JP2014149483A - Zoom lens and imaging device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom lens which has a wide angle of view, facilitates high speed focusing, and has small aberration fluctuation at the time of focusing.SOLUTION: The zoom lens comprises, in order from the object side to the image side, first to fourth lens groups having negative, positive, negative, and positive refractive power, respectively. Four or more lens groups move so that the distances between the adjacent lens groups change. First and second focus groups positioned on the image side of an aperture stop move along loci different from each other. The second focus group is arranged on the object side of the first focus group. The maximum amounts of movement of the first and second focus groups are represented by Df1, Df2, respectively; the maximum distance from the aperture stop to the lens surface closest to the object side in the second focus group is represented by Dmax; the minimum distance from the aperture stop to the lens surface closest to the object side in the second focus group is represented by Dmin; the focal distance of the entire system at the wide angle end is represented by Fw; the focal distance of the second focus group is represented by Ff2; and these values are set appropriately.

Description

  The present invention relates to a zoom lens and is suitable for an imaging apparatus such as a digital camera, a video camera, a TV camera, a surveillance camera, and a silver salt film camera.

  An imaging optical system used in an imaging apparatus (camera) such as a video camera or a digital still camera is required to be a zoom lens having a wide angle of view and high optical performance over the entire zoom range. An imaging apparatus having an automatic focus detection device is required to be a zoom lens that can perform focusing at high speed.

  2. Description of the Related Art Conventionally, a negative lead type zoom lens in which a lens group having a negative refractive power is positioned on the object side is known as a zoom lens that can easily widen the angle of view. In order to perform focusing at high speed, there is known a zoom lens using an inner focus method in which focusing is performed with a lens group that is smaller and lighter on the image side than the lens group on the most object side. A wide-angle zoom lens using a negative lead type and an inner focus method is known (Patent Document 1).

  In addition, a zoom lens is known that reduces aberration fluctuations during focusing by using a floating method in which two lens groups are moved along different trajectories during focusing (Patent Document 2).

  In Patent Document 1, a so-called rear lens is composed of first to sixth lens units having negative, positive, negative, positive, negative, and positive refractive powers in order from the object side to the image side, and focusing is performed by the fifth lens unit. A focus zoom lens is disclosed. In Patent Document 2, the first to sixth lens groups having negative, positive, negative, positive, negative, and positive refractive powers are sequentially arranged from the object side to the image side, and the six groups perform zooming by changing the distance between the lens groups. A zoom lens is disclosed. A zoom lens is disclosed in which two lens groups are moved during focusing to perform floating.

JP 2004-198529 A JP 2009-169051 A

  A negative lead type zoom lens preceded by a lens unit having a negative refractive power is characterized in that a wide angle of view is relatively easy. Further, when the floating method is used for focusing, there is a feature that aberration variation is reduced during focusing, and it becomes easy to obtain high optical performance over the entire object distance.

  However, it is important to set the lens configuration appropriately in order to achieve high optical performance over the entire object distance while using the floating method and achieving high-speed focusing while widening the angle of view in a negative lead type zoom lens. It becomes. In particular, it is important to appropriately set the refractive power (the reciprocal of the focal length) of the two focus lens groups moved in a floating manner, the lens configuration of each lens group, and the like. If the refractive power and the amount of movement of the two focus lens groups moved in a floating state are not set appropriately, it becomes difficult to obtain high optical performance at the time of focusing at a wide angle of view.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a zoom lens that has a wide angle of view, facilitates high-speed focusing, and has little aberration fluctuation during focusing.

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 negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a positive lens having a positive refractive power. The fourth lens group has four or more lens groups so that the distance between adjacent lens groups changes during zooming, and the first focus group and the second focus group located on the image side of the aperture stop during focusing. A zoom lens in which focus groups move along different paths, wherein the second focus group is disposed on the object side of the first focus group, and the first focus group and the second focus group in focusing The maximum movement amount of the focus group is Df1 and Df2, respectively, and the maximum distance from the aperture stop to the lens surface closest to the object of the second focus group is Dmax, The minimum distance from the aperture stop to the most object side lens surface of the second focus group is Dmin, the focal length of the entire system at the wide angle end is Fw, and the focal length of the second focus group is Ff2. When
Df2 <Df1
1.5 <Dmax / Dmin <30.0
0.01 <Fw / Ff2 <0.14
It satisfies the following conditional expression.

  According to the present invention, it is possible to obtain a zoom lens that has a wide angle of view, can be easily focused at high speed, and has little aberration fluctuation during focusing.

