I-3 shown in FIG. 6. 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
21.11164
0.80000
2.00170
20.6



 2
15.12358
2.50000
1.80420
46.5



 3*
88.24478
Variable





 4*
−69.21321
1.00000
1.85976
40.6



 5*
4.93236
1.09570





 6
7.22589
1.70000
2.00170
20.6



 7
14.35270
Variable





 8
∞
0.00000





(Diaphragm)







 9*
4.94313
2.10000
1.77377
47.2



10
10.82877
0.80000
1.92286
20.9



11
4.47121
0.50000





12
11.90782
1.50000
1.80420
46.5



13
−39.79054
Variable





 14*
20.42889
1.80000
1.80420
46.5



15
−248.53400
Variable





16
∞
1.00000
1.51680
64.2



17
∞
(BF)





Image surface
∞

















TABLE I-8





(Aspherical data)







Surface No. 3


K = 0.00000E+00, A4 = 2.27928E−06, A6 = 3.00081E−10,


A8 = 0.00000E+00 A10 = 0.00000E+00


Surface No. 4


K = 0.00000E+00, A4 = 5.20294E−05, A6 = −4.16769E−08,


A8 = 0.00000E+00 A10 = 0.00000E+00


Surface No. 5


K = −2.47053E+00, A4 = 2.06679E−03, A6 = −2.74077E−05,


A8 = 6.95651E−07 A10 = −4.23395E−09


Surface No. 9


K = −4.61701E−01, A4 = 8.60229E−05, A6 = 2.31646E−05,


A8 = −4.52966E−06 A10 = 4.13883E−07


Surface No. 14


K = 0.00000E+00, A4 = 2.57276E−05, A6 = 3.06354E−06,


A8 = 0.00000E+00 A10 = 0.00000E+00
















TABLE I-9





(Various data)







Zooming ratio 6.54191













Wide-angle
Middle
Telephoto




limit
position
limit






Focal length
6.7983
17.3294
44.4739



F-number
3.40234
3.91077
4.59471



View angle
32.0530
12.6173
4.9207



Image height
3.8300
3.8300
3.8300



Overall length
40.8782
44.9165
53.2755



of lens system






BF
0.50271
0.52741
0.50364



d3
0.6000
11.2009
20.8199



d7
14.7539
5.4351
1.4500



d13
2.5571
3.2145
13.2000



d15
7.6688
9.7429
2.5063



Entrance pupil
11.7579
33.9417
82.6375



position






Exit pupil
−16.5435
−19.7880
−56.1280



position






Front principal
15.8449
36.4888
92.1852



points position






Back principal
34.0799
27.5871
8.8016



points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−57.0431


2
2
22.3546


3
4
−5.3221


4
6
12.9783


5
9
10.1707


6
10
−8.7828


7
12
11.5458


8
14
23.5435










Zoom lens unit data
















Front
Back



Initial

Overall
principal
principal


Lens
surface
Focal
length of
points
points


unit
No.
length
lens unit
position
position





1
1
38.26554
3.30000
−0.82482
0.73786


2
4
−9.46936
3.79570
0.23471
1.62366


3
8
12.87340
4.90000
−1.23135
0.84238


4
14
23.54354
1.80000
0.07600
0.87535










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
4
−0.37282
−0.63989
−1.82826


3
8
−0.81370
−1.42546
−0.78982


4
14
0.58564
0.49650
0.80488









Numerical Example I-4
The zoom lens system of Numerical Example I-4 corresponds to Embodiment I-4 shown in FIG. 9. 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
22.01411
0.80000
2.14422
17.5



 2
16.76615
2.50000
1.82080
42.7



 3*
101.42760
Variable





 4*
−71.58793
1.00000
1.85976
40.6



 5*
5.13092
1.09570





 6
7.40182
1.70000
2.00170
20.6



 7
14.35270
Variable





 8
∞
0.00000





(Diaphragm)







 9*
4.80218
2.10000
1.77377
47.2



10
9.87535
0.80000
1.92286
20.9



11
4.30138
0.50000





12
11.64846
1.50000
1.80420
46.5



13
−48.27259
Variable





 14*
19.51788
1.30000
1.80420
46.5



15
−601.21670
Variable





16
∞
1.00000
1.51680
64.2



17
∞
(BF)





Image surface
∞

















TABLE I-11





(Aspherical data)







Surface No. 3


K = 0.00000E+00, A4 = 1.96399E−06, A6 = 8.38790E−10,


A8 = 0.00000E+00 A10 = 0.00000E+00


Surface No. 4


K = 0.00000E+00, A4 = 2.08635E−05, A6 = 4.82445E−07,


A8 = 0.00000E+00 A10 = 0.00000E+00


Surface No. 5


K = −2.72794E+00, A4 = 2.05037E−03, A6 = −3.37206E−05,


A8 = 8.72404E−07 A10 = −5.23638E−09


Surface No. 9


K = −4.61942E−01, A4 = 1.03075E−04, A6 = 2.43831E−05,


A8 = −4.51015E−06 A10 = 4.15499E−07


Surface No. 14


K = 0.00000E+00, A4 = 2.82102E−05, A6 = 3.05454E−06,


A8 = 0.00000E+00 A10 = 0.00000E+00
















TABLE I-12





(Various data)







Zooming ratio 6.54969













Wide-angle
Middle
Telephoto




limit
position
limit






Focal length
6.7999
17.3217
44.5372



F-number
3.42679
4.00985
4.56886



View angle
32.0408
12.5843
4.9066



Image height
3.8300
3.8300
3.8300



Overall length
41.1512
44.8950
53.2882



of lens system






BF
0.50957
0.51183
0.52021



d3
0.6000
10.9391
21.3625



d7
15.4165
5.6233
1.3000



d13
2.4448
3.4802
12.6158



d15
7.8846
10.0448
3.1939



Entrance pupil
11.9887
32.6384
82.8481



position






Exit pupil
−16.1869
−20.1889
−50.2594



position






Front principal
16.0192
35.4659
88.3232



points position






Back principal
34.3513
27.5733
8.7510



points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−66.9089


2
2
24.1504


3
4
−5.5354


4
6
13.5941


5
9
10.2331


6
10
−8.8686


7
12
11.8005


8
14
23.5288










Zoom lens unit data
















Front
Back



Initial

Overall
principal
principal


Lens
surface
Focal
length of
points
points


unit
No.
length
lens unit
position
position





1
1
39.22731
3.30000
−0.83975
0.75865


2
4
−9.73077
3.79570
0.26561
1.66074


3
8
13.01946
4.90000
−1.48970
0.66880


4
14
23.52878
1.30000
0.02268
0.60146










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
4
−0.37298
−0.61781
−1.82667


3
8
−0.79375
−1.44795
−0.79235


4
14
0.58553
0.49362
0.78444









Numerical Example I-5
The zoom lens system of Numerical Example I-5 corresponds to Embodiment I-5 shown in FIG. 11. 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
25.31776
0.80000
1.92286
20.9



 2
18.23858
2.90000
1.77250
49.6



 3
141.43600
Variable





 4*
−74.12426
0.95000
1.85976
40.6



 5*
5.92627
1.47140





 6
8.28920
1.70000
2.14422
17.5



 7
12.83109
Variable





 8
∞
0.00000





(Diaphragm)







 9*
4.63999
2.45000
1.80139
45.4



10
11.40598
0.50000
1.92286
20.9



11
4.08736
0.48000





12
11.58038
1.50000
1.80420
46.5



13
−46.42335
Variable





 14*
16.70893
1.70000
1.80610
40.7



15
−271.10350
Variable





16
∞
1.00000
1.51680
64.2



17
∞
(BF)





Image surface
∞

















TABLE I-14





(Aspherical data)







Surface No. 4


K = 0.00000E+00, A4 = 8.00930E−05, A6 = −8.24171E−07,


A8 = 7.02480E−09 A10 = 0.00000E+00


Surface No. 5


K = −2.80748E+00, A4 = 1.51170E−03, A6 = −1.93182E−05,


A8 = 3.79463E−07 A10 = −1.27953E−09


Surface No. 9


K = −3.81122E−01, A4 = 1.92672E−05, A6 = 2.36355E−05,


A8 = −5.76293E−06 A10 = 5.76364E−07


Surface No. 14


K = 0.00000E+00, A4 = 5.48957E−05, A6 = 4.00480E−07,


A8 = 0.00000E+00 A10 = 0.00000E+00
















TABLE I-15





(Various data)







Zooming ratio 6.54099













Wide-angle
Middle
Telephoto




limit
position
limit






Focal length
6.1338
15.6371
40.1213



F-number
3.35969
3.84965
5.84335



View angle
35.0631
13.8718
5.4025



Image height
3.8300
3.8300
3.8300



Overall length
43.0188
45.0018
57.0268



of lens system






BF
0.49471
0.53782
0.50457



d3
0.5000
11.4355
18.9917



d7
17.0651
5.3765
1.4500



d13
3.8959
4.3424
17.9582



d15
5.6117
7.8582
2.6709



Entrance pupil
12.7522
32.7502
57.3438



position






Exit pupil
−17.6154
−20.9508
309.8164



position






Front principal
16.8085
37.0083
102.6693



points position






Back principal
36.8850
29.3648
16.9055



points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−74.7335


2
2
26.8298


3
4
−6.3478


4
6
17.0587


5
9
8.4064


6
10
−7.1366


7
12
11.6594


8
14
19.5762










Zoom lens unit data
















Front
Back



Initial

Overall
principal
principal


Lens
surface
Focal
length of
points
points


unit
No.
length
lens unit
position
position





1
1
43.09186
3.70000
−0.63212
1.04900


2
4
−10.40411
4.12140
0.28566
1.75797


3
8
12.61365
4.93000
−1.72530
0.54757


4
14
19.57623
1.70000
0.05479
0.81105










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
4
−0.35568
−0.56805
−0.96698


