JP2020064316A - Zoom lens and imaging apparatus having the same - Google Patents

Abstract

To provide a method for obtaining a zoom lens that has high optical performance over all the object distances and facilitates quick focusing.SOLUTION: A zoom lens comprises first, second, third, fourth, and fifth lens groups (L1 to L5) that have a positive, negative, positive, negative, and positive refractive power, respectively, which are arranged in order from an object side to an image side. In zooming from a wide angle end to a telephoto end, a distance between the first lens group L1 and the second lens group L2 widens and the distance between the second lens group L2 and the third lens group L3 narrows, while the fourth lens group L4 and the fifth lens group L5 move. The zoom lens changes a distance between adjacent lens groups in at least one of zooming and focusing. The fourth lens group L4 is composed of one negative lens G4n. In focusing, the fourth lens group L4 moves.SELECTED DRAWING: Figure 1

Description

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

  2. Description of the Related Art In recent years, it has been required for an image pickup optical system used in an image pickup apparatus to be a zoom lens having a high zoom ratio and a high performance even though the entire system is small. In addition to this, it is desired to have an autofocus (automatic focus detection) mechanism or the like because it is easy to shoot moving images as well as still images. As one of zoom lenses that meet these requirements, a so-called rear focus type zoom lens is known in which a lens unit other than the first lens unit on the object side is moved for focusing.

  Generally, in a rear focus type zoom lens, the effective diameter of the first lens group is smaller than that of a zoom lens in which focusing is performed by moving the first lens group, and it is easy to downsize the entire lens system. Further, since focusing can be performed with a small and lightweight lens group, the driving force of the focusing lens group can be small, the focus driving mechanism and the like can be simplified, and quick focusing can be performed.

  Conventionally, various zoom lenses using a rear focus system in which the focus lens group is small and lightweight have been proposed (Patent Documents 1 to 3). In Patent Documents 1 and 2, a zoom including 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 fourth lens group having a negative refractive power. In the lens, focusing is performed by the fourth lens group. Particularly in Patent Document 1, the fourth lens group for focusing is composed of a cemented lens (a single lens component) in which a positive lens and a negative lens are cemented.

  In Patent Document 3, 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 fourth lens group having a positive refractive power. In the zoom lens composed of five lens groups, focusing is performed by the fourth lens group. Patent Document 3 discloses a zoom lens in which the fourth lens group is composed of a single lens, and quick focusing is easy.

JP, 2011-247998, A JP 2012-27261 A JP2012-48199A

  A zoom lens used in an image pickup apparatus is required to have a compact (small size) whole system, easy quick focusing, small aberration variation during focusing, and high optical performance over the entire object distance. It is important to properly set the zoom type and the lens configuration of the zoom and focus lens groups in order to obtain a small optical system with a small aberration variation during focusing and high optical performance over the entire object distance while achieving a compact overall system. Is coming.

  In particular, it is necessary to properly set the refractive power of the focus lens group and the lens configuration of the lens group disposed on the image side of the focus lens group to obtain appropriate focus sensitivity and perform focusing effectively. Becomes important to.

  It is an object of the present invention to provide a zoom lens that has high optical performance over the entire object distance and that allows quick and easy focusing, and an image pickup apparatus including the zoom lens.

  The zoom lens of the present invention includes 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 group arranged in order from the object side to the image side. A zoom lens having a fourth lens unit having a refractive power and a fifth lens unit having a positive refractive power, in which a distance between adjacent lens units changes during at least one of zooming and focusing, and a zoom lens from a wide-angle end to a telephoto end. During zooming, the distance between the first lens group and the second lens group widens, the distance between the second lens group and the third lens group narrows, and the fourth lens group and the fifth lens group move, The zoom lens, wherein the fourth lens group is composed of one negative lens, and the fourth lens group moves during focusing.

  According to the present invention, it is possible to obtain a zoom lens that has high optical performance over the entire object distance and that can easily perform quick focusing.