(A), (B), (C) Lens cross-sectional views at the wide-angle end (short focal length end), the intermediate focal length, and the telephoto end (long focal length end) of Numerical Embodiment 1 of the present invention. (A), (B), (C) Aberration diagrams at the wide-angle end, the intermediate focal length, and the telephoto end of an object at infinity according to Numerical Example 1 of the present invention. (A), (B), (C) Aberration diagrams at the wide-angle end, the intermediate focal length, and the telephoto end of a close-range object according to Numerical Example 1 of the present invention. (A), (B), (C) Lens cross-sectional views at the wide-angle end, intermediate focal length, and telephoto end according to Numerical Example 2 of the present invention. (A), (B), (C) Aberration diagrams at the wide-angle end, the intermediate focal length, and the telephoto end of an object at infinity according to Numerical Example 2 of the present invention. (A), (B), (C) Aberration diagrams at the wide-angle end, the intermediate focal length, and the telephoto end for a close-range object according to Numerical Example 2 of the present invention. (A), (B), (C) Lens cross-sectional views at the wide-angle end, intermediate focal length, and telephoto end according to Numerical Example 3 of the present invention (A), (B), (C) Aberration diagrams at the wide-angle end, intermediate focal length, and telephoto end of an infinitely distant object according to Numerical Example 3 of the present invention. (A), (B), (C) Aberration diagrams at the wide-angle end, intermediate focal length, and telephoto end of a close-range object according to Numerical Example 3 of the present invention. Schematic diagram of main parts of an imaging apparatus of the present invention

  Embodiments of a zoom lens and an image pickup apparatus having the same according to the present invention will be described below 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 negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a positive lens having a positive refractive power. A fourth lens group is included. During zooming, four or more lens groups move, and during focusing, the first focus group and the second focus group located on the image side of the aperture stop move along different paths.

  Here, the second focus group is located closer to the object side than the first focus group. The first focus group has a negative refractive power, and the second focus group has a positive refractive power.

  FIGS. 1A, 1B, and 1C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end of the zoom lens according to Embodiment 1 of the present invention, respectively. FIGS. 2A, 2B, and 2C are aberration diagrams when the zoom lens of Example 1 of the present invention is focused on an object at infinity at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively. FIGS. 3A, 3B, and 3C are aberration diagrams when the zoom lens of Example 1 of the present invention is focused on a close object 0.38m at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively. is there.

  4A, 4B, and 4C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, of the zoom lens according to the second exemplary embodiment of the present invention. FIGS. 5A, 5B, and 5C are aberration diagrams when the zoom lens of Example 2 of the present invention is focused on an object at infinity at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively. FIGS. 6A, 6B, and 6C are aberration diagrams when the zoom lens of Example 2 of the present invention is focused on an object at a close distance of 0.5 m at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively. is there.

  FIGS. 7A, 7B, and 7C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end of the zoom lens according to Embodiment 3 of the present invention, respectively. 8A, 8B, and 8C are aberration diagrams when the zoom lens of Example 3 of the present invention is focused on an object at infinity at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively. FIGS. 9A, 9B, and 9C are aberration diagrams when the zoom lens according to Embodiment 3 of the present invention is focused on a close object 0.5 m at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively. is there.

  FIG. 10 is a schematic diagram of a main part of a single-lens reflex camera (imaging device) including the zoom lens of the present invention.

  The zoom lens of each embodiment is a photographing lens system (optical system) used in an imaging apparatus such as a video camera, a digital video camera, or a silver salt film camera. In the lens cross-sectional view, the left side is the object side (front), and the right side is the image side (rear). In the lens cross-sectional view, i indicates the order of the lens groups from the object side, and Li is the i-th lens group. SP is an aperture stop. SP2 is an F number aperture (Fno aperture). The F number stop SP2 has a constant aperture diameter or changes the aperture diameter during zooming to adjust the F number value at each zoom position.

  IP is an image plane, and when used as a photographing optical system for a video camera or a digital still camera, on the imaging surface of a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor, Corresponds to the film surface. The arrows indicate the movement trajectory of each lens unit during zooming from the wide-angle end to the telephoto end.

  The spherical aberration diagram shows the d-line. In the astigmatism diagram, M and S are a meridional image surface and a sagittal image surface at the d-line. Fno is an F number, and ω is a 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 unit is positioned at both ends of a range in which the zoom lens group can move on the optical axis.

  The zoom lens according to each exemplary embodiment sequentially (continuously) from the object side to the image side, the first lens unit L1 having a negative refractive power, the second lens unit L2 having a positive refractive power, and the third lens unit having a negative refractive power. The lens unit L3 includes a fourth lens unit L4 having a positive refractive power. Four or more lens groups move during zooming. The aperture stop SP is located on the image side of the third lens unit L3, and moves together with the third lens unit L3 during zooming from the wide-angle end to the telephoto end. The third lens unit L3 has an open Fno stop SP2 that moves integrally during zooming.