3
8
−0.65716
−1.29835
−1.26908


4
14
0.60898
0.49202
0.75870









Numerical Example I-6
The zoom lens system of Numerical Example I-6 corresponds to Embodiment I-6 shown in FIG. 13. 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
25.31390
0.80000
1.92286
20.9



 2
18.37307
2.90000
1.77250
49.6



 3
127.09120
Variable





 4*
−72.33967
0.95000
1.85976
40.6



 5*
5.53361
1.50880





 6
8.10144
1.70000
2.14422
17.5



 7
12.83109
Variable





 8
∞
0.00000





(Diaphragm)







 9*
4.58126
2.45000
1.80139
45.4



10
12.89458
0.50000
1.92286
20.9



11
4.09435
0.48000





12
12.11282
1.50000
1.80420
46.5



13
−29.99816
Variable





 14*
16.30826
1.70000
1.82080
42.7



15
−204.49060
Variable





16
∞
1.00000
1.51680
64.2



17
∞
(BF)





Image surface
∞

















TABLE I-17





(Aspherical data)







Surface No. 4


K = 0.00000E+00, A4 = 1.38654E−04, A6 = −2.03482E−06,


A8 = 1.30075E−08 A10 = 0.00000E+00


Surface No. 5


K = −2.38369E+00, A4 = 1.55078E−03, A6 = −1.46113E−05,


A8 = 2.67367E−07 A10 = −2.02236E−09


Surface No. 9


K = −4.10236E−01, A4 = 2.02270E−05, A6 = 2.52654E−05,


A8 = −7.12069E−06 A10 = 8.11753E−07


Surface No. 14


K = 0.00000E+00, A4 = 5.64788E−05, A6 = 4.75905E−07,


A8 = 0.00000E+00 A10 = 0.00000E+00
















TABLE I-18





(Various data)







Zooming ratio 6.54149













Wide-angle
Middle
Telephoto




limit
position
limit






Focal length
5.5377
14.1127
36.2248



F-number
3.29490
3.84420
5.79699



View angle
37.8649
15.3659
5.9868



Image height
3.8300
3.8300
3.8300



Overall length
41.5403
44.0499
56.5476



of lens system






BF
0.51202
0.52769
0.52473



d3
0.5000
11.0956
19.1926



d7
16.2704
5.0362
1.4500



d13
3.8899
4.8390
17.2154



d15
4.8791
7.0627
2.6761



Entrance pupil
12.0360
30.5678
56.7404



position






Exit pupil
−17.3975
−22.2119
209.0752



position






Front principal
15.8615
35.9218
99.2574



points position






Back principal
36.0026
29.9372
20.3228



points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−76.8613


2
2
27.4838


3
4
−5.9453


4
6
16.1170


5
9
7.8392


6
10
−6.6830


7
12
10.9026


8
14
18.4654










Zoom lens unit data
















Front
Back



Initial

Overall
principal
principal


Lens
surface
Focal
length of
points
points


unit
No.
length
lens unit
position
position





1
1
44.06577
3.70000
−0.70119
0.98430


2
4
−9.81147
4.15880
0.22506
1.68504


3
8
11.74129
4.93000
−1.33477
0.80049


4
14
18.46535
1.70000
0.06920
0.83229










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
4
−0.31841
−0.48529
−0.80946


3
8
−0.63113
−1.30361
−1.36507


4
14
0.62535
0.50625
0.74396









The following Table I-19 shows the corresponding values to the individual conditions in the zoom lens systems of each of Numerical Examples.







TABLE I-19







(Values corresponding to conditions)









Example















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


















(2-2)
f2/fW
−1.68
−1.60
−1.39
−1.43
−1.70
−1.77


(b-1)
fT/fW
6.54
6.54
6.54
6.55
6.54
6.54


(a-2)
ωW
34.84
32.06
32.06
32.05
35.06
37.88


(3-2)
(β2T/β2W)/(β3T/β3W)
1.60
1.82
5.05
4.91
1.41
1.18


(4-2)
M1/M3
1.12
1.20
2.26
2.21
1.26
1.35


 (5)
nd2p
1.946
2.002
2.002
2.002
2.144
2.144


 (6)
(r2na + r2nb)/(r2na − r2nb)
0.82
0.95
0.87
0.87
0.85
0.86


 (7)
(r2nb + r2pa)/(r2nb − r2pa)
−6.51
−5.49
−5.30
−5.52
−6.02
−5.31


 (8)
(r1pa + r1pb)/(r1pa − r1pb)
−1.27
−1.48
−1.41
−1.40
−1.30
−1.34


 (9)
f3/fW
1.98
2.02
1.89
1.91
2.06
2.12


(10)
f3IL/f3
1.15
1.30
1.13
1.16
1.14
1.07


(11)
f3n/f3
−0.54
−0.50
−0.68
−0.68
−0.57
−0.57









Numerical Example II-1
The zoom lens system of Numerical Example II-1 corresponds to Embodiment II-1 shown in FIG. 16. 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
21.67895
0.80000
2.00170
20.6


 2
16.21267
3.20000
1.72916
54.7


 3
174.74440
Variable




 4*
−53.85976
1.10000
1.85976
40.6


 5*
5.71997
0.92630




 6
7.76084
1.70000
2.00170
20.6


 7
16.00169
Variable




 8
∞
0.00000




(Diaphragm)






 9*
4.28080
2.50000
1.85135
40.1


10
7.80657
0.40000
2.00170
20.6


11
3.57214
0.50000




12
9.44005
1.50000
1.77250
49.6


13
214.22130
Variable




 14*
12.42141
1.80000
1.62299
58.1


15
−75.23346
Variable




16
∞
1.00000
1.51680
64.2


17
∞
(BF)




Image surface
∞
















TABLE II-2





(Aspherical data)







Surface No. 4


K = 0.00000E+00, A4 = 4.56239E−05, A6 = −6.94009E−07,


A8 = 1.81220E−08 A10 = −8.02787E−11


Surface No. 5


K = −1.98341E+00, A4 = 1.07747E−03, A6 = −7.31374E−06,


A8 = 1.86112E−07 A10 = 5.59108E−10


Surface No. 9


K = −3.53088E−01, A4 = 4.87967E−05, A6 = 2.95696E−05,


A8 = −7.13705E−06 A10 = 7.21043E−07


Surface No. 14


K = 0.00000E+00, A4 = 6.02721E−05, A6 = 2.35414E−06,


A8 = −1.45477E−07 A10 = 3.81222E−09
















TABLE II-3





(Various data)







Zooming ratio 6.58661











Wide-angle
Middle
Telephoto



limit
position
limit





Focal length
7.0002
17.9935
46.1078


F-number
3.42534
4.28755
5.96646


View angle
31.0628
12.2142
4.6470


Image height
3.8300
3.8300
3.8300


Overall length
41.8456
38.5980
53.0305


of lens system





BF
0.50774
0.54740
0.50181


d3
0.6000
6.5818
17.3687


d7
16.6466
2.8215
1.0000


d13
2.3747
3.4807
17.1718


d15
6.2903
9.7403
1.5619


Entrance pupil position
14.0988
19.1342
55.2858


Exit pupil position
−15.3366
−21.2790
122.6438


Front principal
18.0062
22.2940
118.7990


points position





Back principal
34.8454
20.6045
6.9227


points position










Single lens data









Lens element
Initial surface number
Focal length





1
1
−69.2618


2
2
24.3018


3
4
−5.9634


4
6
13.6363


5
9
8.3957


6
10
−6.9006


7
12
12.7428


8
14
17.2488










Zoom lens unit data












Lens
Initial
Focal
Overall length
Front principal
Back principal


unit
surface No.
length
of lens unit
points position
points position





1
1
38.69978
4.00000
−0.62539
1.15784


2
4
−10.96627
3.72630
0.32297
1.75775


3
8
13.67425
4.90000
−3.21446
−0.36143


4
14
17.24879
1.80000
0.15841
0.84054










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
4
−0.45753
−0.60969
−1.52316


3
8
−0.77212
−2.46223
−0.99453


4
14
0.51204
0.30972
0.78651









Numerical Example II-2
The zoom lens system of Numerical Example II-2 corresponds to Embodiment II-2 shown in FIG. 18. 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
22.20034
0.80000
1.92286
20.9


 2
16.29755
3.20000
1.72916
54.7


 3
139.18600
Variable




 4*
−59.14503
1.10000
1.85976
40.6


 5*
5.94383
1.39250




 6
8.10158
1.70000
1.94595
18.0


 7
14.57504
Variable




 8
∞
0.00000




(Diaphragm)






 9*
4.39479
2.50000
1.85135
40.1


10
9.90230
0.40000
1.92286
20.9


11
3.68214
0.50000




12
10.58272
1.50000
1.77250
49.6


13
−59.81446
Variable




 14*
14.64296
1.80000
1.62299
58.1


15
−81.51573
Variable




16
∞
1.00000
1.51680
64.2


17
∞
(BF)




Image surface
∞
















TABLE II-5





(Aspherical data)







Surface No. 4


K = 0.00000E+00, A4 = 1.61461E−04, A6 = −3.32899E−06,


A8 = 4.44142E−08 A10 = −2.25656E−10


Surface No. 5


K = −2.51025E+00, A4 = 1.41935E−03, A6 = −1.36992E−05,


A8 = 1.83402E−07 A10 = 1.40309E−09


Surface No. 9


K = −4.30638E−01, A4 = 1.17618E−04, A6 = 2.71101E−05,


A8 = −5.66873E−06 A10 = 6.02589E−07


Surface No. 14


K = 0.00000E+00, A4 = 5.90546E−05, A6 = 6.41505E−06,


A8 = −3.18335E−07 A10 = 6.30964E−09
















TABLE II-6





(Various data)







