JP2013140307A - Zoom lens and imaging apparatus including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact zoom lens having a wide angle of view and high optical performance over the entire zoom range.SOLUTION: The zoom lens comprises, in order from an object side to an image side: a first lens group L1 having positive refractive power; a second lens group L2 having negative refractive power; a third lens group L3 having positive refractive power; a fourth lens group L4 having negative refractive power; and a fifth lens group L5 having positive refractive power. During zooming, the distances between the lens groups are changed. The first lens group L1 comprises one negative lens and one positive lens. The entire optical length LDw of the zoom lens at the wide angle end, the entire optical length LDt of the zoom lens at the telephoto end, the focal length f1 of the first lens group L1, the focal length f2 of the second lens group L2, and the focal length f4 of the fourth lens group L4 are set to satisfy the following conditional expressions: 0.10<(LDt-LDw)/f1<0.31, and 0.70<f2/f4<1.20.

Description

  The present invention relates to a zoom lens and an image pickup apparatus having the same. For example, an image pickup apparatus using a solid-state image pickup device such as a video camera, an electronic still camera, a broadcast camera, a surveillance camera, or a camera using a silver salt film. It is suitable for an imaging device.

  In recent years, imaging devices such as a video camera using a solid-state imaging device, a digital still camera, a broadcasting camera, a surveillance camera, and a camera using a silver salt film have been improved in function, and the entire device has been downsized. A photographing optical system used therefor is required to be a zoom lens having a wide angle of view, a high zoom ratio (high zoom ratio), and a high resolution.

  In general, when a wide angle of view is achieved in many zoom lenses, a large amount of distortion and curvature of field occur, and the effective diameter of the front lens increases. Therefore, there is a demand for a compact zoom lens that corrects these various aberrations and reduces the increase in the effective diameter of the front lens. As a zoom lens that meets these requirements, a positive lead type zoom lens in which a lens group having a positive refractive power is disposed on the object side is known. As a positive lead type zoom lens, there is known a 5-group zoom lens including five lens groups having positive, negative, positive, negative, and positive refractive powers in order from the object side to the image side (Patent Documents 1 and 2). .

  Patent Document 1 discloses that the shooting half angle of view at the wide angle end is about 35 degrees while reducing the effective diameter of the front lens by reducing the distance from the first lens unit to the aperture stop at the wide angle end and shortening the entrance pupil. A zoom lens is disclosed. Patent Document 2 discloses a small zoom lens having a shooting half angle of view of about 38 degrees and a small amount of movement of the first lens unit in the optical axis direction during zooming.

JP 2007-047538 A JP 2008-191291 A

  In the above-described 5-group zoom lens, in order to obtain a good optical performance over the entire zoom range while achieving a wide angle of view and a reduction in the size of the entire lens system, the refractive power of each lens group, the lens configuration of each lens group, etc. It is important to set this appropriately. In particular, in order to satisfactorily correct distortion and field curvature that often occur when widening the angle of view, the refractive power of the first, second, and fourth lens groups (the reciprocal of the focal length) and the fourth lens are used. It is important to appropriately set the lens configuration of the group. If these configurations are not set appropriately, it becomes very difficult to obtain high optical performance over the entire zoom range while reducing the effective diameter of the front lens and widening the angle of view.

  In Patent Document 1, since the first lens unit moves a lot in the optical axis direction during zooming, for example, in the case of a lens barrel using a cam ring, the cam ring has a large diameter to reduce the driving force. The whole becomes bigger. Further, in Patent Document 2, the refractive power of the first lens group is strong, and distortion and field curvature are often generated as the angle of view increases, making it difficult to correct these aberrations satisfactorily. come.

  An object of the present invention is to provide a small zoom lens having a wide angle of view and high optical performance over the entire zoom range, and an image pickup apparatus having the same.

