# Patent

## Title
Image forming optical system and electronic image pickup apparatus using image forming optical system

## Abstract

In an image forming optical system having a positive lens group, a negative lens group, and an aperture stop, the positive lens group being disposed at an image-plane side of the aperture stop and having a cemented lens, and when a straight line indicated by Nd=α×νd+β (where, α=−0.017) is set, Nd and νd of at least one lens forming the cemented lens are included in both an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1), and a line when an upper limit value is in a range of the following conditional expression (1), and in an area determined by following conditional expressions (2) and (3)

1.45<β<2.15  (1)

1.30<Nd<2.20  (2)

3<νd<25  (3)

Here, Nd denotes a refractive index, and νd denotes an Abbe's number.

## Background
CROSS-REFERENCE TO RELATED APPLICATION
The present application is based upon and claims the benefit of priority from the prior Japanese Patent Application Nos. 2005-264565 filed on Sep. 13, 2005, 2005-264571 filed on Sep. 13, 2005, 2006-241333 filed on Sep. 6, 2006, and 2006-241343 filed on Sep. 6, 2006, the entire contents of which are incorporated herein by reference.
TECHNICAL FIELD
The present invention relates to an image forming optical system which is used in an extremely small image pickup module, and an electronic image pickup apparatus which includes the image forming optical system.
BACKGROUND ART
In recent years, a digital camera has been widely used as a next generation camera replacing a silver salt 35 mm film camera. Recently, there has been an increasing reduction in a size, and thinning of a digital camera. Moreover, a camera function (hereinafter called as ‘image pickup module’) has been mounted even in a portable telephone, the use of which has also been increasing widely. For mounting this image pickup module in the portable telephone, an optical system has to be smaller and thinner than an optical system of the digital camera. Particularly, in a zoom lens, the reduction in size and the thinning have been sought. However, a zoom lens having a size reduced to be capable of being mounted in the portable telephone has not been known much.
As a typical means for reducing the size and thinning the zoom lens, the following two means can be taken into consideration. In other words,
A. To use a collapsible lens barrel, and to accommodate the optical system in a thickness (depth) of a casing. This collapsible lens barrel is a lens barrel having a structure in which, the optical system protrudes from a camera casing at the time of taking a picture, and is accommodated in the camera while carrying.
B. To accommodate the optical system in a direction of width or in a direction of height by adopting a dioptric system. This dioptric system is an optical system having a structure in which an optical path (optical axis) of the optical system is folded by a reflecting optical element such as a mirror or a prism.
However, in the structure in which the abovementioned means A is used, the number of lenses forming the optical system or the number of movable lens groups is still large, and it is difficult to carry out the reduction in the size, and the thinning of the casing.
Moreover, in the structure in which the abovementioned means B is used, it is easy to make the casing thin as compared to a case in which the means in the abovementioned A is used, but an amount of movement of the movable lens group at the time of zooming, and the number of lenses forming the optical system tends to increase. Therefore, volumetrically, it is not at all suitable for the reduction in size.
DISCLOSURE OF THE INVENTION
An image forming optical system according to the present invention is characterized in that, in an image forming optical system having a positive lens group, a negative lens group, and an aperture stop,
the positive lens group is disposed at an image side of the aperture stop,
the positive lens group has a cemented lens which is formed by cementing a plurality of lenses,
in a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=α×νd+β (where, α=−0.017) is set,
Nd and νd of at least one lens forming the cemented lens are included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1a), and a line when an upper limit value is in a range of the following conditional expression (1a), and an area determined by following conditional expressions (2a) and (3a).

1.45<β<2.15  (1a)

1.30<Nd<2.20  (2a)

3<νd<12  (3a)

Here, Nd denotes a refractive index, and νd denotes an Abbe's number.
Moreover, an image forming optical system according to the present invention is characterized in that, in an image forming optical system having a positive lens group, a negative lens group, and an aperture stop,
the positive lens group is disposed at the image side of the aperture stop,
the positive lens group has a cemented lens in which, a plurality of lenses are cemented, and
in a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=α×νd+β (where, α=−0.017) is set),
Nd and νd of at least one lens forming the cemented lens are included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1b), and a line when an upper limit value is in a range of the following conditional expression (1b), and an area determined by following conditional expressions (2b) and (3b).

1.45<β<2.15  (1b)

1.58<Nd<2.20  (2b)

3<νd<40  (3b)

Here, Nd denotes a refractive index, and νd denotes an Abbe's number.
Moreover, an electronic image pickup apparatus of the present invention is characterized in that the electronic image pickup apparatus includes an image forming optical system mentioned in any one above, an electronic image pickup element, and an image processing means which is capable of processing image data obtained by image pickup by the electronic image pickup element of an image which is formed through the image forming optical system, and outputting image data in which, a shape is changed upon processing, and in which the image forming optical system is a zoom lens, and the zoom lens satisfies a following conditional expression at a time of infinite object point focusing.

0.7<y07/(fw·tan ω07w)<0.96

where, y07 is indicated as y07=0.7y10 when, in an effective image pickup surface (surface in which, image pickup is possible), a distance from a center up to a farthest point (maximum image height) is let to be y10. Moreover, ω07w is an angle with respect to an optical axis in a direction of an object point corresponding to an image point connecting from a center on the image pickup surface in a wide angle end up to a position of y07.
According to the present invention, it is possible to achieve a thinning and a size reduction of a volume of the image forming optical system, and further to have both of a widening of an angle and a favorable correction of various aberrations in the electronic image pickup apparatus of the present invention.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view along an optical axis showing an optical arrangement at the time of an infinite object point focusing at a wide angle end of a zoom lens according to a first embodiment of the present invention;
FIG. 2A, FIG. 2B, and FIG. 2C are diagrams showing a spherical aberration, an astigmatism, a distortion, and a chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the first embodiment, where, FIG. 2A shows a state at the wide angle end, FIG. 2B shows an intermediate state, and FIG. 2C shows a state at a telephoto end;
FIG. 3 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a second embodiment of the present invention;
FIG. 4A, FIG. 4B, and FIG. 4C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the second embodiment, where, FIG. 4A shows the state at the wide angle end, FIG. 4B shows the intermediate state, and FIG. 4C shows the state at the telephoto end;
FIG. 5 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a third embodiment of the present invention;
FIG. 6A, FIG. 6B, and FIG. 6C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the third embodiment, where, FIG. 6A shows the state at the wide angle end, FIG. 6B shows the intermediate state, and FIG. 6C shows the state at the telephoto end;
FIG. 7 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fourth embodiment of the present invention;
FIG. 8A, FIG. 8B, and FIG. 8C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fourth embodiment, where, FIG. 8A shows the state at the wide angle end, FIG. 8B shows the intermediate state, and FIG. 8C shows the state at the telephoto end;
FIG. 9 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fifth embodiment of the present invention;
FIG. 10A, FIG. 10B, and FIG. 10C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fifth embodiment, where, FIG. 10A shows the state at the wide angle end, FIG. 10B shows the intermediate state, and FIG. 10C shows the state at the telephoto end;
FIG. 11 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a sixth embodiment of the present invention;
FIG. 12A, FIG. 12B, and FIG. 12C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the sixth embodiment, where, FIG. 12A shows the state at the wide angle end, FIG. 12B shows the intermediate state, and FIG. 12C shows the state at the telephoto end;
FIG. 13 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a seventh embodiment of the present invention;
FIG. 14A, FIG. 14B, and FIG. 14C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the seventh embodiment, where, FIG. 14A shows the state at the wide angle end, FIG. 14B shows the intermediate state, and FIG. 14C shows the state at the telephoto end;
FIG. 15 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to an eighth embodiment of the present invention;
FIG. 16A, FIG. 16B, and FIG. 16C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the eighth embodiment, where, FIG. 16A shows the state at the wide angle end, FIG. 16B shows the intermediate state, and FIG. 16C shows the state at the telephoto end;
FIG. 17 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a ninth embodiment of the present invention;
FIG. 18A, FIG. 18B, and FIG. 18C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the ninth embodiment, where, FIG. 18A shows the state at the wide angle end, FIG. 18B shows the intermediate state, and FIG. 18C shows the state at the telephoto end;
FIG. 19 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a tenth embodiment of the present invention;
FIG. 20A, FIG. 20B, and FIG. 20C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the tenth embodiment, where, FIG. 20A shows the state at the wide angle end, FIG. 20B shows the intermediate state, and FIG. 20C shows the state at the telephoto end;
FIG. 21 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to an eleventh embodiment of the present invention;
FIG. 22A, FIG. 22B, and FIG. 22C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the eleventh embodiment, where, FIG. 22A shows the state at the wide angle end, FIG. 22B shows the intermediate state, and FIG. 22C shows the state at the telephoto end;
FIG. 23 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twelfth embodiment of the present invention;
FIG. 24A, FIG. 24B, and FIG. 24C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twelfth embodiment, where, FIG. 24A shows the state at the wide angle end, FIG. 24B shows the intermediate state, and FIG. 24C shows the state at the telephoto end;
FIG. 25 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirteenth embodiment of the present invention;
FIG. 26A, FIG. 26B, and FIG. 26C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirteenth embodiment, where, FIG. 26A shows the state at the wide angle end, FIG. 26B shows the intermediate state, and FIG. 26C shows the state at the telephoto end;
FIG. 27 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fourteenth embodiment of the present invention;
FIG. 28A, FIG. 28B, and FIG. 28C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fourteenth embodiment, where, FIG. 28A shows the state at the wide angle end, FIG. 28B shows the intermediate state, and FIG. 28C shows the state at the telephoto end;
FIG. 29 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fifteenth embodiment of the present invention;
FIG. 30A, FIG. 30B, and FIG. 30C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fifteenth embodiment, where, FIG. 30A shows the state at the wide angle end, FIG. 30B shows the intermediate state, and FIG. 30C shows the state at the telephoto end;
FIG. 31 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a sixteenth embodiment of the present invention;
FIG. 32A, FIG. 32B, and FIG. 32C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the sixteenth embodiment, where, FIG. 32A shows the state at the wide angle end, FIG. 32B shows the intermediate state, and FIG. 32C shows the state at the telephoto end;
FIG. 33 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a seventeenth embodiment of the present invention;
FIG. 34A, FIG. 34B, and FIG. 34C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the seventeenth embodiment, where, FIG. 34A shows the state at the wide angle end, FIG. 34B shows the intermediate state, and FIG. 34c shows the state at the telephoto end;
FIG. 35 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to an eighteenth embodiment of the present invention;
FIG. 36A, FIG. 36B, and FIG. 36C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the eighteenth embodiment, where, FIG. 36A shows the state at the wide angle end, FIG. 36B shows the intermediate state, and FIG. 36C shows the state at the telephoto end;
FIG. 37 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a nineteenth embodiment of the present invention;
FIG. 38A, FIG. 38B, and FIG. 38C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the nineteenth embodiment, where, FIG. 38A shows the state at the wide angle end, FIG. 38B shows the intermediate state, and FIG. 38C shows the state at the telephoto end;
FIG. 39 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twentieth embodiment of the present invention;
FIG. 40A, FIG. 40B, and FIG. 40C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twentieth embodiment, where, FIG. 40A shows the state at the wide angle end, FIG. 40B shows the intermediate state, and FIG. 40C shows the state at the telephoto end;
FIG. 41 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty first embodiment of the present invention;
FIG. 42A, FIG. 42B, and FIG. 42C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty first embodiment, where, FIG. 42A shows the state at the wide angle end, FIG. 42B shows the intermediate state, and FIG. 42C shows the state at the telephoto end;
FIG. 43 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty second embodiment of the present invention;
FIG. 44A, FIG. 44B, and FIG. 44C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty second embodiment, where, FIG. 44A shows the state at the wide angle end, FIG. 44B shows the intermediate state, and FIG. 44C shows the state at the telephoto end;
FIG. 45 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty third embodiment of the present invention;
FIG. 46A, FIG. 46B, and FIG. 46C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty third embodiment, where, FIG. 46A shows the state at the wide angle end, FIG. 46B shows the intermediate state, and FIG. 46C shows the state at the telephoto end;
FIG. 47 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty fourth embodiment of the present invention;
FIG. 48A, FIG. 48B, and FIG. 48C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty fourth embodiment, where, FIG. 48A shows the state at the wide angle end, FIG. 48B shows the intermediate state, and FIG. 48C shows the state at the telephoto end;
FIG. 49 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty fifth embodiment of the present invention;
FIG. 50A, FIG. 50B, and FIG. 50C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty fifth embodiment, where, FIG. 50A shows the state at the wide angle end, FIG. 50B shows the intermediate state, and FIG. 50C shows the state at the telephoto end;
FIG. 51 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty sixth embodiment of the present invention;
FIG. 52A, FIG. 52B, and FIG. 52C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty sixth embodiment, where, FIG. 52A shows the state at the wide angle end, FIG. 52B shows the intermediate state, and FIG. 52C shows the state at the telephoto end;
FIG. 53 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty seventh embodiment of the present invention;
FIG. 54A, FIG. 54B, and FIG. 54C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty seventh embodiment, where, FIG. 54A shows the state at the wide angle end, FIG. 54B shows the intermediate state, and FIG. 54C shows the state at the telephoto end;
FIG. 55 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty eighth embodiment of the present invention;
FIG. 56A, FIG. 56B, and FIG. 56C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty eighth embodiment, where, FIG. 56A shows the state at the wide angle end, FIG. 56B shows the intermediate state, and FIG. 56C shows the state at the telephoto end;
FIG. 57 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty ninth embodiment of the present invention;
FIG. 58A, FIG. 58B, and FIG. 58C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty ninth embodiment, where, FIG. 58A shows the state at the wide angle end, FIG. 58B shows the intermediate state, and FIG. 58C shows the state at the telephoto end;
FIG. 59 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirtieth embodiment of the present invention;
FIG. 60A, FIG. 60B, and FIG. 60C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirtieth embodiment, where, FIG. 60A shows the state at the wide angle end, FIG. 60B shows the intermediate state, and FIG. 60C shows the state at the telephoto end;
FIG. 61 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty first embodiment of the present invention;
FIG. 62A, FIG. 62B, and FIG. 62C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty first embodiment, where, FIG. 62A shows the state at the wide angle end, FIG. 62B shows the intermediate state, and FIG. 62C shows the state at the telephoto end;
FIG. 63 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty second embodiment of the present invention;
FIG. 64A, FIG. 64B, and FIG. 64C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty second embodiment, where, FIG. 64A shows the state at the wide angle end, FIG. 64B shows the intermediate state, and FIG. 64C shows the state at the telephoto end;
FIG. 65 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty third embodiment of the present invention;
FIG. 66A, FIG. 66B, and FIG. 66C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty third embodiment, where, FIG. 66A shows the state at the wide angle end, FIG. 66B shows the intermediate state, and FIG. 66C shows the state at the telephoto end;
FIG. 67 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty fourth embodiment of the present invention;
FIG. 68A, FIG. 68B, and FIG. 68C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty fourth embodiment, where, FIG. 68A shows the state at the wide angle end, FIG. 68B shows the intermediate state, and FIG. 68C shows the state at the telephoto end;
FIG. 69 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty fifth embodiment of the present invention;
FIG. 70A, FIG. 70B, and FIG. 70C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens-according to the thirty fifth embodiment, where, FIG. 70A shows the state at the wide angle end, FIG. 70B shows the intermediate state, and FIG. 70C shows the state at the telephoto end;
FIG. 71 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty sixth embodiment of the present invention;
FIG. 72A, FIG. 72B, and FIG. 72C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty sixth embodiment, where, FIG. 72A shows the state at the wide angle end, FIG. 72B shows the intermediate state, and FIG. 72C shows the state at the telephoto end;
FIG. 73 is a cross-sectional view along the optical axis showing an optical arrangement at the wide angle end of a zoom lens system according to a thirty seventh embodiment of the present invention;
FIG. 74A, FIG. 74B, and FIG. 74C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty seventh embodiment, where, FIG. 74A shows the state at the wide angle end, FIG. 74B shows the intermediate state, and FIG. 74C shows the state at the telephoto end;
FIG. 75 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty eighth embodiment of the present invention;
FIG. 76A, FIG. 76B, and FIG. 76C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty eighth embodiment, where, FIG. 76A shows the state at the wide angle end, FIG. 76B shows the intermediate state, and FIG. 76C shows the state at the telephoto end;
FIG. 77 is a frontward perspective view showing an appearance of a digital camera 40 in which, a zoom optical system according to the present invention is incorporated;
FIG. 78 is a rearward perspective view of the digital camera 40;
FIG. 79 is a cross-sectional view showing an optical arrangement of the digital camera 40;
FIG. 80 is a frontward perspective view of a personal computer 300 with its cover opened, which is an example of an information processing apparatus in which, the zoom optical system of the present invention is built-in as an objective optical system;
FIG. 81 is a cross-sectional view of a photographic optical system 303 of the personal computer 300;
FIG. 82 is a side view of the personal computer 300; and
FIG. 83A, FIG. 83B, and FIG. 83C are diagrams showing a portable telephone which is an example of the information processing apparatus in which, the zoom optical system of the present invention is built-in as the taking optical system, where, FIG. 83A is a front view of a portable telephone 400, FIG. 83B is a side of the portable telephone 400, and FIG. 83C is a cross-sectional view of a taking optical system 405.



BEST MODE FOR CARRYING OUT THE INVENTION
Prior to a description of embodiments, an action and an effect of the present invention will be described below.
An image forming optical system of the present invention, where the image forming optical system includes a positive lens group, a negative lens group, and an aperture stop, has a basic structure in which, the positive lens group is disposed at a image side of the aperture stop, and the positive lens group includes a cemented lens which is formed by cementing a plurality of lenses.
In this manner, in the basic structure, since the cemented lens is used in the positive lens group on an image-plane side of the aperture stop, a change in a longitudinal chromatic aberration in a zoom lens, at the time of zooming, is easily suppressed. Moreover, with a fewer number of lenses, it is possible to suppress sufficiently an occurrence of color spreading over a zoom range. Moreover, although it is effective to enhance a refracting power of the lens groups for making small the entire optical system, in this basic structure, since the refracting power can be easily imparted without making thick as far as possible, the positive lens group (the positive lens group on the image side of the aperture stop) of which the refractive index is to be made strong it is easy to make small the entire optical system.
Further, in the abovementioned basic structure, it is preferable that at least one lens forming the cemented lens has the following characteristics. In other words, in a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=α×νd+β (where, α=−0.017) is set, it is desirable that Nd and νd of at least one lens forming the cemented lens are included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1a), and a line when an upper limit value is in a range of the following conditional expression (1a), and an area determined by following conditional expressions (2a) and (3a).

1.45<β<2.15  (1a)

1.30<Nd<2.20  (2a)

3<νd<12  (3a)

Here, Nd denotes a refractive index, and νd denotes an Abbe's number.
Here, a glass means a lens material such as a glass and a resin. Moreover, as a cemented lens, a lens in which a plurality of lenses made of a glass selected appropriately is cemented, is selected.
When a value is lower than the lower limit value in the conditional expression (1a), since a refractive index is low, an effect when an aspheric surface is provided on a side which is in contact with air is small, and a correction of a spherical aberration, a coma aberration, and a distortion becomes difficult. Or, since the Abbe's number is low, a correction of a chromatic aberration, as an extremely thin cemented lens is possible, but when the side in contact with air is made to be an aspheric surface, a chromatic coma and a chromatic aberration of magnification of high order is susceptible to occur, and a degree of freedom of an aberration correction is decreased.
When a value is higher than an upper limit value in the conditional expression (1a), since a power and a thickness of the cemented lens is required to be more than a certain magnitude for the correction of the chromatic aberration, it becomes susceptible to be effected by optical characteristics which depend on an environment of the material.
When a value is lower than a lower limit value in the conditional expression (2a), the effect when the aspheric surface is provided on the side which is in contact with air is small, and the correction of the spherical aberration, the coma aberration, and the distortion becomes difficult.
When a value is higher than an upper limit value in the conditional expression (2a), in a case of a material which includes organic properties, when the refractive index is excessively high, a temperature variance becomes excessively high, and optical characteristics which depend on the environment are susceptible to become unstable. Moreover, a reflectivity becomes excessively high, and a ghost is susceptible to occur even when coating is optimized.
When a value is lower than a lower limit value in the conditional expression (3a), the correction of the chromatic aberration, as an extremely thin cemented lens is possible, but when the side in contact with air is made to be an aspheric surface, the chromatic coma and the chromatic aberration of magnification of high order are susceptible to occur, and the degree of freedom of the aberration correction is decreased.
When a value is higher than an upper limit value in the conditional expression (3a), it is necessary to enhance a refracting power of the cemented lens for correcting the chromatic aberration, and it is advantageous for a correction of a Petzval's sum, but it becomes susceptible to be effected by the optical characteristics which depend on the environment of the material.
It is more preferable when a following conditional expression (1a′) is satisfied.