Zooming ratio 6.54203











Wide-angle
Middle
Telephoto



limit
position
limit





Focal length
6.1188
12.9779
40.0295


F-number
3.23953
3.96695
5.67089


View angle
34.8313
16.7900
5.3897


Image height
3.8300
3.8300
3.8300


Overall length
41.5545
37.1082
52.5801


of lens system





BF
0.50591
0.51794
0.52121


d3
0.6000
4.2068
17.3105


d7
16.5610
4.8693
1.0000


d13
2.3036
3.1689
16.2175


d15
5.6914
8.4528
1.6384


Entrance pupil
13.4247
15.7784
54.0064


position





Exit pupil
−14.4333
−18.8833
−435.0709


position





Front principal
17.0374
20.0751
90.3573


points position





Back principal
35.4356
24.1303
12.5506


points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−71.0393


2
2
25.0404


3
4
−6.2333


4
6
17.1001


5
9
7.6785


6
10
−6.5541


7
12
11.7490


8
14
20.0692










Zoom lens unit data












Lens
Initial
Focal
Overall length
Front principal
Back principal


unit
surface No.
length
of lens unit
points position
points position





1
1
39.94948
4.00000
−0.67384
1.09928


2
4
−10.25874
4.19250
0.24741
1.66395


3
8
12.13874
4.90000
−2.11245
0.31040


4
14
20.06917
1.80000
0.17011
0.85302










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
4
−0.39544
−0.45929
−1.11120


3
8
−0.63375
−1.49544
−1.11002


4
14
0.61117
0.47297
0.81236









Numerical Example II-3
The zoom lens system of Numerical Example II-3 corresponds to Embodiment II-3 shown in FIG. 21. 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
20.56187
0.80000
1.92286
20.9


 2
14.81270
3.20000
1.72916
54.7


 3
158.73300
Variable




 4*
−59.17839
1.10000
1.85976
40.6


 5*
5.51137
1.13160




 6
7.62681
1.70000
1.94595
18.0


 7
14.57504
Variable




 8
∞
0.00000




(Diaphragm)






 9*
4.20287
2.50000
1.85135
40.1


10
9.49076
0.40000
1.92286
20.9


11
3.47256
0.50000




12
9.45232
1.50000
1.77250
49.6


13
−630.07970
Variable




 14*
12.45881
1.80000
1.62299
58.1


15
−53.07139
Variable




16
∞
1.00000
1.51680
64.2


17
∞
(BF)




Image surface
∞
















TABLE II-8





(Aspherical data)







Surface No. 4


K = 0.00000E+00, A4 = 7.16481E−05, A6 = −9.20654E−07,


A8 = 9.31422E−09 A10 = −1.08989E−11


Surface No. 5


K = −1.96424E+00, A4 = 1.20304E−03, A6 = −7.06323E−06,


A8 = 1.22887E−07 A10 = 1.45469E−09


Surface No. 9


K = −4.49892E−01, A4 = 1.71358E−04, A6 = 2.95164E−05,


A8 = −5.81944E−06 A10 = 6.34879E−07


Surface No. 14


K = 0.00000E+00, A4 = 3.68685E−05, A6 = 7.24260E−06,


A8 = −3.15541E−07 A10 = 5.13901E−09
















TABLE II-9





(Various data)







Zooming ratio 6.52948











Wide-angle
Middle
Telephoto



limit
position
limit





Focal length
6.1187
12.9818
39.9518


F-number
3.12003
3.77592
5.46453


View angle
34.8394
16.8681
5.3822


Image height
3.8300
3.8300
3.8300


Overall length
40.0820
35.9984
50.0898


of lens system





BF
0.50106
0.53718
0.50627


d3
0.6000
4.1205
15.5150


d7
15.7290
4.5669
1.0000


d13
2.2919
3.2444
15.6615


d15
5.3284
7.8978
1.7755


Entrance pupil
13.4079
15.7987
50.2041


position





Exit pupil
−14.5439
−19.3553
134.0690


position





Front principal
17.0381
20.3085
102.1063


points position





Back principal
33.9633
23.0165
10.1380


points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−61.5140


2
2
22.1975


3
4
−5.8185


4
6
15.1150


5
9
7.2781


6
10
−6.1295


7
12
12.0675


8
14
16.3687










Zoom lens unit data












Lens
Initial
Focal
Overall length
Front principal
Back principal


unit
surface No.
length
of lens unit
points position
points position





1
1
35.95275
4.00000
−0.57161
1.19624


2
4
−9.80239
3.93160
0.32635
1.74700


3
8
12.20044
4.90000
−2.62124
0.03460


4
14
16.36872
1.80000
0.21311
0.89223










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
4
−0.43721
−0.51865
−1.30606


3
8
−0.71015
−1.78990
−1.11238


4
14
0.54813
0.38896
0.76487









Numerical Example II-4
The zoom lens system of Numerical Example II-4 corresponds to Embodiment II-4 shown in FIG. 24. 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
23.92026
0.80000
2.00170
20.6


 2
17.23850
2.50000
1.80420
46.5


 3*
91.93466
Variable




 4*
−86.26322
1.00000
1.85976
40.6


 5*
5.30963
1.09570




 6
7.43523
1.70000
2.00170
20.6


 7
14.35270
Variable




 8
∞
0.00000




(Diaphragm)






 9*
4.78659
2.10000
1.77377
47.2


10
10.28002
0.80000
1.92286
20.9


11
4.30394
0.50000




12
11.80608
1.50000
1.80420
46.5


13
−41.97623
Variable




 14*
18.23360
1.80000
1.80420
46.5


15
449.20610
Variable




16
∞
1.00000
1.51680
64.2


17
∞
(BF)




Image surface
∞
















TABLE II-11





(Aspherical data)







Surface No. 3


K = 0.00000E+00, A4 = 1.16573E−06, A6 = 3.73564E−10,


A8 = 0.00000E+00 A10 = 0.00000E+00


Surface No. 4


K = 0.00000E+00, A4 = 4.11218E−05, A6 = 4.14113E−07,


A8 = 0.00000E+00 A10 = 0.00000E+00


Surface No. 5


K = −2.55557E+00, A4 = 1.78988E−03, A6 = −2.05242E−05,


A8 = 4.89013E−07 A10 = 9.76558E−10


Surface No. 9


K = −4.57612E−01, A4 = 8.64666E−05, A6 = 3.31418E−05,


A8 = −6.94709E−06 A10 = 6.20715E−07


Surface No. 14


K = 0.00000E+00, A4 = 3.07143E−05, A6 = 2.65662E−06,


A8 = 0.00000E+00 A10 = 0.00000E+00
















TABLE II-12





(Various data)







Zooming ratio 6.54154











Wide-angle
Middle
Telephoto



limit
position
limit





Focal length
6.7983
17.3298
44.4713


F-number
3.35579
3.99862
4.53813


View angle
32.0536
12.6171
4.8991


Image height
3.8300
3.8300
3.8300


Overall length
40.9465
44.9233
56.8471


of lens system





BF
0.50091
0.52914
0.50678


d3
0.6000
11.6273
24.8265


d7
15.2623
4.7479
1.4500


d13
2.5571
3.4896
12.7618


d15
7.2306
9.7337
2.5063


Entrance pupil
12.0260
31.2012
94.2363


position





Exit pupil
−15.9753
−20.1365
−50.5394


position





Front principal
16.0192
33.9985
99.9644


points position





Back principal
34.1483
27.5935
12.3759


points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−65.5343


2
2
25.9947


3
4
−5.7884


4
6
13.7142


5
9
9.9217


6
10
−8.5733


7
12
11.6022


8
14
23.5883










Zoom lens unit data












Lens
Initial
Focal
Overall length
Front principal
Back principal


unit
surface No.
length
of lens unit
points position
points position





1
1
44.68006
3.30000
−0.90484
0.65703


2
4
−10.42881
3.79570
0.26532
1.66111


3
8
12.81592
4.90000
−1.39579
0.73000


4
14
23.58831
1.80000
−0.04213
0.76205










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
4
−0.33923
−0.52896
−1.60039


3
8
−0.74721
−1.48745
−0.77711


4
14
0.60028
0.49297
0.80031









Numerical Example II-5
The zoom lens system of Numerical Example II-5 corresponds to Embodiment II-5 shown in FIG. 27. 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
21.11164
0.80000
2.00170
20.6


 2
15.12358
2.50000
1.80420
46.5


 3*
88.24478
Variable




 4*
−69.21321
1.00000
1.85976
40.6


 5*
4.93236
1.09570




 6
7.22589
1.70000
2.00170
20.6


 7
14.35270
Variable




 8
∞
0.00000




(Diaphragm)






 9*
4.94313
2.10000
1.77377
47.2


10
10.82877
0.80000
1.92286
20.9


11
4.47121
0.50000




12
11.90782
1.50000
1.80420
46.5


13
−39.79054
Variable




 14*
20.42889
1.80000
1.80420
46.5


15
−248.53400
Variable




16
∞
1.00000
1.51680
64.2


17
∞
(BF)




Image surface
∞
















TABLE II-14





(Aspherical data)







Surface No. 3


K = 0.00000E+00, A4 = 2.27928E−06, A6 = 3.00081E−10,


A8 = 0.00000E+00 A10 = 0.00000E+00


Surface No. 4


K = 0.00000E+00, A4 = 5.20294E−05, A6 = −4.16769E−08,


A8 = 0.00000E+00 A10 = 0.00000E+00


Surface No. 5


K = −2.47053E+00, A4 = 2.06679E−03, A6 = −2.74077E−05,


A8 = 6.95651E−07 A10 = −4.23395E−09


Surface No. 9


K = −4.61701E−01, A4 = 8.60229E−05, A6 = 2.31646E−05,


A8 = −4.52966E−06 A10 = 4.13883E−07


Surface No. 14


K = 0.00000E+00, A4 = 2.57276E−05, A6 = 3.06354E−06,


A8 = 0.00000E+00 A10 = 0.00000E+00
















TABLE II-15





(Various data)