  Each embodiment has a first focus group (first focus lens group) LF1 and a second focus group (second focus lens group) LF2 that move along different paths during focusing from the aperture stop SP to the image side. . Let Df1 and Df2 be the maximum movement amounts of the first focus group LF1 and the second focus group LF2 in focusing from an infinitely distant object to a very close object, respectively.

Let Dmax be the maximum distance from the aperture stop SP in focusing to the lens surface on the object side of the most object side lens in the second focus group LF2. Let Dmin be the minimum distance from the aperture stop SP during focusing to the lens surface on the object side of the lens on the most object side in the second focus group LF2. The focal length of the entire system at the wide angle end is Fw, and the focal length of the second focus group LF2 is Ff2. At this time,
Df2 <Df1 (1)
1.5 <Dmax / Dmin <30.0 (2)
0.01 <Fw / Ff2 <0.14 (3)
The following conditional expression is satisfied.

  In general, with respect to aberrations of an optical system, it is known that the higher the height of off-axis rays from the optical axis, the higher the contribution to off-axis aberrations such as field curvature. Further, in order to perform quick focusing with little aberration fluctuation during focusing, it is desirable to use a so-called floating that moves a plurality of lens groups behind an aperture stop that reduces the weight of the focus lens group.

  The present inventor suppresses fluctuations in various aberrations such as curvature of field by using a focus lens group having negative refractive power when performing floating using a plurality of lens groups on the image side of the aperture stop, It has been found that aberration fluctuation due to focus can be reduced.

  Each embodiment uses two lens groups that move independently (with different trajectories) during focusing. The two lens groups are a second focus group LF2 having a positive refractive power and a first focus group LF1 having a negative refractive power in order from the aperture stop toward the image side. Here, the first focus group LF1 has a larger movement amount in focusing. The maximum movement amounts Df1 and Df2 of the first focus group LF1 and the second focus group LF2 at the time of focusing are set as in the conditional expression (1) to reduce the variation in field curvature at the time of focusing.

  Conditional expression (2) relates to the position of the second focus group LF2 in the optical axis direction and is for improving the field curvature mainly at the wide angle end. As the upper limit of conditional expression (2) is exceeded, the entire system becomes larger when the second focus group LF2 and the aperture stop SP are separated at the wide-angle end. If the second focus group LF2 and the aperture stop SP become closer at the wide angle end as the lower limit of conditional expression (2) is exceeded, it becomes difficult to correct field curvature.

  Conditional expression (3) relates to the refractive power of the second focus group Lf2. If the refractive power of the second focus group Lf2 becomes stronger as the upper limit of conditional expression (3) is exceeded, it becomes difficult to suppress aberration fluctuation during focusing due to floating and correct aberration fluctuation due to zooming in a balanced manner. If the refractive power of the second focus group Lf2 becomes weaker as the lower limit of conditional expression (3) is exceeded, it becomes difficult to reduce aberration fluctuations during focusing. More preferably, the numerical ranges of conditional expressions (2) and (3) are set as follows.

10 <Dmax / Dmin <25 (2a)
0.02 <Fw / Ff2 <0.12 (3a)
In the present invention, it is more preferable that the following conditional expression is satisfied. The second focus group LF2 is composed of one positive lens and one negative lens.

In each embodiment, the second focus group LF2 includes a cemented lens of a positive lens and a negative lens. The focal length of the positive lens of the second focus group LF2 is Ff2P, and the focal length of the negative lens of the second focus group LF2 is Ff2N. At this time,
0.01 <| 1- | Ff2P / Ff2N || <0.50 (4)
It is good to satisfy the following conditional expression.

  Conditional expression (4) relates to the ratio of the refractive powers of the positive lens and the negative lens constituting the second focus group LF2. The second focus group LF2 uses a part of the lens group of the fourth lens group L4 that moves during zooming. Therefore, the amount of decentering of the lens group with respect to the manufacturing error of the mechanical parts constituting the movement during zooming and focusing increases. Therefore, in order to maintain good optical performance, it is preferable that the influence on the optical performance due to eccentricity is as small as possible.

If there is a difference in refractive power between the positive lens and the negative lens in the second focus group LF2 that exceeds the upper limit of conditional expression (4), the change in aberration due to decentering at the boundary between the positive lens and the negative lens increases. Degradation of optical performance due to manufacturing errors increases. If the difference in refractive power between the positive lens and the negative lens is so small that the lower limit of conditional expression (4) is exceeded, the improvement in optical performance due to floating is reduced. Conditional expression (4) is more desirably in the following numerical range.
0.01 <| 1- | Ff2P / Ff2N || <0.25 (4a)

  As described above, according to each embodiment, with a zoom ratio of 3 and an F number of about 2.8, the field curvature due to focusing, particularly the variation in field curvature at the wide-angle end is corrected well, and the entire object distance is excellent. A zoom lens having optical performance can be easily obtained.