(A), (B), (C) Lens cross-sectional views at a wide-angle end, a middle zoom position, and a telephoto end when focusing on infinity according to the first embodiment of the present invention. (A), (B), (C) Aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on infinity according to the first embodiment of the present invention. (A), (B), (C) Aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end when the object distance is 1.1 m in Example 1 of the present invention. (A), (B), (C) Lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on infinity according to the second embodiment of the present invention. (A), (B), (C) Aberration diagrams at the wide-angle end, the middle zoom position, and the telephoto end when focusing on infinity according to the second embodiment of the present invention. (A), (B), (C) Aberration diagrams at the wide-angle end, at the intermediate zoom position, and at the telephoto end when focused on an object distance of 1.1 m according to the second embodiment of the present invention. Schematic diagram of the main part of the imaging device of the present invention

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The zoom lens of the present invention includes 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 group arranged in order from the object side to the image side. It is composed of a fourth lens group having a refractive power and a fifth lens group having a positive refractive power. During zooming from the wide-angle end to the telephoto end, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group decreases, and the fourth lens group and the fifth lens group move. . Then, the spacing between the adjacent lens groups changes during at least one of zooming and focusing.

  1A, 1B, and 1C are lens cross sections at a wide-angle end (short focal length end), an intermediate zoom position, and a telephoto end (long focal length end) of a zoom lens according to a first exemplary embodiment of the present invention. It is a figure. 2A, 2B, and 2C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end when the zoom lens of Example 1 is focused at infinity, respectively.

  FIGS. 3A, 3B, and 3C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, when the object distance of the zoom lens of Embodiment 1 is 1.1 m. Here, the object distance is a value when numerical data described later is expressed in mm. This also applies to the following examples. Example 1 is a zoom lens having a zoom ratio of 4.37 and an aperture ratio of about 4.16 to 5.88.

  4A, 4B, and 4C are lens cross-sectional views of the zoom lens according to the second exemplary embodiment of the present invention at the wide-angle end, the intermediate zoom position, and the telephoto end. 5A, 5B, and 5C are aberration diagrams of the zoom lens of the second embodiment at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, when focused on infinity.

  FIGS. 6A, 6B, and 6C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively, when the object distance of the zoom lens of the second embodiment is 1.1 m. The second embodiment is a zoom lens having a zoom ratio of 4.33 and an aperture ratio of about 4.16 to 5.88. FIG. 7 is a schematic view of a main part of a digital still camera (imaging device) including the zoom lens of the present invention.

  The zoom lens of each embodiment is an image pickup optical system used in an image pickup apparatus such as a silver salt film camera, a digital still camera, a video camera, and a digital video 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, Li is the i-th lens group, where i is the order of the lens groups from the object side. SP is a diaphragm (aperture diaphragm).

  IP is an image plane, and when used as an image pickup optical system of a video camera or a digital still camera, when the image pickup surface (photoelectric conversion element) of a CCD sensor or a CMOS sensor is a silver salt film camera. It corresponds to the film surface. The arrow indicates the direction of movement during zooming from the wide-angle end to the telephoto end.

  Each vertical aberration diagram represents spherical aberration, astigmatism, distortion, and chromatic aberration of magnification in order from the left. In the figures showing spherical aberration and chromatic aberration of magnification, the solid line d represents the d line (587.6 nm), and the broken line g represents the g line (435.8 nm). In the diagram showing astigmatism, the solid line ΔS represents the d-line sagittal image plane, and the broken line ΔM represents the d-line meridional image plane. In addition, the diagram showing the distortion represents the distortion at the d line. Fno is an F number, and ω is a half angle of view (degree).

  The zoom lens according to the present invention includes a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, and a third lens unit L3 having a positive refractive power, which are sequentially arranged from the object side to the image side. , A fourth lens unit L4 having a negative refractive power, and a fifth lens unit L5 having a positive refractive power. The back focus BF is relatively long at 0.7 fw to 0.8 fw with respect to the focal length fw of the entire system at the wide angle end.

  During zooming from the wide-angle end to the telephoto end, the distance between the first lens unit L1 and the second lens unit L2 increases, the distance between the second lens unit L2 and the third lens unit L3 decreases, and the fourth lens unit L4 and the fifth lens L3. Group L5 moves. The distance between the adjacent lens groups changes in at least one of zooming and focusing. An aperture stop SP is arranged between the second lens unit L2 and the third lens unit L3. The first lens unit L1, the second lens unit L2, the third lens unit L3, the fourth lens unit L4, and the fifth lens unit L5 move during zooming. The second lens unit L2 is stationary.

  In the lens-type zoom lens described above, the effective diameter of the light flux tends to be small in the lens group behind the aperture stop SP and close to the image side. Therefore, when the lens group behind the aperture stop and close to the image side is used as the focusing lens group, the holding mechanism and the drive mechanism can be simplified and the entire system can be easily downsized. Furthermore, if the lens configuration of the focus lens group is configured by one lens, it is easy to reduce the weight of the focus lens group.