The zoom lens according to the present invention includes, in order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a negative lens having a negative refractive power. The fourth lens group is composed of a fifth lens group having a positive refractive power, and the distance between the lens groups is changed during zooming. The first lens group is composed of one negative lens and one positive lens at the wide-angle end. When the optical total length is LDw, the optical total length at the telephoto end is LDt, the focal length of the first lens group is f1, the focal length of the second lens group is f2, and the focal length of the fourth lens group is f4.
0.10 <(LDt−LDw) / f1 <0.31
0.70 <f2 / f4 <1.20
It satisfies the following conditional expression.

  According to the present invention, a small zoom lens having a wide angle of view and high optical performance over the entire zoom range can be obtained.

2 is a lens cross-sectional view of Numerical Example 1. FIG. (A), (B), (C) are aberration diagrams of Numerical Example 1 at the wide angle end, an intermediate focal length (intermediate zoom position), and a telephoto end. 6 is a lens cross-sectional view of Numerical Example 2. FIG. (A), (B), (C) are aberration diagrams of Numerical Example 2 at the wide angle end, an intermediate focal length (intermediate zoom position), and a telephoto end. 10 is a lens cross-sectional view of Numerical Example 3. FIG. (A), (B), (C) are aberration diagrams of Numerical Example 3 at the wide-angle end, the intermediate focal length (intermediate zoom position), and the telephoto end. 6 is a lens cross-sectional view of Numerical Example 4. FIG. (A), (B), (C) are aberration diagrams of Numerical Example 4 at the wide-angle end, the intermediate focal length (intermediate zoom position), and the telephoto end. FIG. 10 is a lens cross-sectional view of the zoom lens of Numerical Example 4 when the first lens unit is set as a reference position when zooming. It is explanatory drawing of embodiment when the zoom lens of this invention is applied to a still camera.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The zoom lens according to the present invention includes, in order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a negative lens having a negative refractive power. It is composed of a fourth lens group and a fifth lens group having a positive refractive power. During zooming, the distance between the lens groups changes.

  Specifically, the distance between the first lens group and the second lens group increases at the telephoto end with respect to the wide-angle end, the distance between the second lens group and the third lens group decreases, and the third lens group and the fourth lens. Group spacing increases. Further, at least the first to fourth lens groups move so that the distance between the fourth lens group and the fifth lens group increases.

  FIG. 1 is a lens cross-sectional view at the wide-angle end (short focal length end) of the zoom lens according to the first exemplary embodiment of the present invention. FIGS. 2A, 2B, and 2C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end (long focal length end), respectively, of the zoom lens according to the first exemplary embodiment. Example 1 is a zoom lens having a zoom ratio of 4.86 and an aperture ratio of about 2.06 to 3.60.

  FIG. 3 is a lens cross-sectional view at the wide-angle end of the zoom lens according to the second embodiment of the present invention. 4A, 4B, and 4C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, of the zoom lens according to the second embodiment. The second embodiment is a zoom lens having a zoom ratio of 9.75 and an aperture ratio of about 2.47 to 4.64.

  FIG. 5 is a lens cross-sectional view at the wide-angle end of the zoom lens according to Embodiment 3 of the present invention. FIGS. 6A, 6B, and 6C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, of the zoom lens according to the third exemplary embodiment. The third embodiment is a zoom lens having a zoom ratio of 9.75 and an aperture ratio of about 2.47 to 4.94.

  FIG. 7 is a lens cross-sectional view at the wide-angle end of the zoom lens according to the fourth exemplary embodiment of the present invention. 8A, 8B, and 8C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, of the zoom lens according to the fourth exemplary embodiment. Example 4 is a zoom lens having a zoom ratio of 9.45 and an aperture ratio of about 2.88 to 5.23.

  FIG. 9 is a lens cross-sectional view when the first lens unit is set as a reference position during zooming in Embodiment 4 of the present invention.