1.48<β<2.04  (1a′)

Furthermore, it is even more preferable when a following conditional expression (1a′′) is satisfied.

1.50<β<2.00  (1a′′)

Moreover, it is more preferable when a following conditional expression (2a′) is satisfied.

1.58<Nd<2.10  (2a′)

Furthermore, it is more preferable when a following conditional expression (2a′′) is satisfied.

1.63<Nd<1.95  (2a′′)

Moreover, it is more preferable when a following conditional expression (3a′) is satisfied.

5<νd<10  (3a′)

Furthermore, it is more preferable when a following conditional expression (3a′′) is satisfied.

6<νd<9  (3a′′)

Or, in the abovementioned basic structure, it is preferable that at least one lens forming the cemented lens has the following characteristics. In other words, in a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=α×νd+β (where, α=−0.017) is set, it is desirable that Nd and νd of at least one lens forming the cemented lens is included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1b), and a line when an upper limit value is in a range of the following conditional expression (1b), and an area determined by following conditional expressions (2b) and (3b).

1.45<β<2.15  (1b)

1.58<Nd<2.20  (2b)

3<νd<40  (3b)

Here, Nd denotes the refractive index, and νd denotes the Abbe's number.
When a value is lower than a lower limit value in the conditional expression (1b), since the refractive index is low, the effect when the aspheric surface is provided on the side which is in contact with air is small, and the correction of the spherical aberration, the coma aberration, and the distortion becomes difficult. Or, since the Abbe's number is low, the correction of the chromatic aberration, as an extremely thin cemented lens is possible, but when the side in contact with air is made to be an aspheric surface, the chromatic coma, and the chromatic aberration of magnification of high order are susceptible to occur, and the degree of freedom of the aberration correction is decreased.
When a value is higher than an upper limit value in the conditional expression (1b), a correction level of the chromatic aberration and the Petzval's sum become same as of a general optical glass lens, and characteristics of the present invention are not achieved.
When a value is lower than a lower limit value in the conditional expression (2b), the effect when the aspheric surface is provided on the side which is in contact with air is small, and the correction of the spherical aberration, the coma aberration, and the distortion becomes difficult.
When a value is higher than an upper limit value in the conditional expression (2b), in the case of a material which includes organic properties, when the refractive index is excessively high, the temperature variance becomes excessively high, and the optical characteristics which depend on the environment are susceptible to become unstable. Moreover, the reflectivity becomes excessively high, and a ghost is susceptible to occur even when the coating is optimized.
When a value is lower than a lower limit value in the conditional expression (3b), the correction of the chromatic aberration, as an extremely thin cemented lens is possible, but when the side in contact with air is made to be an aspheric surface, the chromatic coma and the chromatic aberration of magnification of high order are susceptible to occur, and the degree of freedom of the aberration correction is decreased.
When a value is higher than an upper limit value in the conditional expression (3b), it is necessary to enhance the refracting power of the cemented lens for correcting the chromatic aberration, and it is advantageous for the correction of the Petzval's sum, but it becomes susceptible to be effected by the optical characteristics which depend on the environment of the material.
It is more preferable when a following conditional expression (1b′) is satisfied.

1.48<β<2.04  (1b′)

Furthermore, it is even more preferable when a following conditional expression (1b′′) is satisfied.

1.50<β<2.00  (1b′′)

Moreover, it is more preferable when a following conditional expression (2b′) is satisfied.

1.60<Nd<2.10  (2b′)

Furthermore, it is more preferable when a following conditional expression (2b′′) is satisfied.

1.63<Nd<1.95  (2b′′)

Moreover, it is more preferable when a following conditional expression (3b′) is satisfied.

5<νd<30  (3b′)

Furthermore, it is more preferable when a following conditional expression (3b′′) is satisfied.

6<νd<25  (3b′′)

Moreover, it is preferable that the cemented lens is formed by a lens having the values of Nd and νd which are included in both the areas mentioned above (hereinafter, called as a ‘predetermined lens’), and a lens other than the predetermined lens, and a center thickness along an optical axis of the predetermined lens is less than a center thickness along an optical axis of the other lens. By making such an arrangement, it is possible to realize a more favorable correction of each aberration mentioned above, and thinning of the lens group.
Moreover, the cemented lens may be a compound lens which is formed by closely adhering and hardening a resin on a lens surface (lens surface of the other lens), in order to improve a manufacturing accuracy. Here, the resin which is adhered closely and hardened corresponds to the predetermined lens.
Moreover, the cemented lens may be a compound lens which is formed by closely adhering and hardening a glass on the lens surface (lens surface of the other lens), as it is advantageous for resistance such as a light resistance and a chemical resistance. Here, the glass which is adhered closely and hardened corresponds to the predetermined lens.
Furthermore, in the cemented lens, a center thickness t1 along the optical axis of the predetermined lens (one lens in which Nd and νd are included in both the areas mentioned above) may satisfy a following conditional expression (4), in order to make a size small and to carry out molding stably.

0.22<t1<2.0  (4)

It is more preferable that a following conditional expression (4′) is satisfied.

0.3<t1<1.5  (4′)

Furthermore, it is even more preferable that a following conditional expression (4′′) is satisfied.

0.32<t1<1.0  (4′′)

Moreover, the image forming optical system may be a zoom lens of which, a group on the closest side of an object is a positive lens group, from a viewpoint of having a high magnification of the zoom, and an improvement in a brightness of the lens.
Moreover, the image forming optical system may be a zoom lens of which, a group on the closest side of an object is a negative lens group, for making the size small.
Moreover, the image forming optical system may have a prism for folding, for facilitating thinning of an optical system with respect to a direction of taking a photo.
Moreover, in the image forming optical system, the prism may be in a group on the closest side of an object, for facilitating thinning.
Incidentally, when a pixel size of the electronic image pickup element becomes smaller than a certain size, a component of a frequency higher than a Nyquist frequency is eliminated due to an effect of diffraction. Therefore, when this is used, it is possible to omit an optical low-pass filter. This is preferable from a point of making the entire optical system extremely thin.
For this, it is preferable that a following conditional expression (6) is satisfied.

Fw≧a (μm)  (6)

where, Fw is a full-aperture F value, and a is a distance between pixels in a horizontal direction of the electronic image pickup element (unit: μm).
When the conditional expression (6) is satisfied, the optical low-pass filter is not required to be disposed in an optical path. Accordingly, it is possible to make the optical system small.
In a case of satisfying the conditional expression (6), it is preferable that the aperture stop is let to be open only. This means that the optical system in this case is an optical system with a constant diameter of the aperture stop all the time. Moreover, in the optical system in this case, since an operation of narrowing is not necessary, it is possible to omit a narrowing mechanism. Accordingly, the size can be made small saving that much space. When the conditional expression (6) is not satisfied, the optical low-pass filter is necessary.
Moreover, it is more preferable that a conditional expression (6′) is satisfied.

Fw≧1.2a (μm)  (6′)

Furthermore, it is even more preferable that a conditional expression (6′′) is satisfied.

Fw≧1.4a (μm)  (6′′)

Finally, an electronic image pickup apparatus will be described below. As the electronic image pickup apparatus, an electronic image pickup apparatus in which, both a thinning of depth and a widening of image angle are realized is preferable.
Here, it is assumed that an infinite object is imaged by an optical system which has no distortion. In this case, since the image which is formed has no distortion,

f=y/tan ω

holds.

Here, y is a height of an image point from an optical axis, f is a focal length of the image forming system, and ω is an angle with respect to an optical axis in a direction of an object point corresponding to the image point connecting from a center on an image pickup surface up to a position of y.
On the other hand, when the optical system has a barrel distortion,

f>y/tan ω

holds. In other words, when f and y are let to be constant values, ω becomes a substantial value.

Therefore, in the electronic image pickup apparatus, it is preferable to use a zoom lens as the image forming optical system. As a zoom lens, particularly in a focal length near a wide angle end, an optical system having a substantial barrel distortion may be used intentionally. In this case, since a purpose is served without correcting the distortion, it is possible to achieve the widening of the image angle of the optical system. However, an image of the object is formed on the electronic image pickup element, in a state of having the barrel distortion. Therefore, in the electronic image pickup apparatus, image data obtained by the electronic image pickup element is processed by an image processing. In this process, the image data (a shape of the image) is changed such that the barrel distortion is corrected. By changing the image data, image data which is obtained finally, takes a shape almost similar to the object. Accordingly, based on this image data, the image of the object may be output to a CRT or a printer.
Here, as the image forming optical system (zoom lens), an image forming optical system which satisfies a following conditional expression (7) at the time of infinite object point focusing may be adopted.

0.7<y07/(fw·tan ω07w)<0.96  (7)

where, y07 is indicated as y07=0.7y10 when, in an effective image pickup surface (surface in which image pickup is possible), a distance from a center up to a farthest point (maximum image height) is let to be y10. Moreover, ω07w is an angle with respect to an optical axis in a direction of an object point corresponding to an image point connecting from a center on the image pickup surface in a wide angle end up to a position of y07.
The conditional expression (7) mentioned above is an expression in which, a degree of the barrel distortion in a zoom wide angle end is regulated. When the conditional expression (7) is satisfied, it is possible to fetch information of the wide image angle without-making the optical system enlarged. An image which is distorted to barrel shape is subjected to photoelectric conversion, and becomes image data which is distorted to barrel shape. However, on the image data which is distorted to the barrel shape, a process equivalent to a shape change of the image is carried out electrically by the image processing means which is a signal processing system of the electronic image pickup apparatus. When this process is carried out, even when the image data output from the image processing means is reproduced finally by a display apparatus, the distortion is corrected, and an image almost similar to a shape of an object to be photographed is obtained.
Here, when a value is higher than an upper limit value in the conditional expression (7), particularly, when a value close to 1 is to be taken, it is possible to carry out by the image processing means, a correction equivalent to a correction in which the distortion is corrected favorably optically, but it is difficult to fetch an image over a wide angle of visibility. On the other hand, when a value is lower than a lower limit value in the conditional expression (7), a rate of enlarging in a direction of radiating in a portion around an image angle when the image distortion due to the distortion of the optical system is corrected by the image processing means, becomes excessively high. As a result of this, a deterioration in a sharpness of the area around the image becomes remarkable.
On the other hand, by satisfying the conditional expression (7), it is possible to widen the angle (make an angle in a vertical direction in the distortion to be 38° or more) and to make small the optical system.
Moreover, it is more preferable when a following conditional expression (7′′) is satisfied.

0.75<y07/(fw·tan ω07w)<0.94  (7′)

Furthermore, it is even more preferable when a following conditional expression (7′′) is satisfied.

0.80<y07/(fw·tan ω07w)<0.92  (7′′)

The image forming optical system of the present invention, even when an electronic image pickup element of a large number of pixels is used, is capable of achieving thinning and reduction in size of a volume of the image forming optical system, by satisfying or providing each of conditional expressional and structural characteristics mentioned above, and realizing a favorable correction of aberration. Moreover, the image forming optical system of the present invention is capable of providing (satisfying) in combination the conditional expressional and structural characteristics mentioned above. In this case, it is possible to achieve further reduction in size and thinning, or the favorable aberration correction. Moreover, in the electronic image pickup apparatus having the image forming optical system of the present invention, it is possible to achieve the thinning and reduction in size of the volume of the image forming optical system, and further, to have both of the favorable correction of various aberrations, and widening of the angle.
Embodiments of the present invention will be described below by using accompanying diagrams.
As a zoom lens of the present invention, a five-group structure or a four-group structure can be taken into consideration. In a zoom lens of the five-group structure, it is preferable to dispose from object side, each lens group in order of a first lens group having a positive refracting power, a second lens group having a negative refracting power, a third lens group having a positive refracting power, a fourth lens group having a negative refracting power, and a fifth lens group having a positive refracting power.
Here, it is preferable that the first lens group includes a negative lens, a prism, and a positive lens. At this time, it is more preferable to dispose these in order of the negative lens, the prism and the positive lens, from the object side. Moreover, the first lens group may include only one negative lens, one prism, and one positive lens.
Moreover, it is preferable that the second lens group includes a positive lens and a negative lens. At this time, it is more preferable to dispose these in order of the negative lens and the positive lens, from the object side. The second lens group may include only one positive lens and one negative lens.
Moreover, it is preferable that the third lens group includes a positive lens and a negative lens. At this time, it is more preferable to form a cemented lens by the positive lens and the negative lens, and to dispose cemented lens such that the positive lens is positioned at the object side. Furthermore, a negative lens or a positive lens may be cemented on an image side. The third lens group may be formed by only one cemented lens. In this case, the cemented lens is formed by one positive lens and two negative lenses, or by two positive lenses and one negative lens.
Moreover, it is preferable that the fourth lens group includes a negative lens. At this time, it is preferable to form the fourth lens group by only one negative lens.
Moreover, it is preferable that the fifth lens group includes a positive lens. At this time, it is preferable to form the fifth lens group by only one positive lens.
Moreover, in a zoom of the four-group structure, it is preferable to dispose each lens group in order of a first lens group having a negative refracting power, a second lens group having a positive refracting power, a third lens group having a negative refracting power, a fourth lens group having a positive refracting power, from the object side.
Here, it is preferable that the first lens group includes a negative lens, a prism, and a cemented lens. At this time, it is more preferable to dispose these in order of the negative lens, the prism, and the cemented lens, from the object side. Moreover, it is preferable to form the cemented lens by a positive lens and a negative lens, and to dispose the cemented lens such that the positive lens is positioned at the object side. Or, it is preferable to form the cemented lens by only the negative lens. The first lens group may be formed by only one negative lens, one prism, and one cemented lens. In this case, the cemented lens is formed by one positive lens and one negative lens, or by two negative lenses.
Moreover, it is preferable that the second lens group includes a positive lens and a negative lens. At this time, it is more preferable to form a cemented lens by a positive lens and a negative lens, and to dispose the cemented lens such that the positive lens is positioned at the object side. The second lens group may be formed by only one cemented lens. In this case, the cemented lens is formed by one positive lens and one negative lens.
Moreover, it is preferable that the third lens group includes a positive lens and a negative lens. At this time, it is more preferable to form a cemented lens by a positive lens and a negative lens, and to dispose the cemented lens such that the negative lens is positioned at the object side. The third lens group may include only one cemented lens. In this case, the cemented lens is formed by one positive lens and one negative lens.
Moreover, it is preferable that the fourth lens group includes a positive lens and a negative lens. At this time, it is preferable to form a cemented lens by a positive lens and a negative lens, and to dispose the cemented lens such that the positive lens is positioned at the object side. The fourth lens group may be formed by only one cemented lens. In this case, the cemented lens includes one positive lens and one negative lens.
It is possible to distribute a refracting power of one lens into two lenses. Accordingly, in each of the lens groups mentioned above, it is possible to substitute one lens by two lenses. However, from a point of view of the reduction in size and thinning, it is preferable to let the number of lenses to be substituted by two lenses in each lens group, to be one.
First Embodiment
FIG. 1 is a cross-sectional view along an optical axis showing an optical arrangement at the time of an infinite object point focusing at a wide angle end of a zoom lens according to a first embodiment.
FIG. 2A, FIG. 2B, and FIG. 2C are diagrams showing a spherical aberration, an astigmatism, a distortion, and a chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the first embodiment, where, FIG. 2A shows a state at the wide angle end, FIG. 2B shows an intermediate state, and FIG. 2C shows a state at a telephoto end.
The zoom lens of the first embodiment, as shown in FIG. 1, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.
The second lens group G2 includes a biconcave lens L121 and a biconvex lens L122, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131, a negative meniscus lens L132 having a convex surface directed toward an image side, and a biconcave lens L133, and has a positive refracting power as a whole. The negative meniscus lens L132 having the convex surface directed toward the image side is a lens having a thin center-thickness.
The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.
An aspheric surface is provided on a surface toward the object side, of the biconvex lens L113 in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface toward the object side of the biconvex lens L131, and a surface toward the image side of the biconcave lens L133 in the third lens group G3, and a surface toward the object side of the biconvex lens L142 in the fifth lens group G5.
Next, numerical data of optical members forming the zoom lens of the first embodiment will be enumerated.
In the numerical data of the first embodiment, r1, r2, . . . denote a radius of curvature of each lens surface; d1, d2, . . . denote a thickness or an air space of each lens; nd1, nd2, . . . denote a refractive index at line d of each lens; νd1, νd2, . . . denote the Abbe's number for each lens; Fno. denotes an F number; f denotes a focal length of an overall system; and D0 denotes a distance from the object to a first surface.
An aspheric surface shape is expressed by a following expression when a direction of an optical axis is let to be z, a direction orthogonal to the optical axis is let to be y, a conical coefficient is let to be K, and an aspheric coefficient is let to be A4, A6, A8; and A10.




  z
  =
  
    
      
        (
        
          
            y
            2
          
          /
          r
        
        )
      
      /
      
        [
        
          1
          +
          
            
              {
              
                1
                -
                
                  
                    (
                    
                      1
                      +
                      K
                    
                    )
                  
                  ⁢
                  
                    
                      (
                      
                        y
                        /
                        r
                      
                      )
                    
                    2
                  
                
              
              }
            
            
              1
              /
              2
            
          
        
        ]
      
    
    +
    
      

    
    ⁢
    
      
    
    ⁢
    
      A
      ⁢
      
        
      
      ⁢
      4
      ⁢
      
        y
        4
      
    
    +
    
      A
      ⁢
      
        
      
      ⁢
      6
      ⁢
      
        y
        6
      
    
    +
    
      A
      ⁢
      
        
      
      ⁢
      8
      ⁢
      
        y
        8
      
    
    +
    
      A
      ⁢
      
        
      
      ⁢
      10
      ⁢
      
        y
        10
      
    
  




Moreover, E denotes a power of 10. These symbols of data values are common even in numerical data of embodiments which will be described later. The conical coefficient might also be denoted by k.
Next, numerical data of the first embodiment will be enumerated.










Numerical data 1


















r1 = 27.091
d1 = 1
Nd1 = 1.801
νd1 = 34.97


r2 = 10
d2 = 2.9




r3 = ∞
d3 = 12
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.3




r5 = 24.357
d5 = 3.54
Nd5 = 1.741
νd5 = 52.64


(Aspheric surface)





r6 = −27.16
d6 = D6




r7 = −52.772
d7 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 5.283
d8 = 0.7




(Aspheric surface)





r9 = 7.825
d9 = 2.2
Nd9 = 1.7552
νd9 = 27.51


r10 = −122.045
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = 9.973
d12 = 5.05
Nd12 = 1.804
νd12 = 46.57


(Aspheric surface)





r13 = −11.26
d13 = 0.1
Nd13 = 1.41244
νd13 = 12.42


r14 = −14.068
d14 = 0.7
Nd14 = 1.84666
νd14 = 23.78


r15 = 20.667
d15 = D15




(Aspheric surface)





r16 = 49.976
d16 = 0.6
Nd16 = 1.497
νd16 = 81.54


r17 = 10.281
d17 = D17




r18 = 9.328
d18 = 1.8
Nd18 = 1.7432
νd18 = 49.34


(Aspheric surface)





r19 = −570.249
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





 5th surface


k = 0


A4 = −6.73153E−06


A6 = 2.07071E−07


A8 = 0


 7th surface


k = 0


A4 = −1.19857E−04


A6 = −2.89366E−07


A8 = 9.02125E−08


 8th surface


k = 0


A4 = −8.29199E−04


A6 = −4.30970E−06


A8 = −8.66290E−07


12th surface


k = 0


A4 = 1.04075E−04


A6 = −1.01064E−06


A8 = 2.01696E−08


15th surface


k = 0


A4 = 4.99806E−04


A6 = 1.75190E−09


A8 = 2.59710E−07


18th surface


k = 0


A4 = −1.16782E−04


A6 = 1.61178E−06


A8 = −7.88512E−08





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
5.999
13.7
18.001


FNO.
2.89
4.96
6.07


D6
0.8
6.75
9.02


D10
9.62
3.67
1.4


D11
11.56
2.94
1.2


D15
1.7
14.1
18.02


D17
0.66
0.49
0.2


D19
6
2.38
0.5


D23
1.36
1.36
1.36









Second Embodiment
FIG. 3 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens system according to a second embodiment of the present invention.
FIG. 4A, FIG. 4B, and FIG. 4C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the second embodiment, where, FIG. 4A shows the state at the wide angle end, FIG. 4B shows the intermediate state, and FIG. 4C shows the state at the telephoto end.
The zoom lens of the second embodiment, as shown in FIG. 3, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refractive power as a whole.
The second lens group G2 includes a biconcave lens L121 and a biconvex lens L122, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131, a negative meniscus lens L132 having a convex surface directed toward an image side, and a biconcave lens L133, and has a positive refracting power as a whole. The negative meniscus lens L132 having the convex surface directed toward the object side is a lens having a thin center-thickness.
The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.
An aspheric surface is provided on the surface toward the object side, of the biconvex lens L113 in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface toward the object side of the biconvex lens L131, and a surface toward the image side of the biconcave lens L133 on the object side in the third lens group G3, and a surface toward the object side, of the biconvex lens L142 in the fifth lens group G5.
Next, numerical data of the second embodiment will be enumerated.