  Further, if a lens unit having a small zooming effect on the image side of the aperture stop SP is used as a focusing lens unit, a change in image magnification can be reduced when focusing from infinity to a close distance. This point is optimal when shooting a moving image because the change in the angle of view can be reduced when the subject changes from infinity to the closest distance.

  Therefore, in each embodiment, the fourth lens unit L4, which is behind the aperture stop SP and near the image side, is used as the focusing lens unit. As a result, the size of the focusing lens unit is reduced, and the change in image magnification when focusing from infinity to the close distance is reduced. When focusing from infinity to a short distance, the fourth lens L4 moves to the image side. In the lens type zoom lens described above, by appropriately setting the lens configuration of the fifth lens unit L5, the fourth lens unit L4 is provided with appropriate focus sensitivity and the total lens length is shortened. .

The fourth lens unit L4 is composed of one negative lens G4n, and the fourth lens unit L4 moves during focusing. The focal length of the fourth lens unit L4 is f4, and the focal length of the fifth lens unit L5 is f5. At this time,
7.0 <| f5 / f4 | <20.0 (1)
Satisfies the conditional expression

  Conditional expression (1) is for appropriately setting the focus sensitivity at the time of focusing to reduce aberration fluctuation. When the negative refracting power of the fourth lens unit L4 becomes strong (the absolute value of the negative refracting power becomes large) beyond the upper limit of the conditional expression (1), the fluctuation of the optical performance at the time of focusing becomes large. Further, if the refractive power of the fifth lens unit L5 becomes weak, the total lens length becomes long and it becomes difficult to downsize the entire system. Further, when zooming to the wide-angle end, the image plane variation becomes large, and it becomes difficult to maintain high optical performance.

  When the lower limit of conditional expression (1) is exceeded and the refractive power of the fourth lens unit L4 becomes weak (the absolute value of the negative refractive power becomes small), the focus sensitivity of the fourth lens unit L4 becomes small and the focusing becomes small. At that time, the moving amount increases and the total lens length increases. Further, when the positive refractive power of the fifth lens unit L5 becomes strong, the exit pupil becomes too long and the total lens length increases. Furthermore, the lens effective diameter of the lens unit located behind the aperture stop SP becomes large, which makes it difficult to reduce the size and weight of the fourth lens unit L4.

Further, the positional sensitivity of the fourth lens unit L4 and the fifth lens unit L5 is increased, which makes manufacturing difficult. More preferably, the numerical range of conditional expression (1) should be set as follows.
10.0 <| f5 / f4 | <16.0 (1a)

  According to each embodiment, by specifying the lens configuration as described above, it is possible to obtain a zoom lens having a compact and lightweight focusing lens group which is optimal for moving images. In each of the embodiments, in order to obtain high optical performance while having a smaller and lighter focusing, it is preferable to satisfy at least one of the following conditional expressions.

The focal length of the entire system at the wide angle end is fw, and the Abbe number of the material of the negative lens G4n is νd4n. The radii of curvature of the object-side lens surface and the image-side lens surface of the negative lens G4n are R4f and R4R, respectively. The fifth lens group L5 is composed of a negative lens G5n and a positive lens G5p, and the refractive index of the material of the negative lens G5n is nd5n and the refractive index of the material of the positive lens G5p is nd5p. The focal length of the first lens unit L1 is f1. During image blur correction, the second lens unit L2 moves in a direction including a component perpendicular to the optical axis, and the focal length of the second lens unit L2 is set to f2. At this time, it is preferable to satisfy at least one of the following conditional expressions.
1.0 <| f4 / fw | <1.5 (2)
νd4n> 50.0 (3)
1.2 <(R4f + R4R) / (R4f-R4R) <4.0 (4)
nd5n> nd5p (5)
2.0 <f1 / fw <2.8 (6)
0.35 <| f2 / fw | <0.65 (7)

  Next, the technical contents of the above-mentioned conditional expressions will be described. The conditional expression (2) is for setting the sensitivity of the focus lens group more appropriately, like the conditional expression (1). If the upper limit of conditional expression (2) is exceeded and the negative refractive power of the fourth lens unit L4 weakens, the focus sensitivity of the fourth lens unit L4 decreases, which is not desirable. When the lower limit of conditional expression (2) is exceeded and the refracting power of the fourth lens unit L4 becomes strong, fluctuations in optical performance during focusing become large.

