JP2014041196A - Zoom lens and imaging apparatus using the same - Google Patents

Abstract

A small zoom lens having a wide angle of view is provided.
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 having a positive refractive power in order from the object side. The second lens group moves to the image side during zooming, the third lens group moves so as to have a convex locus on the object side, and the fourth lens group moves on the optical axis. A zoom lens that satisfies the following conditional expression in a moving zoom lens.
13.0 <f1 / fw <26.0 (1)
2.6 <M3 / fw <5.5 (2)
fw: focal length at the wide-angle end of the entire system f1: focal length of the first lens unit M3: amount of movement in the optical axis direction with respect to the wide-angle end when the third lens unit is positioned closest to the object side during zooming Figure 1

Description

  The present invention relates to a zoom lens and an image pickup apparatus using the same, and more particularly to a zoom lens suitable for a video camera, a digital still camera, a surveillance camera, a silver salt photograph camera, and an image pickup apparatus having the same.

  Various examples of so-called rear focus systems have been proposed in which zoom lenses used in photographic cameras and video cameras have been used to focus by moving the lens group behind the first lens group on the object side. Yes.

  As a rear focus type zoom lens, the refractive power of each group is made positive, negative, positive, positive in order from the object side, the second lens group is moved to perform zooming, and the fourth lens group is moved. There is known a four-group zoom lens that corrects image plane variation accompanying zooming and performs focusing.

  In recent years, with the increase in the number of pixels of a solid-state imaging device, there has been a demand for a small zoom lens having a wide angle of view while maintaining high optical performance. However, in general, when the angle of view is wide, the front lens diameter is large, and it is difficult to reduce the size of the lens. For this reason, it is difficult to achieve both a wide angle of view and a reduction in size in a method in which zooming is performed by moving only the second lens group and the fourth lens group in order from the object side to positive, negative, positive, and positive.

  In response to these demands, the refractive power of each group is made positive, negative, positive, and positive in order from the object side, the second lens group is moved to the image side during zooming, and the third and fourth lenses are moved. Zoom lenses that move groups have been proposed (Patent Documents 1 and 2).

JP-A-4-324812 Japanese Patent No. 3161160

  It is a problem to realize high optical performance with a wider angle of view than these conventional techniques.

  In view of these problems, an object of the present invention is to provide a zoom lens that realizes downsizing of a lens system while having a wide angle of view, and an imaging apparatus using the zoom lens.

In order to achieve the above object, 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 fourth lens group having a positive refractive power in order from the object side. ,
During zooming, the second lens group moves to the image side, the third lens group moves so as to have a convex locus on the object side, and the fourth lens group is a zoom lens that moves on the optical axis. ,
The following conditional expression is satisfied.
13.0 <f1 / fw <26.0 (1)
2.6 <M3 / fw <5.5 (2)
fw: focal length at the wide-angle end of the entire system f1: focal length of the first lens group M3: amount of movement in the optical axis direction with respect to the wide-angle end when the third lens group is located closest to the object side during zooming

  According to the present invention, it is possible to obtain a small zoom lens while having a wide angle of view exceeding 75 degrees.

Lens cross-sectional view of the zoom lens of Example 1 Aberration diagram at the wide-angle end of the zoom lens of Example 1 Aberration diagram in the middle of the zoom lens of Example 1 Aberration diagram at the telephoto end of the zoom lens of Example 1 Lens sectional view of the zoom lens of Example 2 Aberration diagram at the wide-angle end of the zoom lens of Example 2 Aberration diagram in the middle of the zoom lens of Example 2 Aberration diagram at the telephoto end of the zoom lens of Example 2 Lens sectional view of the zoom lens of Example 3 Aberration diagram at the wide-angle end of the zoom lens of Example 3 Aberration diagram in the middle of zoom lens of Example 3 Aberration diagram at the telephoto end of the zoom lens of Example 3 Lens sectional view of the zoom lens of Example 4 Aberration diagram at the wide-angle end of the zoom lens of Example 4 Aberration diagram in the middle of zoom lens of Example 4 Aberration diagram at the telephoto end of the zoom lens of Example 4

  The zoom lens of the present invention is for achieving a reduction in size while realizing a wide angle of view and high performance.