Numerical data 2


















r1 = 27.305
d1 = 1
Nd1 = 1.801
νd1 = 34.97


r2 = 10
d2 = 2.9




r3 = ∞
d3 = 12
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.3




r5 = 24.066
d5 = 3.54
Nd5 = 1.741
νd5 = 52.64


(Aspheric surface)





r6 = −27.444
d6 = D6




r7 = −57.402
d7 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 5.276
d8 = 0.7




(Aspheric surface)





r9 = 7.778
d9 = 2.2
Nd9 = 1.7552
νd9 = 27.51


r10 = −149.557
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = 10.032
d12 = 5.06
Nd12 = 1.804
νd12 = 46.57


(Aspheric surface)





r13 = −12.839
d13 = 0.1
Nd13 = 1.42001
νd13 = 6.55


r14 = −14.428
d14 = 0.7
Nd14 = 1.84666
νd14 = 23.78


r15 = 23.100
d15 = D15




(Aspheric surface)





r16 = 48.967
d16 = 0.6
Nd16 = 1.497
νd16 = 81.54


r17 = 10.328
d17 = D17




r18 = 9.453
d18 = 1.8
Nd18 = 1.7432
νd18 = 49.34


(Aspheric surface)





r19 = −357.316
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





 5th surface


k = 0


A4 = −7.34410E−06


A6 = 2.00459E−07


A8 = 0


 7th surface


k = 0


A4 = −1.13262E−04


A6 = −7.61267E−07


A8 = 9.49467E−08


 8th surface


k = 0


A4 = −8.14616E−04


A6 = −4.70726E−06


A8 = −8.86698E−07


12th surface


k = 0


A4 = 1.27486E−04


A6 = −8.35273E−07


A8 = 4.14848E−08


15th surface


k = 0


A4 = 5.02324E−04


A6 = −5.77517E−07


A8 = 3.06301E−07


18th surface


k = 0


A4 = −1.14796E−04


A6 = 1.98364E−06


A8 = −8.65629E−08





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6
13.7
18.001


FNO.
2.89
4.96
6.07


D6
0.8
6.73
9.03


D10
9.63
3.7
1.4


D11
11.62
2.9
1.2


D15
1.7
14.09
18.04


D17
0.6
0.53
0.2


D19
6.02
2.42
0.5


D23
1.36
1.36
1.36









Third Embodiment
FIG. 5 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a third embodiment of the present invention.
FIG. 6A, FIG. 6B, and FIG. 6C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the third embodiment, where, FIG. 6A shows the state at the wide angle end, FIG. 6B shows the intermediate state, and FIG. 6C shows the state at the telephoto end.
The zoom lens of the third embodiment, as shown in FIG. 5, has in order from the object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.
The second lens group G2 includes a biconcave lens L121 and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131, a negative meniscus lens L132 having a convex surface directed toward an image side, and a biconcave lens L133, and has a positive refracting power as a whole. The negative meniscus lens L132 having the convex surface directed toward the image side is a lens having a thin center-thickness.
The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.
An aspheric surface is provided on a surface toward the object side of the biconvex lens L113 in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface on the object side of the biconvex lens L131, and a surface on the image side of the biconcave lens L133 in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.
Next, numerical data of the third embodiment will be enumerated.










Numerical data 3


















r1 = 28.193
d1 = 1
Nd1 = 1.801
νd1 = 34.97


r2 = 9.999
d2 = 2.9




r3 = ∞
d3 = 12
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.3




r5 = 25.359
d5 = 3.54
Nd5 = 1.741
νd5 = 52.64


(Aspheric surface)





r6 = −28.525
d6 = D6




r7 = −264.123
d7 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 5.616
d8 = 0.7




(Aspheric surface)





r9 = 7.773
d9 = 2.2
Nd9 = 1.7552
νd9 = 27.51


r10 = 73.334
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = 10.185
d12 = 5.11
Nd12 = 1.8061
νd12 = 40.92


(Aspheric surface)





r13 = −12.406
d13 = 0.1
Nd13 = 1.51824
νd13 = 12.85


r14 = −19.845
d14 = 0.7
Nd14 = 1.84666
νd14 = 23.78


r15 = 22.352
d15 = D15




(Aspheric surface)





r16 = 97.109
d16 = 0.6
Nd16 = 1.48749
νd16 = 70.23


r17 = 10.672
d17 = D17




r18 = 10.017
d18 = 1.8
Nd18 = 1.7432
νd18 = 49.34


(Aspheric surface)





r19 = −150.581
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





 5th surface


k = 0


A4 = −1.81628E−06


A6 = 2.04189E−07


A8 = 0


 7th surface


k = 0


A4 = −8.82020E−05


A6 = −7.61927E−08


A8 = 4.48030E−08


 8th surface


k = 0


A4 = −5.67266E−04


A6 = −1.59006E−06


A8 = −5.65980E−07


12th surface


k = 0


A4 = 9.43759E−05


A6 = −7.36065E−07


A8 = 1.41924E−08


15th surface


k = 0


A4 = 4.70445E−04


A6 = 1.03990E−07


A8 = 2.03174E−07


18th surface


k = 0


A4 = −9.34998E−05


A6 = 1.21534E−06


A8 = −6.39947E−08





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6
13.7
18


FNO.
2.89
4.96
6.07


D6
0.8
6.58
9.05


D10
9.65
3.87
1.4


D11
11.96
2.95
1.2


D15
1.7
13.89
18.23


D17
0.28
0.93
0.2


D19
6.19
2.35
0.5


D23
1.36
1.36
1.36









Fourth Embodiment
FIG. 7 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fourth embodiment of the present invention.
FIG. 8A, FIG. 8B, and FIG. 8C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fourth embodiment, where, FIG. 8A shows the state at the wide angle end, FIG. 8B shows the intermediate state, and FIG. 8C shows the state at the telephoto end.
The zoom lens of the fourth embodiment, as shown in FIG. 7, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group. G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface (plane) of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.
The second lens group G2 includes a biconcave lens L121, and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131, a negative meniscus lens L132 having a convex surface directed toward an image side, and a biconcave lens L133. The negative meniscus lens L132 having the convex surface directed toward the object side is a lens having a thin center-thickness.
The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fifth lens group G5 includes a positive meniscus lens L142 having a convex surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and fifth lens group G5 moves toward the image side.
An aspheric surface is provided on a surface toward the object side of the biconvex lens L113 in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface toward the object side of the biconvex lens L131, and a surface toward the image side of the biconcave lens in the third lens group G3 in the third lens group G3, and the surface toward the object side of the positive meniscus lens having the convex surface directed toward the object side in the fifth lens group G5.
Next, numerical data of the fourth embodiment will be enumerated.










Numerical data 4


















r1 = 26.261
d1 = 1
Nd1 = 1.8061
νd1 = 40.92


r2 = 10.015
d2 = 2.9




r3 = ∞
d3 = 12
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.3




r5 = 30.416
d5 = 3.54
Nd5 = 1.741
νd5 = 52.64


(Aspheric surface)





r6 = −26.222
d6 = D6




r7 = −118.144
d17 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 6.357
d8 = 0.7




(Aspheric surface)





r9 = 8.382
d9 = 2.2
Nd9 = 1.7552
νd9 = 27.51


r10 = 48.241
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = 7.645
d12 = 5.69
Nd12 = 1.6935
νd12 = 53.21


(Aspheric surface)





r13 = −11.39
d13 = 0.1
Nd13 = 1.54856
νd13 = 7.04


r14 = −15.146
d14 = 0.7
Nd14 = 1.8061
νd14 = 40.92


r15 = 20.515
d15 = D15




(Aspheric surface)





r16 = 69.149
d16 = 0.6
Nd16 = 1.48749
νd16 = 70.23


r17 = 13.226
d17 = D17




r18 = 10.459
d18 = 1.8
Nd18 = 1.7432
νd18 = 49.34


(Aspheric surface)





r19 = 619.393
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





 5th surface


k = 0


A4 = 4.85177E−06


A6 = 3.10522E−07


A8 = 0.00000E+00


 7th surface


k = 0


A4 = −2.08176E−04


A6 = 1.45691E−05


A8 = −3.61648E−07


 8th surface


k = 0


A4 = −5.42849E−04


A6 = 2.33191E−05


A8 = −9.62550E−07


12th surface


k = 0


A4 = 5.40628E−05


A6 = 5.05620E−06


A8 = −5.44853E−08


15th surface


k = 0


A4 = 7.69573E−04


A6 = 1.53918E−05


A8 = 1.34313E−06


18th surface


k = 0


A4 = −1.27205E−04


A6 = 1.00133E−05


A8 = −2.75445E−07





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
5.997
13.7
18.005


FNO.
2.91
4.93
6.02


D6
0.8
6.93
8.37


D10
8.98
2.84
1.41


D11
11.45
3.9
1.21


D15
1.71
11.83
14.13


D17
1.24
2.08
3.17


D19
4.62
1.23
0.51


D23
1.36
1.36
1.36









Fifth Embodiment
FIG. 9 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fifth embodiment of the present invention.
FIG. 10A, FIG. 10B, and FIG. 10C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fifth embodiment, where, FIG. 10A shows the state at the wide angle end, FIG. 10B shows the intermediate state, and FIG. 10C shows the state at the telephoto end.
The zoom lens of the fifth embodiment, as shown in FIG. 9, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward an object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.
The second lens group G2 includes a biconcave lens L121, and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a negative meniscus lens L133 having a convex surface directed toward the object side, and has a positive refracting power as a whole. The negative meniscus lens L133 having the convex surface directed toward the object side is a lens having a thin center-thickness.
The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.
An aspheric surface is provided on a surface toward the object side of the biconvex lens L113 in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface on the object side of the biconvex lens L131, and a surface on the image side of the negative meniscus lens L133 having the convex surface directed toward the object side in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.
Next, numerical data of the fifth embodiment will be enumerated.










Numerical data 5


















r1 = 24.139
d1 = 1
Nd1 = 1.8061
νd1 = 40.92


r2 = 9.346
d2 = 3.72




r3 = ∞
d3 = 12
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.3




r5 = 28.592
d5 = 3.54
Nd5 = 1.741
νd5 = 52.64


(Aspheric surface)





r6 = −31.035
d6 = D6




r7 = −126.911
d7 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 6.287
d8 = 0.7




(Aspheric surface)





r9 = 8.413
d9 = 2.2
Nd9 = 1.7552
νd9 = 27.51


r10 = 68.335
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = 7.646
d12 = 6.13
Nd12 = 1.6935
νd12 = 53.21


(Aspheric surface)





r13 = −12.777
d13 = 0.7
Nd13 = 1.84666
νd13 = 23.78


r14 = 33.605
d14 = 0.1
Nd14 = 1.65228
νd14 = 12.75


r15 = 27.968
d15 = D15




(Aspheric surface)





r16 = 43.474
d16 = 0.6
Nd16 = 1.48749
νd16 = 70.23


r17 = 9.639
d17 = D17




r18 = 11.114
d18 = 1.8
Nd18 = 1.7432
νd18 = 49.34


(Aspheric surface)





r19 = −63.843
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





 5th surface


k = 0


A4 = 1.98225E−05


A6 = 1.90373E−07


A8 = 0


 7th surface


k = 0


A4 = −6.38785E−05


A6 = 6.11369E−06


A8 = −3.84846E−08


 8th surface


k = 0


A4 = −3.65611E−04


A6 = 3.98896E−06


A8 = −1.11425E−07


12th surface


k = 0


A4 = 8.17413E−05


A6 = 5.53907E−07


A8 = 1.30474E−07


15th surface


k = 0


A4 = 9.46156E−04


A6 = 1.36955E−05


A8 = 1.58843E−06


18th surface


k = 0


A4 = −8.67276E−05


A6 = 7.65460E−06


A8 = −1.57646E−07





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
 6.101
13.42
17.995


FNO.
3.45
5.26
6.25


D6
1.87
8.14
9.44


D10
14.62 
4.03
0.47


D11
3.17
1.04
0.4


D15
1.24
11.13
13.79


D17
1.21
2.09
3.31


D19
4.78
1.31
0.49


D23
1.36
1.36
1.36









Sixth Embodiment
FIG. 11 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a sixth embodiment of the present invention.
FIG. 12A, FIG. 12B, and FIG. 12C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the sixth embodiment, where, FIG. 12A shows the state at the wide angle end, FIG. 12B shows the intermediate state, and FIG. 12C shows the state at the telephoto end.
The zoom lens of the sixth embodiment, as shown in FIG. 11, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.
The second lens group G2 includes a negative meniscus lens L121 having a convex surface directed toward the object side, and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131, a negative meniscus lens L132 having a convex surface directed toward an image side, and a positive meniscus lens L133 having a convex surface directed toward the image side, and has a positive refracting power as a whole. The positive meniscus lens L133 having the convex surface directed toward the image side is a lens having a thin center-thickness.
The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fifth lens group G5 includes a positive meniscus lens L142 having a convex surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifths lens group G5 moves toward the image side.
An aspheric surface is provided on a surface toward the object side of the biconvex lens L113 in the first lens group G1, both surfaces of the negative meniscus lens L121 having the convex surface directed toward the object side in the second lens group G2, a surface on the object side of the biconvex lens L131, and a surface on the image side of the positive meniscus lens L133 having the convex surface directed toward the image side in the third lens group G3, and a surface on the object side of the positive meniscus lens L142 having a convex surface directed toward the object side in the fifth lens group G5.
Next, numerical data of the sixth embodiment will be enumerated.










Numerical data 6


















r1 = 30.147
d1 = 1
Nd1 = 1.8061
νd1 = 40.92


r2 = 9.988
d2 = 2.9




r3 = ∞
d3 = 12
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.3




r5 = 21.536
d5 = 3.54
Nd5 = 1.741
νd5 = 52.64


(Aspheric surface)





r6 = −35.204
d6 = D6




r7 = 49.210
d7 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 5.838
d8 = 0.7




(Aspheric surface)





r9 = 6.738
d9 = 2.2
Nd9 = 1.7552
νd9 = 27.51


r10 = 14.193
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = 10.080
d12 = 6.02
Nd12 = 1.6935
νd12 = 53.21


(Aspheric surface)





r13 = −10.735
d13 = 0.7
Nd13 = 1.84666
νd13 = 23.78


r14 = −133.971
d14 = 0.1
Nd14 = 1.59885
νd14 = 6.52


r15 = −120.568
d15 = D15




(Aspheric surface)





r16 = 35.344
d16 = 0.6
Nd16 = 1.48749
νd16 = 70.23


r17 = 9.672
d17 = D17




r18 = 7.968
d18 = 1.8
Nd18 = 1.7432
νd18 = 49.34


(Aspheric surface)





r19 = 39.032
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





 5th surface


k = 0


A4 = 1.49401E−05


A6 = 6.81675E−08


A8 = 0


 7th surface


k = 0


A4 = 3.14125E−04


A6 = 4.96920E−06


A8 = −1.36962E−07


 8th surface


k = 0


A4 = 2.07725E−04


A6 = 1.45217E−05


A8 = −1.48176E−07


12th surface


k = 0


A4 = −1.84952E−05


A6 = 9.27696E−06


A8 = −9.79367E−08


15th surface


k = 0


A4 = 2.08929E−04


A6 = 1.12826E−05


A8 = 2.77941E−07


18th surface


k = 0


A4 = −1.65261E−04


A6 = 4.86444E−07


A8 = −5.90284E−08





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
5.999
10.405
17.998


FNO.
2.87
3.91
5.64


D6
0.8
5.36
8.6


D10
9.2
4.63
1.39


D11
9.9
5.87
1.2


D15
1.7
8.94
15.57


D17
4.07
3.15
3.28


D19
4.88
2.56
0.5


D23
1.36
1.41
1.36









Seventh Embodiment
FIG. 13 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a seventh embodiment of the present invention.
FIG. 14A, FIG. 14B, and FIG. 14C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the seventh embodiment, where, FIG. 14A shows the state at the wide angle end, FIG. 14B shows the intermediate state, and FIG. 14C shows the state at the telephoto end.
The zoom lens of the seventh embodiment, as shown in FIG. 13, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.
The second lens group G2 includes a negative meniscus lens L121 having a convex surface directed toward the object side, and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131, a negative meniscus lens L132 having a convex surface directed toward an image side, and a positive meniscus lens L133 having a convex surface directed toward the image side, and has a positive refracting power as a whole. The positive meniscus lens L133 having the convex surface directed toward the image side is a lens having a thin center-thickness.
The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fifth lens group G5 includes a positive meniscus lens L142 having a convex surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.
An aspheric surface is provided on a surface toward the object side of the biconvex lens L113 in the first lens group G1, both surfaces of the negative meniscus lens L121 having the convex surface directed toward the object side in the second lens group G2, a surface toward the object side of the biconvex lens L131, and a surface toward the image side of the positive meniscus lens L133 having the convex surface directed toward the image side in the third lens group G3, and a surface toward the image side of the positive meniscus lens L142 having the convex surface directed toward the object side in the fifth lens group G5.
Next, numerical data of the seventh embodiment will be enumerated.










Numerical data 7


















r1 = 29.536
d1 = 1
Nd1 = 1.8061
νd1 = 40.92


r2 = 10
d2 = 2.9




r3 = ∞
d3 = 12
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.3




r5 = 23.086
d5 = 3.54
Nd5 = 1.741
νd5 = 52.64


(Aspheric surface)





r6 = −32.568
d6 = D6




r7 = 49.426
d7 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 5.508
d8 = 0.7




(Aspheric surface)





r9 = 6.275
d9 = 2.2
Nd9 = 1.7552
νd9 = 27.51


r10 = 13.895
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = 10.122
d12 = 6.02
Nd12 = 1.6935
νd12 = 53.21


(Aspheric surface)





r13 = −9.941
d13 = 0.7
Nd13 = 1.84666
νd13 = 23.78


r14 = −111.236
d14 = 0.1
Nd14 = 1.79525
νd14 = 9.95


r15 = −100.111
d15 = D15




(Aspheric surface)





r16 = 20.978
d16 = 0.6
Nd16 = 1.48749
νd16 = 70.23


r17 = 8.727
d17 = D17




r18 = 8.050
d18 = 1.8
Nd18 = 1.7432
νd18 = 49.34


(Aspheric surface)





r19 = 30.854
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





 5th surface


k = 0


A4 = 1.53520E−05


A6 = 7.22705E−08


A8 = 0


 7th surface


k = 0


A4 = 4.65044E−04


A6 = −2.25659E−06


A8 = −4.27282E−08


 8th surface


k = 0


A4 = 3.69076E−04


A6 = 1.33083E−05


A8 = −4.56802E−07


12th surface


k = 0


A4 = 3.22189E−05


A6 = 6.78190E−06


A8 = −3.73660E−08


15th surface


k = 0


A4 = 2.39851E−04


A6 = 5.36491E−06


A8 = 2.73962E−07


18th surface


k = 0


A4 = −1.05075E−04


A6 = 4.62091E−07


A8 = −4.85192E−08





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
5.998
10.399
17.998


FNO.
2.89
4
5.7


D6
0.8
5.12
8.62


D10
9.22
4.91
1.4


D11
10.29
5.95
1.2


D15
1.7
9.45
15.68


D17
4
3.15
3.43


D19
4.81
2.24
0.5


D23
1.36
1.37
1.36









Eighth Embodiment
FIG. 15 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to an eighth embodiment of the present invention.
FIG. 16A, FIG. 16B, and FIG. 16C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the eighth embodiment, where, FIG. 16A shows the state at the wide angle end, FIG. 16B shows the intermediate state, and FIG. 16C shows the state at the telephoto end.
The zoom lens of the eighth embodiment, as shown in FIG. 15, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.
The second lens group G2 includes a negative meniscus lens L121 having a convex surface directed toward the object side, and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131, a negative meniscus lens L132 having a convex surface directed toward an image side, and a positive meniscus lens L133 having a convex surface directed toward the image side, and has a positive refracting power as a whole. The positive meniscus lens L133 having the convex surface directed toward the image side is a lens having a thin center-thickness.
The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fifth lens group G5 includes a positive meniscus lens L142 having a convex surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.
An aspheric surface is provided on a surface toward the object side of the biconvex lens L113 in the first lens group G1, both surfaces of the negative meniscus lens L121 having the convex surface directed toward the object side in the second lens group G2, a surface toward the object side of the biconvex lens L131, and a surface toward the image side of the positive meniscus lens L133 having the convex surface directed toward the image side in the third lens group G3, and a surface toward the object side of the positive meniscus lens L142 having the convex surface directed toward the object side in the fifth lens group G5.
Next, numerical data of the eighth embodiment will be enumerated.