Zooming ratio 6.54191











Wide-angle
Middle
Telephoto



limit
position
limit





Focal length
6.7983
17.3294
44.4739


F-number
3.40234
3.91077
4.59471


View angle
32.0530
12.6173
4.9207


Image height
3.8300
3.8300
3.8300


Overall length
40.8782
44.9165
53.2755


of lens system





BF
0.50271
0.52741
0.50364


d3
0.6000
11.2009
20.8199


d7
14.7539
5.4351
1.4500


d13
2.5571
3.2145
13.2000


d15
7.6688
9.7429
2.5063


Entrance pupil
11.7579
33.9417
82.6375


position





Exit pupil
−16.5435
−19.7880
−56.1280


position





Front principal
15.8449
36.4888
92.1852


points position





Back principal
34.0799
27.5871
8.8016


points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−57.0431


2
2
22.3546


3
4
−5.3221


4
6
12.9783


5
9
10.1707


6
10
−8.7828


7
12
11.5458


8
14
23.5435










Zoom lens unit data












Lens
Initial
Focal
Overall length
Front principal
Back principal


unit
surface No.
length
of lens unit
points position
points position





1
1
38.26554
3.30000
−0.82482
0.73786


2
4
−9.46936
3.79570
0.23471
1.62366


3
8
12.87340
4.90000
−1.23135
0.84238


4
14
23.54354
1.80000
0.07600
0.87535










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
4
−0.37282
−0.63989
−1.82826


3
8
−0.81370
−1.42546
−0.78982


4
14
0.58564
0.49650
0.80488









Numerical Example II-6
The zoom lens system of Numerical Example II-6 corresponds to Embodiment II-6 shown in FIG. 30. 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
22.01411
0.80000
2.14422
17.5


 2
16.76615
2.50000
1.82080
42.7


 3*
101.42760
Variable




 4*
−71.58793
1.00000
1.85976
40.6


 5*
5.13092
1.09570




 6
7.40182
1.70000
2.00170
20.6


 7
14.35270
Variable




 8
∞
0.00000




(Diaphragm)






 9*
4.80218
2.10000
1.77377
47.2


10
9.87535
0.80000
1.92286
20.9


11
4.30138
0.50000




12
11.64846
1.50000
1.80420
46.5


13
−48.27259
Variable




 14*
19.51788
1.30000
1.80420
46.5


15
−601.21670
Variable




16
∞
1.00000
1.51680
64.2


17
∞
(BF)




Image surface
∞
















TABLE II-17





(Aspherical data)







Surface No. 3


K = 0.00000E+00, A4 = 1.96399E−06, A6 = 8.38790E−10,


A8 = 0.00000E+00 A10 = 0.00000E+00


Surface No. 4


K = 0.00000E+00, A4 = 2.08635E−05, A6 = 4.82445E−07,


A8 = 0.00000E+00 A10 = 0.00000E+00


Surface No. 5


K = −2.72794E+00, A4 = 2.05037E−03, A6 = −3.37206E−05,


A8 = 8.72404E−07 A10 = −5.23638E−09


Surface No. 9


K = −4.61942E−01, A4 = 1.03075E−04, A6 = 2.43831E−05,


A8 = −4.51015E−06 A10 = 4.15499E−07


Surface No. 14


K = 0.00000E+00, A4 = 2.82102E−05, A6 = 3.05454E−06,


A8 = 0.00000E+00 A10 = 0.00000E+00
















TABLE II-18





(Various data)







Zooming ratio 6.54969











Wide-angle
Middle
Telephoto



limit
position
limit





Focal length
6.7999
17.3217
44.5372


F-number
3.42679
4.00985
4.56886


View angle
32.0408
12.5843
4.9066


Image height
3.8300
3.8300
3.8300


Overall length
41.1512
44.8950
53.2882


of lens system





BF
0.50957
0.51183
0.52021


d3
0.6000
10.9391
21.3625


d7
15.4165
5.6233
1.3000


d13
2.4448
3.4802
12.6158


d15
7.8846
10.0448
3.1939


Entrance pupil
11.9887
32.6384
82.8481


position





Exit pupil
−16.1869
−20.1889
−50.2594


position





Front principal
16.0192
35.4659
88.3232


points position





Back principal
34.3513
27.5733
8.7510


points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−66.9089


2
2
24.1504


3
4
−5.5354


4
6
13.5941


5
9
10.2331


6
10
−8.8686


7
12
11.8005


8
14
23.5288










Zoom lens unit data












Lens
Initial
Focal
Overall length
Front principal
Back principal


unit
surface No.
length
of lens unit
points position
points position





1
1
39.22731
3.30000
−0.83975
0.75865


2
4
−9.73077
3.79570
0.26561
1.66074


3
8
13.01946
4.90000
−1.48970
0.66880


4
14
23.52878
1.30000
0.02268
0.60146










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
4
−0.37298
−0.61781
−1.82667


3
8
−0.79375
−1.44795
−0.79235


4
14
0.58553
0.49362
0.78444









Numerical Example II-7
The zoom lens system of Numerical Example II-7 corresponds to Embodiment II-7 shown in FIG. 32. 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)











Surface number
r
d
nd
vd














Object surface
∞





 1
25.31776
0.80000
1.92286
20.9


 2
18.23858
2.90000
1.77250
49.6


 3
141.43600
Variable




 4*
−74.12426
0.95000
1.85976
40.6


 5*
5.92627
1.47140




 6
8.28920
1.70000
2.14422
17.5


 7
12.83109
Variable




 8
∞
0.00000




(Diaphragm)






 9*
4.63999
2.45000
1.80139
45.4


10
11.40598
0.50000
1.92286
20.9


11
4.08736
0.48000




12
11.58038
1.50000
1.80420
46.5


13
−46.42335
Variable




 14*
16.70893
1.70000
1.80610
40.7


15
−271.10350
Variable




16
∞
1.00000
1.51680
64.2


17
∞
(BF)




Image surface
∞
















TABLE II-20





(Aspherical data)







Surface No. 4


K = 0.00000E+00, A4 = 8.00930E−05, A6 = −8.24171E−07,


A8 = 7.02480E−09 A10 = 0.00000E+00


Surface No. 5


K = −2.80748E+00, A4 = 1.51170E−03, A6 = −1.93182E−05,


A8 = 3.79463E−07 A10 = −1.27953E−09


Surface No. 9


K = −3.81122E−01, A4 = 1.92672E−05, A6 = 2.36355E−05,


A8 = −5.76293E−06 A10 = 5.76364E−07


Surface No. 14


K = 0.00000E+00, A4 = 5.48957E−05, A6 = 4.00480E−07,


A8 = 0.00000E+00 A10 = 0.00000E+00
















TABLE II-21





(Various data)







Zooming ratio 6.54099











Wide-angle
Middle
Telephoto



limit
position
limit





Focal length
6.1338
15.6371
40.1213


F-number
3.35969
3.84965
5.84335


View angle
35.0631
13.8718
5.4025


Image height
3.8300
3.8300
3.8300


Overall length
43.0188
45.0018
57.0268


of lens system





BF
0.49471
0.53782
0.50457


d3
0.5000
11.4355
18.9917


d7
17.0651
5.3765
1.4500


d13
3.8959
4.3424
17.9582


d15
5.6117
7.8582
2.6709


Entrance pupil
12.7522
32.7502
57.3438


position





Exit pupil
−17.6154
−20.9508
309.8164


position





Front principal
16.8085
37.0083
102.6693


points position





Back principal
36.8850
29.3648
16.9055


points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−74.7335


2
2
26.8298


3
4
−6.3478


4
6
17.0587


5
9
8.4064


6
10
−7.1366


7
12
11.6594


8
14
19.5762










Zoom lens unit data












Lens
Initial
Focal
Overall length
Front principal
Back principal


unit
surface No.
length
of lens unit
points position
points position





1
1
43.09186
3.70000
−0.63212
1.04900


2
4
−10.40411
4.12140
0.28566
1.75797


3
8
12.61365
4.93000
−1.72530
0.54757


4
14
19.57623
1.70000
0.05479
0.81105










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
4
−0.35568
−0.56805
−0.96698


3
8
−0.65716
−1.29835
−1.26908


4
14
0.60898
0.49202
0.75870









Numerical Example II-8
The zoom lens system of Numerical Example II-8 corresponds to Embodiment II-8 shown in FIG. 34. 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)











Surface number
r
d
nd
vd














Object surface
∞





 1
25.31390
0.80000
1.92286
20.9


 2
18.37307
2.90000
1.77250
49.6


 3
127.09120
Variable




 4*
−72.33967
0.95000
1.85976
40.6


 5*
5.53361
1.50880




 6
8.10144
1.70000
2.14422
17.5


 7
12.83109
Variable




 8
∞
0.00000




(Diaphragm)






 9*
4.58126
2.45000
1.80139
45.4


10
12.89458
0.50000
1.92286
20.9


11
4.09435
0.48000




12
12.11282
1.50000
1.80420
46.5


13
−29.99816
Variable




 14*
16.30826
1.70000
1.82080
42.7


15
−204.49060
Variable




16
∞
1.00000
1.51680
64.2


17
∞
(BF)




Image surface
∞
















TABLE II-23





(Aspherical data)







Surface No. 4


K = 0.00000E+00, A4 = 1.38654E−04, A6 = −2.03482E−06,


A8 = 1.30075E−08 A10 = 0.00000E+00


Surface No. 5


K = −2.38369E+00, A4 = 1.55078E−03, A6 = −1.46113E−05,


A8 = 2.67367E−07 A10 = −2.02236E−09


Surface No. 9


K = −4.10236E−01, A4 = 2.02270E−05, A6 = 2.52654E−05,


A8 = −7.12069E−06 A10 = 8.11753E−07


Surface No. 14


K = 0.00000E+00, A4 = 5.64788E−05, A6 = 4.75905E−07,


A8 = 0.00000E+00 A10 = 0.00000E+00
















TABLE II-24





(Various data)







Zooming ratio 6.54149











Wide-angle
Middle
Telephoto



limit
position
limit





Focal length
5.5377
14.1127
36.2248


F-number
3.29490
3.84420
5.79699


View angle
37.8649
15.3659
5.9868


Image height
3.8300
3.8300
3.8300


Overall length
41.5403
44.0499
56.5476


of lens system





BF
0.51202
0.52769
0.52473


d3
0.5000
11.0956
19.1926


d7
16.2704
5.0362
1.4500


d13
3.8899
4.8390
17.2154


d15
4.8791
7.0627
2.6761


Entrance pupil
12.0360
30.5678
56.7404


position





Exit pupil
−17.3975
−22.2119
209.0752


position





Front principal
15.8615
35.9218
99.2574


points position





Back principal
36.0026
29.9372
20.3228


points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−76.8613


2
2
27.4838


3
4
−5.9453


4
6
16.1170


5
9
7.8392


6
10
−6.6830


7
12
10.9026


8
14
18.4654










Zoom lens unit data












Lens
Initial
Focal
Overall length
Front principal
Back principal


unit
surface No.
length
of lens unit
points position
points position





1
1
44.06577
3.70000
−0.70119
0.98430


2
4
−9.81147
4.15880
0.22506
1.68504


3
8
11.74129
4.93000
−1.33477
0.80049


4
14
18.46535
1.70000
0.06920
0.83229










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
4
−0.31841
−0.48529
−0.80946


3
8
−0.63113
−1.30361
−1.36507


4
14
0.62535
0.50625
0.74396









The following Table II-25 shows the corresponding values to the individual conditions in the zoom lens systems of each of Numerical Examples.