  FIG. 10 is a schematic view of the main part of the imaging apparatus of the present invention. The zoom lens of the present invention is used in an imaging apparatus such as a digital camera, a video camera, and a silver salt film camera, and an optical apparatus such as a telescope, a binocular observation apparatus, a copying machine, and a projector. In the lens cross-sectional view, the left is the front (object side, enlargement side) and the right is the rear (image side, reduction side). In the lens cross-sectional view, i indicates the order of the lens groups from the object side to the image side, and Li is the i-th lens group.

  Next, features of the zoom lens of each embodiment will be described. In the lens cross-sectional views of each example, L1 is a first lens unit having a positive refractive power (optical power = reciprocal of focal length), L2 is a second lens unit having a negative refractive power, and L3 is a positive refractive power. The third lens group, L4 is a fourth lens group having a negative refractive power, and L5 is a fifth lens group having a positive refractive power. SP is an aperture stop, and P is an optical block corresponding to an optical filter, a face plate, a crystal low-pass filter, an infrared cut filter, or the like.

  Reference numeral I denotes an image plane. When used as a photographing optical system for a video camera or a digital still camera, an imaging plane of a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor is placed. Further, when used as a photographing optical system for a silver salt film camera, a photosensitive surface corresponding to the film surface is provided.

  In the aberration diagrams, the solid line d of spherical aberration is the d line, the dash-dot line g is the g line, the astigmatism broken line ΔM is the meridional image plane, the solid line ΔS is the sagittal image plane, and the chromatic aberration of magnification is the g line. Is represented by. Fno is the F number, and ω is the shooting half angle of view (degrees). In each of the following embodiments, the wide-angle end and the telephoto end refer to zoom positions when the zoom lens group is positioned at both ends of a range in which the zoom lens unit can move on the optical axis. The arrows indicate the movement trajectories of the lens units and the aperture stop SP during zooming from the wide-angle end to the telephoto end.

  In Embodiments 1 to 3 of FIGS. 1, 3, and 5, during zooming from the wide-angle end to the telephoto end, the first lens unit L1 moves along a locus convex toward the image side. The second lens unit L2 moves to the image side. The third lens unit L3 moves to the object side. The fourth lens unit L4 moves to the object side. At this time, the third lens unit L3 and the fourth lens unit L4 move along different paths. The fifth lens unit L5 is stationary. The aperture stop SP moves nonlinearly. Focusing from an infinitely distant object to a close object is performed by moving the fourth lens unit L4 to the image side or the fifth lens unit L5 to the object side.

  In Example 4 of FIG. 7, during zooming from the wide-angle end to the telephoto end, the first lens unit L1 moves along a locus convex toward the image side. The second lens unit L2 moves to the image side. The third lens unit L3 moves along a locus convex toward the object side integrally with the aperture stop SP. The fourth lens unit L4 moves along a locus convex toward the object side. The fifth lens unit L5 moves along a locus convex toward the object side. Focusing from an infinitely distant object to a close object is performed by moving the fourth lens unit L4 to the image side or the fifth lens unit L5 to the object side.

  9A, 9B, and 9C show that the first lens unit L1 does not move during zooming in Example 4, the second lens unit L2 to the fifth lens unit L5, and the image plane (solid-state imaging device). FIG. 6 is a lens cross-sectional view at a wide angle end, an intermediate zoom position, and a telephoto end when moved. The mechanism for moving the first lens unit L1 and moving the other lens unit and the image plane (solid-state imaging device) during zooming can be similarly applied to the other embodiments.

  In each embodiment, an increase in the effective diameter of the front lens is suppressed by reducing the number of lenses in each lens unit on the object side of the aperture stop SP. At the same time, instead of reducing the number of lenses in each lens group on the object side from the aperture stop SP, aberration correction is performed on the lens group on the image side from the aperture stop SP. Furthermore, the amount of change in the total optical length (distance from the first lens surface to the final lens surface) during zooming is reduced to reduce the size of the lens barrel mechanism.

  In each embodiment, first, in order to efficiently perform zooming by changing the distance between the lens groups, the first lens unit L1 having a positive refractive power and the second lens having a negative refractive power in order from the object side to the image side. A group L2 and a third lens unit L3 having a positive refractive power are arranged.