Numerical data 8


















r1 = 27.09
d1 = 1
Nd1 = 1.8061
νd1 = 40.92


r2 = 9.998
d2 = 2.9




r3 = ∞
d3 = 12
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.3




r5 = 25.058
d5 = 3.54
Nd5 = 1.741
νd5 = 52.64


(Aspheric surface)





r6 = −40.797
d6 = D6




r7 = 51.714
d7 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 5.415
d8 = 0.7




(Aspheric surface)





r9 = 6.522
d9 = 2.2
Nd9 = 1.7552
νd9 = 27.51


r10 = 17.116
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = 8.862
d12 = 6.01
Nd12 = 1.6935
νd12 = 53.21


(Aspheric surface)





r13 = −9.201
d13 = 0.7
Nd13 = 1.84666
νd13 = 25.78


r14 = −332.698
d14 = 0.1
Nd14 = 1.9712
νd14 = 12.88


r15 = −299.436
d15 = D15




(Aspheric surface)





r16 = 66.397
d16 = 0.6
Nd16 = 1.48749
νd16 = 70.23


r17 = 10.427
d17 = D17




r18 = 9.518
d18 = 1.8
Nd18 = 1.7432
νd18 = 49.34


(Aspheric surface)





r19 = 80.399
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





 5th surface


k = 0


A4 = 1.82936E−05


A6 = 2.19287E−07


A8 = 0


 7th surface


k = 0


A4 = 2.14374E−04


A6 = 8.90498E−06


A8 = −2.02404E−07


 8th surface


k = 0


A4 = −9.62206E−05


A6 = 2.68656E−05


A8 = −7.87125E−07


12th surface


k = 0


A4 = 5.80429E−05


A6 = 4.79927E−06


A8 = 4.71202E−08


15th surface


k = 0


A4 = 3.91395E−04


A6 = −1.85098E−06


A8 = 7.46043E−07


18th surface


k = 0


A4 = −2.21543E−05


A6 = −1.97720E−06


A8 = 1.36609E−08





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
5.985
10.398
17.997


FNO.
2.98
4.16
6.21


D6
0.8
5.57
8.57


D10
9.16
4.39
1.4


D11
10.59
6.39
1.2


D15
1.7
8.68
15.9


D17
3.79
3.81
3.42


D19
4.94
2.13
0.5


D23
1.36
1.38
1.36









Ninth Embodiment
FIG. 17 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a ninth embodiment of the present invention.
FIG. 18A, FIG. 18B, and FIG. 18C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the ninth embodiment, where, FIG. 18A shows the state at the wide angle end, FIG. 18B shows the intermediate state, and FIG. 18C shows the state at the telephoto end.
The zoom lens of the ninth embodiment, as shown in FIG. 17, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.
The second lens group G2 includes a negative meniscus lens L121 having a convex surface directed toward the object side, and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131, a negative meniscus lens L132 having a convex surface directed toward an image side, and a positive meniscus lens L133 having a convex surface directed toward the image side, and has a positive refracting power as a whole.
The fourth lens group G4 includes a biconcave lens L141, and has a negative refracting power as whole.
The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.
An aspheric surface is provided on a surface toward the object side of the biconvex lens L113 in the first lens group G1, both surfaces of the negative meniscus lens L121 having the convex surface directed toward the object side in the second lens group G2, both surfaces of the biconvex lens L131, and a surface toward the image side of the positive meniscus lens L133 having the convex surface directed toward the image side in the third lens group G3, and a surface toward the object side of the biconvex lens L142 in the fifth lens group G5.
Next, numerical data of the ninth embodiment will be enumerated.










Numerical data 9


















r1 = 30.295
d1 = 1
d1 = 1.8061
νd1 = 45.9


r2 = 10
d2 = 2.9




r3 = ∞
d3 = 12
Nd3 = 1.741
νd3 = 55.64


r4 = ∞
d4 = 0.3




r5 = 18.286
d5 = 3.54
Nd5 = 1.741
νd5 = 65.6


(Aspheric surface)





r6 = −42.655
d6 = D6




r7 = 40.666
d7 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 5.986
d8 = 0.7




(Aspheric surface)





r9 = 6.666
d9 = 2.2
Nd9 = 1.7552
νd9 = 27.51


r10 = 11.373
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = 10.097
d12 = 6
Nd12 = 1.6935
νd12 = 65.2


(Aspheric surface)





r13 = −25.149
d13 = 0.7
Nd13 = 1.84666
νd13 = 23.7


r14 = −5644.305
d14 = 0.1
Nd14 = 2.05122
νd14 = 6.28


r15 = −5079.893
d15 = D15




(Aspheric surface)





r16 = −69.07
d16 = 0.6
Nd16 = 1.48749
νd16 = 40.2


r17 = 14.791
d17 = D17




r18 = 12.723
d18 = 1.8
Nd18 = 1.7432
νd18 = 60.3


(Aspheric surface)





r19 = −32.451
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





 5th surface


k = 0


A4 = −3.11363E−06


A6 = 5.76079E−08


A8 = 0


 7th surface


k = 0


A4 = 2.48925E−04


A6 = 3.22844E−07


A8 = 6.56210E−08


 8th surface


k = 0


A4 = 1.17922E−04


A6 = 5.62435E−06


A8 = 3.78036E−07


12th surface


k = 0


A4 = −1.18367E−05


A6 = 1.50314E−06


A8 = 2.72652E−09


15th surface


k = 0


A4 = 1.65967E−04


A6 = 1.91161E−06


A8 = 1.63255E−08


18th surface


k = 0


A4 = −1.10641E−04


A6 = −5.17961E−08


A8 = −2.99128E−08





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6
10.401
18.001


FNO.
2.76
3.53
5.5


D6
0.8
5.89
7.59


D10
8.19
3.1
1.4


D11
9.78
6.76
1.2


D15
1.7
8.53
18.27


D17
2.93
1.06
0.08


D19
5.64
3.7
0.5


D23
1.36
1.36
1.36









Tenth Embodiment
FIG. 19 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a tenth embodiment of the present invention.
FIG. 20A, FIG. 20B, and FIG. 20C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the tenth embodiment, where, FIG. 20A shows the state at the wide angle end, FIG. 20B shows the intermediate state, and FIG. 20C shows the state at the telephoto end.
The zoom lens of the tenth embodiment, as shown in FIG. 19, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a positive meniscus lens L213 having a convex surface directed toward an image side, and a biconcave lens L214, and has a negative refracting power as a whole.
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221, and a negative meniscus lens L222 having a convex surface directed toward the image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by the biconcave lens L231, and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface toward the object side, of the positive meniscus lens L213 having the convex surface directed toward the image side in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, a surface on the object side of the biconvex lens L241, and a surface on the image side of the negative meniscus lens L242 having the concave surface directed toward the object side in the fourth lens group G4.
Next, numerical data of the tenth embodiment will be enumerated.










Numerical data 10


















r1 = 28.304
d1 = 1.1
Nd1 = 1.7432
νd1 = 49.34


r2 = 10.645
d2 = 3




r3 = ∞
d3 = 12.5
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.4




r5 = −90.406
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = −16.547
d6 = 0.7
Nd6 = 1.51633
νd6 = 64.14


r7 = 23.458
d7 = D7




r8 = 14.181
d8 = 3.5
Nd8 = 1.691
νd8 = 54.82


(Aspheric surface)





r9 = −12
d9 = 0.7
Nd9 = 1.84666
νd9 = 23.78


r10 = −24.206
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = −10.998
d12 = 0.7
Nd12 = 1.51823
νd12 = 58.9


r13 = 8.875
d13 = 1.6
Nd13 = 1.816
νd13 = 46.62


r14 = 31.054
d14 = D14




r15 = 16.482
d15 = 3.5
Nd15 = 1.497
νd15 = 81.54


(Aspheric surface)





r16 = −6.2
d16 = 0.35
Nd16 = 1.41244
νd16 = 12.42


r17 = −8.539
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





 5th surface


k = 0


A4 = 1.07368E−05


A6 = 8.06831E−07


A8 = 0


 8th surface


k = 0


A4 = −4.93554E−05


A6 = −6.02686E−07


A8 = 0.00000E+00


15th surface


k = 0


A4 = −3.50136E−04


A6 = −5.02569E−05


A8 = 0.00000E+00


17th surface


k = 0


A4 = 2.79665E−04


A6 = −3.52493E−05


A8 = 0.00000E+00





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
5.993
13.699
17.996


FNO.
2.83
3.38
3.72


D7
12.73
3.86
0.8


D10
1.61
10.48
13.55


D11
1.42
5.2
8.34


D14
5.72
5.18
2.99


D17
5.4
2.16
1.22


D21
1.36
1.36
1.36









Eleventh Embodiment
FIG. 21 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to an eleventh embodiment of the present invention.
FIG. 22A, FIG. 22B, and FIG. 22C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the eleventh embodiment, where, FIG. 22A shows the state at the wide angle end, FIG. 22B shows the intermediate state, and FIG. 22C shows the state at the telephoto end.
The zoom lens of the eleventh embodiment, as shown in FIG. 21, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a negative meniscus lens L213 having a convex surface directed toward the object side and a negative meniscus lens L214 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface toward the object side of the negative meniscus lens L213 having the convex surface directed toward the object side in the first lens group G1, a surface toward the object side of the biconvex lens L221 in the second lens group G2, and a surface toward the object side of the biconvex lens L241, and a surface toward the image side of the negative meniscus lens L242 having the concave surface directed toward the object side in the fourth lens group G4.
Next, numerical data of the eleventh embodiment will be enumerated.










Numerical data 11


















r1 = 23.87
d1 = 1.1
Nd1 = 1.72916
νd1 = 54.68


r2 = 10.163
d2 = 3.4




r3 = ∞
d3 = 12.5
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.4




r5 = 65.968
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = 34.34
d6 = 0.7
Nd6 = 1.497
νd6 = 81.54


r7 = 16.507
d7 = D7




r8 = 12.709
d8 = 3.5
Nd8 = 1.691
νd8 = 54.82


(Aspheric surface)





r9 = −12
d9 = 0.7
Nd9 = 1.84666
νd9 = 23.78


r10 = −19.22
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = −11.798
d12 = 0.7
Nd12 = 1.51823
νd12 = 58.9


r13 = 9.026
d13 = 1.6
Nd13 = 1.816
νd13 = 46.62


r14 = 28.27
d14 = D14




r15 = 17.528
d15 = 3.5
Nd15 = 1.43875
νd15 = 94.93


(Aspheric surface)





r16 = −6.2
d16 = 0.35
Nd16 = 1.42001
νd16 = 6.55


r17 = −7.105
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





 5th surface


k = 0


A4 = 2.33447E−05


A6 = 9.26176E−07


A8 = 0


 8th surface


k = 0


A4 = −9.41230E−05


A6 = −8.51740E−07


A8 = 0.00000E+00


15th surface


k = 0


A4 = −1.87050E−04


A6 = −7.75271E−05


A8 = 0.00000E+00


17th surface


k = 0


A4 = 6.13858E−04


A6 = −4.72544E−05


A8 = 0.00000E+00





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
5.963
13.628
17.92


FNO.
2.83
3.38
3.72


D7
12.07
3.24
0.8


D10
1.65
10.49
12.92


D11
1.43
2.38
7.19


D14
5.7
6.73
2.99


D17
4.24
2.26
1.19


D21
1.34
1.24
1.15









Twelfth Embodiment
FIG. 23 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twelfth embodiment of the present invention.
FIG. 24A, FIG. 24B, and FIG. 24c are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twelfth embodiment, where, FIG. 24A shows the state at the wide angle end, FIG. 24B shows the intermediate state, and FIG. 24C shows the state at the telephoto end.
The zoom lens of the twelfth embodiment, as shown in FIG. 23, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a positive meniscus lens L213 having a convex surface directed toward an image side, and a biconcave lens L214, and has a negative refracting power as a whole.
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward the image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface toward the object side, of the positive meniscus lens L213 having the convex surface directed toward the image side in the first lens group G1, a surface toward the object side of the biconvex lens L221 in the second lens group G2, a surface toward the object side of the biconvex lens L241 and a surface toward the image side of the negative meniscus lens L242 having the concave surface directed toward the object side in the fourth lens group G4.
Next, numerical data of the twelfth embodiment will be enumerated.










Numerical data 12


















r1 = 28.491
d1 = 1.1
Nd1 = 1.7432
νd1 = 49.34


r2 = 10.662
d2 = 3




r3 = ∞
d3 = 12.5
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.4




r5 = −91.781
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = −16.295
d6 = 0.7
Nd6 = 1.51633
νd6 = 64.14


r7 = 23.208
d7 = D7




r8 = 14.159
d8 = 3.5
Nd8 = 1.691
νd8 = 54.82


(Aspheric surface)





r9 = −12
d9 = 0.7
Nd9 = 1.84666
νd9 = 23.78


r10 = −24.369
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = −10.997
d12 = 0.7
Nd12 = 1.51823
νd12 = 58.9


r13 = 8.725
d13 = 1.6
Nd13 = 1.816
νd13 = 46.62


r14 = 30.384
d14 = D14




r15 = 15.557
d15 = 3.5
Nd15 = 1.497
νd15 = 81.54


(Aspheric surface)





r16 = −6.2
d16 = 0.35
Nd16 = 1.51824
νd16 = 12.85


r17 = −8.133
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





 5th surface


k = 0


A4 = 1.06669E−05


A6 = 7.86702E−07


A8 = 0


 8th surface


k = 0


A4 = −4.86780E−05


A6 = −5.91891E−07


A8 = 0.00000E+00


15th surface


k = 0


A4 = −3.14285E−04


A6 = −5.03578E−05


A8 = 0.00000E+00


17th surface


k = 0


A4 = 2.46731E−04


A6 = −2.88817E−05


A8 = 0.00000E+00





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
5.993
13.699
17.995


FNO.
2.83
3.38
3.72


D7
12.75
3.89
0.8


D10
1.61
10.47
13.57


D11
1.42
5.24
8.35


D14
5.74
5.17
2.99


D17
5.4
2.14
1.22


D21
1.36
1.36
1.36









Thirteenth Embodiment
FIG. 25 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirteenth embodiment of the preset invention.
FIG. 26A, FIG. 26B, and FIG. 26C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirteenth embodiment, where, FIG. 26A shows the state at the wide angle end, FIG. 26B shows the intermediate state, and FIG. 26C shows the state at the telephoto end.
The zoom lens of the thirteenth embodiment, as shown in FIG. 25, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface toward the object side of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241, and a surface on the image side of the negative meniscus lens L242 having the concave surface directed toward the object side, in the fourth lens group G4.
Next, numerical data of the thirteenth embodiment will be enumerated.










Numerical data 13


















r1 = 43.452
d1 = 1.1
Nd1 = 1.7432
νd1 = 49.34


r2 = 11.422
d2 = 3




r3 = ∞
d3 = 12.5
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.4




r5 = 87.233
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = −15.765
d6 = 0.7
Nd6 = 1.51633
νd6 = 64.14


r7 = 16.387
d7 = D7




r8 = 14.037
d8 = 3.5
Nd8 = 1.6935
νd8 = 53.21


(Aspheric surface)





r9 = −12.01
d9 = 0.7
Nd9 = 1.84666
νd9 = 23.78


r10 = −32.606
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = −11.339
d12 = 0.7
Nd12 = 1.51823
νd12 = 58.9


r13 = 9.151
d13 = 1.6
Nd13 = 1.816
νd13 = 46.62


r14 = 30.576
d14 = D14




r15 = 9.988
d15 = 3.5
Nd15 = 1.56384
νd15 = 60.67


(Aspheric surface)





r16 = −12.961
d16 = 0.35
Nd16 = 1.54856
νd16 = 7.04


r17 = −15.176
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





 5th surface


k = 0


A4 = 1.44888E−05


A6 = 2.91935E−07


A8 = 0.00000E+00


 8th surface


k = 0


A4 = −2.19450E−05


A6 = −2.51977E−07


A8 = −4.21441E−07


15th surface


k = 0


A4 = −2.38581E−04


A6 = 3.48651E−06


A8 = −1.28129E−06


17th surface


k = 0


A4 = 1.57016E−04


A6 = 7.12163E−06


A8 = 5.27383E−08





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.031
13.703
17.982


FNO.
2.86
3.4
3.73


D7
13.87
4.03
0.8


D10
1.59
11.42
14.67


D11
1.4
5.74
8.82


D14
6.25
5.01
2.99


D17
5.34
2.25
1.18


D21
1.36
1.35
1.36









Fourteenth Embodiment
FIG. 27 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fourteenth embodiment of the present invention.
FIG. 28A, FIG. 28B, and FIG. 28C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fourteenth embodiment, where, FIG. 28A shows the state at the wide angle end, FIG. 28B shows the intermediate state, and FIG. 28C shows the state at the telephoto end.
The zoom lens of the fourteenth embodiment, as shown in FIG. 27, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a positive meniscus lens L213 having a convex surface directed toward an image side, and a biconcave lens L214, and has a negative refracting power as a whole.
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward the image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface toward the object side of the positive meniscus lens L213 having the convex surface directed toward the image side in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 and a surface on the image side of the negative meniscus lens L242 having the concave surface directed toward the object side in the fourth lens group G4.
Next, numerical data of the fourteenth embodiment will be enumerated.










Numerical data 14


















r1 = 21.073
d1 = 0.9
Nd1 = 1.74738
νd1 = 38.67


r2 = 9.328
d2 = 3.67




r3 = ∞
d3 = 10
Nd3 = 1.88
νd3 = 41


r4 = ∞
d4 = 0.72




r5 = −55.494
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = −11.72
d6 = 5.54
Nd6 = 1.51633
νd6 = 64.14


r7 = 30.291
d7 = D7




r8 = 16.684
d8 = 6.34
Nd8 = 1.69397
νd8 = 56.88


(Aspheric surface)





r9 = −12
d9 = 0.9
Nd9 = 1.84465
νd9 = 25.34


r10 = −25.607
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = −19.599
d12 = 0.9
Nd12 = 1.52152
νd12 = 63.05


r13 = 6.828
d13 = 1.49
Nd13 = 1.81464
νd13 = 45.43


r14 = 17.305
d14 = D14




r15 = 25.754
d15 = 5.67
Nd15 = 1.56907
νd15 = 71.31


(Aspheric surface)





r16 = −6.2
d16 = 0.35
Nd16 = 1.65228
νd16 = 12.75


r17 = −8.121
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





 5th surface


k = 0


A4 = 1.59251E−05


A6 = 4.32015E−07


A8 = 0


 8th surface


k = 0


A4 = −3.16339E−05


A6 = −1.13143E−07


A8 = 0.00000E+00


15th surface


k = 0


A4 = −7.25293E−04


A6 = −2.99773E−05


A8 = 0.00000E+00


17th surface


k = 0


A4 = −1.43049E−04


A6 = −5.80127E−06


A8 = 0.00000E+00





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.1
13.42
17.993


FNO.
3.06
3.21
3.94


D7
13.91
3.96
0.51


D10
0.46
12.72
14.27


D11
1.34
2.96
8.18


D14
6.23
4.96
3.09


D17
5.33
2.26
1.09


D21
1.36
1.36
1.36









Fifteenth Embodiment
FIG. 29 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fifteenth embodiment of the present invention.
FIG. 30A, FIG. 30B, and FIG. 30C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fifteenth embodiment, where, FIG. 30A shows the state at the wide angle end, FIG. 30B shows the intermediate state, and FIG. 30C shows the state at the telephoto end.
The zoom lens of the fifteenth embodiment, as shown in FIG. 29, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface toward the object side of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 and a surface on the image side of the negative meniscus lens L242 having the concave surface directed toward the object side in the fourth lens group G4.
Next, numerical data of the fifteenth embodiment will be enumerated.