TABLE II-25







(Values corresponding to conditions)









Example

















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




















(3-2)
(β2T/β2W)/(β3T/β3W)
2.58
1.60
1.91
4.54
5.05
4.91
1.41
1.18


(b-1)
fT/fW
6.59
6.54
6.53
6.54
6.54
6.55
6.54
6.54


(a-2)
ωW
31.08
34.84
34.84
32.05
32.06
32.05
35.06
37.88


(2-2)
f2/fW
−1.57
−1.68
−1.60
−1.53
−1.39
−1.43
−1.70
−1.77


(4-2)
M1/M3
1.11
1.12
1.02
2.90
2.26
2.21
1.26
1.35


 (5)
nd2p
2.002
1.946
1.946
2.002
2.002
2.002
2.144
2.144


 (6)
(r2na + r2nb)/(r2na − r2nb)
0.81
0.82
0.83
0.88
0.87
0.87
0.85
0.86


 (7)
(r2nb + r2pa)/(r2nb − r2pa)
−6.61
−6.51
−6.21
−6.00
−5.30
−5.52
−6.02
−5.31


 (8)
(r1pa + r1pb)/(r1pa − r1pb)
−1.20
−1.27
−1.21
−1.46
−1.41
−1.40
−1.30
−1.34


 (9)
f3/fW
1.95
1.98
1.99
1.89
1.89
1.91
2.06
2.12


(10)
f3IL/f3
1.25
1.15
1.18
1.14
1.13
1.16
1.14
1.07


(11)
f3n/f3
−0.50
−0.54
−0.50
−0.67
−0.68
−0.68
−0.57
−0.57









Numerical Example III-1
The zoom lens system of Numerical Example III-1 corresponds to Embodiment III-1 shown in FIG. 37. 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
22.52601
0.80000
1.92286
20.9


 2
16.32565
3.20000
1.72916
54.7


 3
207.73150
Variable




 4*
−58.88450
1.10000
1.85976
40.6


 5*
6.29064
1.27740




 6
8.20213
1.70000
1.94595
18.0


 7
14.57504
Variable




 8
∞
0.00000




(Diaphragm)






 9*
4.28717
2.50000
1.85135
40.1


10
8.64793
0.40000
1.92286
20.9


11
3.51077
0.50000




12
9.89324
1.50000
1.77250
49.6


13
270.24380
Variable




 14*
11.85559
1.80000
1.62299
58.1


15
−149.18250
Variable




16
∞
1.00000
1.51680
64.2


17
∞
(BF)




Image surface
∞
















TABLE III-2





(Aspherical data)







Surface No. 4


K = 0.00000E+00, A4 = 1.54676E−04, A6 = −4.85701E−06,


A8 = 9.08996E−08 A10 = −5.94484E−10


Surface No. 5


K = −3.54307E+00, A4 = 1.75093E−03, A6 = −3.51461E−05,


A8 = 7.02807E−07 A10 = −2.85240E−09


Surface No. 9


K = −4.49859E−01, A4 = 1.95364E−04, A6 = 3.06104E−05,


A8 = −5.88023E−06 A10 = 6.62772E−07


Surface No. 14


K = 0.00000E+00, A4 = −2.47044E−05, A6 = 1.82158E−05,


A8 = −1.04997E−06 A10 = 2.22666E−08
















TABLE III-3





(Various data)







Zooming ratio 6.54045











Wide-angle
Middle
Telephoto



limit
position
limit





Focal length
6.7980
14.4234
44.4619


F-number
3.39347
4.04095
5.95026


View angle
31.8253
15.2211
4.8154


Image height
3.8300
3.8300
3.8300


Overall length
41.8818
41.2742
52.8975


of lens system





BF
0.48940
0.49563
0.49986


d3
0.6000
6.5818
17.0242


d7
16.5617
6.2213
1.0000


d13
2.2867
4.3897
17.0896


d15
6.1665
7.8084
1.5064


Entrance pupil
14.0166
22.5786
54.5990


position





Exit pupil
−14.9034
−21.4736
161.1283


position





Front principal
17.8124
27.5327
111.3679


points position





Back principal
35.0838
26.8508
8.4356


points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−68.5116


2
2
24.1292


3
4
−6.5594


4
6
17.5542


5
9
7.9030


6
10
−6.6527


7
12
13.2601


8
14
17.7050










Zoom lens unit data












Lens
Initial
Focal
Overall length
Front principal
Back principal


unit
surface No.
length
of lens unit
points position
points position





1
1
38.39330
4.00000
−0.49622
1.26336


2
4
−10.80549
4.07740
0.32173
1.75074


3
8
13.40495
4.90000
−3.09913
−0.28853


4
14
17.70499
1.80000
0.08200
0.76816










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
4
−0.45156
−0.60206
−1.43973


3
8
−0.74187
−1.43294
−1.01668


4
14
0.52855
0.43546
0.79117









Numerical Example III-2
The zoom lens system of Numerical Example III-2 corresponds to Embodiment III-2 shown in FIG. 39. 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
20.56187
0.80000
1.92286
20.9


 2
14.81270
3.20000
1.72916
54.7


 3
158.73300
Variable




 4*
−59.17839
1.10000
1.85976
40.6


 5*
5.51137
1.13160




 6
7.62681
1.70000
1.94595
18.0


 7
14.57504
Variable




 8
∞
0.00000




(Diaphragm)






 9*
4.20287
2.50000
1.85135
40.1


10
9.49076
0.40000
1.92286
20.9


11
3.47256
0.50000




12
9.45232
1.50000
1.77250
49.6


13
−630.07970
Variable




 14*
12.45881
1.80000
1.62299
58.1


15
−53.07139
Variable




16
∞
1.00000
1.51680
64.2


17
∞
(BF)




Image surface
∞
















TABLE III-5





(Aspherical data)







Surface No. 4


K = 0.00000E+00, A4 = 7.16481E−05, A6 = −9.20654E−07,


A8 = 9.31422E−09 A10 = −1.08989E−11


Surface No. 5


K = −1.96424E+00, A4 = 1.20304E−03, A6 = −7.06323E−06,


A8 = 1.22887E−07 A10 = 1.45469E−09


Surface No. 9


K = −4.49892E−01, A4 = 1.71358E−04, A6 = 2.95164E−05,


A8 = −5.81944E−06 A10 = 6.34879E−07


Surface No. 14


K = 0.00000E+00, A4 = 3.68685E−05, A6 = 7.24260E−06,


A8 = −3.15541E−07 A10 = 5.13901E−09
















TABLE III-6





(Various data)







Zooming ratio 6.52948











Wide-angle
Middle
Telephoto



limit
position
limit





Focal length
6.1187
12.9818
39.9518


F-number
3.12003
3.77592
5.46453


View angle
34.8394
16.8681
5.3822


Image height
3.8300
3.8300
3.8300


Overall length
40.0820
35.9984
50.0898


of lens system





BF
0.50106
0.53718
0.50627


d3
0.6000
4.1205
15.5150


d7
15.7290
4.5669
1.0000


d13
2.2919
3.2444
15.6615


d15
5.3284
7.8978
1.7755


Entrance pupil
13.4079
15.7987
50.2041


position





Exit pupil
−14.5439
−19.3553
134.0690


position





Front principal
17.0381
20.3085
102.1063


points position





Back principal
33.9633
23.0165
10.1380


points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−61.5140


2
2
22.1975


3
4
−5.8185


4
6
15.1150


5
9
7.2781


6
10
−6.1295


7
12
12.0675


8
14
16.3687










Zoom lens unit data












Lens
Initial
Focal
Overall length
Front principal
Back principal


unit
surface No.
length
of lens unit
points position
points position





1
1
35.95275
4.00000
−0.57161
1.19624


2
4
−9.80239
3.93160
0.32635
1.74700


3
8
12.20044
4.90000
−2.62124
0.03460


4
14
16.36872
1.80000
0.21311
0.89223










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
4
−0.43721
−0.51865
−1.30606


3
8
−0.71015
−1.78990
−1.11238


4
14
0.54813
0.38896
0.76487









Numerical Example III-3
The zoom lens system of Numerical Example III-3 corresponds to Embodiment III-3 shown in FIG. 42. 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
24.21902
0.80000
1.92286
20.9


 2
17.02733
3.00000
1.77250
49.6


 3
141.43600
Variable




 4*
−74.12426
1.00000
1.85976
40.6


 5*
5.93476
1.39220




 6
8.14754
1.70000
1.94595
18.0


 7
14.57504
Variable




 8
∞
0.00000




(Diaphragm)