  Next, by arranging the fourth lens unit L4 having a negative refractive power and the fifth lens unit L5 having a positive refractive power on the image side of the third lens unit L3, various aberrations, in particular, field curvature and distortion aberration are provided. Is corrected well. In the zoom lens of each embodiment, a zooming effect is obtained by changing the interval between a plurality of lens groups to achieve a high zoom ratio. First, the zooming effect is obtained by increasing (expanding) the distance between the first lens unit L1 and the second lens unit L2 at the telephoto end as compared with the wide-angle end. Further, a zooming effect is obtained by reducing (narrowing) the distance between the second lens unit L2 and the third lens unit L3 at the telephoto end as compared with the wide-angle end.

  Further, in the zoom lens of each embodiment, the distance between the third lens unit L3 and the fourth lens unit L4 is increased at the telephoto end compared to the wide angle end. Further, the distance between the fourth lens unit L4 and the fifth lens unit L5 is increased at the telephoto end compared to the wide angle end.

In each embodiment, the first lens unit L1 includes one negative lens and one positive lens. Accordingly, the entrance pupil is shortened by reducing the thickness of the first lens unit L1, and the effective diameter of the front lens is reduced. The optical total length at the wide angle end is LDw, the optical total length at the telephoto end is LDt, the focal length of the first lens unit L1 is f1, the focal length of the second lens unit L2 is f2, and the focal length of the fourth lens unit L4 is f4. . At this time,
0.10 <(LDt−LDw) / f1 <0.31 (1)
0.70 <f2 / f4 <1.20 (2)
The following conditional expression is satisfied.

  Conditional expression (1) is an expression that defines the amount of change in the total optical length during zooming. If the amount of change in the optical total length increases beyond the upper limit value of conditional expression (1), the lens barrel mechanism increases in size. For example, in order to move the lens group with a low driving force, the diameter of the cam ring increases. On the other hand, if the lower limit is exceeded, the total optical length is shortened at the telephoto end, and the refractive power of the second lens group must be increased in order to maintain the desired zoom ratio. As a result, the field curvature increases, It becomes difficult to correct this.

  Conditional expression (2) defines the ratio between the focal length of the second lens unit L2 and the focal length of the fourth lens unit L4. First, in order to shorten the entrance pupil position and reduce the effective diameter of the front lens, it is preferable to reduce the number of lenses of the second lens unit L2 and make it thinner. Therefore, in each embodiment, the distortion and field curvature are corrected not only by the second lens unit L2 but also by the fourth lens unit L4, thereby preventing an increase in the number of lenses of the second lens unit L2. When the upper limit of conditional expression (2) is exceeded and the refractive power of the second lens unit L2 becomes weak, the amount of movement in the optical axis direction for zooming increases.

  On the other hand, when the refractive power of the second lens unit L2 is increased beyond the lower limit, distortion and field curvature increase, making it difficult to correct these. More preferably, the numerical ranges of conditional expressions (1) and (2) are set as follows.

0.12 <(LDt−LDw) / f1 <0.31 (1a)
0.72 <f2 / f4 <1.13 (2a)
As described above, a zoom lens capable of satisfactorily correcting distortion and field curvature when the lens barrel diameter is reduced and the angle of view is increased is obtained. In each embodiment, it is more preferable that the following configuration is satisfied.

  The fourth lens unit L4 includes a negative lens including an aspherical surface. The radius of curvature of the object side lens surface of the negative lens is R4o, and the radius of curvature of the image side lens surface is R4i. Let fw be the focal length of the entire system at the wide-angle end. Let the focal length of the positive lens in the first lens group be f1p. At this time, it is preferable to satisfy one or more of the following conditional expressions.

−2.0 <(R4i + R4o) / (R4i−R4o) <− 0.3 (3)
10.5 <f1 / fw <15.0 (4)
0.35 <f1p / f1 <0.60 (5)
Next, the technical meaning of each conditional expression described above will be described.