Numerical data 15


















r1 = 55.095
d1 = 1.1
Nd1 = 1.7432
νd1 = 49.34


r2 = 11.694
d2 = 3




r3 = ∞
d3 = 12.5
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.4




r5 = 51.903
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = −15.372
d6 = 0.7
Nd6 = 1.51633
νd6 = 64.14


r7 = 14.817
d7 = D7




r8 = 14.093
d8 = 3.5
Nd8 = 1.6935
νd8 = 53.21


(Aspheric surface)





r9 = −12
d9 = 0.7
Nd9 = 1.84666
νd9 = 23.78


r10 = −37.146
d10 = D10




r11 =
d11 = D11




Aperture stop





r12 = −12.922
d12 = 0.7
Nd12 = 1.51823
νd12 = 58.9


r13 = 7.163
d13 = 1.6
Nd13 = 1.816
νd13 = 46.62


r14 = 19.642
d14 = D14




r15 = 12.565
d15 = 3.5
Nd15 = 1.80907
νd15 = 20.3


(Aspheric surface)





r16 = −11.756
d16 = 0.35
Nd16 = 1.59885
νd16 = 6.52


r17 = −49.133
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





 5th surface


k = 0


A4 = 2.17334E−05


A6 = 1.29516E−07


A8 = 0


 8th surface


k = 0


A4 = −2.20346E−05


A6 = −1.08152E−07


A8 = 0.00000E+00


15th surface


k = 0


A4 = −2.09817E−04


A6 = −9.83727E−06


A8 = 0.00000E+00


17th surface


k = 0


A4 = 9.24813E−06


A6 = −1.26856E−05


A8 = 0.00000E+00





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.004
10.395
17.998


FNO.
2.85
3.33
3.73


D7
14.5
8.24
0.8


D10
1.6
7.85
15.3


D11
1.4
5.72
9.32


D14
6.77
4.87
3


D17
5.35
2.93
1.2


D21
1.36
1.36
1.36









Sixteenth Embodiment
FIG. 31 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a sixteenth embodiment of the present invention.
FIG. 32A, FIG. 32B, and FIG. 32C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the sixteenth embodiment, where, FIG. 32A shows the state at the wide angle end, FIG. 32B shows the intermediate state, and FIG. 32C shows the state at the telephoto end.
The zoom lens of the sixteenth embodiment, as shown in FIG. 31, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface toward the object side of the biconvex lens L231 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 and a surface on the image side of the negative meniscus lens L242 having a concave surface directed toward the object side in the fourth lens group G4.
Next, numerical data of the sixteenth embodiment will be enumerated.










Numerical data 16


















r1 = 54.751
d1 = 1.1
Nd1 = 1.7432
νd1 = 49.34


r2 = 11.599
d2 = 3




r3 = ∞
d3 = 12.5
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.4




r5 = 48.588
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = −15.271
d6 = 0.7
Nd6 = 1.51633
νd6 = 64.14


r7 = 14.609
d7 = D7




r8 = 14.138
d8 = 3.5
Nd8 = 1.6935
νd8 = 53.21


(Aspheric surface)





r9 = −12
d9 = 0.7
Nd9 = 1.84666
νd9 = 23.78


r10 = −37.788
d10 = D10




r11 =
d11 = D11




Aperture stop





r12 = −12.861
d12 = 0.7
Nd12 = 1.51823
νd12 = 58.9


r13 = 7.159
d13 = 1.6
Nd13 = 1.816
νd13 = 46.62


r14 = 19.721
d14 = D14




r15 = 12.075
d15 = 3.5
Nd15 = 1.80907
νd15 = 25.3


(Aspheric surface)





r16 = −10.075
d16 = 0.35
Nd16 = 1.79525
νd16 = 9.95


r17 = −30.341
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





 5th surface


k = 0


A4 = 2.17595E−05


A6 = 1.16192E−07


A8 = 0


 8th surface


k = 0


A4 = −2.06326E−05


A6 = −9.41435E−08


A8 = 0.00000E+00


15th surface


k = 0


A4 = −1.73586E−04


A6 = −9.45101E−06


A8 = 0.00000E+00


17th surface


k = 0


A4 = 4.10023E−05


A6 = −9.23729E−06


A8 = 0.00000E+00





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.004
10.395
17.998


FNO.
2.85
3.33
3.73


D7
14.56
8.25
0.8


D10
1.6
7.9
15.36


D11
1.4
5.75
9.35


D14
6.78
4.84
3


D17
5.37
2.97
1.2


D21
1.36
1.36
1.36









Seventeenth Embodiment
FIG. 33 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a seventeenth embodiment of the present invention.
FIG. 34A, FIG. 34B, and FIG. 34C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the seventeenth embodiment, where, FIG. 34A shows the state at the wide angle end, FIG. 34B shows the intermediate state, and FIG. 34C shows the state at the telephoto end.
The zoom lens of the seventeenth embodiment, as shown in FIG. 33, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 and a surface on the image side of the negative meniscus lens L242 having the concave surface directed toward the object side in the fourth lens group G4.
Next, numerical data of the seventeenth embodiment will be enumerated.










Numerical data 17


















r1 = 55.039
d1 = 1.1
Nd1 = 1.7432
νd1 = 49.34


r2 = 11.565
d2 = 3




r3 = ∞
d3 = 12.5
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.4




r5 = 46.410
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = −15.146
d6 = 0.7
Nd6 = 1.51633
νd6 = 64.14


r7 = 14.418
d7 = D7




r8 = 14.090
d8 = 3.5
Nd8 = 1.6935
νd8 = 53.21


(Aspheric surface)





r9 = −12
d9 = 0.7
Nd9 = 1.84666
νd9 = 23.78


r10 = −38.595
d10 = D10




r11 =
d11 = D11




Aperture stop





r12 = −12.608
d12 = 0.7
Nd12 = 1.51823
νd12 = 58.9


r13 = 7.064
d13 = 1.6
Nd13 = 1.816
νd13 = 46.62


r14 = 19.84
d14 = D14




r15 = 11.880
d15 = 3.5
Nd15 = 1.80907
νd15 = 25.3


(Aspheric surface)





r16 = −7.278
d16 = 0.35
Nd16 = 1.9712
νd16 = 12.88


r17 = −19.802
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





 5th surface


k = 0


A4 = 2.14569E−05


A6 = 1.05477E−07


A8 = 0


 8th surface


k = 0


A4 = −1.98881E−05


A6 = −8.44877E−08


A8 = 0.00000E+00


15th surface


k = 0


A4 = −1.45589E−04


A6 = −8.37650E−06


A8 = 0.00000E+00


17th surface


k = 0


A4 = 2.35364E−05


A6 = −6.65483E−06


A8 = 0.00000E+00





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.004
10.395
17.998


FNO.
2.84
3.31
3.72


D7
14.56
8.23
0.8


D10
1.6
7.92
15.36


D11
1.4
5.76
9.32


D14
6.72
4.76
3


D17
5.4
3
1.2


D21
1.36
1.36
1.36









Eighteenth Embodiment
FIG. 35 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to an eighteenth embodiment of the present invention.
FIG. 36A, FIG. 36B, and FIG. 36C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the eighteenth embodiment, where, FIG. 36A shows the state at the wide angle end, the FIG. 36B shows the intermediate state, and FIG. 36C shows the state at the telephoto end.
The zoom lens of the eighteenth embodiment, as shown in FIG. 35, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface toward the object side of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241, and a surface on the image side of the negative meniscus lens L242 having the concave surface directed toward the object side in the fourth lens group G4.
Next, numerical data of the eighteenth embodiment will be enumerated.










Numerical data 18


















r1 = 54.8
d1 = 1.1
Nd1 = 1.7432
νd1 = 49.34


r2 = 11.521
d2 = 3




r3 = ∞
d3 = 12.5
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.4




r5 = 45.176
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = −15.199
d6 = 0.7
Nd6 = 1.51633
νd6 = 64.14


r7 = 14.337
d7 = D7




r8 = 14.161
d8 = 3.5
Nd8 = 1.6935
νd8 = 53.21


(Aspheric surface)





r9 = −12
d9 = 0.7
Nd9 = 1.84666
νd9 = 23.78


r10 = −38.568
d10 = D10




r11 =
d11 = D11




Aperture stop





r12 = −12.826
d12 = 0.7
Nd12 = 1.51823
νd12 = 58.9


r13 = 7.165
d13 = 1.6
Nd13 = 1.816
νd13 = 46.62


r14 = 19.791
d14 = D14




r15 = 11.637
d15 = 3.5
Nd15 = 1.80907
νd15 = 25.3


(Aspheric surface)





r16 = −15.346
d16 = 0.35
Nd16 = 2.05122
νd16 = 6.28


r17 = −25.733
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





 5th surface


k = 0


A4 = 2.18388E−05


A6 = 1.00228E−07


A8 = 0


 8th surface


k = 0


A4 = −1.92478E−05


A6 = −7.78797E−08


A8 = 0.00000E+00


15th surface


k = 0


A4 = −1.55987E−04


A6 = −8.82328E−06


A8 = 0.00000E+00


17th surface


k = 0


A4 = 5.03879E−05


A6 = −6.66888E−06


A8 = 0.00000E+00





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.004
10.395
17.998


FNO.
2.84
3.32
3.73


D7
14.62
8.27
0.8


D10
1.6
7.94
15.42


D11
1.4
5.79
9.39


D14
6.8
4.8
3


D17
5.39
3
1.2


D21
1.36
1.36
1.36









Nineteenth Embodiment
FIG. 37 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a nineteenth embodiment of the present invention.
FIG. 38A, FIG. 38B, and FIG. 38C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the nineteenth embodiment of the present invention, where, FIG. 38A shows the state at the wide angle end, FIG. 38B shows the intermediate state, and FIG. 38C shows the state at the telephoto end.
The zoom lens of the nineteenth embodiment, as shown in FIG. 37, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.
The second lens group G2 includes a biconcave lens L121, and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131, a biconcave lens L132, and a negative meniscus lens L133 having a convex surface directed toward the object side, and has a positive refracting power as a whole.
The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the negative meniscus lens L133 having the convex surface directed toward the object side in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.
Next, numerical data of the nineteenth embodiment will be enumerated.










Numerical data 19


















r1 = 26.309
d1 = 1
Nd1 = 1.8061
νd1 = 40.92


r2 = 10.007
d2 = 2.9




r3 = ∞
d3 = 12
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.3




r5 = 27.469
d5 = 3.54
Nd5 = 1.741
νd5 = 52.64


(Aspheric surface)





r6 = −29.847
d6 = D6




r7 = −169.301
d7 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 5.955
d8 = 0.7




(Aspheric surface)





r9 = 7.954
d9 = 2.2
Nd9 = 1.7552
νd9 = 27.51


r10 = 59.904
d10 = D10




r11 =
d11 = D11




Aperture stop





r12 = 7.719
d12 = 5.76
Nd12 = 1.6935
νd12 = 53.21


(Aspheric surface)





r13 = −11.556
d13 = 0.7
Nd13 = 1.84666
νd13 = 23.78


r14 = 31.15
d14 = 0.1
Nd14 = 1.60687
νd14 = 27.03


r15 = 28.035
d15 = D15




(Aspheric surface)





r16 = 99.095
d16 = 0.6
Nd16 = 1.48749
νd16 = 70.23


r17 = 11.195
d17 = D17




r18 = 10.936
d18 = 1.8
Nd18 = 1.7432
νd18 = 49.34


(Aspheric surface)





r19 = −57.317
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





 5th surface


k = 0


A4 = 4.21388E−06


A6 = 2.34608E−07


A8 = 0.00000E+00


 7th surface


k = 0


A4 = −9.57362E−05


A6 = 3.57186E−06


A8 = −9.67167E−08


 8th surface


k = 0


A4 = −4.74268E−04


A6 = 4.28874E−06


A8 = −6.11770E−07


12th surface


k = 0


A4 = 1.25571E−04


A6 = 1.69323E−06


A8 = 2.78465E−08


15th surface


k = 0


A4 = 1.07847E−03


A6 = 1.65980E−05


A8 = 1.16265E−06


18th surface


k = 0


A4 = −1.05221E−04


A6 = 9.18492E−06


A8 = −2.45045E−07





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.007
13.699
17.991


FNO.
2.89
4.96
6.07


D6
0.8
6.93
8.37


D10
8.95
2.82
1.38


D11
11.47
3.83
1.19


D15
1.71
11.94
14.18


D17
1.2
2.11
3.28


D19
4.79
1.29
0.52


D23
1.36
1.36
1.36









Twentieth Embodiment
FIG. 39 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twentieth embodiment of the present invention.
FIG. 40A, FIG. 40B, and FIG. 40C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twentieth embodiment, where, FIG. 40A shows the state at the wide angle end, FIG. 40B shows the intermediate state, and FIG. 40C shows the state at the telephoto end.
The zoom lens of the twentieth embodiment, as shown in FIG. 39, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.
The second lens group G2 includes a biconcave lens L121, and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131, a biconcave lens L132, and a negative meniscus lens L133 having a convex surface directed toward the object side, and has a positive refracting power as a whole.
The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the negative meniscus lens L133 having the convex surface directed toward the object side in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.
Next, numerical data of the twentieth embodiment will be enumerated.










Numerical data 20


















r1 = 32.897
d1 = 1
Nd1 = 1.8061
νd1 = 40.92


r2 = 10.029
d2 = 2.9




r3 = ∞
d3 = 12
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.3




r5 = 30.741
d5 = 3.54
Nd5 = 1.741
νd5 = 52.64


(Aspheric surface)





r6 = −31.825
d6 = D6




r7 = −240.726
d7 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 6.554
d8 = 0.7




(Aspheric surface)





r9 = 8.382
d9 = 2.2
Nd9 = 1.7552
νd9 = 27.51


r10 = 67.095
d10 = D10




r11 =
d11 = D11




Aperture stop





r12 = 8.011
d12 = 5.88
Nd12 = 1.6935
νd12 = 53.21


(Aspheric surface)





r13 = −11.976
d13 = 0.7
Nd13 = 1.84666
νd13 = 23.78


r14 = 33.989
d14 = 0.1
Nd14 = 1.60258
νd14 = 18.58


r15 = 30.589
d15 = D15




(Aspheric surface)





r16 = 113.335
d16 = 0.6
Nd16 = 1.48749
νd16 = 70.23


r17 = 10.068
d17 = D17




r18 = 10.644
d18 = 1.8
Nd18 = 1.7432
νd18 = 49.34


(Aspheric surface)





r19 = −88.438
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





 5th surface


k = 0


A4 = 2.13406E−05


A6 = 3.06995E−08


A8 = 0


 7th surface


k = 0


A4 = −5.07440E−06


A6 = 8.60261E−06


A8 = −4.48905E−08


 8th surface


k = 0


A4 = −2.37779E−04


A6 = 8.45137E−06


A8 = 8.50211E−08


12th surface


k = 0


A4 = 1.06894E−04


A6 = 4.88697E−07


A8 = 2.12640E−07


15th surface


k = 0


A4 = 9.64254E−04


A6 = −1.99314E−07


A8 = 2.76437E−06


18th surface


k = 0


A4 = −1.20324E−04


A6 = 8.42830E−06


A8 = −1.72829E−07





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.055
13.698
17.943


FNO.
2.89
4.62
5.64


D6
0.8
10.59
12.48


D10
13.03
3.24
1.35


D11
10.18
3.91
1.13


D15
1.69
12.78
15


D17
2.42
1.86
3.04


D19
5.41
1.14
0.52


D23
1.37
1.36
1.37









Twenty First Embodiment
FIG. 41 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty first embodiment of the present invention.
FIG. 42A, FIG. 42B, and FIG. 42C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty first embodiment, where, FIG. 42A shows the state at the wide angle end, FIG. 42B shows the intermediate state, and FIG. 42C shows the state at the telephoto end.
The zoom lens of the twenty first embodiment, as shown in FIG. 41, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.
The second lens group G2 includes a biconcave lens L121 and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131, a biconcave lens L132, and a negative meniscus lens L133 having a convex surface directed toward the object side, and has a positive refracting power as a whole.
The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the negative meniscus lens L133 having the convex surface directed toward the object side in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.
Next, numerical data of the twenty first embodiment will be enumerated.










Numerical data 21


















r1 = 25.94
d1 = 1
Nd1 = 1.8061
νd1 = 40.92


r2 = 10.076
d2 = 2.9




r3 = ∞
d3 = 12
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.3




r5 = 27.400
d5 = 3.53
Nd5 = 1.741
νd5 = 52.64


(Aspheric surface)





r6 = −29.816
d6 = D6




r7 = −162.920
d7 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 5.941
d8 = 0.7




(Aspheric surface)





r9 = 7.976
d9 = 2.18
Nd9 = 1.7552
νd9 = 27.51


r10 = 58.792
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = 8.417
d12 = 5.76
Nd12 = 1.7432
νd12 = 49.34


(Aspheric surface)





r13 = −11.49
d13 = 0.7
Nd13 = 1.84666
νd13 = 23.78


r14 = 30.643
d14 = 0.1
Nd14 = 1.69556
νd14 = 25.02


r15 = 27.578
d15 = D15




(Aspheric surface)





r16 = 97.811
d16 = 0.6
Nd16 = 1.48749
νd16 = 70.23


r17 = 11.204
d17 = D17




r18 = 10.926
d18 = 1.8
Nd18 = 1.7432
νd18 = 49.34


(Aspheric surface)





r19 = −57.258
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





 5th surface


k = 0


A4 = −3.17272E−07


A6 = 2.27157E−07


A8 = 0


 7th surface


k = 0


A4 = −7.84011E−05


A6 = 3.75164E−06


A8 = −2.06701E−08


 8th surface


k = 0


A4 = −4.71705E−04


A6 = 3.03269E−06


A8 = −2.77842E−07


12th surface


k = 0


A4 = 1.24086E−04


A6 = 1.45409E−06


A8 = 1.98337E−08


15th surface


k = 0


A4 = 8.26142E−04


A6 = 1.47361E−05


A8 = 5.68785E−07


18th surface


k = 0


A4 = −7.65491E−05


A6 = 6.95161E−06


A8 = −1.94682E−07





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
5.934
13.632
17.941


FNO.
2.59
4.8
6.28


D6
0.8
6.93
8.37


D10
8.95
2.82
1.38


D11
11.47
3.83
1.19


D15
1.71
11.94
14.18


D17
1.2
2.11
3.28


D19
4.79
1.29
0.52


D23
1.38
1.39
1.38









Twenty Second Embodiment
FIG. 43 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty second embodiment of the present invention.
FIG. 44A, FIG. 44B, and FIG. 44C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty second embodiment, where, FIG. 44A shows the state at the wide angle end, FIG. 44B shows the intermediate state, and FIG. 44C shows the state at the telephoto end.
The zoom lens of the twenty second embodiment, as shown in FIG. 43, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.
The second lens group G2 includes a biconcave lens L121, and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131, a biconcave lens L132, and a negative meniscus lens L133 having a convex surface directed toward the object side, and has a positive refracting power as a whole.
The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the negative meniscus lens L133 having a convex surface directed toward the object side in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.
Next, numerical data of the twenty second embodiment will be enumerated.