 9*
4.60150
2.50000
1.77377
47.2


10
13.28805
0.40000
1.84666
23.8


11
4.00087
0.50000




12
11.41115
1.50000
1.80420
46.5


13
−89.00278
Variable




 14*
14.81798
1.80000
1.58913
61.3


15
−135.33920
Variable




16
∞
1.00000
1.51680
64.2


17
∞
(BF)




Image surface
∞
















TABLE III-8





(Aspherical data)







Surface No. 4


K = 0.00000E+00, A4 = 3.17769E−05, A6 = 2.52415E−07,


A8 = 0.00000E+00 A10 = 0.00000E+00


Surface No. 5


K = −2.05246E+00, A4 = 1.03297E−03, A6 = −6.21595E−06,


A8 = 1.71504E−07 A10 = 9.00685E−10


Surface No. 9


K = −3.68884E−01, A4 = 4.03259E−05, A6 = 1.87605E−05,


A8 = −4.20225E−06 A10 = 3.87468E−07


Surface No. 14


K = 0.00000E+00, A4 = 5.68131E−05, A6 = 5.49828E−07,


A8 = 0.00000E+00 A10 = 0.00000E+00
















TABLE III-9





(Various data)







Zooming ratio 6.53845













Wide-angle
Middle
Telephoto




limit
position
limit






Focal length
6.7994
17.3321
44.4573



F-number
3.53136
4.13883
6.02867



View angle
32.0505
12.5574
4.8706



Image height
3.8300
3.8300
3.8300



Overall length
44.4149
45.3982
57.3942



of lens system






BF
0.49954
0.53445
0.50459



d3
0.5000
10.2297
18.3237



d7
17.4263
5.3660
1.4500



d13
3.9465
4.4359
18.9880



d15
6.4503
9.2400
2.5357



Entrance pupil
13.0906
30.2684
57.6472



position






Exit pupil
−18.0633
−21.8942
−616.8088



position






Front principal
17.3994
34.2068
98.9028



points position






Back principal
37.6156
28.0661
12.9369



points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−65.6394


2
2
24.7980


3
4
−6.3544


4
6
17.3061


5
9
8.0824


6
10
−6.8974


7
12
12.6612


8
14
22.7714










Zoom lens unit data













Initial

Overall




Lens
surface
Focal
length of
Front principal
Back principal


unit
No.
length
lens unit
points position
points position





1
1
41.13377
3.80000
−0.62624
1.10007


2
4
−10.47225
4.09220
0.22232
1.59429


3
8
13.29663
4.90000
−1.92701
0.36187


4
14
22.77144
1.80000
0.11228
0.77452










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
4
−0.38445
−0.59809
−1.11222


3
8
−0.69257
−1.41819
−1.22617


4
14
0.62081
0.49677
0.79250









Numerical Example III-4
The zoom lens system of Numerical Example III-4 corresponds to Embodiment III-4 shown in FIG. 45. 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
23.92026
0.80000
2.00170
20.6


 2
17.23850
2.50000
1.80420
46.5


 3*
91.93466
Variable




 4*
−86.26322
1.00000
1.85976
40.6


 5*
5.30963
1.09570




 6
7.43523
1.70000
2.00170
20.6


 7
14.35270
Variable




 8
∞
0.00000




(Diaphragm)






 9*
4.78659
2.10000
1.77377
47.2


10
10.28002
0.80000
1.92286
20.9


11
4.30394
0.50000




12
11.80608
1.50000
1.80420
46.5


13
−41.97623
Variable




 14*
18.23360
1.80000
1.80420
46.5


15
449.20610
Variable




16
∞
1.00000
1.51680
64.2


17
∞
(BF)




Image surface
∞
















TABLE III-11





(Aspherical data)







Surface No. 3


K = 0.00000E+00, A4 = 1.16573E−06, A6 = 3.73564E−10,


A8 = 0.00000E+00 A10 = 0.00000E+00


Surface No. 4


K = 0.00000E+00, A4 = 4.11218E−05, A6 = 4.14113E−07,


A8 = 0.00000E+00 A10 = 0.00000E+00


Surface No. 5


K = −2.55557E+00, A4 = 1.78988E−03, A6 = −2.05242E−05,


A8 = 4.89013E−07 A10 = 9.76558E−10


Surface No. 9


K = −4.57612E−01, A4 = 8.64666E−05, A6 = 3.31418E−05,


A8 = −6.94709E−06 A10 = 6.20715E−07


Surface No. 14


K = 0.00000E+00, A4 = 3.07143E−05, A6 = 2.65662E−06,


A8 = 0.00000E+00 A10 = 0.00000E+00
















TABLE III-12





(Various data)







Zooming ratio 6.54154













Wide-angle
Middle
Telephoto




limit
position
limit






Focal length
6.7983
17.3298
44.4713



F-number
3.35579
3.99862
4.53813



View angle
32.0536
12.6171
4.8991



Image height
3.8300
3.8300
3.8300



Overall length
40.9465
44.9233
56.8471



of lens system






BF
0.50091
0.52914
0.50678



d3
0.6000
11.6273
24.8265



d7
15.2623
4.7479
1.4500



d13
2.5571
3.4896
12.7618



d15
7.2306
9.7337
2.5063



Entrance pupil
12.0260
31.2012
94.2363



position






Exit pupil
−15.9753
−20.1365
−50.5394



position






Front principal
16.0192
33.9985
99.9644



points position






Back principal
34.1483
27.5935
12.3759



points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−65.5343


2
2
25.9947


3
4
−5.7884


4
6
13.7142


5
9
9.9217


6
10
−8.5733


7
12
11.6022


8
14
23.5883










Zoom lens unit data













Initial

Overall




Lens
surface
Focal
length of
Front principal
Back principal


unit
No.
length
lens unit
points position
points position





1
1
44.68006
3.30000
−0.90484
0.65703


2
4
−10.42881
3.79570
0.26532
1.66111


3
8
12.81592
4.90000
−1.39579
0.73000


4
14
23.58831
1.80000
−0.04213
0.76205










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
4
−0.33923
−0.52896
−1.60039


3
8
−0.74721
−1.48745
−0.77711


4
14
0.60028
0.49297
0.80031









Numerical Example III-5
The zoom lens system of Numerical Example III-5 corresponds to Embodiment III-5 shown in FIG. 48. 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
21.11164
0.80000
2.00170
20.6


 2
15.12358
2.50000
1.80420
46.5


 3*
88.24478
Variable




 4*
−69.21321
1.00000
1.85976
40.6


 5*
4.93236
1.09570




 6
7.22589
1.70000
2.00170
20.6


 7
14.35270
Variable




 8
∞
0.00000




(Diaphragm)






 9*
4.94313
2.10000
1.77377
47.2


10
10.82877
0.80000
1.92286
20.9


11
4.47121
0.50000




12
11.90782
1.50000
1.80420
46.5


13
−39.79054
Variable




 14*
20.42889
1.80000
1.80420
46.5


15
−248.53400
Variable




16
∞
1.00000
1.51680
64.2


17
∞
(BF)




Image surface
∞
















TABLE III-14





(Aspherical data)







Surface No. 3


K = 0.00000E+00, A4 = 2.27928E−06, A6 = 3.00081E−10,


A8 = 0.00000E+00 A10 = 0.00000E+00


Surface No. 4


K = 0.00000E+00, A4 = 5.20294E−05, A6 = −4.16769E−08,


A8 = 0.00000E+00 A10 = 0.00000E+00


Surface No. 5


K = −2.47053E+00, A4 = 2.06679E−03, A6 = −2.74077E−05,


A8 = 6.95651E−07 A10 = −4.23395E−09


Surface No. 9


K = −4.61701E−01, A4 = 8.60229E−05, A6 = 2.31646E−05,


A8 = −4.52966E−06 A10 = 4.13883E−07


Surface No. 14


K = 0.00000E+00, A4 = 2.57276E−05, A6 = 3.06354E−06,


A8 = 0.00000E+00 A10 = 0.00000E+00
















TABLE III-15





(Various data)







Zooming ratio 6.54191













Wide-angle
Middle
Telephoto




limit
position
limit






Focal length
6.7983
17.3294
44.4739



F-number
3.40234
3.91077
4.59471



View angle
32.0530
12.6173
4.9207



Image height
3.8300
3.8300
3.8300



Overall length
40.8782
44.9165
53.2755



of lens system






BF
0.50271
0.52741
0.50364



d3
0.6000
11.2009
20.8199



d7
14.7539
5.4351
1.4500



d13
2.5571
3.2145
13.2000



d15
7.6688
9.7429
2.5063



Entrance pupil
11.7579
33.9417
82.6375



position






Exit pupil
−16.5435
−19.7880
−56.1280



position






Front principal
15.8449
36.4888
92.1852



points position






Back principal
34.0799
27.5871
8.8016



points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−57.0431


2
2
22.3546


3
4
−5.3221


4
6
12.9783


5
9
10.1707


6
10
−8.7828


7
12
11.5458


8
14
23.5435










Zoom lens unit data













Initial

Overall




Lens
surface
Focal
length of
Front principal
Back principal


unit
No.
length
lens unit
points position
points position





1
1
38.26554
3.30000
−0.82482
0.73786


2
4
−9.46936
3.79570
0.23471
1.62366


3
8
12.87340
4.90000
−1.23135
0.84238


4
14
23.54354
1.80000
0.07600
0.87535










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
4
−0.37282
−0.63989
−1.82826


3
8
−0.81370
−1.42546
−0.78982


4
14
0.58564
0.49650
0.80488









Numerical Example III-6
The zoom lens system of Numerical Example III-6 corresponds to Embodiment III-6 shown in FIG. 51. 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
24.63915
0.80000
1.92286
20.9


 2
17.69162
2.90000
1.77250
49.6


 3
141.43600
Variable




 4*
−74.12426
0.95000
1.85976
40.6


 5*
5.96172
1.39660




 6
8.26210
1.70000
2.14422
17.5


 7
12.83109
Variable




 8
∞
0.00000




(Diaphragm)