It is known that the front lens diameter becomes smaller when the four groups of positive, negative, positive, and positive are sequentially arranged from the object side and the third group is moved so as to have a convex locus on the object side. Furthermore, if the power of the first group is weakened, the incident angle to the second group can be reduced, so that the front lens diameter can be reduced. On the other hand, if the power of the first group is weakened, the movement amount of the second group becomes longer in order to maintain the zoom ratio, so that the total length tends to be longer. The inventor was able to achieve miniaturization in spite of a wide angle by setting the focal length of one group to an appropriate value.
In order to solve the above problems, 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, and a third lens group having a positive refractive power in order from the object side. , And a fourth lens group having a positive refractive power,
During zooming, the second lens group moves to the image side, the third lens group moves so as to have a convex locus on the object side, and the fourth lens group is a zoom lens that moves on the optical axis. ,
The following conditional expression is satisfied.
13.0 <f1 / fw <26.0 (1)
2.6 <M3 / fw <5.5 (2)
fw: focal length at the wide-angle end of the entire system f1: focal length of the first lens unit M3: amount of movement in the optical axis direction with respect to the wide-angle end when the third lens unit is located closest to the object side during zooming In order to secure a magnification ratio and correct aberrations favorably, positive, negative, positive, and positive were set in order from the object side.

  When the third lens group is fixed during zooming, the front lens diameter is determined at an intermediate zoom position. Therefore, by moving the third lens group so as to have a convex locus on the object side, the distance from the first lens group to the entrance pupil is shortened at an intermediate zoom position, and the front lens diameter can be reduced. It is.

  Conditional expression (1) defines the refractive power of the first lens group. If the lower limit of the conditional expression is exceeded and the refractive power of the first lens group becomes strong, it becomes difficult to correct spherical aberration and field curvature. On the other hand, if the refractive power of the first lens group becomes weaker than the upper limit, aberration correction becomes easy, but the total lens length becomes longer, which is not preferable.

  Conditional expression (2) defines the amount of movement of the third lens group. If the lower limit of the conditional expression is exceeded and the amount of movement of the third lens group is reduced, it is difficult to reduce the front lens diameter at an intermediate zoom position. On the other hand, if the amount of movement of the third lens unit increases beyond the upper limit value of the conditional expression, the variation in field curvature due to zooming increases, making it difficult to correct aberrations.

  Although the object of the present invention is achieved by satisfying the above conditional expression, it is desirable to satisfy the following conditional expression in order to realize high performance while widening the angle of view.

5.0 <f3 / fw <7.7 (3)
Conditional expression (3) defines the refractive power of the third lens group. If the lower limit of the conditional expression is exceeded and the refractive power of the third lens group becomes strong, it becomes difficult to correct spherical aberration and axial chromatic aberration at the wide angle end. On the other hand, if the refractive power of the third lens group becomes weaker than the upper limit value, aberration correction becomes easy, but the total length becomes longer, which is not preferable.

Moreover, it is desirable to satisfy the following conditional expressions.
1.0 <f4 / √ (fw · ft) <1.8 (4)
Conditional expression (4) defines the refractive power of the fourth lens group. If the lower limit of the conditional expression is exceeded and the refractive power of the fourth lens group becomes strong, the variation in field curvature due to zooming from the wide-angle end to the telephoto end increases. On the other hand, if the refractive power of the fourth lens unit becomes weaker beyond the upper limit, the amount of movement increases in order to correct image plane variation due to zooming, which is not preferable because the total length becomes longer.

  In the zoom lens of the present invention, the stop moves together with the third lens group.

When the aperture is fixed and the third lens unit is moved, it is necessary to provide a distance so that the aperture and the third lens unit do not interfere with each other in the entire zoom range.
By moving the stop integrally with the third lens group, the front lens diameter can be reduced without increasing the total length.

  The zoom lens according to the present invention is an image pickup apparatus having an image pickup element having an image pickup element that receives a formed image.