  Conditional expression (3) is for reducing the variation of chromatic aberration during focusing. If the Abbe's number of the material of the negative lens G4 constituting the fourth lens unit L4 becomes smaller than the lower limit of conditional expression (3), the variation of chromatic aberration during focusing becomes large, and the optical performance deteriorates.

  Conditional expression (4) is a shape factor indicating the meniscus shape of the negative lens G4n forming the fourth lens unit L4. When the value exceeds the upper limit of the conditional expression (4), the fluctuation of the image surface during focusing becomes large, and it becomes difficult to configure the fourth lens unit L4 with one lens. When the value goes below the lower limit of the conditional expression (4), coma aberration varies greatly during focusing, and it becomes difficult to form the fourth lens unit L4 with one lens.

  Conditional expression (5) relates to the refractive indices of the material of the negative lens G5n and the material of the positive lens G5p that form the fifth lens unit L5. When the conditional expression (5) is satisfied, the Petzval sum increases. This is effective in increasing the refracting power of each lens surface in order to shorten the total lens length and correcting the reduced Petzval sum. Further, this makes it possible to reduce the occurrence of lateral chromatic aberration and at the same time maintain good image surface performance (image surface characteristics).

  Conditional expression (6) is for obtaining good optical performance while reducing the size and weight of the entire system. When the upper limit of conditional expression (6) is exceeded and the positive refractive power of the first lens unit L1 becomes weak, the entire system becomes large. If the positive refractive power of the first lens unit L1 is increased beyond the lower limit of conditional expression (6), chromatic aberration increases at the telephoto end, and it becomes difficult to maintain high optical performance.

  In each embodiment, the second lens unit L2 is moved so as to have a component in the direction perpendicular to the optical axis when correcting the image blur. That is, vibration isolation is performed.

  Conditional expression (7) is for achieving miniaturization of the drive mechanism for image stabilization while maintaining good optical performance during image stabilization at this time.

  Conditional expression (7) makes the negative refractive power of the second lens unit L2 appropriate for the focal length of the entire system at the wide-angle end. This maintains a good balance between the sensitivity of aberration variation and the sensitivity of image position correction when the second lens unit L2 is moved so as to have a component in the direction perpendicular to the optical axis during image blur correction. ing.

  When the upper limit of conditional expression (7) is exceeded and the negative refractive power of the second lens unit L2 becomes weak, the amount of driving in the direction having the vertical component during image stabilization becomes large and the drive mechanism becomes large. .

  If the negative refractive power of the second lens unit L2 becomes strong beyond the lower limit of conditional expression (7), a large amount of eccentric aberration will occur during image stabilization, and the optical performance during image stabilization will deteriorate. Further, the amount of change in the image position with respect to the amount of displacement of the second lens unit L2 (hereinafter referred to as image stabilization sensitivity) becomes large. For this reason, the displacement amount of the second lens unit L2 for obtaining the necessary vibration damping effect becomes too small, and it becomes difficult to control the displacement amount electrically or mechanically with high precision.

More preferably, the numerical ranges of conditional expressions (2) to (4), (6), and (7) should be set as follows.
1.0 <| f4 / fw | <1.2 (2a)
νd4n> 55.0 (3a)
1.3 <(R4f + R4R) / (R4f-R4R) <2.0 (4a)
2.05 <f1 / fw <2.60 (6a)
0.45 <| f2 / fw | <0.60 (7a)

  In each embodiment, the fourth lens unit L4 and the fifth lens unit L5 are moved integrally (with the same movement locus) during zooming, but they may be moved independently (with different loci).

  In each embodiment, the first lens unit L1 is preferably composed of a positive lens arranged in order from the object side to the image side, and a cemented lens in which a negative lens and a positive lens are cemented. It is preferable that the second lens unit L2 includes a cemented lens in which a negative lens and a positive lens, which are sequentially arranged from the object side to the image side, are cemented, and a negative lens. It is preferable that the third lens unit L3 is composed of a positive lens, a positive lens, a negative lens, a positive lens, and a negative lens, which are sequentially arranged from the object side to the image side.

  Next, an embodiment of a single-lens reflex camera system (imaging device) using the zoom lens of the present invention will be described with reference to FIG.