 9*
4.65521
2.50090
1.80139
45.4


10
11.21394
0.50000
1.92286
20.9


11
4.06867
0.50000




12
11.22865
1.50000
1.80420
46.5


13
−68.81526
Variable




 14*
15.96294
1.70000
1.80610
40.7


15
−270.01270
Variable




16
∞
1.00000
1.51680
64.2


17
∞
(BF)




Image surface
∞
















TABLE III-17





(Aspherical data)







Surface No. 4


K = 0.00000E+00, A4 = 3.83404E−05, A6 = 5.29405E−08,


A8 = 1.02032E−09 A10 = 0.00000E+00


Surface No. 5


K = −3.21567E+00, A4 = 1.68391E−03, A6 = −3.06050E−05,


A8 = 7.28861E−07 A10 = −5.38787E−09


Surface No. 9


K = −3.45514E−01, A4 = −2.07950E−05, A6 = 2.45075E−05,


A8 = −6.29992E−06 A10 = 6.15382E−07


Surface No. 14


K = 0.00000E+00, A4 = 5.07793E−05, A6 = 3.47763E−07,


A8 = 0.00000E+00 A10 = 0.00000E+00
















TABLE III-18





(Various data)







Zooming ratio 6.54156













Wide-angle
Middle
Telephoto




limit
position
limit






Focal length
6.4574
16.4623
42.2414



F-number
3.43301
3.85000
5.93349



View angle
33.6879
13.1888
5.1236



Image height
3.8300
3.8300
3.8300



Overall length
43.0231
45.0104
57.0342



of lens system






BF
0.49458
0.54184
0.50628



d3
0.5000
11.6929
18.6778



d7
16.7547
5.2707
1.4500



d13
3.9231
3.9579
18.3061



d15
5.9032
8.0996
2.6465



Entrance pupil
12.9125
34.3781
57.9941



position






Exit pupil
−18.2489
−20.5320
155.8859



position






Front principal
17.1452
37.9805
111.7193



points position






Back principal
36.5657
28.5482
14.7928



points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−71.9643


2
2
25.9114


3
4
−6.3830


4
6
16.9188


5
9
8.4915


6
10
−7.1597


7
12
12.1049


8
14
18.7469










Zoom lens unit data













Initial

Overall




Lens
surface
Focal
length of
Front principal
Back principal


unit
No.
length
lens unit
points position
points position





1
1
41.71577
3.70000
−0.61640
1.06461


2
4
−10.48715
4.04660
0.32254
1.79750


3
8
13.07665
5.00090
−1.99839
0.39268


4
14
18.74694
1.70000
0.05268
0.80892










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
4
−0.37763
−0.63260
−1.09323


3
8
−0.71161
−1.36698
−1.23644


4
14
0.57603
0.45635
0.74913









Numerical Example III-7
The zoom lens system of Numerical Example III-7 corresponds to Embodiment III-7 shown in FIG. 53. 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)











Surface number
r
d
nd
vd





Object surface
∞





 1
25.31390
0.80000
1.92286
20.9


 2
18.37307
2.90000
1.77250
49.6


 3
127.09120
Variable




 4*
−72.33967
0.95000
1.85976
40.6


 5*
5.53361
1.50880




 6
8.10144
1.70000
2.14422
17.5


 7
12.83109
Variable




 8
∞
0.00000




(Diaphragm)






 9*
4.58126
2.45000
1.80139
45.4


10
12.89458
0.50000
1.92286
20.9


11
4.09435
0.48000




12
12.11282
1.50000
1.80420
46.5


13
−29.99816
Variable




 14*
16.30826
1.70000
1.82080
42.7


15
−204.49060
Variable




16
∞
1.00000
1.51680
64.2


17
∞
(BF)




Image surface
∞
















TABLE III-20





(Aspherical data)







Surface No. 4


K = 0.00000E+00, A4 = 1.38654E−04, A6 = −2.03482E−06,


A8 = 1.30075E−08 A10 = 0.00000E+00


Surface No. 5


K = −2.38369E+00, A4 = 1.55078E−03, A6 = −1.46113E−05,


A8 = 2.67367E−07 A10 = −2.02236E−09


Surface No. 9


K = −4.10236E−01, A4 = 2.02270E−05, A6 = 2.52654E−05,


A8 = −7.12069E−06 A10 = 8.11753E−07


Surface No. 14


K = 0.00000E+00, A4 = 5.64788E−05, A6 = 4.75905E−07,


A8 = 0.00000E+00 A10 = 0.00000E+00
















TABLE III-21





(Various data)







Zooming ratio 6.54149













Wide-angle
Middle
Telephoto




limit
position
limit






Focal length
5.5377
14.1127
36.2248



F-number
3.29490
3.84420
5.79699



View angle
37.8649
15.3659
5.9868



Image height
3.8300
3.8300
3.8300



Overall length
41.5403
44.0499
56.5476



of lens system






BF
0.51202
0.52769
0.52473



d3
0.5000
11.0956
19.1926



d7
16.2704
5.0362
1.4500



d13
3.8899
4.8390
17.2154



d15
4.8791
7.0627
2.6761



Entrance pupil
12.0360
30.5678
56.7404



position






Exit pupil
−17.3975
−22.2119
209.0752



position






Front principal
15.8615
35.9218
99.2574



points position






Back principal
36.0026
29.9372
20.3228



points position










Single lens data









Lens
Initial surface
Focal


element
number
length





1
1
−76.8613


2
2
27.4838


3
4
−5.9453


4
6
16.1170


5
9
7.8392


6
10
−6.6830


7
12
10.9026


8
14
18.4654










Zoom lens unit data













Initial

Overall




Lens
surface
Focal
length of
Front principal
Back principal


unit
No.
length
lens unit
points position
points position





1
1
44.06577
3.70000
−0.70119
0.98430


2
4
−9.81147
4.15880
0.22506
1.68504


3
8
11.74129
4.93000
−1.33477
0.80049


4
14
18.46535
1.70000
0.06920
0.83229










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
4
−0.31841
−0.48529
−0.80946


3
8
−0.63113
−1.30361
−1.36507


4
14
0.62535
0.50625
0.74396









The following Table III-22 shows the corresponding values to the individual conditions in the zoom lens systems of each of Numerical Examples.







TABLE III-22







(Values corresponding to conditions)









Example
















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



















(4-2)
M1/M3
1.08
1.02
1.17
2.90
2.26
1.26
1.35


(b-1)
fT/fW
6.54
6.53
6.54
6.54
6.54
6.54
6.54


(a-2)
ωW
31.81
34.84
32.05
32.05
32.06
33.68
37.88


(2-2)
f2/fW
−1.59
−1.60
−1.54
−1.53
−1.39
−1.62
−1.77


(3-2)
(β2T/β2W)/(β3T/β3W)
2.33
1.91
1.63
4.54
5.05
1.67
1.18


 (5)
nd2p
1.946
1.946
1.946
2.002
2.002
2.144
2.144


 (6)
(r2na + r2nb)/(r2na − r2nb)
0.81
0.83
0.85
0.88
0.87
0.85
0.86


 (7)
(r2nb + r2pa)/(r2nb − r2pa)
−7.58
−6.21
−6.36
−6.00
−5.30
−6.18
−5.31


 (8)
(r1pa + r1pb)/(r1pa − r1pb)
−1.17
−1.21
−1.27
−1.46
−1.41
−1.29
−1.34


 (9)
f3/fW
1.97
1.99
1.96
1.89
1.89
2.03
2.12


(10)
f3IL/f3
1.30
1.18
1.24
1.14
1.13
1.19
1.07


(11)
f3n/f3
−0.50
−0.50
−0.52
−0.67
−0.68
−0.55
−0.57









INDUSTRIAL APPLICABILITY
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.
DESCRIPTION OF THE REFERENCE CHARACTERS


    
    
        G1 first lens unit
        G2 second lens unit
        G3 third lens unit
        G4 fourth lens unit
        L1 first lens element
        L2 second lens element
        L3 third lens element
        L4 fourth lens element
        L5 fifth lens element
        L6 sixth lens element
        L7 seventh lens element
        L8 eighth lens element
        A aperture diaphragm
        P plane parallel plate
        S image surface
        1 zoom lens system
        2 image sensor
        3 liquid crystal display monitor
        4 body
        5 main barrel
        6 moving barrel
        7 cylindrical cam

## 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 at most two lens elements,
the second lens unit is composed of two lens elements,
the third lens unit is composed of three lens elements, in order from the object side to the image side, including an object side lens element having positive optical power, a lens element having negative optical power, and an image side lens element having positive optical power, and
the following conditions (2-2), (b-1) and (a-2) are satisfied:


−2.0<f2/fW<−1.1  (2-2)



fT/fW>6.0  (b-1)



ωW≧30  (a-2)


where,
f2 is a composite focal length of the second lens unit,
fT is a focal length of the entire system at a telephoto limit,
fW is a focal length of the entire system at a wide-angle limit, and
ωW is a half view angle (°) at a wide-angle limit.

2. The zoom lens system as claimed in claim 1, wherein the second lens unit includes a lens element having positive optical power, and the following condition (5) is satisfied:


1.88<nd2p<2.20  (5)

where,
nd2p is a refractive index to the d-line of the lens element having positive optical power, which is included in the second lens unit.

3. The zoom lens system as claimed in claim 1, wherein the second lens unit includes a lens element having negative optical power, and the following condition (6) is satisfied:


0.35<(r2na+r2nb)/(r2na−r2nb)<1.20  (6)

where,
r2na is a radius of curvature of an object side surface of the lens element having negative optical power, which is included in the second lens unit, and
r2np is a radius of curvature of an image side surface of the lens element having negative optical power, which is included in the second lens unit.

4. The zoom lens system as claimed in claim 1, wherein the second lens unit is composed of two lens elements, in order from the object side to the image side, including a lens element having negative optical power, and a lens element having positive optical power, and the following condition (7) is satisfied:


−8.5<(r2nb+r2pa)/(r2nb−r2pa)<−3.5  (7)

where,
r2np is a radius of curvature of an image side surface of the lens element having negative optical power, which is included in the second lens unit, and
r2pa is a radius of curvature of an object side surface of the lens element having positive optical power, which is included in the second lens unit.