  The fourth lens unit L4 has negative refractive power, and the object side and image side lens units are third and fifth lens units having positive refractive power. Both on the side and on the image side. Therefore, a lot of coma aberration occurs particularly at an intermediate focal length (intermediate zoom position), and it is preferable to use an aspherical surface in order to correct this well.

  Conditional expression (3) defines the lens shape (paraxial shape) of the aspheric negative lens having the aspheric shape in the fourth lens unit L4. When the upper limit of conditional expression (3) is exceeded and the refractive power of the object side surface of the aspherical negative lens increases, the rear principal point of the fourth lens unit L4 moves to the object side, and the fifth lens unit L5 Effective diameter increases.

  In addition, when a positive lens for achromatism is cemented on the object side of the aspherical negative lens, if the refractive power of the object side surface of the aspherical negative lens becomes strong, the lens thickness of the positive lens increases and the lens barrel is retracted. The total lens length will be longer. Conversely, when the lower limit is exceeded and the refractive power of the image-side surface of the aspherical negative lens becomes strong, a lot of coma occurs particularly at the intermediate focal length, and it is difficult to correct this well.

  Conditional expression (4) defines the ratio of the focal length of the first lens unit L1 to the focal length of the entire system at the wide angle end. If the upper limit of conditional expression (4) is exceeded and the refractive power of the first lens unit L1 becomes weak, the amount of movement in the optical axis direction for zooming increases. Conversely, if the lower limit is exceeded and the refractive power of the first lens unit L1 increases, the variation in lateral chromatic aberration increases at the wide-angle end and the telephoto end, making it difficult to correct this well.

  Conditional expression (5) defines the ratio of the focal length of the positive lens included in the first lens unit L1 to the focal length of the first lens unit L1. When the upper limit of conditional expression (5) is exceeded and the refractive power of the positive lens becomes weaker, the refractive power of the negative lens in the first lens unit L1 also becomes weaker accordingly, and the chromatic aberration of magnification varies at the wide-angle end and the telephoto end. It becomes more difficult to correct this well.

  Conversely, when the refractive power of the positive lens of the first lens unit L1 increases beyond the lower limit value, the lens thickness of the positive lens increases. For this reason, the weight increases, the entrance pupil position becomes longer, and the effective diameter of the front lens becomes larger. More preferably, it is desirable to specify the numerical ranges of conditional expressions (3), (4), and (5) as follows.

−1.8 <(R4i + R4o) / (R4i−R4o) <− 0.4 (3a)
11.2 <f1 / fw <14.4 (4a)
0.44 <f1p / f1 <0.52 (5a)
With the above configuration, the effective diameter of the front lens is reduced without increasing the amount of movement of the first lens unit L1 in the optical axis direction during zooming, various aberrations are corrected well, and the lens barrel diameter is also reduced. It is easy to obtain a zoom lens with a high zoom ratio and a wide angle of view.

  Next, an embodiment of a still camera using the zoom lens of the present invention as a photographing optical system will be described with reference to FIG. In FIG. 10, 10 is a still camera body, 11 is a photographing optical system constituted by the zoom lens of the present invention, and 12 is an image pickup device (solid-state image pickup device) for receiving an image formed by the zoom lens.

  Thus, by applying the zoom lens of the present invention to an imaging apparatus such as a still camera, an imaging apparatus having high optical performance can be realized. If an electronic image sensor such as a CCD is used as the solid-state image sensor, various aberrations such as distortion and chromatic aberration can be corrected electronically, and the output image can be easily improved in image quality. The zoom lens of the present invention can also be applied to a mirrorless single-lens reflex camera without a quick return mirror.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

  Next, numerical examples of the respective embodiments of the present invention will be shown. In each numerical example, i indicates the order of the surfaces from the object side. In the numerical examples, ri is the radius of curvature of the i-th lens surface in order from the object side. di is the i-th lens thickness and air spacing in order from the object side. ndi and νdi are respectively the refractive index and Abbe number for the d-line of the glass of the i-th material in order from the object side. The aspherical shape is the X axis in the optical axis direction, the H axis in the direction perpendicular to the optical axis, the light traveling direction is positive, R is the paraxial radius of curvature, K is the conic constant, A4, A6, A8, A10, A12 Aspheric coefficient

It is expressed by the following formula. [E + X] means [× 10 + x], and [eX] means [× 10 ^−x ].