  This relates to an imaging apparatus having an element that receives an image photographed by a zoom lens. In recent years, CCDs (Charge Coupled Devices) and CMOSs (Complementary Metal Oxide Semiconductors) are mainly used for digitally processing images, and the present invention also has an image pickup device having an image pickup device corresponding thereto. Is.

  In the zoom lens according to the present invention, the aberration is corrected by an electric correcting means.

  Unlike silver-salt film, this uses the characteristic that images can be acquired as digital data in digital cameras, etc., and image conversion processing is performed on the image obtained from the lens to reduce various aberrations as much as possible. An image is obtained.

  For example, by performing electrical correction of distortion and chromatic aberration, an image in which various aberrations are further corrected than before can be obtained. Further, from the viewpoint of cost, there is also an advantage that it is possible to avoid using an aspherical surface or anomalous dispersion glass as much as possible.

In each embodiment, it is more preferable to set the numerical ranges of conditional expressions (1) to (4) as follows in terms of aberration correction.
14.0 <f1 / fw <25.0 (1a)
2.7 <M3 / fw <5.3 (2a)
5.3 <f3 / fw <7.4 (3a)
1.05 <f4 / √ (fw · ft) <1.75 (4a)
More preferably, the numerical ranges of the conditional expressions (1) to (4) are set as follows.
15.0 <f1 / fw <24.0 (1b)
2.8 <M3 / fw <5.1 (2b)
5.6 <f3 / fw <7.1 (3b)
1.1 <f4 / √ (fw · ft) <1.7 (4b)
In each embodiment, each lens group is configured as described above to obtain a small zoom lens with a wide angle of view.

  Embodiments (numerical examples) of a zoom lens according to the present invention will be described below with reference to the drawings.

  1 to 20 are sectional views and aberration diagrams of numerical examples 1 to 5 described later.

  FIG. 1 is a lens cross-sectional view at the wide-angle end of the zoom lens of Example 1, and FIGS. 2, 3, and 4 are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively.

  FIG. 5 is a lens cross-sectional view at the wide-angle end of the zoom lens according to the second embodiment. FIGS. 6, 7, and 8 are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively.

  FIG. 9 is a lens cross-sectional view at the wide-angle end of the zoom lens according to Embodiment 3, and FIGS. 10, 11, and 12 are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively.

  FIG. 13 is a lens cross-sectional view at the wide-angle end of the zoom lens of Example 4, and FIGS. 14, 15, and 16 are aberration diagrams of the zoom lens of Example 4 at the wide-angle end, the intermediate zoom position, and the telephoto end, respectively.

  In the lens cross-sectional views, L1 to L4 are first to fourth lens groups, SP is a diaphragm or a light amount adjusting device, GB is a glass block such as a face plate or a low-pass filter, and IP is an image plane.

  In the aberration diagrams, d and g are d-line and g-line, and ΔM and ΔS are meridional image surface and sagittal image surface. Lateral chromatic aberration is represented by the g-line. Also, Fno. Is the F number, and ω is the half angle of view. D-line (solid line) and g-line (broken line) are displayed for spherical aberration, ΔM and ΔS for d-line are displayed for astigmatism, d-line is displayed for distortion, and d-line for chromatic aberration of magnification. The g-line aberration with respect to is shown.

  In the following description and drawings, ri is the radius of curvature of the i-th surface in order from the object side, di is the distance between the i-th surface and the (i + 1) -th surface, and ni and νi are the materials of the i-th lens, respectively. Refractive index and Abbe number at d-line.

  In the aspherical shape, the X axis is in the optical axis direction, the h axis is perpendicular to the optical axis, the light traveling direction is positive, R is the paraxial radius of curvature, and each aspheric coefficient is K, B (A4), C (A6). ), D (A8), E,

It is expressed by the following formula.

Further, for example, the display of “e-Z” means “10 ^−Z ”.