  Next, the lens configuration of each example will be described. In Example 1 of FIG. 1, L1 is a first lens group having a negative refractive power, L2 is a second lens group having a positive refractive power, L3 is a third lens group having a negative refractive power, and L4 is a positive refractive power. The fourth lens group, L5 is a fifth lens group having negative refractive power, and L6 is a sixth lens group having positive refractive power.

  During zooming from the wide-angle end to the telephoto end, the first lens unit L1 is moved to the image side, the second lens unit L2 is moved to the object side, and the third lens unit L3 is integrated with the aperture stop SP and the open Fno stop SP2. ) To move along a convex locus toward the object side. Further, the fourth lens unit L4 moves to the object side, and the fifth lens unit L5 moves to the object side. The sixth lens unit L6 does not move during zooming and focusing.

  The first lens unit L1, the second lens unit L2, the fourth lens unit L4, and the fifth lens unit L5 perform zooming, and the image plane that changes due to zooming is corrected by the movement of the third lens unit L3. . In the first embodiment, five lens groups move during zooming to obtain a necessary zoom ratio and reduce fluctuations in various aberrations accompanying zooming. At the time of focusing from an object at infinity to a close object, the fifth lens unit L5 as the first focus unit LF1 is moved to the image side.

  Further, a part of the lens group in the fourth lens group L4 is moved to the object side as a second focus group Lf2 that moves separately from the first focus group LF1. As a result, fluctuations in aberration due to focusing are reduced.

  As described above, in Example 1, the first lens unit L1 to the fifth lens unit L5 move during zooming. The second focus group LF2 is composed of a part of the fourth lens group L4, and the first focus group LF1 is composed of the fifth lens group L5. In Example 1, two aspheric surfaces are arranged in the first lens group. This facilitates the correction of the meridional image plane and the correction of the distortion, which are suddenly insufficiently corrected by improving the sagittal image plane curvature around the angle of view at the wide angle end. In Example 1, two aspheric surfaces are arranged in the sixth lens unit L6. This facilitates correction of field curvature at the wide-angle end.

  In Example 2 of FIG. 4, L1 is a first lens group having a negative refractive power, L2 is a second lens group having a positive refractive power, L3 is a third lens group having a negative refractive power, and L4 is a positive refractive power. 4a lens group, L5 is a fifth lens group having negative refractive power. During zooming from the wide-angle end to the telephoto end, the first lens unit L1 moves to the image side, and the second lens unit L2 moves to the object side. The third lens unit L3 moves together with the aperture stop SP and the open Fno stop SP2 along a locus that is convex toward the object side. Further, the fourth lens unit L4 moves to the object side, and the fifth lens unit L5 moves to the object side.

  The first lens unit L1, the second lens unit L2, the fourth lens unit L4, and the fifth lens unit L5 perform zooming, and the image plane that changes due to zooming is corrected by the movement of the third lens unit L3. . In Example 2, the five lens groups move during zooming to obtain a necessary zoom ratio and to reduce fluctuations in various aberrations accompanying zooming. During focusing from an object at infinity to a close object, the fifth lens unit L5 as the first focusing lens unit LF1 is moved to the image side.

  Further, a part of the lens group in the fourth lens group L4 is moved to the object side as a second focus group Lf2 that moves separately from the first focus group LF1. This reduces fluctuations in aberration due to focusing.

  As described above, in Example 2, the first lens unit L1 to the fifth lens unit L5 move during zooming. The second focus group LF2 is composed of a part of the fourth lens group L4, and the first focus group LF1 is composed of the fifth lens group L5. In Example 2, two aspheric surfaces are disposed in the first lens group. This facilitates the correction of the meridional image plane and the correction of distortion, which are suddenly insufficiently corrected by improving the sagittal image plane curvature around the angle of view at the wide angle end.

  In Example 2, one aspherical surface is arranged in the second lens group. This facilitates correction of spherical aberration at the telephoto end. In Example 2, two aspheric surfaces are arranged in the fifth lens group. This facilitates correction of field curvature at the wide-angle end.

  In Example 3 of FIG. 7, L1 is a first lens unit having a negative refractive power, L2 is a second lens unit having a positive refractive power, L3 is a third lens unit having a negative refractive power, and L4 is a positive refractive power. 4th lens group. During zooming from the wide-angle end to the telephoto end, the first lens unit L1 is on the image side, the second lens unit L2 is on the object side, and the third lens unit L3 is on the object side together with the aperture stop SP and the open Fno stop SP2. Move along a convex trajectory. Further, the fourth lens unit L4 moves to the object side.