  BF is the air-converted distance (back focus) from the final lens surface to the paraxial image plane. The total lens length is obtained by adding BF to the distance from the lens front surface to the lens final surface. An aspherical surface is indicated by adding * after the surface number. Table 1 shows the relationship between the above-described conditional expressions and numerical examples.

[Numerical Example 1]
Unit mm

Surface data surface number rd nd νd
1 40.493 1.20 1.80000 29.8
2 23.970 3.83 1.71300 53.9
3 257.458 (variable)
4 33.412 0.90 1.88300 40.8
5 8.388 5.00
6 -29.583 0.90 1.80 400 46.6
7 23.914 0.49
8 18.501 2.13 1.92286 18.9
9 177.794 (variable)
10 (Aperture) ∞ (Variable)
11 * 13.810 2.58 1.76802 49.2
12 * -118.119 1.11
13 11.867 2.70 1.59282 68.6
14 -30.515 0.29
15 66.678 0.90 2.00069 25.5
16 7.801 0.53
17 13.118 2.17 1.51823 58.9
18 -20.350 (variable)
19 134.738 0.90 1.58313 59.4
20 * 7.126 (variable)
21 63.675 2.24 1.85 135 40.1
22 * -18.192 3.58
23 ∞ 1.10 1.51633 64.1
24 ∞
Image plane ∞

Aspheric data 11th surface
K = -2.99830e-001 A 4 = -5.03231e-005 A 6 = -8.63739e-008
A 8 = -1.32651e-008 A10 = 5.94352e-011

12th page
K = 1.19287e + 002 A 4 = 1.00585e-004 A 6 = 1.58433e-007
A 8 = -1.50149e-008 A10 = 1.93437e-010

20th page
K = 2.83989e-001 A 4 = 1.77690e-004 A 6 = 2.12750e-006
A 8 = -3.41549e-007 A10 = 2.91120e-009

22nd page
K = 6.21632e + 000 A 4 = 4.88902e-005 A 6 = 5.83675e-007
A 8 = 5.33089e-009 A10 = 1.18864e-009

Various data Zoom ratio 4.86
Wide angle Medium Telephoto focal length 6.22 17.59 30.25
F number 2.06 3.20 3.60
Angle of view 36.75 14.80 8.74
Image height 4.65 4.65 4.65
Total lens length 66.30 67.88 75.85
BF 5.31 5.31 5.31

d 3 0.34 13.70 23.77
d 9 17.43 6.43 1.67
d10 8.90 2.27 2.15
d18 2.03 5.54 8.10
d20 4.40 6.76 6.97

Zoom lens group data group Start surface Focal length
1 1 73.85
2 4 -10.42
3 10 ∞
4 11 11.71
5 19 -12.94
6 21 16.83
7 23 ∞

[Numerical Example 2]
Unit mm

Surface data surface number rd nd νd
1 40.066 1.20 1.90366 31.3
2 23.509 4.53 1.71300 53.9
3 744.323 (variable)
4 61.726 0.90 1.88300 40.8
5 9.649 5.31
6 -31.049 0.90 1.69680 55.5
7 32.766 0.09
8 19.600 2.13 1.92286 18.9
9 82.668 (variable)
10 (Aperture) ∞ (Variable)
11 * 10.517 2.71 1.75501 51.2
12 * -62.782 2.00
13 30.426 0.90 1.84666 23.9
14 8.356 0.26
15 10.969 2.32 1.49700 81.5
16 -17.200 (variable)
17 67.802 1.03 1.84666 23.9
18 -20.590 0.90 1.83441 37.3
19 * 7.689 (variable)
20 38.797 2.69 1.76802 49.2
21 * -16.181 3.34
22 ∞ 1.10 1.51633 64.1
23 ∞
Image plane ∞