  In each numerical example, when zooming from the wide-angle end to the telephoto end, the second lens unit L2 is moved to the image side as indicated by the arrow in the lens cross-sectional view, and the third lens unit L3 and the stop are integrated with each other. The object is moved so as to have a convex locus on the object side. Image plane fluctuations associated with zooming are corrected by moving the fourth lens unit L4 along the optical axis.

  In addition, a rear focus type that performs focusing by moving the fourth lens unit L4 on the optical axis is employed. Curves 4a and 4b relating to the fourth lens unit L4 are movement trajectories for correcting image plane fluctuations accompanying zooming when focusing on an object at infinity and an object at close distance, respectively. In each embodiment, for example, when focusing from an infinitely distant object to a close object at the telephoto end, the fourth lens unit L4 is extended to the object side as indicated by a straight line 4c.

In each embodiment, the following means may be taken.
-It is not limited to the shape and the number of glasses shown in the examples, but should be changed as appropriate.
-The material of the aspherical lens is not limited to glass material, but a hybrid type aspherical lens in which an aspherical surface is formed with a resin material on the spherical lens surface (with an aspherical component on it) or an aspherical lens made of plastic material. Use it.
-Move some lenses and lens groups so that they have a component in the direction perpendicular to the optical axis, thereby correcting image blur due to vibration such as camera shake.

  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 corresponding to the respective examples will be shown. Table 1 shows the relationship between the above conditional expressions and numerical values in the numerical examples.

[Numerical Example 1]

Unit mm

Surface data surface number rd nd vd
1 62.223 1.30 1.84666 23.9
2 35.484 7.50 1.69680 55.5
3 583.350 0.18
4 39.542 3.50 1.69680 55.5
5 80.618 (variable)
6 29.127 0.70 1.88300 40.8
7 8.286 5.00
8 -18.510 0.60 1.71300 53.9
9 9.549 0.75
10 11.498 1.80 1.92286 18.9
11 37.527 (variable)
12 * 40.151 2.80 1.58313 59.4
13 -17.452 1.30
14 (Aperture) ∞ 2.20
15 -16.198 0.60 1.76182 26.5
16 180.629 1.00
17 * 117.183 2.80 1.58313 59.4
18 -10.365 (variable)
19 19.081 2.20 1.80 400 46.6
20 -11.306 0.55 1.84666 23.9
21 -61.168 (variable)
22 ∞ 3.41 1.54400 60.0
23 ∞ (variable)
Image plane ∞

Aspheric data 12th surface
K = -2.82538e + 000 A 4 = -1.09933e-004 A 6 = -1.41359e-006 A 8 = 4.45629e-009

17th page
K = -7.12531e + 002 A 4 = -2.96136e-005

Various data Zoom ratio 12.97

Wide angle Medium Telephoto focal length 3.31 9.42 42.98
F number 1.85 2.73 3.00
Angle of view 38.55 15.65 3.51
Image height 2.64 2.64 2.64
Total lens length 91.53 91.53 91.53
BF 4.85 9.17 13.02

d 5 0.68 17.86 37.08
d11 36.15 13.77 1.05
d18 15.08 15.95 5.60
d21 2.13 6.46 10.31
d23 0.50 0.50 0.50

Entrance pupil position 21.19 69.21 325.05
Exit pupil position 131.01 101.81 -54.47
Front principal point position 24.59 79.51 334.42
Rear principal point position -2.81 -8.92 -42.48

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 58.00 12.48 1.29 -6.05
2 6 -6.80 8.85 2.20 -4.64
3 12 18.63 10.70 6.01 -4.02
4 19 19.41 2.75 0.32 -1.22
5 22 ∞ 3.41 1.11 -1.11

Single lens Data lens Start surface Focal length
1 1 -99.75
2 2 53.92
3 4 107.61
4 6 -13.32
5 8 -8.76
6 10 17.39
7 12 21.24
8 15 -19.49
9 17 16.46
10 19 9.12
11 20 -16.46
12 22 0.00


[Numerical Example 2]