  The first lens unit L1, the second lens unit L2, and the fourth lens unit L4 perform zooming, and the image plane that fluctuates due to zooming is corrected by the movement of the third lens unit L3. In Example 3, four lens groups move during zooming to obtain a necessary zoom ratio and to reduce fluctuations in various aberrations accompanying zooming.

  A part of the fourth lens unit L1 as the first focus unit LF1 is moved to the image side during focusing from an infinitely distant object to a close object. Further, by moving a part of the lens group in the fourth lens group L4 to the object side as the second focus group Lf2 that moves separately from the first focus group LF1, fluctuation of aberration due to focus is reduced. .

  In Example 3, each lens unit moves during zooming. The second focus group LF2 includes a part of the lens group of the fourth lens group L4, and the first focus group LF1 includes a part of the lens group on the image side of the second focus group LF2. In Example 3, two aspheric surfaces are arranged in the first lens group. This facilitates the correction of the meridional image plane and the correction of the distortion, which are suddenly insufficiently corrected by improving the sagittal image plane curvature around the angle of view at the wide angle end.

  In Example 3, one aspherical surface is disposed in the second lens group. This facilitates correction of spherical aberration at the telephoto end. In Example 3, two aspheric surfaces are arranged in the fourth lens group. This facilitates correction of field curvature at the wide-angle end.

  Next, an embodiment in which the zoom lens shown in Embodiments 1 to 3 is applied to an imaging apparatus will be described with reference to FIG. FIG. 10 is a schematic view of the main part of a single-lens reflex camera. In FIG. 10, reference numeral 10 denotes a photographic lens having the zoom lens 1 of Examples 1 to 3. The zoom lens 1 is held by a lens barrel 2 that is a holding member. Reference numeral 20 denotes a camera body, which includes a quick return mirror 3 that reflects the light beam from the photographing lens 10 upward, and a focusing screen 4 that is disposed at an image forming position of the photographing lens 10. Further, it is constituted by a penta roof prism 5 for converting an inverted image formed on the focusing screen 4 into an erect image, an eyepiece 6 for observing the erect image, and the like.

  Reference numeral 7 denotes a photosensitive surface, on which a solid-state imaging device (photoelectric conversion device) or a silver salt film that receives an image formed by a zoom lens such as a CCD sensor or a CMOS sensor is arranged. At the time of photographing, the quick return mirror 3 is retracted from the optical path, and an image is formed on the photosensitive surface 7 by the photographing lens 10.

  The zoom lens of the present invention can be similarly applied to a so-called mirrorless camera having no quick return mirror.

  Numerical Examples 1 to 3 corresponding to Examples 1 to 3 are shown below. In each numerical example, i indicates the order of the surfaces from the object side. In 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, and ndi and νdi are the i-th lens in order from the object side. The refractive index and Abbe number of the material. BF is a back focus. 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, and each aspheric coefficient is A4, A6, A8. , A10, A12,

Shall be given in “E ± xx” in each aspheric coefficient means “× 10 ± ^xx ”. Table 1 shows the relationship between the conditional expressions (2), (3), (4) and the numerical examples.

[Numerical Example 1]
Unit mm

Surface data surface number rd nd νd Effective diameter
1 * 263.552 2.08 1.7725 49.6 63.63
2 34.5 16.68 51.55
3 -78.411 2.5 1.804 46.6 51.03
4 -1642.17 0.1 51
5 * 147.491 4.18 1.7495 35.3 50.92
6 -486.702 (variable) 50.69
7 -1026.21 3 1.618 63.4 40.4
8 -116.115 0.5 40.62
9 82.197 2 1.84666 23.9 40.73
10 47.711 7.07 1.59282 68.6 39.89
11 -188.861 0.15 39.71
12 57.999 4.44 1.883 40.8 38.33
13 1191.271 (variable) 37.68
14 (Fno aperture) ∞ 2.25 25.91
15 -97.536 1.3 1.8061 40.9 25.21
16 56.152 2.87 24.7
17 -94.524 1.3 1.7432 49.3 24.77
18 40.268 4.09 1.84666 23.9 25.48
19 -156.617 1.69 25.66
20 (Aperture) ∞ (Variable) 25.85
21 119.789 1.39 1.80809 22.8 26.14
22 34.608 6.1 1.43875 94.9 25.98
23 -53.323 (variable) 26.26
24 56.617 3.28 1.59282 68.6 26.22
25 -177.495 0.97 25.98
26 57.209 3.07 1.43875 94.9 26.65
27 -450.614 (variable) 26.65
28 -498.043 3.8 1.80518 25.4 26.61
29 -35.865 0.15 26.63
30 -35.888 1.5 1.72047 34.7 26.5
31 30.102 (variable) 26.3
32 * 55.891 5.1 1.58313 59.4 36
33 * -1801.29 36.22
Image plane ∞