Aspheric data 11th surface
K = -9.13254e-001 A 4 = 3.28751e-005 A 6 = 3.81751e-007
A 8 = -1.31646e-009

12th page
K = -3.69985e + 001 A 4 = 9.67476e-005 A 6 = -3.13787e-007

19th page
K = 6.33550e-002 A 4 = 1.16664e-004 A 6 = 2.33683e-006
A 8 = -5.91286e-007 A10 = 5.92312e-008 A12 = -2.08174e-009

21st page
K = 3.03390e + 000 A 4 = 1.30432e-004 A 6 = -4.15618e-007
A 8 = 3.10928e-008

Various data Zoom ratio 9.75
Wide angle Medium Telephoto focal length 6.22 31.75 60.71
F number 2.47 4.26 4.64
Angle of view 36.75 8.33 4.38
Image height 4.65 4.65 4.65
Total lens length 77.94 83.06 93.14
BF 5.07 5.07 5.07

d 3 0.33 23.65 36.77
d 9 28.09 5.98 1.72
d10 8.35 2.26 1.76
d16 2.97 6.95 7.95
d19 5.27 11.29 12.01

Zoom lens group data group Start surface Focal length
1 1 73.25
2 4 -11.49
3 10 ∞
4 11 12.37
5 17 -10.64
6 20 15.19
7 22 ∞

[Numerical Example 3]

Unit mm

Surface data surface number rd nd νd
1 36.806 1.20 2.00069 25.5
2 23.555 4.53 1.74400 44.8
3 265.388 (variable)
4 46.190 0.90 1.88300 40.8
5 8.663 5.15
6 * -28.621 0.90 1.77377 47.2
7 18.367 0.70
8 18.108 2.18 1.92286 18.9
9 195.341 (variable)
10 (Aperture) ∞ (Variable)
11 * 10.337 2.45 1.72903 54.0
12 * -46.630 2.25
13 30.255 0.90 1.84666 23.9
14 8.056 0.18
15 9.991 2.27 1.49700 81.5
16 -16.682 (variable)
17 37.143 1.09 1.84666 23.9
18 -21.209 0.90 1.83441 37.3
19 * 7.667 (variable)
20 54.866 2.86 1.72903 54.0
21 * -12.831 3.21
22 ∞ 1.10 1.51633 64.1
23 ∞
Image plane ∞

Aspheric data 6th surface
K = -3.57187e + 000 A 4 = 1.59999e-006 A 6 = 8.04718e-008
A 8 = -1.56727e-009

11th page
K = -1.03192e + 000 A 4 = 3.68039e-005 A 6 = 6.21886e-007
A 8 = -3.26861e-009

12th page
K = -4.53558e + 000 A 4 = 1.18443e-004 A 6 = -2.66897e-007

19th page
K = -8.59779e-001 A 4 = 4.34148e-004 A 6 = 2.56536e-006
A 8 = 5.65556e-008

21st page
K = 1.30898e + 000 A 4 = 1.80996e-004 A 6 = -8.31667e-007
A 8 = 3.05369e-008

Various data Zoom ratio 9.75
Wide angle Medium Telephoto focal length 5.31 27.08 51.77
F number 2.47 4.35 4.94
Angle of View 41.20 9.74 5.13
Image height 4.65 4.65 4.65
Total lens length 71.60 82.93 93.14
BF 4.94 4.94 4.94

d 3 0.33 23.82 35.39
d 9 21.80 5.27 1.65
d10 8.43 2.21 1.71
d16 2.39 7.00 9.12
d19 5.25 11.23 11.87