  In FIG. 7, 10 is a single-lens reflex camera main body, and 11 is an interchangeable lens equipped with the zoom lens according to the present invention. Reference numeral 12 is a recording unit such as a film or an image pickup device that receives a subject image obtained through the interchangeable lens 11. Reference numeral 13 is a finder optical system for observing the subject image from the interchangeable lens 11, and 14 is a rotating quick return mirror for switching and transmitting the subject image formed by the interchangeable lens 11 to the recording means 12 and the finder optical system 13. is there.

  When observing the subject image with the finder, the subject image formed on the focusing plate 15 through the quick return mirror 14 is made into an erect image by the pentaprism 16 and then magnified and observed by the eyepiece optical system 17. At the time of shooting, the quick return mirror 14 is rotated in the direction of the arrow and the subject image is formed and recorded on the recording means 12. Reference numeral 18 is a sub-mirror, and 19 is a focus detection device.

  As described above, by applying the zoom lens of the present invention to an image pickup apparatus such as an interchangeable lens such as a single-lens reflex camera, an image pickup apparatus having high optical performance is obtained. Further, the image pickup apparatus of the present invention may be a mirrorless single-lens reflex camera that does not have the quick return mirror 14 or the like, or may be applied to a configuration that is not a lens interchangeable type.

  Hereinafter, specific numerical data corresponding to Examples 1 and 2 will be shown. In each numerical data, i indicates the surface number counted from the object side. ri is the radius of curvature of the i-th optical surface (i-th surface). di is an axial distance between the i-th surface and the (i + 1) th surface. ndi and νdi are the refractive index and Abbe number of the material of the i-th optical member with respect to the d-line, respectively. The wide angle indicates the wide-angle end, the middle indicates the middle zoom position, and the telephoto indicates the telephoto end. BF is a back focus and represents the distance from the final lens surface to the paraxial image plane.

  The total lens length is obtained by adding the back focus BF to the distance from the lens surface closest to the object to the final lens surface. Table 1 shows the correspondence with the above-described conditional expressions in each example.

(Numerical data 1)
Unit mm

Surface data Surface number rd nd νd
1 56.117 4.61 1.48749 70.2
2 336.254 0.15
3 84.159 2.00 1.83400 37.2
4 45.033 5.44 1.49700 81.5
5 327.226 (variable)
6 -246.749 1.20 1.76200 40.1
7 17.931 4.29 1.80809 22.8
8 87.951 2.11
9 -42.910 1.00 1.80610 40.9
10 113.279 (variable)
11 (aperture) ∞ 1.00
12 64.213 4.34 1.51633 64.1
13 -32.475 0.15
14 37.791 2.66 1.59522 67.7
15 286.536 1.89
16 -38.518 1.00 1.84666 23.8
17 -195.936 0.15
18 33.287 5.16 1.58913 61.1
19 -164.075 0.10
20 18.476 1.17 1.51633 64.1
21 14.349 (variable)
22 218.373 0.80 1.59522 67.7
23 29.991 17.32
24 -41.222 0.80 1.80100 35.0
25 35.310 5.12 1.67270 32.1
26 -29.606 (variable)
Image plane ∞

Various data zoom ratio 4.37
Wide-angle mid-telephoto focal length 56.47 133.45 246.72
F number 4.16 5.15 5.88
Half angle of view (degree) 13.60 5.84 3.17
Image height 13.66 13.66 13.66
Total lens length 150.00 184.93 191.02
BF 41.97 57.83 68.71

Interval at infinity
d 5 5.75 40.67 46.77
d10 33.96 19.91 2.65
d21 5.89 4.08 10.46
d26 41.97 57.83 68.71

Distance at object distance of 1.1 m
d 5 5.75 40.67 46.77
d10 33.96 19.91 2.65
d21 6.93 8.46 25.26
d23 16.28 12.94 2.51
d26 41.97 57.83 68.71

Zoom lens group Data group Start surface Focal length
1 1 11 9.35
2 6 -27.50
3 11 28.33
4 22 -58.50
5 24 700.00