Aspheric data 1st surface
K = 0.00E + 00 A 4 = 2.63451E-06 A 6 = -1.13606E-09 A 8 = 1.57408E-13
A10 = 2.10327E-16 A12 = -7.19037E-20
5th page
K = 0.00E + 00 A 4 = -8.16931E-07 A 6 = 2.32636E-10 A 8 = 1.72998E-12
A10 = -2.09561E-15 A12 = 5.99777E-19
32nd page
K = 0.00E + 00 A 4 = 8.24588E-07 A 6 = -3.80587E-09 A 8 = 6.11912E-12
A10 = 1.37029E-14 A12 = -2.07864E-18
Side 33
K = 0.00E + 00 A 4 = 7.31749E-07 A 6 = -6.39483E-09 A 8 = 2.10283E-12
A10 = 4.36987E-14 A12 = -4.03388E-17

Various data
Zoom ratio 2.75

Focal length 24.69 34.99 67.9
F number 2.9 2.9 2.9
Half angle of view (degrees) 41.23 31.73 17.67
Image height 21.64 21.64 21.64
Total lens length 211.75 196.67 173.34
BF 38.38 38.38 38.38

d6 59.6 35.77 2.17
d13 3.33 7.61 23.14
d20 21.81 16.92 2.74
d23 0.7 0.7 0.7
d27 2.08 2.12 6.38
d31 4.29 13.61 18.26

Near object distance
d20 20.938 16.048 1.868
d23 1.572 1.572 1.572
d27 3.469 4.378 13.978
d31 2.903 11.359 10.661

Entrance pupil position 34.43 34.01 45.22
Exit pupil position -65.14 -77.47 -58.93
Front principal point position 53.24 58.44 65.74
Rear principal point position 13.68 3.38 -29.53

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 -43.3 25.55 2.9 -18.59
2 7 37.94 17.16 5.82 -4.8
3 14 -45.33 13.49 1.86 -8.8
4 21 37.72 15.51 7.29 -3.59
5 28 -43.3 5.45 3.14 0.02
6 32 93.06 5.1 0.1 -3.13


Single lens Data lens Start surface Focal length
1 1 -51.59
2 3 -102.49
3 5 151.45
4 7 211.59
5 9 -137.99
6 10 64.97
7 12 68.92
8 15 -44.04
9 17 -37.84
10 18 38.2
11 21 -60.67
12 22 48.87
13 24 72.79
14 26 115.91
15 28 47.82
16 30 -22.51
17 32 93.06

[Numerical Example 2]
Unit mm

Surface data surface number rd nd νd Effective diameter
1 * 638.428 2.08 1.7725 49.6 65.19
2 35.152 16.12 52.72
3 -110.645 2.5 1.804 46.6 52.21
4 569.675 0.1 52.06
5 * 149.5 4.73 1.7495 35.3 52.12
6 -367.969 (variable) 51.88
7 1110.9 3 1.618 63.4 40.69
8 -139.527 0.5 40.84
9 79.949 2 1.84666 23.9 40.85
10 45.706 6.94 1.59282 68.6 39.91
11 -281.166 0.15 39.7
12 * 54.598 4.44 1.883 40.8 38.44
13 467.363 (variable) 37.77
14 (Fno aperture) ∞ 2.4 25.83
15 -92.618 1.3 1.8061 40.9 25.12
16 61.026 2.87 24.69
17 -88.584 1.3 1.7432 49.3 24.77
18 34.325 4.49 1.84666 23.9 25.62
19 -140.325 1.29 25.8
20 (Aperture) ∞ (Variable) 25.94
21 107.005 1.39 1.80809 22.8 26.09
22 29.467 6.16 1.43875 94.9 25.85
23 -71.134 (variable) 26.18
24 76.42 3.37 1.59282 68.6 26.41
25 -86.921 0.5 26.31
26 82.433 3 1.43875 94.9 25.56
27 -92.126 (variable) 25.7
28 -133.927 3.15 1.80518 25.4 25.95
29 -35.47 0.15 26.1
30 -36.938 1.5 1.7495 35.3 25.97
31 47.531 4.29 26.4
32 * 118.072 2.39 1.7859 44.2 28.3
33 * -669.031 (variable) 28.71
Image plane ∞