5. The zoom lens system as claimed in claim 1, wherein the first lens unit includes a lens element having positive optical power, and the following condition (8) is satisfied:


−1.8<(r1pa+r1pb)/(r1pa−r1pb)<0.0  (8)

where,
r1pa is a radius of curvature of an object side surface of the lens element having positive optical power, which is included in the first lens unit, and
r1pb is a radius of curvature of an image side surface of the lens element having positive optical power, which is included in the first lens unit.

6. The zoom lens system as claimed in claim 1, wherein the following condition (9) is satisfied:


1.87<f3/fW<3.00  (9)

where,
f3 is a composite focal length of the third lens unit, and
fW is a focal length of the entire system at a wide-angle limit.

7. The zoom lens system as claimed in claim 1, wherein the following condition (10) is satisfied:


0.5<f3IL/f3<1.5  (10)

where,
f3IL is a focal length of the image side lens element having positive optical power, which is included in the third lens unit, and
f3 is a composite focal length of the third lens unit.

8. The zoom lens system as claimed in claim 1, wherein the third lens unit includes a cemented lens element which is obtained by cementing the object side lens element having positive optical power with the lens element having negative optical power.

9. The zoom lens system as claimed in claim 1, wherein the fourth lens unit comprises solely a lens element having positive optical power.

10. The zoom lens system as claimed in claim 1, wherein the following condition (11) is satisfied:


−1.00<f3n/f3<−0.25  (11)

where,
f3n is a focal length of the lens element having negative optical power, which is included in the third lens unit, and
f3 is a composite focal length of the third lens unit.

11. An imaging device capable of outputting an optical image of an object as an electric image signal, comprising:
a zoom lens system that forms an 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
the zoom lens system is the zoom lens system as claimed in claim 1.

12. 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
the zoom lens system is the zoom lens system as claimed in claim 1.

13. 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 at most two lens elements,
the second lens unit is composed of two lens elements,
the third lens unit is composed of three lens elements, in order from the object side to the image side, including an object side lens element having positive optical power, a lens element having negative optical power, and an image side lens element having positive optical power, and
the following conditions (3-2), (b-1) and (a-2) are satisfied:


1.1<(β2T/β2W)/(P3T/β3W)<5.2  (3-2)



fT/fW>6.0  (b-1)



ωW≧30  (a-2)


where,
β2T is a lateral magnification of the second lens unit at a telephoto limit,
β2W is a lateral magnification of the second lens unit at a wide-angle limit,
β3T is a lateral magnification of the third lens unit at a telephoto limit,
β3W is a lateral magnification of the third lens unit at a wide-angle limit,
fT is a focal length of the entire system at a telephoto limit,
fW is a focal length of the entire system at a wide-angle limit, and
ωW is a half view angle (°) at a wide-angle limit.

14. The zoom lens system as claimed in claim 13, wherein the second lens unit includes a lens element having positive optical power, and the following condition (5) is satisfied:


1.88<nd2p<2.20  (5)

where,
nd2p is a refractive index to the d-line of the lens element having positive optical power, which is included in the second lens unit.

15. The zoom lens system as claimed in claim 13, wherein the second lens unit includes a lens element having negative optical power, and the following condition (6) is satisfied:


0.35<(r2na+r2nb)/(r2na−r2nb)<1.20  (6)

where,
r2na is a radius of curvature of an object side surface of the lens element having negative optical power, which is included in the second lens unit, and
r2nb is a radius of curvature of an image side surface of the lens element having negative optical power, which is included in the second lens unit.

16. The zoom lens system as claimed in claim 13, wherein the second lens unit is composed of two lens elements, in order from the object side to the image side, including a lens element having negative optical power, and a lens element having positive optical power, and the following condition (7) is satisfied:


−8.5<(r2nb+r2pa)/(r2nb−r2pa)<−3.5  (7)

where,
r2nb is a radius of curvature of an image side surface of the lens element having negative optical power, which is included in the second lens unit, and
r2pa is a radius of curvature of an object side surface of the lens element having positive optical power, which is included in the second lens unit.

17. The zoom lens system as claimed in claim 13, wherein the first lens unit includes a lens element having positive optical power, and the following condition (8) is satisfied:


−1.8<(r1pa+r1pb)/(r1pa−r1pb)<0.0  (8)

where,
r1pa is a radius of curvature of an object side surface of the lens element having positive optical power, which is included in the first lens unit, and
r1pb is a radius of curvature of an image side surface of the lens element having positive optical power, which is included in the first lens unit.

18. The zoom lens system as claimed in claim 13, wherein the following condition (9) is satisfied:


1.87<f3/fW<3.00  (9)

where,
f3 is a composite focal length of the third lens unit, and
fW is a focal length of the entire system at a wide-angle limit.

19. The zoom lens system as claimed in claim 13, wherein the following condition (10) is satisfied:


0.5<f3IL/f3<1.5  (10)

where,
f3IL is a focal length of the image side lens element having positive optical power, which is included in the third lens unit, and
f3 is a composite focal length of the third lens unit.

20. The zoom lens system as claimed in claim 13, wherein the third lens unit includes a cemented lens element which is obtained by cementing the object side lens element having positive optical power with the lens element having negative optical power.

21. The zoom lens system as claimed in claim 13, wherein the fourth lens unit comprises solely a lens element having positive optical power.

22. The zoom lens system as claimed in claim 13, wherein the following condition (11) is satisfied:


−1.00<f3n/f3<−0.25  (11)

where,
f3n is a focal length of the lens element having negative optical power, which is included in the third lens unit, and
f3 is a composite focal length of the third lens unit.

23. An imaging device capable of outputting an optical image of an object as an electric image signal, comprising:
a zoom lens system that forms an 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
the zoom lens system is the zoom lens system as claimed in claim 13.

24. 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
the zoom lens system is the zoom lens system as claimed in claim 13.

25. 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 at most two lens elements,
the second lens unit is composed of two lens elements,
the third lens unit is composed of three lens elements, in order from the object side to the image side, including an object side lens element having positive optical power, a lens element having negative optical power, and an image side lens element having positive optical power, and
the following conditions (4-2), (b-1) and (a-2) are satisfied:


0.9<M1/M3<3.0  (4-2)



fT/fW>6.0  (b-1)



ωW≧30  (a-2)


where,
M1 is an amount of movement of the first lens unit in the direction along the optical axis during zooming from a wide-angle limit to a telephoto limit (movement from the image side to the object side is positive),
M3 is an amount of movement of the third lens unit in the direction along the optical axis during zooming from a wide-angle limit to a telephoto limit (movement from the image side to the object side is positive),
fT is a focal length of the entire system at a telephoto limit,
fW is a focal length of the entire system at a wide-angle limit, and
ωW is a half view angle (°) at a wide-angle limit.

26. The zoom lens system as claimed in claim 25, wherein the second lens unit includes a lens element having positive optical power, and the following condition (5) is satisfied:


1.88<nd2p<2.20  (5)

where,
nd2p is a refractive index to the d-line of the lens element having positive optical power, which is included in the second lens unit.

27. The zoom lens system as claimed in claim 25, wherein the second lens unit includes a lens element having negative optical power, and the following condition (6) is satisfied:


0.35<(r2na+r2nb)/(r2na−r2na)<1.20  (6)

where,
r2na is a radius of curvature of an object side surface of the lens element having negative optical power, which is included in the second lens unit, and
r2nb is a radius of curvature of an image side surface of the lens element having negative optical power, which is included in the second lens unit.

28. The zoom lens system as claimed in claim 25, wherein the second lens unit is composed of two lens elements, in order from the object side to the image side, including a lens element having negative optical power, and a lens element having positive optical power, and the following condition (7) is satisfied:


−8.5<(r2nb+r2pa)/(r2nb−r2pa)<−3.5  (7)

where,
r2nb is a radius of curvature of an image side surface of the lens element having negative optical power, which is included in the second lens unit, and
r2pa is a radius of curvature of an object side surface of the lens element having positive optical power, which is included in the second lens unit.

29. The zoom lens system as claimed in claim 25, wherein the first lens unit includes a lens element having positive optical power, and the following condition (8) is satisfied:


−1.8<(r1pa+r1pb)/(r1pa−r1pb)<0.0  (8)

where,
r1pa is a radius of curvature of an object side surface of the lens element having positive optical power, which is included in the first lens unit, and
r1pb is a radius of curvature of an image side surface of the lens element having positive optical power, which is included in the first lens unit.

30. The zoom lens system as claimed in claim 25, wherein the following condition (9) is satisfied:


1.87<f3/fW<3.00  (9)

where,
f3 is a composite focal length of the third lens unit, and
fW is a focal length of the entire system at a wide-angle limit.

31. The zoom lens system as claimed in claim 25, wherein the following condition (10) is satisfied:


0.5<f3IL/f3<1.5  (10)

where,
f3IL is a focal length of the image side lens element having positive optical power, which is included in the third lens unit, and
f3 is a composite focal length of the third lens unit.

32. The zoom lens system as claimed in claim 25, wherein the third lens unit includes a cemented lens element which is obtained by cementing the object side lens element having positive optical power with the lens element having negative optical power.

33. The zoom lens system as claimed in claim 25, wherein the fourth lens unit comprises solely a lens element having positive optical power.

34. The zoom lens system as claimed in claim 25, wherein the following condition (11) is satisfied:


−1.00<f3n/f3<−0.25  (11)

where,
f3n is a focal length of the lens element having negative optical power, which is included in the third lens unit, and
f3 is a composite focal length of the third lens unit.

35. An imaging device capable of outputting an optical image of an object as an electric image signal, comprising:
a zoom lens system that forms an 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
the zoom lens system is the zoom lens system as claimed in claim 25.

36. 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
the zoom lens system is the zoom lens system as claimed in claim 25.