Numerical data 22


















r1 = 33.099
d1 = 1
Nd1 = 1.8061
νd1 = 40.92


r2 = 10.002
d2 = 2.9




r3 = ∞
d3 = 12
Nd3 = 1.8061
νD3 = 40.92


r4 = ∞
d4 = 0.3




r5 = 31.273
d5 = 3.54
Nd5 = 1.741
νd5 = 52.64


(Aspheric surface)





r6 = −31.54
d6 = D6




r7 = −220.371
d7 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 6.585
d8 = 0.7




(Aspheric surface)





r9 = 8.386
d9 = 2.2
Nd9 = 1.7552
νd9 = 27.51


r10 = 68.764
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = 8.010
d12 = 5.91
Nd12 = 1.6935
νd12 = 53.21


(Aspheric surface)





r13 = −11.855
d13 = 0.7
Nd13 = 1.84666
νd13 = 23.78


r14 = 34.48
d14 = 0.1
Nd14 = 1.72568
νd14 = 18.68


r15 = 31.034
d15 = D15




(Aspheric surface)





r16 = 128.367
d16 = 0.6
Nd16 = 1.48749
νd16 = 70.23


r17 = 9.957
d17 = D17




r18 = 10.408
d18 = 1.8
Nd18 = 1.7432
νd18 = 49.34


(Aspheric surface)





r19 = −98.053
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





 5th surface


k = 0


A4 = 2.24993E−05


A6 = 5.31492E−08


A8 = 0


 7th surface


k = 0


A4 = −4.81766E−09


A6 = 7.54588E−06


A8 = −5.54767E−08


 8th surface


k = 0


A4 = −2.25374E−04


A6 = 6.37750E−06


A8 = 5.09209E−08


12th surface


k = 0


A4 = 9.87983E−05


A6 = −2.03794E−08


A8 = 1.94321E−07


15th surface


k = 0


A4 = 7.88337E−04


A6 = 5.49424E−08


A8 = 1.94392E−06


18th surface


k = 0


A4 = −9.94528E−05


A6 = 5.03941E−06


A8 = −8.78271E−08





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.019
13.701
17.953


FNO.
2.89
4.63
5.65


D6
0.8
10.89
12.82


D10
13.44
3.35
1.41


D11
10.17
4.05
1.14


D15
1.69
12.96
14.72


D17
2.55
1.89
3.37


D19
5.38
0.89
0.56


D23
1.37
1.37
1.37









Twenty Third Embodiment
FIG. 45 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty third embodiment of the present invention.
FIG. 46A, FIG. 46B, and FIG. 46C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty third embodiment, where, FIG. 46A shows the state at the wide angle end, FIG. 46B shows the intermediate state, and FIG. 46C shows the state at the telephoto end.
The zoom lens system of the twenty third embodiment, as shown in FIG. 45, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.
The second lens group G2 includes a biconcave lens L121 and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131, a biconcave lens L132, and a negative meniscus lens L133 having a convex surface directed toward the object side, and has a positive refracting power as a whole.
The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the negative meniscus lens L133 having the convex surface directed toward the object side in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.
Next, numerical data of the twenty third embodiment will be enumerated.










Numerical data 23


















r1 = 36.107
d1 = 1
Nd1 = 1.8061
νd1 = 40.92


r2 = 9.992
d2 = 2.9




r3 = ∞
d3 = 12
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.3




r5 = 36.775
d5 = 3.54
Nd5 = 1.741
νd5 = 52.64


(Aspheric surface)





r6 = −31.106
d6 = D6




r7 = −303.247
d7 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 7.332
d8 = 0.7




(Aspheric surface)





r9 = 9.101
d9 = 2.2
Nd9 = 1.7552
νd9 = 27.51


r10 = 67.146
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = 8.974
d12 = 7.89
Nd12 = 1.6935
νd12 = 53.21


(Aspheric surface)





r13 = −11.679
d13 = 0.7
Nd13 = 1.84666
νd13 = 23.78


r14 = 46.242
d14 = 0.1
Nd14 = 1.852
νd14 = 14.02


r15 = 41.616
d15 = D15




(Aspheric surface)





r16 = 203.724
d16 = 0.6
Nd16 = 1.48749
νd16 = 70.23


r17 = 15.902
d17 = D17




r18 = 11.809
d18 = 1.8
Nd18 = 1.7432
νd18 = 49.34


(Aspheric surface)





r19 = −89.532
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





 5th surface


k = 0


A4 = 2.37243E−05


A6 = 1.18072E−07


A8 = 0


 7th surface


k = 0


A4 = 2.22368E−04


A6 = −3.32751E−06


A8 = −7.74649E−09


 8th surface


k = 0


A4 = 6.45457E−05


A6 = 3.83741E−07


A8 = −2.51959E−07


12th surface


k = 0


A4 = 4.70683E−05


A6 = 3.78749E−06


A8 = −1.87568E−08


15th surface


k = 0


A4 = 3.61492E−04


A6 = 1.24256E−05


A8 = 3.70281E−07


18th surface


k = 0


A4 = −8.86674E−05


A6 = 3.00407E−06


A8 = −2.58363E−08





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.024
13.703
17.975


FNO.
2.89
4.4
5.72


D6
0.8
14.39
14.62


D10
15.16
1.57
1.34


D11
11.03
4.34
1.13


D15
1.72
10.63
14.88


D17
4.75
4.27
4.95


D19
4.01
2.27
0.56


D23
1.37
1.37
1.37









Twenty Fourth Embodiment
FIG. 47 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty fourth embodiment of the present invention.
FIG. 48A, FIG. 48B, and FIG. 48C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty fourth embodiment, where, FIG. 48A shows the state at the wide angle end, FIG. 48B shows the intermediate state, and FIG. 48C shows the state at the telephoto end.
The zoom lens of the twenty fourth embodiment, as shown in FIG. 47, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex side directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.
The second lens group G2 includes a biconcave lens L121 and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131, a biconcave lens L132, and a negative meniscus lens L133 having a convex surface directed toward the object side, and has a positive refracting power as a whole.
The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, a surface on the object side of the biconcave lens L121 in the second lens group G2, both surfaces of the biconvex lens L131 and a surface on the image side of the negative meniscus lens L133 having the convex surface directed toward the object side in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.
Next, numerical data of the twenty fourth embodiment will be enumerated.










Numerical data 24


















r1 = 24.139
d1 = 1
Nd1 = 1.8061
νd1 = 40.92


r2 = 9.346
d2 = 3.72




r3 = ∞
d3 = 12
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.3




r5 = 28.592
d5 = 3.54
Nd5 = 1.741
νd5 = 52.64


(Aspheric surface)





r6 = −31.035
d6 = D6




r7 = −126.911
d7 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 6.287
d8 = 0.7




(Aspheric surface)





r9 = 8.413
d9 = 2.2
Nd9 = 1.7552
νd9 = 27.51


r10 = 68.335
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = 7.646
d12 = 6.13
Nd12 = 1.6935
νd12 = 53.21


(Aspheric surface)





r13 = −12.777
d13 = 0.7
Nd13 = 1.84666
νd13 = 23.78


r14 = 33.605
d14 = 0.1
Nd14 = 1.65228
νd14 = 12.75


r15 = 27.968
d15 = D15




(Aspheric surface)





r16 = 43.474
d16 = 0.6
Nd16 = 1.48749
νd16 = 70.23


r17 = 9.639
d17 = D17




r18 = 11.114
d18 = 1.8
Nd18 = 1.7432
νd18 = 49.34


(Aspheric surface)





r19 = −63.843
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





 5th surface


k = 0


A4 = 1.98225E−05


A6 = 1.90373E−07


A8 = 0


 7th surface


k = 0


A4 = −6.38785E−05


A6 = 6.11369E−06


A8 = −3.84846E−08


 8th surface


k = 0


A4 = −3.65611E−04


A6 = 3.98896E−06


A8 = −1.11425E−07


12th surface


k = 0


A4 = 8.17413E−05


A6 = 5.53907E−07


A8 = 1.30474E−07


15th surface


k = 0


A4 = 9.46156E−04


A6 = 1.36955E−05


A8 = 1.58843E−06


18th surface


k = 0


A4 = −8.67276E−05


A6 = 7.65460E−06


A8 = −1.57646E−07





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.101
13.42
17.995


FNO.
3.45
5.26
6.25


D6
1.87
8.14
9.44


D10
14.62
4.03
0.47


D11
3.17
1.04
0.4


D15
1.24
11.13
13.79


D17
1.21
2.09
3.31


D19
4.78
1.31
0.49


D23
1.36
1.36
1.36









Twenty Fifth Embodiment
FIG. 49 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty fifth embodiment of the present invention.
FIG. 50A, FIG. 50B, and FIG. 50C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty fifth embodiment, where, FIG. 50A shows a state at the wide angle end, FIG. 50B shows the intermediate state, and FIG. 50C shows the state at the telephoto end.
The zoom lens of the twenty fifth embodiment, as shown in FIG. 49, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.
The second lens group G2 includes a negative meniscus lens L121 having a convex surface directed toward the object side and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131, a negative meniscus lens L132 having a convex surface directed toward an image side, and a positive meniscus lens L133 having a convex surface directed toward the image side, and has a positive refracting power as a whole.
The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fifth lens group G5 includes a positive meniscus lens L142 having a convex surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, both surfaces of the negative meniscus lens L121 having the convex surface directed toward the object side in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the positive meniscus lens L133 having the convex surface directed toward the image side in the third lens group G3, and a surface on the object side of the positive meniscus lens L142 having the convex surface directed toward the object side in the fifth lens group G5.
Next, numerical data of the twenty fifth embodiment will be enumerated.










Numerical data 25


















r1 = 30.147
d1 = 1
Nd1 = 1.8061
νd1 = 40.92


r2 = 9.988
d2 = 2.9




r3 = ∞
D3 = 12
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.3




r5 = 21.536
d5 = 3.54
Nd5 = 1.741
νd5 = 52.64


(Aspheric surface)





r6 = −35.204
d6 = D6




r7 = 49.210
d7 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 5.838
d8 = 0.7




(Aspheric surface)





r9 = 6.738
d9 = 2.2
Nd9 = 1.7552
νd9 = 27.51


r10 = 14.193
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = 10.080
d12 = 6.02
Nd12 = 1.6935
νd12 = 53.21


(Aspheric surface)





r13 = −10.735
d13 = 0.7
Nd13 = 1.84666
νd13 = 23.78


r14 = −133.971
d14 = 0.1
Nd14 = 1.59885
νd14 = 6.52


r15 = −120.568
d15 = D15




(Aspheric surface)





r16 = 35.344
d16 = 0.6
Nd16 = 1.48749
νd16 = 70.23


r17 = 9.672
d17 = D17




r18 = 7.968
d18 = 1.8
Nd18 = 1.7432
νd18 = 49.34


(Aspheric surface)





r19 = 39.032
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





 5th surface


k = 0


A4 = 1.49401E−05


A6 = 6.81675E−08


A8 = 0


 7th surface


k = 0


A4 = 3.14125E−04


A6 = 4.96920E−06


A8 = −1.36962E−07


 8th surface


k = 0


A4 = 2.07725E−04


A6 = 1.45217E−05


A8 = −1.48176E−07


12th surface


k = 0


A4 = −1.84952E−05


A6 = 9.27696E−06


A8 = −9.79367E−08


15th surface


k = 0


A4 = 2.08929E−04


A6 = 1.12826E−05


A8 = 2.77941E−07


18th surface


k = 0


A4 = −1.65261E−04


A6 = 4.86444E−07


A8 = −5.90284E−08





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
5.999
10.405
17.998


FNO.
2.87
3.91
5.64


D6
0.8
5.36
8.6


D10
9.2
4.63
1.39


D11
9.9
5.87
1.2


D15
1.7
8.94
15.57


D17
4.07
3.15
3.28


D19
4.88
2.56
0.5


D23
1.36
1.41
1.36









Twenty Sixth Embodiment
FIG. 51 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty sixth embodiment of the present invention.
FIG. 52A, FIG. 52B, and FIG. 52C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty sixth embodiment, where, FIG. 52A shows the state at the wide angle end, FIG. 52B shows the intermediate state, and FIG. 52C shows the state at the telephoto end.
The zoom lens of the twenty sixth embodiment, as shown in FIG. 51, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.
The second lens group G2 includes a negative meniscus lens L121 having a convex surface directed toward the object side and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131, a negative meniscus lens L132 having a convex surface directed toward an image side, and a positive meniscus lens L133 having a convex surface directed toward the image side, and has a positive refracting power as a whole.
The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fifth lens group G5 includes a positive meniscus lens L142 having a convex surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, both surfaces of the negative meniscus lens L121 having the convex surface directed toward the object side in the second lens group G2, a surface on the object side of the biconvex lens L131, and a surface on the image side of the positive meniscus lens L133 having the convex surface directed toward the object side in the third lens group G3, and a surface on the object side of the positive meniscus lens L142 having the convex surface directed toward the object side in the fifth lens group G5.
Next, numerical data of the twenty sixth embodiment will be enumerated.










Numerical data 26


















r1 = 29.536
d1 = 1
Nd1 = 1.8061
νd1 = 40.92


r2 = 10
d2 = 2.9




r3 = ∞
d3 = 12
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.3




r5 = 23.086
d5 = 3.54
Nd5 = 1.741
νd5 = 52.64


(Aspheric surface)





r6 = −32.568
d6 = D6




r7 = 49.426
d7 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 5.508
d8 = 0.7




(Aspheric surface)





r9 = 6.275
d9 = 2.2
Nd9 = 1.7552
νd9 = 27.51


r10 = 13.895
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = 10.122
d12 = 6.02
Nd12 = 1.6935
νd12 = 53.21


(Aspheric surface)





r13 = −9.941
d13 = 0.7
Nd13 = 1.84666
νd13 = 23.78


r14 = −111.236
d14 = 0.1
Nd14 = 1.79525
νd14 = 9.95


r15 = −100.111
d15 = D15




(Aspheric surface)





r16 = 20.978
d16 = 0.6
Nd16 = 1.48749
νd16 = 70.23


r17 = 8.727
d17 = D17




r18 = 8.050
d18 = 1.8
Nd18 = 1.7432
νd18 = 49.34


(Aspheric surface)





r19 = 30.854
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





 5th surface


k = 0


A4 = 1.53520E−05


A6 = 7.22705E−08


A8 = 0


 7th surface


k = 0


A4 = 4.65044E−04


A6 = −2.25659E−06


A8 = −4.27282E−08


 8th surface


k = 0


A4 = 3.69076E−04


A6 = 1.33083E−05


A8 = −4.56802E−07


12th surface


k = 0


A4 = 3.22189E−05


A6 = 6.78190E−06


A8 = −3.73660E−08


15th surface


k = 0


A4 = 2.39851E−04


A6 = 5.36491E−06


A8 = 2.73962E−07


18th surface


k = 0


A4 = −1.05075E−04


A6 = 4.62091E−07


A8 = −4.85192E−08





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
5.998
10.399
17.998


FNO.
2.89
4
5.7


D6
0.8
5.12
8.62


D10
9.22
4.91
1.4


D11
10.29
5.95
1.2


D15
1.7
9.45
15.68


D17
4
3.15
3.43


D19
4.81
2.24
0.5


D23
1.36
1.37
1.36









Twenty Seventh Embodiment
FIG. 53 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty seventh embodiment of the present invention.
FIG. 54A, FIG. 54B, and FIG. 54C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty seventh embodiment, where, FIG. 54A shows the state at the wide angle end, FIG. 54B shows the intermediate state, and FIG. 54C shows the state at the telephoto end.
The zoom lens of the twenty seventh embodiment, as shown in FIG. 53, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.
The second lens group G2 includes a negative meniscus lens L121 having a convex surface directed toward the object side and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131, a negative meniscus lens L132 having a convex surface directed toward an image side, and a positive meniscus lens L133 having a convex surface directed toward the image side, and has a positive refracting power as a whole.
The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fifth lens group G5 includes a positive meniscus lens L142 having a convex surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group G1, both surfaces of the negative meniscus lens L121 having the convex surface directed toward the object side, a surface on the object side of the biconvex lens L131 and a surface on the image side of the positive meniscus lens L133 having the convex surface directed toward the image side in the third lens group G3, and a surface on the object side of the positive meniscus lens L142 having the convex surface directed toward the object side in the fifth lens group G5.
Next, numerical data of the twenty seventh embodiment will be enumerated.










Numerical data 27


















r1 = 27.09
d1 = 1
Nd1 = 1.8061
νd1 = 40.92


r2 = 9.998
d2 = 2.9




r3 = ∞
d3 = 12
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.3




r5 = 25.058
d5 = 3.54
Nd5 = 1.741
νd5 = 52.64


(Aspheric surface)





r6 = −40.797
d6 = D6




r7 = 51.714
d7 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 5.415
d8 = 0.7




(Aspheric surface)





r9 = 6.522
d9 = 2.2
Nd9 = 1.7552
νd9 = 27.51


r10 = 17.116
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = 8.862
d12 = 6.01
Nd12 = 1.6935
νd12 = 53.21


(Aspheric surface)





r13 = −9.201
d13 = 0.7
Nd13 = 1.84666
νd13 = 25.78


r14 = −332.698
d14 = 0.1
Nd14 = 1.9712
νd14 = 12.88


r15 = −299.436
d15 = D15




(Aspheric surface)





r16 = 66.397
d16 = 0.6
Nd16 = 1.48749
νd16 = 70.23


r17 = 10.427
d17 = D17




r18 = 9.518
d18 = 1.8
Nd18 = 1.7432
νd18 = 49.34


(Aspheric surface)





r19 = 80.399
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





5th surface


k = 0


A4 = 1.82936E−05


A6 = 2.19287E−07


A8 = 0


7th surface


k = 0


A4 = 2.14374E−04


A6 = 8.90498E−06


A8 = −2.02404E−07


8th surface


k = 0


A4 = −9.62206E−05


A6 = 2.68656E−05


A8 = −7.87125E−07


12th surface


k = 0


A4 = 5.80429E−05


A6 = 4.79927E−06


A8 = 4.71202E−08


15th surface


k = 0


A4 = 3.91395E−04


A6 = −1.85098E−06


A8 = 7.46043E−07


18th surface


k = 0


A4 = −2.21543E−05


A6 = −1.97720E−06


A8 = 1.36609E−08





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
5.985
10.398
17.997


FNO.
2.98
4.16
6.21


D6
0.8
5.57
8.57


D10
9.16
4.39
1.4


D11
10.59
6.39
1.2


D15
1.7
8.68
15.9


D17
3.79
3.81
3.42


D19
4.94
2.13
0.5


D23
1.36
1.38
1.36









Twenty Eighth Embodiment
FIG. 55 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty eighth embodiment of the present invention.
FIG. 56A, FIG. 56B, and FIG. 56C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty eighth embodiment, where, FIG. 56A shows the state at the wide angle end, FIG. 56B shows the intermediate state, and FIG. 56C shows the state at the telephoto end.
The zoom lens of the twenty eighth embodiment, as shown in FIG. 55, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a biconvex lens L113, and has a positive refracting power as a whole.
The second lens group G2 includes a negative meniscus lens L121 having a convex surface directed toward the object side and a positive (meniscus) lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131, a negative meniscus lens L132 having a convex surface directed toward an image side, and a positive meniscus lens L133 having a convex surface directed toward the image side, and has a positive refracting power as a whole.
The fourth lens group G4 includes a biconcave lens L141, and has a negative refracting power as a whole.
The fifth lens group G5 includes a biconvex lens L142 and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the biconvex lens L113 in the first lens group, both surfaces of the negative meniscus lens L121 having the convex surface directed toward the object side in the second lens group G2, a surface on the object side of the biconvex lens L131 and a surface on the image side of the positive meniscus lens L133 having the convex surface directed toward the image side in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.
Next, numerical data of the twenty eighth embodiment will be enumerated.