Aspheric data 1st surface
K = 0.00E + 00 A 4 = 2.98785E-06 A 6 = -1.39501E-09
A 8 = 1.78892E-13 A10 = 2.08249E-16 A12 = -1.05452E-19
5th page
K = 0.00E + 00 A 4 = -5.75137E-07 A 6 = -1.89268E-10
A 8 = 2.94024E-12 A10 = -3.24708E-15 A12 = 1.52626E-18
12th page
K = 0.00E + 00 A 4 = -1.55 150E-08 A 6 = -4.11437E-11
A 8 = 4.03702E-14 A10 = 2.36907E-17 A12 = -6.67811E-19
32nd page
K = 0.00E + 00 A 4 = -1.86353E-06 A 6 = -1.79792E-08
A 8 = 7.18781E-11 A10 = -4.43174E-13 A12 = 6.90523E-16
Side 33
K = 0.00E + 00 A 4 = -1.62531E-06 A 6 = -1.57734E-08
A 8 = 4.25444E-11 A10 = -2.89266E-13 A12 = 3.91402E-16

Various data Zoom ratio 2.75

Focal length 24.7 34.87 67.9
F number 2.9 2.9 2.9
Angle of view 41.22 31.82 17.67
Image height 21.64 21.64 21.64
Total lens length 209.13 192.53 168.6
BF 39.38 50.68 53.89

d6 59.6 34.89 1.44
d13 2.75 6.48 24.32
d20 19.88 15.61 1.33
d23 0.66 0.66 0.66
d27 4.75 2.1 4.86
d33 39.38 50.68 53.89

Near object distance
d20 18.968 14.698 0.418
d23 1.569 1.569 1.569
d27 6.131 4.169 12.124
d33 37.999 48.607 46.616

Entrance pupil position 33.8 32.93 45.55
Exit pupil position -59.41 -47.9 -25.32
Front principal point position 52.33 55.46 55.24
Rear principal point position 14.68 15.81 -14.02

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 -44.44 25.54 1.72 -19.87
2 7 39.18 17.03 5.43 -5.1
3 14 -48.36 13.65 1.68 -9.01
4 21 38.87 15.72 8.73 -2.27
5 28 -91.94 11.49 -1.48 -10.19


Single lens Data lens Start surface Focal length
1 1 -48.23
2 3 -115.05
3 5 142.4
4 7 200.76
5 9 -129.51
6 10 66.85
7 12 69.66
8 15 -45.46
9 17 -33.14
10 18 32.96
11 21 -50.73
12 22 48.39
13 24 69.13
14 26 99.68
15 28 59.08
16 30 -27.52
17 32 127.87

[Numerical Example 3]
Unit mm

Surface data surface number rd nd νd Effective diameter
1 * 291.444 2.08 1.7725 49.6 63.9
2 31.991 16.98 51
3 -121.328 2.5 1.804 46.6 50.45
4 343.168 0.1 50.51
5 * 139.24 5.02 1.7495 35.3 50.75
6 -445.88 (variable) 50.49
7 1015.43 3 1.618 63.4 41.23
8 -127.839 0.5 41.38
9 78.593 2 1.84666 23.9 41.45
10 44.823 8 1.59282 68.6 40.48
11 -241.531 0.15 40.19
12 * 55.226 4.44 1.883 40.8 38.84
13 613.437 (variable) 38.24
14 (Fno aperture) ∞ 3.02 26.34
15 -97.447 1.3 1.8061 40.9 25.23
16 52.972 2.87 24.68
17 -89.406 1.3 1.7432 49.3 24.74
18 39.118 5 1.84666 23.9 25.53
19 -122.993 1.06 25.81
20 (Aperture) ∞ (Variable) 25.93
21 108.329 1.39 1.80809 22.8 26.09
22 31.354 5.34 1.43875 94.9 25.85
23 -71.379 (variable) 26.04
24 76.655 3.14 1.59282 68.6 26.16
25 -90.475 0.5 26.05
26 82.589 3 1.43875 94.9 25.82
27 -102.454 2.63 25.94
28 -127.703 2.74 1.80518 25.4 26.03
29 -36.112 0.15 26.13
30 -37.596 1.5 1.7495 35.3 26.01
31 47.648 8.13 26.41
32 * 90.394 2.39 1.7859 44.2 30.79
33 * -8046.92 (variable) 31.14
Image plane ∞

Aspheric data 1st surface
K = 0.00000E + 00 A 4 = 3.19133E-06 A 6 = -1.55329E-09
A 8 = -2.72390E-14 A10 = 1.88906E-16 A12 = -1.13810E-20
5th page
K = 0.00000E + 00 A 4 = -4.91496E-07 A 6 = 7.41072E-11
A 8 = 3.74404E-12 A10 = -2.48251E-15 A12 = 3.09080E-19
12th page
K = 0.00000E + 00 A 4 = 1.97927E-07 A 6 = -4.15353E-10
A 8 = 5.63712E-13 A10 = -1.05891E-15 A12 = -4.18498E-19
32nd page
K = 0.00000E + 00 A 4 = -2.12962E-06 A 6 = -1.56417E-09
A 8 = -2.16331E-11 A10 = -3.11391E-13 A12 = 3.24771E-16
Side 33
K = 0.00000E + 00 A 4 = -1.48869E-06 A 6 = -8.33440E-09
A 8 = 4.28439E-11 A10 = -5.86017E-13 A12 = 7.40622E-16