Zoom lens group data group Start surface Focal length
1 1 72.30
2 4 -9.20
3 10 ∞
4 11 11.90
5 17 -12.08
6 20 14.52
7 22 ∞

[Numerical Example 4]
Unit mm

Surface data surface number rd nd νd
1 41.272 1.20 1.90366 31.3
2 25.799 4.73 1.60311 60.6
3 -465.856 (variable)
4 * -47.397 1.00 1.72903 54.0
5 * 8.516 3.31
6 13.283 1.86 1.94595 18.0
7 18.476 (variable)
8 (Aperture) ∞ 1.57
9 * 7.376 2.51 1.76802 49.2
10 39.959 0.98 1.69895 30.1
11 6.313 0.64
12 * 9.801 2.42 1.55332 71.7
13 -24.227 (variable)
14 38.297 0.90 1.85 135 40.1
15 * 10.235 (variable)
16 30.604 2.57 1.60311 60.6
17 -15.830 (variable)
18 ∞ 1.10 1.51633 64.1
19 ∞
Image plane ∞

Aspheric data 4th surface
K = 1.00148e + 001 A 4 = 7.06614e-005 A 6 = -2.59450e-007
A 8 = 9.07909e-010

5th page
K = -8.10262e-001 A 4 = 8.53208e-005 A 6 = 7.20510e-007
A 8 = -1.98421e-009

9th page
K = -2.40813e-001 A 4 = 1.18874e-005

12th page
K = -1.00748e + 000 A 4 = -9.28947e-005

15th page
K = -4.74090e-001 A 4 = 2.32792e-004 A 6 = 6.71061e-007
A 8 = -4.45210e-008

Various data Zoom ratio 9.45
Wide angle Medium telephoto focal length 6.27 31.96 59.23
F number 2.88 4.54 5.23
Angle of view 36.57 8.27 4.49
Image height 4.65 4.65 4.65
Total lens length 72.20 84.05 97.40
BF 6.42 6.62 3.34

d 3 1.31 29.17 44.67
d 7 32.96 5.63 3.42
d13 4.75 9.65 10.10
d15 3.07 9.28 12.19
d17 4.69 4.90 1.61

Zoom lens group data group Start surface Focal length
1 1 85.89
2 4 -13.31
3 8 13.35
4 14 -16.65
5 16 17.67
6 18 ∞

L1 1st lens group L2 2nd lens group L3 3rd lens group L4 4th lens group L5 5th lens group SP Aperture P Filters I Image surface

Claims (7)

In order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a negative refractive power, and a positive lens It consists of a fifth lens group with refractive power, and the distance between each lens group changes during zooming. The first lens group consists of one negative lens and one positive lens, and the optical total length at the wide angle end is LDw, and the telephoto end. When the optical total length is LDt, the focal length of the first lens group is f1, the focal length of the second lens group is f2, and the focal length of the fourth lens group is f4.
0.10 <(LDt−LDw) / f1 <0.31
0.70 <f2 / f4 <1.20
A zoom lens satisfying the following conditional expression: When the fourth lens group includes a negative lens including an aspheric surface, the radius of curvature of the object-side lens surface of the negative lens is R4o, and the radius of curvature of the image-side lens surface is R4i.
−2.0 <(R4i + R4o) / (R4i−R4o) <− 0.3
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the focal length of the entire system at the wide angle end is fw,
10.5 <f1 / fw <15.0
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the focal length of the positive lens included in the first lens group is f1p,
0.35 <f1p / f1 <0.60
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.   During zooming from the wide-angle end to the telephoto end, the first lens group moves along a convex locus toward the image side, the second lens group moves toward the image side, and the third lens group and the fourth lens group The zoom lens according to claim 1, wherein the zoom lens moves toward the object side.   The zoom lens according to claim 5, wherein the zoom lens moves from a wide-angle end to a telephoto end, and the fifth lens group moves along a locus convex toward the object side.   An image pickup apparatus comprising: the zoom lens according to claim 1; and an image pickup element that receives an image formed by the zoom lens.