Numerical data 28


















r1 = 30.295
d1 = 1
Nd1 = 1.8061
νd1 = 45.9


r2 = 10
d2 = 2.9




r3 = ∞
d3 = 12
Nd3 = 1.741
νd3 = 55.64


r4 = ∞
d4 = 0.3




r5 = 18.286
d5 = 3.54
Nd5 = 1.741
νd5 = 65.6


(Aspheric surface)





r6 = −42.655
d6 = D6




r7 = 40.666
d7 = 0.8
Nd7 = 1.8061
νd7 = 40.92


(Aspheric surface)





r8 = 5.986
d8 = 0.7




(Aspheric surface)





r9 = 6.666
d9 = 2.2
Nd9 = 1.7552
νd9 = 27.51


r10 = 11.373
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = 10.097
d12 = 6
Nd12 = 1.6935
νd12 = 65.2


(Aspheric surface)





r13 = −25.149
d13 = 0.7
Nd13 = 1.84666
νd13 = 23.7


r14 = −5644.305
d14 = 0.1
Nd14 = 2.05122
νd14 = 6.28


r15 = −5079.893
d15 = D15




(Aspheric surface)





r16 = −69.07
d16 = 0.6
Nd16 = 1.48749
νd16 = 40.2


r17 = 14.791
d17 = D17




r18 = 12.723
d18 = 1.8
Nd18 = 1.7432
νd18 = 60.3


(Aspheric surface)





r19 = −32.451
d19 = D19




r20 = ∞
d20 = 1.9
Nd20 = 1.54771
νd20 = 62.84


r21 = ∞
d21 = 0.8




r22 = ∞
d22 = 0.75
Nd22 = 1.51633
νd22 = 64.14


r23 = ∞
d23 = D23










Aspherical coefficients





5th surface


k = 0


A4 = −3.11363E−06


A6 = 5.76079E−08


A8 = 0


7th surface


k = 0


A4 = 2.48925E−04


A6 = 3.22844E−07


A8 = 6.56210E−08


8th surface


k = 0


A4 = 1.17922E−04


A6 = 5.62435E−06


A8 = 3.78036E−07


12th surface


k = 0


A4 = −1.18367E−05


A6 = 1.50314E−06


A8 = 2.72652E−09


15th surface


k = 0


A4 = 1.65967E−04


A6 = 1.91161E−06


A8 = 1.63255E−08


18th surface


k = 0


A4 = −1.10641E−04


A6 = −5.17961E−08


A8 = −2.99128E−08





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6
10.401
18.001


FNO.
2.76
3.53
5.5


D6
0.8
5.89
7.59


D10
8.19
3.1
1.4


D11
9.78
6.76
1.2


D15
1.7
8.53
18.27


D17
2.93
1.06
0.08


D19
5.64
3.7
0.5


D23
1.36
1.36
1.36









Twenty Ninth Embodiment
FIG. 57 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty ninth embodiment of the present invention.
FIG. 58A, FIG. 58B, and FIG. 58C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty ninth embodiment, where, FIG. 58A shows the state at the wide angle end, FIG. 58B shows the intermediate state, and FIG. 58C shows the state at the telephoto end.
The zoom lens of the twenty ninth embodiment, as shown in FIG. 57, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 and a surface on the image side of the negative meniscus lens L242 having the concave surface directed toward the object side in the fourth lens group G4.
Next, numerical data of the twenty ninth embodiment will be enumerated.










Numerical data 29


















r1 = 40.282
d1 = 1.1
Nd1 = 1.7432
νd1 = 49.34


r2 = 11.066
d2 = 3




r3 = ∞
d3 = 12.5
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.4




r5 = 71.018
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = −14.842
d6 = 0.7
Nd6 = 1.51633
νd6 = 64.14


r7 = 15.241
d7 = D7




r8 = 13.878
d8 = 3.5
Nd8 = 1.6935
νd8 = 53.21


(Aspheric surface)





r9 = −12
d9 = 0.7
Nd9 = 1.84666
νd9 = 23.78


r10 = −33.882
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = −11.331
d12 = 0.7
Nd12 = 1.51823
νd12 = 58.9


r13 = 7.641
d13 = 1.6
Nd13 = 1.816
νd13 = 46.62


r14 = 24.592
d14 = D14




r15 = 11.013
d15 = 3.5
Nd15 = 1.56907
νd15 = 71.3


(Aspheric surface)





r16 = −6.2
d16 = 0.35
Nd16 = 1.60687
νd16 = 27.03


r17 = −12.084
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





5th surface


k = 0


A4 = 1.53992E−05


A6 = 2.42526E−07


A8 = 0.00000E+00


8th surface


k = 0


A4 = −1.85002E−05


A6 = −2.19368E−07


A8 = −4.21441E−07


15th surface


k = 0


A4 = −3.37616E−04


A6 = −2.07732E−05


A8 = −1.28129E−06


17th surface


k = 0


A4 = 6.27990E−05


A6 = −1.62144E−05


A8 = 5.27383E−08





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.005
13.701
17.99


FNO.
2.83
3.38
3.72


D7
13.84
4
0.8


D10
1.6
11.44
14.65


D11
1.4
5.73
8.78


D14
6.22
4.95
3


D17
5.33
2.27
1.17


D21
1.36
1.36
1.36









Thirtieth Embodiment
FIG. 59 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirtieth embodiment of the present invention.
FIG. 60A, FIG. 60B, and FIG. 60C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirtieth embodiment, where, FIG. 60A shows the state at the wide angle end, FIG. 60B shows the intermediate state, and FIG. 60C shows the state at the telephoto end.
The zoom lens of the thirtieth embodiment, as shown in FIG. 59, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconcave lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 and a surface on the image side of the negative meniscus lens L242 having the concave surface directed toward the object side in the fourth lens group G4.
Next, numerical data of the thirtieth embodiment will be enumerated.










Numerical data 30


















r1 = 28.356
d1 = 1.1
Nd1 = 1.7432
νd1 = 49.34


r2 = 10.03
d2 = 3




r3 = ∞
d3 = 12.5
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.4




r5 = 641.586
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = −13.014
d6 = 0.7
Nd6 = 1.51633
νd6 = 64.14


r7 = 17.999
d7 = D7




r8 = 14.436
d8 = 3.5
Nd8 = 1.6935
νd8 = 53.21


(Aspheric surface)





r9 = −12
d9 = 0.7
Nd9 = 1.84666
νd9 = 23.78


r10 = −29.444
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = −11.39
d12 = 0.7
Nd12 = 1.51823
νd12 = 58.9


r13 = 7.828
d13 = 1.6
Nd13 = 1.83481
νd13 = 42.71


r14 = 23.898
d14 = D14




r15 = 13.575
d15 = 3.5
Nd15 = 1.56907
νd15 = 71.3


(Aspheric surface)





r16 = −6.2
d16 = 0.35
Nd16 = 1.60258
νd16 = 18.58


r17 = −10.357
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





5th surface


k = 0


A4 = 1.15333E−05


A6 = 3.80977E−07


A8 = 0


8th surface


k = 0


A4 = −2.24509E−05


A6 = −2.96464E−07


A8 = 0.00000E+00


15th surface


k = 0


A4 = −3.62526E−04


A6 = −3.88741E−05


A8 = 0.00000E+00


17th surface


k = 0


A4 = 2.81895E−05


A6 = −2.50709E−05


A8 = 0.00000E+00





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.02
13.964
17.997


FNO.
2.83
3.42
3.76


D7
13.4
4
0.8


D10
1.6
11.44
14.19


D11
1.4
5.73
8.82


D14
6.06
4.95
2.99


D17
5.55
2.27
1.2


D21
1.36
1.2
1.36









Thirty First Embodiment
FIG. 61 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty first embodiment of the present invention.
FIG. 62A, FIG. 62B, and FIG. 62C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty first embodiment, where, FIG. 62A shows the state at the wide angle end, FIG. 62B shows the intermediate state, and FIG. 62C shows the state at the telephoto end.
The zoom lens of the thirty first embodiment, as shown in FIG. 61, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 and a surface on the image side of the negative meniscus lens L242 having the concave surface directed toward the object side in the fourth lens group G4.
Next, numerical data of the thirty first embodiment will be enumerated.










Numerical data 31


















r1 = 40.522
d1 = 1.1
Nd1 = 1.7432
νd1 = 49.34


r2 = 11.04
d2 = 3




r3 = ∞
d3 = 12.5
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.4




r5 = 71.610
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = −14.88
d6 = 0.7
Nd6 = 1.51633
νd6 = 64.14


r7 = 15.213
d7 = D7




r8 = 13.889
d8 = 3.5
Nd8 = 1.6935
νd8 = 53.21


(Aspheric surface)





r9 = −12
d9 = 0.7
Nd9 = 1.84666
νd9 = 23.78


r10 = −33.95
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = −11.384
d12 = 0.7
Nd12 = 1.51823
νd12 = 58.9


r13 = 7.603
d13 = 1.6
Nd13 = 1.816
νd13 = 46.62


r14 = 24.858
d14 = D14




r15 = 10.879
d15 = 3.5
Nd15 = 1.56907
νd15 = 71.3


(Aspheric surface)





r16 = −6.2
d16 = 0.35
Nd16 = 1.69556
νd16 = 25.02


r17 = −11.875
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





5th surface


k = 0


A4 = 1.42784E−05


A6 = 2.93964E−07


A8 = 0


8th surface


k = 0


A4 = −1.52653E−05


A6 = −3.01808E−07


A8 = 0.00000E+00


15th surface


k = 0


A4 = −2.75447E−04


A6 = −1.24778E−05


A8 = 0.00000E+00


17th surface


k = 0


A4 = 2.75599E−05


A6 = −7.58484E−06


A8 = 0.00000E+00





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.245
13.935
18.127


FNO.
2.96
3.48
3.8


D7
13.84
4
0.8


D10
1.6
11.44
14.65


D11
1.4
5.73
8.78


D14
6.22
4.95
3


D17
5.33
2.27
1.17


D21
1.75
1.67
1.75









Thirty Second Embodiment
FIG. 63 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty second embodiment of the present invention.
FIG. 64A, FIG. 64B, and FIG. 64C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty second embodiment, where, FIG. 64A shows the state at the wide angle end, FIG. 64B shows the intermediate state, and FIG. 64C shows the state at the telephoto end.
The zoom lens of the thirty second embodiment, as shown in FIG. 63, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a positive meniscus lens L213 having a convex surface directed toward an image side and a biconcave lens L214, and has a negative refracting power as a whole. A surface on the object side of the positive meniscus lens L213 having the convex surface directed toward the image side has a shape close to almost a flat surface (plane).
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward the image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the positive meniscus lens L213 having the convex surface directed toward the image side in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 and a surface on the image side of the image side of the negative meniscus lens L242 having the concave surface directed toward the object side in the fourth lens group G4.
Next, numerical data of the thirty second embodiment will be enumerated.










Numerical data 32


















r1 = 42.382
d1 = 1.1
Nd1 = 1.72
νd1 = 41.98


r2 = 12.354
d2 = 3




r3 = ∞
d3 = 12.5
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.4




r5 = −19898.215
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = −20.027
d6 = 0.7
Nd6 = 1.51633
νd6 = 64.14


r7 = 14.432
d7 = D7




r8 = 12.774
d8 = 3.5
Nd8 = 1.6935
νd8 = 53.21


(Aspheric surface)





r9 = −12
d9 = 0.7
Nd9 = 1.84666
νd9 = 23.78


r10 = −23.454
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = −17.162
d12 = 0.7
Nd12 = 1.51823
νd12 = 58.9


r13 = 10.232
d13 = 1.6
Nd13 = 1.83481
νd13 = 42.71


r14 = 20.544
d14 = D14




r15 = 10.418
d15 = 3.5
Nd15 = 1.51633
νd15 = 64.14


(Aspheric surface)





r16 = −6.2
d16 = 0.35
Nd16 = 1.72568
νd16 = 18.68


r17 = −9.981
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





5th surface


k = 0


A4 = 4.35719E−05


A6 = 9.40495E−08


A8 = 0


8th surface


k = 0


A4 = −7.92344E−05


A6 = −1.71554E−07


A8 = 0.00000E+00


15th surface


k = 0


A4 = −3.91186E−04


A6 = −2.20035E−05


A8 = 0.00000E+00


17th surface


k = 0


A4 = −6.38383E−05


A6 = −1.11941E−05


A8 = 0.00000E+00





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.322
15.275
17.912


FNO.
2.83
3.29
3.61


D7
11.99
4
0.8


D10
1.62
11.44
12.81


D11
1.46
5.73
8.91


D14
7.19
4.95
2.95


D17
4.41
2.27
1.2


D21
1.36
−1.27
1.36









Thirty Third Embodiment
FIG. 65 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty third embodiment of the present invention.
FIG. 66A, FIG. 66B, and FIG. 66C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty third embodiment, where, FIG. 66A shows the state at the wide angle end, FIG. 66B shows the intermediate state, and FIG. 66C shows the state at the telephoto end. The zoom lens of the thirty third embodiment, as shown in FIG. 65, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a positive meniscus lens L213 having a convex surface directed toward an image side and a biconcave lens L214, and has a negative refracting power as a whole. A surface on the object side of the positive meniscus lens L213 having the convex surface directed toward the image side has a shape close to almost a flat surface (plane).
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward the image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the positive meniscus lens L213 having the convex surface directed toward the image side in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, a surface on the object side of the biconvex lens L241 and a surface on the image side of the negative meniscus lens L242 having the concave surface directed toward the object side in the fourth lens group G4.
Next, numerical data of the thirty third embodiment will be enumerated.










Numerical data 33


















r1 = 43.427
d1 = 1.1
Nd1 = 1.72
νd1 = 41.98


r2 = 12.699
d2 = 3




r3 = ∞
d3 = 12.5
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.4




r5 = −16568.136
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = −23.933
d6 = 0.7
Nd6 = 1.51633
νd6 = 64.14


r7 = 14.038
d7 = D7




r8 = 12.360
d8 = 3.5
Nd8 = 1.6935
νd8 = 53.21


(Aspheric surface)





r9 = −12
d9 = 0.7
Nd9 = 1.84666
νd9 = 23.78


r10 = −22.5
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = −17.935
d12 = 0.7
Nd12 = 1.51823
νd12 = 58.9


r13 = 10.815
d13 = 1.6
Nd13 = 1.83481
νd13 = 42.71


r14 = 20.769
d14 = D14




r15 = 11.700
d15 = 3.5
Nd15 = 1.51633
νd15 = 64.14


(Aspheric surface)





r16 = −6.2
d16 = 0.35
Nd16 = 1.852
νd16 = 14.02


r17 = −8.759
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





5th surface


k = 0


A4 = 5.11574E−05


A6 = 6.92167E−08


A8 = 0


8th surface


k = 0


A4 = −9.52937E−05


A6 = −2.01996E−07


A8 = 0.00000E+00


15th surface


k = 0


A4 = −5.63606E−04


A6 = −3.50134E−05


A8 = 0.00000E+00


17th surface


k = 0


A4 = −1.65115E−04


A6 = −1.28198E−05


A8 = 0.00000E+00





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.303
15.891
17.895


FNO.
2.83
3.32
3.55


D7
11.91
4
0.8


D10
1.61
11.44
12.71


D11
1.48
5.73
8.38


D14
6.88
4.95
2.94


D17
4.23
2.27
1.27


D21
1.36
−2.14
1.36









Thirty Fourth Embodiment
FIG. 67 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty fourth embodiment of the present invention.
FIG. 68A, FIG. 68B, and FIG. 68C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty fourth embodiment, where, FIG. 68A shows the state at the wide angle end, FIG. 68B shows the intermediate state, and FIG. 68C shows the state at the telephoto end.
The zoom lens of the thirty fourth embodiment, as shown in FIG. 67, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a positive meniscus lens L213 having a convex surface directed toward an image side and a biconcave lens L214, and has a negative refracting power as a whole.
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward the image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the positive meniscus lens L213 having the convex surface directed toward the image side in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 and a surface on the image side of the negative meniscus lens L242 having the concave surface directed toward the object side in the fourth lens group G4.
Next, numerical data of the thirty fourth embodiment will be enumerated.










Numerical data 34


















r1 = 21.073
d1 = 0.9
Nd1 = 1.74738
νd1 = 38.67


r2 = 9.328
d2 = 3.67




r3 = ∞
d3 = 10
Nd3 = 1.88
νd3 = 41


r4 = ∞
d4 = 0.72




r5 = −55.494
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = −11.72
d6 = 5.54
Nd6 = 1.51633
νd6 = 64.14


r7 = 30.291
d7 = D7




r8 = 16.684
d8 = 6.34
Nd8 = 1.69397
νd8 = 56.88


(Aspheric surface)





r9 = −12
d9 = 0.9
Nd9 = 1.84465
νd9 = 25.34


r10 = −25.607
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = −19.599
d12 = 0.9
Nd12 = 1.52152
νd12 = 63.05


r13 = 6.828
d13 = 1.49
Nd13 = 1.81464
νd13 = 45.43


r14 = 17.305
d14 = D14




r15 = 25.754
d15 = 5.67
Nd15 = 1.56907
νd15 = 71.31


(Aspheric surface)





r16 = −6.2
d16 = 0.35
Nd16 = 1.65228
νd16 = 12.75


r17 = −8.121
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





5th surface


k = 0


A4 = 1.59251E−05


A6 = 4.32015E−07


A8 = 0


8th surface


k = 0


A4 = −3.16339E−05


A6 = −1.13143E−07


A8 = 0.00000E+00


15th surface


k = 0


A4 = −7.25293E−04


A6 = −2.99773E−05


A8 = 0.00000E+00


17th surface


k = 0


A4 = −1.43049E−04


A6 = −5.80127E−06


A8 = 0.00000E+00





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.1
13.42
17.993


FNO.
3.06
3.21
3.94


D7
13.91
3.96
0.51


D10
0.46
12.72
14.27


D11
1.34
2.96
8.18


D14
6.23
4.96
3.09


D17
5.33
2.26
1.09


D21
1.36
1.36
1.36









Thirty Fifth Embodiment
FIG. 69 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty fifth embodiment of the present invention.
FIG. 70A, FIG. 70B, and FIG. 70C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty fifth embodiment, where, FIG. 70A shows the state at the wide angle end, FIG. 70B shows the intermediate state, and FIG. 70C shows the state at the telephoto end.
The zoom lens of the thirty fifth embodiment, as shown in FIG. 69, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 and a surface on the image side of the negative meniscus lens L242 having the concave surface directed toward the object side in the fourth lens group G4.
Next, numerical data of the thirty fifth embodiment will be enumerated.










Numerical data 35


















r1 = 55.095
d1 = 1.1
Nd1 = 1.7432
νd1 = 49.34


r2 = 11.694
d2 = 3




r3 = ∞
d3 = 12.5
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.4




r5 = 51.903
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = −15.372
d6 = 0.7
Nd6 = 1.51633
νd6 = 64.14


r7 = 14.817
d7 = D7




r8 = 14.093
d8 = 3.5
Nd8 = 1.6935
νd8 = 53.21


(Aspheric surface)





r9 = −12
d9 = 0.7
Nd9 = 1.84666
νd9 = 23.78


r10 = −37.146
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = −12.922
d12 = 0.7
Nd12 = 1.51823
νd12 = 58.9


r13 = 7.163
d13 = 1.6
Nd13 = 1.816
νd13 = 46.62


r14 = 19.642
d14 = D14




r15 = 12.565
d15 = 3.5
Nd15 = 1.80907
νd15 = 20.3


(Aspheric surface)





r16 = −11.756
d16 = 0.35
Nd16 = 1.59885
νd16 = 6.52


r17 = −49.133
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





5th surface


k = 0


A4 = 2.17334E−05


A6 = 1.29516E−07


A8 = 0


8th surface


k = 0


A4 = −2.20346E−05


A6 = −1.08152E−07


A8 = 0.00000E+00


15th surface


k = 0


A4 = −2.09817E−04


A6 = −9.83727E−06


A8 = 0.00000E+00


17th surface


k = 0


A4 = 9.24813E−06


A6 = −1.26856E−05


A8 = 0.00000E+00





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.004
10.395
17.998


FNO.
2.85
3.33
3.73


D7
14.5
8.24
0.8


D10
1.6
7.85
15.3


D11
1.4
5.72
9.32


D14
6.77
4.87
3


D17
5.35
2.93
1.2


D21
1.36
1.36
1.36









Thirty Sixth Embodiment
FIG. 71 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point-focusing at the wide angle end of a zoom lens according to a thirty sixth embodiment of the present invention.
FIG. 72A, FIG. 72B, and FIG. 72C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty sixth embodiment, where, FIG. 72A shows the state at the wide angle end, FIG. 72B shows the intermediate state, and FIG. 72C shows the state at the telephoto end.
The zoom lens of the thirty sixth embodiment, as shown in FIG. 71, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 and a surface on the image side of the negative meniscus lens L242 having the concave surface directed toward the object side in the fourth lens group G4.
Next, numerical data of the thirty sixth embodiment will be enumerated.