Various data Zoom ratio 2.75

Focal length 24.7 35.75 67.9
F number 2.9 2.9 2.9
Half angle of view (degrees) 41.22 31.18 17.67
Image height 21.64 21.64 21.64
Total lens length 215.39 192.52 172.54
BF 40.3 47.04 55.41

d6 60.11 29.89 1.29
d13 2.38 6.7 23.35
d20 21.87 18.16 1.77
d23 0.48 0.48 0.48
d33 40.3 47.04 55.41

Near object distance
d20 20.414 16.704 0.314
d23 1.934 1.934 1.934
d27 3.943 4.956 9.844
d33 38.993 44.718 48.200

Entrance pupil position 33.33 32.52 45.33
Exit pupil position -73.05 -61.36 -28.9
Front principal point position 52.65 56.48 58.54
Rear principal point position 15.6 11.29 -12.49

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 -42.26 26.69 2.12 -20.34
2 7 37.84 18.09 5.91 -5.37
3 14 -46.53 14.55 2.09 -9.35
4 21 63.42 31.39 7.64 -17.85

Single lens Data lens Start surface Focal length
1 1 -46.68
2 3 -111.22
3 5 142.09
4 7 183.91
5 9 -126.65
6 10 64.44
7 12 68.48
8 15 -42.41
9 17 -36.46
10 18 35.56
11 21 -55.05
12 22 50.45
13 24 70.49
14 26 104.74
15 28 61.71
16 30 -27.83
17 32 113.76

L1 1st lens group L2 2nd lens group L3 3rd lens group L3 3rd lens group L4 4th lens group L5 5th lens group L6 6th lens group Lf2 2nd focus group Lf1 1st focus group SP Aperture stop SP2 Open Fno aperture

Claims (9)

In order from the object side to the image side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens group having a positive refractive power are provided. Four or more lens groups move so that the distance between adjacent lens groups changes during zooming, and the first focus group and the second focus group located on the image side of the aperture stop follow different trajectories during focusing. A zoom lens that moves, wherein the second focus group is disposed on the object side of the first focus group, and the maximum amount of movement of the first focus group and the second focus group during focusing is determined. Df1, Df2, and Dmax are the maximum distances from the aperture stop in focusing to the lens surface closest to the object in the second focus group, respectively. When the minimum distance al to the most object side lens surface of the second focusing unit Dmin, Fw is a focal length of the entire system at the wide angle end, the focal length of the second focusing unit and Ff2,
Df2 <Df1
1.5 <Dmax / Dmin <30.0
0.01 <Fw / Ff2 <0.14
A zoom lens satisfying the following conditional expression: The second focus group includes one positive lens and one negative lens, the focal length of the positive lens of the second focus group is Ff2P, and the focal length of the negative lens of the second focus group is Ff2N. and when,
0.01 <| 1- | Ff2P / Ff2N || <0.50
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.   The zoom lens according to claim 1, wherein the second focus group includes a cemented lens of a positive lens and a negative lens.   4. The zoom lens according to claim 1, wherein the aperture stop is disposed on an image side of the third lens group, and moves together with the third lens group during zooming. 5.   5. The zoom lens according to claim 1, further comprising an open Fno aperture that moves integrally with the third lens unit during zooming. 6.   In order from the object side to the image side, the lens unit includes a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens group having a positive refractive power. 6. Each lens group is moved during zooming, and the first focus group and the second focus group are part of the fourth lens group, respectively. Zoom lens of the term.   In order from the object side to the image side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, a fourth lens group having a positive refractive power, and a negative lens group The first lens group to the fifth lens group move during zooming, and the second focus group is a part of the fourth lens group. 6. The zoom lens according to claim 1, wherein the focus group includes the fifth lens group.   In order from the object side to the image side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, a fourth lens having a positive refractive power, and a negative refraction. A fifth lens group having a positive power and a sixth lens group having a positive refractive power, and the first lens group to the fifth lens group move during zooming, and the second focus group is the same as that of the fourth lens group. 6. The zoom lens according to claim 1, wherein the zoom lens is a part of the zoom lens, and the first focus group includes the fifth lens group.   An image pickup apparatus comprising: the zoom lens according to claim 1; and a photoelectric conversion element that receives an image formed by the zoom lens.