(Numerical data 2)
Unit mm

Surface data Surface number rd nd νd
1 55.713 4.84 1.48749 70.2
2 481.454 0.15
3 81.243 2.00 1.83400 37.2
4 43.632 5.26 1.49700 81.5
5 219.054 (variable)
6 -162.631 1.20 1.76200 40.1
7 19.287 4.16 1.80809 22.8
8 96.647 2.42
9 -42.859 1.00 1.80400 46.6
10 137.325 (variable)
11 (aperture) ∞ 1.00
12 85.832 5.48 1.51742 52.4
13 -33.068 0.15
14 38.853 3.25 1.59522 67.7
15 -222.885 1.24
16 -45.621 1.00 1.84666 23.8
17 638.179 0.15
18 28.610 5.21 1.51633 64.1
19 -246.941 0.81
20 18.150 1.00 1.51823 58.9
21 14.371 (variable)
22 187.777 0.80 1.60738 56.8
23 30.385 17.68
24 -43.159 0.80 1.83400 37.2
25 40.671 3.03 1.68893 31.1
26 -30.079 (variable)
Image plane ∞

Various data zoom ratio 4.33
Wide-angle mid-telephoto focal length 57.03 133.45 246.73
F number 4.16 5.14 5.88
Half angle of view (degree) 13.47 5.84 3.17
Image height 13.66 13.66 13.66
Total lens length 150.01 184.93 191.12
BF 43.18 58.53 68.43

Interval at infinity
d 5 5.01 39.93 46.12
d10 33.42 19.64 2.57
d21 5.77 4.20 11.36
d26 43.18 58.53 68.43

Distance at object distance of 1.1 m
d 5 5.01 39.93 46.12
d10 33.42 19.64 2.57
d21 6.86 8.66 26.52
d23 16.60 13.22 2.52
d26 43.18 58.53 68.43

Zoom lens group Data group Start surface Focal length
1 1 120.38
2 6 -27.56
3 11 28.90
4 22 -59.80
5 24 895.00

L1 First lens group L2 Second lens group L3 Third lens group L4 Fourth lens group L5 Fifth lens group SP Aperture stop

Claims (11)

A first lens unit having a positive refracting power, a second lens unit having a negative refracting power, a third lens unit having a positive refracting power, and a fourth lens unit having a negative refracting power, which are sequentially arranged from the object side to the image side. A zoom lens which has a fifth lens unit having a positive refractive power, and in which the distance between adjacent lens units changes during at least one of zooming and focusing,
During zooming from the wide-angle end to the telephoto end, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group decreases, and the fourth lens group and the fourth lens group move. 5 lens groups move,
The fourth lens group is composed of one negative lens,
A zoom lens, wherein the fourth lens group moves during focusing. When the focal length of the fourth lens group is f4 and the focal length of the zoom lens at the wide angle end is fw,
1.0 <| f4 / fw | <1.5
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the Abbe number of the material of the negative lens is νd4n,
νd4n> 50.0
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the radius of curvature of the object-side lens surface and the image-side lens surface of the negative lens are R4f and R4R, respectively,
1.2 <(R4f + R4R) / (R4f-R4R) <4.0
The zoom lens according to any one of claims 1 to 3, wherein the following conditional expression is satisfied. The fifth lens group includes a negative lens and a positive lens. When the material of the negative lens included in the fifth lens group has a refractive index of nd5n and the material of the positive lens has a refractive index of nd5p,
nd5n> nd5p
The zoom lens according to any one of claims 1 to 4, wherein the following conditional expression is satisfied. When the focal length of the first lens group is f1 and the focal length of the zoom lens at the wide-angle end is fw,
2.0 <f1 / fw <2.8
The zoom lens according to any one of claims 1 to 5, wherein the zoom lens satisfies the following conditional expression. At the time of image blur correction, the second lens group moves in a direction including a component perpendicular to the optical axis,
When the focal length of the second lens group is f2 and the focal length of the zoom lens at the wide-angle end is fw,
0.35 <| f2 / fw | <0.65
The zoom lens according to any one of claims 1 to 6, wherein the zoom lens satisfies the following conditional expression.   Upon zooming from the wide-angle end to the telephoto end, the first lens group, the third lens group, the fourth lens group, and the fifth lens group move to the object side, and the second lens group does not move. The zoom lens according to claim 1, wherein the zoom lens is a zoom lens.   9. The zoom lens according to claim 1, wherein the fourth lens group moves toward the image side during focusing from infinity to a short distance. When the focal length of the fourth lens group is f4 and the focal length of the fifth lens group is f5,
7.0 <| f5 / f4 | <20.0
The zoom lens according to any one of claims 1 to 9, which satisfies the following conditional expression.   An image pickup apparatus comprising: the zoom lens according to any one of claims 1 to 10; and an image pickup element that receives an image formed by the zoom lens.