Numerical data 36


















r1 = 54.751
d1 = 1.1
Nd1 = 0.7432
νd1 = 49.34


r2 = 11.599
d2 = 3




r3 = ∞
d3 = 12.5
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.4




r5 = 48.588
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = −15.271
d6 = 0.7
Nd6 = 1.51633
νd6 = 64.14


r7 = 14.609
d7 = D7




r8 = 14.138
d8 = 3.5
Nd8 = 1.6935
νd8 = 53.21


(Aspheric surface)





r9 = −12
d9 = 0.7
Nd9 = 1.84666
νd9 = 23.78


r10 = −37.788
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = −12.861
d12 = 0.7
Nd12 = 1.51823
νd12 = 58.9


r13 = 7.159
d13 = 1.6
Nd13 = 1.816
νd13 = 46.62


r14 = 19.721
d14 = D14




r15 = 12.075
d15 = 3.5
Nd15 = 1.80907
νd15 = 25.3


(Aspheric surface)





r16 = −10.075
d16 = 0.35
Nd16 = 1.79525
νd16 = 9.95


r17 = −30.341
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





5th surface


k = 0


A4 = 2.17595E−05


A6 = 1.16192E−07


A8 = 0


8th surface


k = 0


A4 = −2.06326E−05


A6 = −9.41435E−08


A8 = 0.00000E+00


15th surface


k = 0


A4 = −1.73586E−04


A6 = −9.45101E−06


A8 = 0.00000E+00


17th surface


k = 0


A4 = 4.10023E−05


A6 = −9.23729E−06


A8 = 0.00000E+00





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.004
10.395
17.998


FNO.
2.85
3.33
3.73


D7
14.56
8.25
0.8


D10
1.6
7.9
15.36


D11
1.4
5.75
9.35


D14
6.78
4.84
3


D17
5.37
2.97
1.2


D21
1.36
1.36
1.36









Thirty Seventh Embodiment
FIG. 73 is a cross-sectional view along the optical axis showing an optical arrangement at the wide angle end of a zoom lens according to a thirty seventh embodiment of the present invention.
FIG. 74A, FIG. 74B, and FIG. 74C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty seventh embodiment, where, FIG. 74A shows the state at the wide angle end, FIG. 74B shows the intermediate state, and FIG. 74C shows the state at the telephoto end.
The zoom lens of the thirty seventh embodiment, as shown in FIG. 73, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 and a surface on the image side of the negative meniscus lens L242 having the concave surface directed toward the object side in the fourth lens group G4.
Next, numerical data of the thirty seventh embodiment will be enumerated.










Numerical data 37


















r1 = 55.039
d1 = 1.1
Nd1 = 1.7432
νd1 = 49.34


r2 = 11.565
d2 = 3




r3 = ∞
d3 = 12.5
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.4




r5 = 46.410
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = −15.146
d6 = 0.7
Nd6 = 1.51633
νd6 = 64.14


r7 = 14.418
d7 = D7




r8 = 14.090
d8 = 3.5
Nd8 = 1.6935
νd8 = 53.21


(Aspheric surface)





r9 = −12
d9 = 0.7
Nd9 = 1.84666
νd9 = 23.78


r10 = −38.595
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = −12.608
d12 = 0.7
Nd12 = 1.51823
νd12 = 58.9


r13 = 7.064
d13 = 1.6
Nd13 = 1.816
νd13 = 46.62


r14 = 19.84
d14 = D14




r15 = 11.880
d15 = 3.5
Nd15 = 1.80907
νd15 = 25.3


(Aspheric surface)





r16 = −7.278
d16 = 0.35
Nd16 = 1.9712
νd16 = 12.88


r17 = −19.802
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





5th surface


k = 0


A4 = 2.14569E−05


A6 = 1.05477E−07


A8 = 0


8th surface


k = 0


A4 = −1.98881E−05


A6 = −8.44877E−08


A8 = 0.00000E+00


15th surface


k = 0


A4 = −1.45589E−04


A6 = −8.37650E−06


A8 = 0.00000E+00


17th surface


k = 0


A4 = 2.35364E−05


A6 = −6.65483E−06


A8 = 0.00000E+00





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.004
10.395
17.998


FNO.
2.84
3.31
3.72


D7
14.56
8.23
0.8


D10
1.6
7.92
15.36


D11
1.4
5.76
9.32


D14
6.72
4.76
3


D17
5.4
3
1.2


D21
1.36
1.36
1.36









Thirty Eighth Embodiment
FIG. 75 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty eighth embodiment of the present invention.
FIG. 76A, FIG. 76B, and FIG. 76C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty eighth embodiment, where, FIG. 76A shows the state at the wide angle end, FIG. 76B shows the intermediate state, and FIG. 76C shows the state at the telephoto end.
The zoom lens of the thirty eighth embodiment, as shown in FIG. 75, has in order from an object side thereof, a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.
The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.
The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.
The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.
The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.
At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.
An aspheric surface is provided on a surface on the object side of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2, and a surface on the object side of the biconvex lens L241 and a surface on the image side of the negative meniscus lens L242 having the concave surface directed toward the object side in the fourth lens group G4.
Next, numerical data of the thirty eighth embodiment will be enumerated.










Numerical data 38


















r1 = 54.8
d1 = 1.1
Nd1 = 1.7432
νd1 = 49.34


r2 = 11.521
d2 = 3




r3 = ∞
d3 = 12.5
Nd3 = 1.8061
νd3 = 40.92


r4 = ∞
d4 = 0.4




r5 = 45.176
d5 = 2.2
Nd5 = 1.8061
νd5 = 40.92


(Aspheric surface)





r6 = −15.199
d6 = 0.7
Nd6 = 1.51633
νd6 = 64.14


r7 = 14.337
d7 = D7




r8 = 14.161
d8 = 3.5
Nd8 = 1.6935
νd8 = 53.21


(Aspheric surface)





r9 = −12
d9 = 0.7
Nd9 = 1.84666
νd9 = 23.78


r10 = −38.568
d10 = D10




r11 = Aperture stop
d11 = D11




r12 = −12.826
d12 = 0.7
Nd12 = 1.51823
νd12 = 58.9


r13 = 7.165
d13 = 1.6
Nd13 = 1.816
νd13 = 46.62


r14 = 19.791
d14 = D14




r15 = 11.637
d15 = 3.5
Nd15 = 1.80907
νd15 = 25.3


(Aspheric surface)





r16 = −15.346
d16 = 0.35
Nd16 = 2.05122
νd16 = 6.28


r17 = −25.733
d17 = D17




(Aspheric surface)





r18 = ∞
d18 = 1.44
Nd18 = 1.54771
νd18 = 62.84


r19 = ∞
d19 = 0.8




r20 = ∞
d20 = 0.6
Nd20 = 1.51633
νd20 = 64.14


r21 = ∞
d21 = D21










Aspherical coefficients





5th surface


k = 0


A4 = 2.18388E−05


A6 = 1.00228E−07


A8 = 0


8th surface


k = 0


A4 = −1.92478E−05


A6 = −7.78797E−08


A8 = 0.00000E+00


15th surface


k = 0


A4 = −1.55987E−04


A6 = −8.82328E−06


A8 = 0.00000E+00


17th surface


k = 0


A4 = 5.03879E−05


A6 = −6.66888E−06


A8 = 0.00000E+00





Zoom data


When D0 (distance from object up to 1st surface) is ∞











wide-angle end
intermediate
telephoto end





Focal length
6.004
10.395
17.998


FNO.
2.84
3.32
3.73


D7
14.62
8.27
0.8


D10
1.6
7.94
15.42


D11
1.4
5.79
9.39


D14
6.8
4.8
3


D17
5.39
3
1.2


D21
1.36
1.36
1.36









Thirty Ninth Embodiment
Thus, it is possible to use such image forming optical system of the present invention in a photographic apparatus in which an image of an object is photographed by an electronic image pickup element such as a CCD and a CMOS, particularly a digital camera and a video camera, a personal computer, a telephone, and a portable terminal which are examples of an information processing unit, particularly a portable telephone which is easy to carry. Embodiments thereof will be exemplified below.
In FIG. 77 to FIG. 79 show conceptual diagrams of structures in which the image forming optical system according to the present invention is incorporated in a photographic optical system 41 of a digital camera. FIG. 77 is a frontward perspective view showing an appearance of a digital camera 40, FIG. 78 is a rearward perspective view of the same, and FIG. 79 is a cross-sectional view showing an optical arrangement of the digital camera 40.
The digital camera 40, in a case of this example, includes the photographic optical system 41 (an objective optical system for photography 48) having an optical path for photography 42, a finder optical system 43 having an optical path for finder 44, a shutter 45, a flash 46, and a liquid-crystal display monitor 47. Moreover, when the shutter 45 disposed at an upper portion of the camera 40 is pressed, in conjugation with this, a photograph is taken through the photographic optical system 41 (objective optical system for photography 48) such as the zoom lens in the first embodiment.
An object image formed by the photographic optical system 41 (photographic objective optical system 48) is formed on an image pickup surface 50 of a CCD 49. The object image photoreceived at the CCD 49 is displayed on the liquid-crystal display monitor 47 which is provided on a camera rear surface as an electronic image, via an image processing means 51. Moreover, a memory etc. is disposed in the image processing means 51, and it is possible to record the electronic image photographed. This memory may be provided separately from the image processing means 51, or may be formed by carrying out by writing by recording (recorded writing) electronically by a floppy (registered trademark) disc, memory card, or an MO etc.
Furthermore, an objective optical system for finder 53 is disposed in the optical path for finder 44. This objective optical system for finder 53 includes a cover lens 54, a first prism 10, an aperture stop 2, a second prism 20, and a lens for focusing 66. An object image is formed on an image forming surface 67 by this objective optical system for finder 53. This object image is formed in a field frame of a Porro prism which is an image erecting member equipped with a first reflecting surface 56 and a second reflecting surface 58. On a rear side of this Porro prism, an eyepiece optical system 59 which guides an image formed as an erected normal image is disposed.
By the digital camera 40 structured in such manner, it is possible to realize an optical image pickup apparatus having a zoom lens with a reduced size and thickness, in which the number of structural components is reduced.
Next, a personal computer which is an example of an information processing apparatus with a built-in image forming system as an objective optical system is shown in FIG. 80 to FIG. 82. FIG. 80 is a frontward perspective view of a personal computer 300 with its cover opened, FIG. 81 is a cross-sectional view of a photographic optical system 303 of the personal computer 300, and FIG. 82 is a side view of FIG. 80. As it is shown in FIG. 80 to FIG. 82, the personal computer 300 has a keyboard 301, an information processing means and a recording means, a monitor 302, and a photographic optical system 303.
Here, the keyboard 301 is for an operator to input information from an outside. The information processing means and the recording means are omitted in the diagram. The monitor 302 is for displaying the information to the operator. The photographic optical system 303 is for photographing an image of the operator or a surrounding. The monitor 302 may be a display such as a liquid-crystal display or a CRT display. As the liquid-crystal display, a transmission liquid-crystal display device which illuminates from a rear surface by a backlight not shown in the diagram, and a reflection liquid-crystal display device which displays by reflecting light from a front surface are available. Moreover, in the diagram, the photographic optical system 303 is built-in at a right side of the monitor 302, but without restricting to this location, the photographic optical system 303 may be anywhere around the monitor 302 and the keyboard 301.
This photographic optical system 303 has an objective optical system 100 which includes the zoom lens in the first embodiment for example, and an electronic image pickup element chip 162 which receives an image. These are built into the personal computer 300.
At a front end of a mirror frame, a cover glass 102 for protecting the objective optical system 100 is disposed.
An object image received at the electronic image pickup element chip 162 is input to a processing means of the personal computer 300 via a terminal 166. Further, the object image is displayed as an electronic image on the monitor 302. In FIG. 40, an image 305 photographed by the user is displayed as an example of the electronic image. Moreover, it is also possible to display the image 305 on a personal computer of a communication counterpart from a remote location via a processing means. For transmitting the image to the remote location, the Internet and telephone are used.
Next, a telephone which is an example of an information processing apparatus in which the image forming optical system of the present invention is built-in as a photographic optical system, particularly a portable telephone which is easy to carry is shown in FIG. 83A, FIG. 83B, and FIG. 83C. FIG. 83A is a front view of a portable telephone 400, FIG. 83B is a side view of the portable telephone 400, and FIG. 83C is a cross-sectional view of a photographic optical system 405. As shown in FIG. 83A to FIG. 83C, the portable telephone 400 includes a microphone section 401, a speaker section 402, an input dial 403, a monitor 404, the photographic optical system 405, an antenna 406, and a processing means.
Here, the microphone section 401 is for inputting a voice of the operator as information. The speaker section 402 is for outputting a voice of the communication counterpart. The input dial 403 is for the operator to input information. The monitor 404 is for displaying a photographic image of the operator himself and the communication counterpart, and information such as a telephone number. The antenna 406 is for carrying out a transmission and a reception of communication electric waves. The processing means (not shown in the diagram) is for carrying out processing of image information, communication information, and input signal etc.
Here, the monitor 404 is a liquid-crystal display device. Moreover, in the diagram, a position of disposing each structural element is not restricted in particular to a position in the diagram. This photographic optical system 405 has an objective optical system 100 which is disposed in a photographic optical path 407 and an image pickup element chip 162 which receives an object image. As the objective optical system 100, the zoom lens in the first embodiment for example, is used. These are built into the portable telephone 400.
At a front end of a mirror frame, a cover glass 102 for protecting the objective optical system 100 is disposed.
An object image received at the electronic image pickup element chip 162 is input to an image processing means which is not shown in the diagram, via a terminal 166. Further, the object image finally displayed as an electronic image on the monitor 404 or a monitor of the communication counterpart, or both. Moreover, a signal processing function is included in the processing means. In a case of transmitting an image to the communication counterpart, according to this function, information of the object image received at the electronic image pickup element chip 162 is converted to a signal which can be transmitted.
As it has been described above, the image forming optical system of the present invention, and the electronic image pickup apparatus in which the image forming optical system is used have the following characteristics.

    (1) It is characterized in that, instead of condition (1a), the following conditional expression is satisfied.

1.48<β<2.04

Here, Nd denotes a refractive index of a glass used in a cemented lens, νd denotes an Abbe's number for the glass used in the cemented lens, and a relation Nd=α×νd+β is satisfied.

    (2) It is characterized in that, instead of condition (1a), the following conditional expression is satisfied.

1.50<β<2.00

Here, Nd denotes a refractive index of the glass used in the cemented lens, νd denotes the Abbe's number for the glass used in the cemented lens, and the relation Nd=α×νd+β is satisfied.

    (3) It is characterized in that, instead of condition (2a), the following conditional expression is satisfied.

1.58<Nd<2.10

Here, Nd denotes the refractive index of the glass used in the cemented lens.

    (4) It is characterized in that, instead of condition (2a), the following conditional expression is satisfied.

1.63<Nd<1.95



Here, Nd denotes the refractive index of the glass used in the cemented lens.

    (5) It is characterized in that, instead of condition (3a), the following conditional expression is satisfied.

5<νd<10

Here, νd denotes the Abbe's number for the glass used in the cemented lens.

    (6) It is characterized in that, instead of condition (3a), the following conditional expression is satisfied.

6<νd<9

Here, νd denotes the Abbe's number for the glass used in the cemented lens.

    (7) It is characterized in that, instead of condition (1b), the following conditional expression is satisfied.

1.48<β<2.04

Here, Nd denotes the refractive index of the glass used in the cemented lens, νd denotes the Abbe's number for the glass used in the cemented lens, and the relation Nd=α×νd+β is satisfied.

    (8) It is characterized in that, instead of condition (1b), the following conditional expression is satisfied.

1.50<β<2.00

Here, Nd denotes the refractive index of the glass used in the cemented lens, νd denotes the Abbe's number for the glass used in the cemented lens, and the relation Nd=α×νd+β is satisfied.

    (9) It is characterized in that, instead of condition (2b), the following conditional expression is satisfied.

1.60<Nd<2.10

Here, Nd denotes the refractive index of the glass used in the cemented lens.

    (10) It is characterized in that, instead of condition (2b), the following conditional expression is satisfied.

1.63<Nd<1.95

Here, Nd denotes the refractive index of the glass used in the cemented lens.

    (11) It is characterized in that, instead of condition (3b), the following conditional expression is satisfied.

5<νd<30

Here, νd denotes the Abbe's number for the glass used in the cemented lens.

    (12) It is characterized in that, instead of condition (3b), the following conditional expression is satisfied.

6<νd<25

Here, νd denotes the Abbe's number for the glass used in the cemented lens.

    (13) It is characterized in that, instead of condition (7), the following conditional expression is satisfied at the time of almost infinite object point focusing.

0.75<y07/(fw·tan ω07w)<0.94

where, y07 is indicated as y07=0.7y10 when, in an effective image pickup surface (surface in which, image pickup is possible), a distance from a center up to a farthest point (maximum image height) is let to be y10. Moreover, ω07w is an angle with respect to an optical axis in a direction of an object point corresponding to an image point connecting from a center on the image pickup surface at a wide angle end up to a position of y07.

    (14) It is characterized in that, instead of condition (7), the following conditional expression is satisfied at the time of almost infinite object point focusing.

0.80<y07/(fw·tan ω07w)<0.92



where, y07 is indicated by y07=0.7y10 when, in an effective image pickup surface (surface in which, image pickup is possible), a distance from a center up to a farthest point (maximum image height) is let to be y10. Moreover, ω07w is an angle with respect to an optical axis in a direction of an object point corresponding to an image point connecting from a center on the image pickup surface in a wide angle end up to a position of y07.
The present invention can have various modified embodiments which fall within the basic teachings herein set forth.
INDUSTRIAL APPLICABILITY
An image forming optical system according to the present invention is useful in an optical system with a reduced size and thickness made thin, and furthermore, an electronic image pickup apparatus of the present invention is useful in an apparatus in which, both a favorable correction and a widening of an angle have been realized.

## Claims

1. An image forming optical system comprising:
a positive lens group;
a negative lens group; and
an aperture stop, wherein
the positive lens group is disposed at an image-plane side of the aperture stop, and
the positive lens group includes a cemented lens which is formed by cementing a plurality of lenses, and in a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=α×νd+β(where, α=−0.017) is set,
Nd and νd of at least one lens forming the cemented lens are included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1b), and a line when an upper limit value is in a range of the following conditional expression (1b), and an area determined by following conditional expressions (2b) and (3b)


1.45<β<2.15  (1b)



1.30<Nd<2.20  (2b)



3<νd<25  (3b)


where, Nd denotes a refractive index, and νd denotes an Abbe's number.

2. The image forming optical system according to claim 1, wherein when the one lens of which, Nd and νd are included in both the areas is let to be a predetermined lens, a center thickness of the predetermined lens along an optical axis of the predetermined lens is less than the center thickness along the optical axis of the other lens.

3. The image forming optical system according to claim 2, wherein the image forming optical system satisfies a following conditional expression


0.22<t1<2.0

where, t1 is the center thickness of the predetermined lens along an optical axis of the predetermined lens.

4. The image forming optical system according to claim 1, wherein the cemented lens is a compound lens which is formed by closely adhering and hardening a resin on a lens surface of the one lens which forms the cemented lens.

5. The image forming optical system according to claim 1, wherein the cemented lens is a compound lens which is formed by closely adhering and hardening a glass on a lens surface of the one lens which forms the cemented lens.

6. The image forming optical system according to claim 1, wherein the image forming optical system is a zoom lens of which, a lens group on the closest side of an object is a positive lens group.

7. The image forming optical system according to claim 1, wherein the image forming optical system is a zoom lens of which, a lens group on the closest side of an object is a negative lens group.

8. The image forming optical system according to claim 1, further comprising:
a prism for folding.

9. The image forming optical system according to claim 8, wherein the prism is in a lens group on the closest side of an object.

10. An image forming optical system comprising:
a positive lens group;
a negative lens group; and
an aperture stop, wherein
the positive lens group is disposed at an image-plane side of the aperture stop, and
the positive lens group includes a cemented lens which is formed by cementing a plurality of lenses, and in a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=α×νd+β (where, α=−0.017) is set,
Nd and νd of at least one lens forming the cemented lens are included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1b), and a line when an upper limit value is in a range of the following conditional expression (1b), and an area determined by following conditional expressions (2b) and (3b)


1.45<β<2.04  (1b)



1.30<Nd<2.20  (2b)



3<νd<40  (3b)


where, Nd denotes a refractive index, and νd denotes an Abbe's number.

11. An image forming optical system comprising:
a positive lens group;
a negative lens group; and
an aperture stop, wherein
the positive lens group is disposed at an image-plane side of the aperture stop, and
the positive lens group includes a cemented lens which is formed by cementing a plurality of lenses, and in a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=α×νd+β(where, α=−0.017) is set,
Nd and νd of at least one lens forming the cemented lens are included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1b), and a line when an upper limit value is in a range of the following conditional expression (1b), and an area determined by following conditional expressions (2b) and (3b)


1.45<β<2.15  (1b)



1.60<Nd<2.20  (2b)



3<νd<40  (3b)


where, Nd denotes a refractive index, and νd denotes an Abbe's number.