Unit mm

Surface data surface number rd nd vd
1 93.179 1.20 1.92286 18.9
2 40.049 7.70 1.88300 40.8
3 5359.694 0.18
4 35.020 3.90 1.88300 40.8
5 57.739 (variable)
6 32.571 0.70 1.88300 40.8
7 7.936 5.60
8 -13.857 0.60 1.77250 49.6
9 15.269 0.75
10 17.535 2.60 1.84666 23.9
11 -48.021 (variable)
12 (Aperture) ∞ 2.00
13 * 10.096 3.30 1.58313 59.4
14 * -40.274 0.70
15 10.582 1.00 1.92286 18.9
16 7.523 (variable)
17 14.334 3.00 1.69680 55.5
18 -7.180 0.55 1.84666 23.9
19 -18.481 (variable)
20 ∞ 3.41 1.54400 60.0
21 ∞ (variable)
Image plane ∞

Aspherical data 13th surface
K = 8.30630e-001 A 4 = -1.58785e-004 A 6 = 1.05814e-006 A 8 = -5.13417e-008
A 5 = -2.32729e-006 A 7 = -3.02943e-007

14th page
K = -1.75934e + 001 A 4 = 1.26374e-004 A 6 = 2.22673e-006 A 8 = -5.66113e-008
A 5 = -9.63346e-006

Various data Zoom ratio 12.62

Wide angle Medium telephoto focal length 3.40 9.49 42.92
F number 1.85 2.11 1.74
Angle of view 37.82 15.55 3.52
Image height 2.64 2.64 2.64
Total lens length 82.22 82.22 82.22
BF 6.92 9.33 8.79

d 5 0.70 14.89 33.34
d11 31.07 11.66 2.03
d16 8.56 11.36 3.08
d19 4.20 6.62 6.08
d21 0.50 0.50 0.50

Entrance pupil position 21.06 60.28 329.50
Exit pupil position -1770.97 77.73 -31.03
Front principal point position 24.45 70.93 314.00
Rear principal point position -2.90 -8.99 -42.41

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 51.87 12.98 1.00 -5.82
2 6 -7.99 10.25 1.33 -7.31
3 12 19.94 7.00 -0.28 -4.87
4 17 14.08 3.55 0.82 -1.33
5 20 ∞ 3.41 1.11 -1.11

Single lens Data lens Start surface Focal length
1 1 -76.94
2 2 45.67
3 4 93.29
4 6 -12.04
5 8 -9.32
6 10 15.45
7 13 14.19
8 15 -33.44
9 17 7.28
10 18 -14.18
11 20 0.00


[Numerical Example 3]

Unit mm

Surface data surface number rd nd vd
1 77.268 1.30 1.84666 23.9
2 39.655 8.50 1.69680 55.5
3 320.805 0.18
4 39.904 5.50 1.77250 49.6
5 90.912 (variable)
6 36.617 0.70 1.88300 40.8
7 9.197 5.50
8 -24.460 1.20 1.77250 49.6
9 9.769 0.75
10 11.304 2.50 1.92286 18.9
11 35.248 (variable)
12 (Aperture) ∞ 1.50
13 * 21.875 2.80 1.58313 59.4
14 -11.378 1.00
15 -31.182 0.60 1.76182 26.5
16 36.517 1.50
17 * -8.905 2.70 1.58313 59.4
18 * -7.324 (variable)
19 16.776 3.50 1.80 400 46.6
20 -9.128 0.55 1.84666 23.9
21 -48.112 (variable)
22 ∞ 3.41 1.54400 60.0
23 ∞ (variable)
Image plane ∞

Aspherical data 13th surface
K = -4.85560e + 000 A 4 = -2.92633e-004 A 6 = -2.01761e-006 A 8 = -9.75086e-008

17th page
K = -5.26689e-002 A 4 = -6.07693e-005

18th page
K = -1.18985e + 000 A 4 = -3.46318e-004 A 6 = -1.28465e-006 A 8 = -1.26414e-007

Various data Zoom ratio 13.77

Wide angle Medium Telephoto focal length 3.12 7.76 42.93
F number 1.85 2.73 3.00
Angle of View 40.27 18.78 3.52
Image height 2.64 2.64 2.64
Total lens length 97.16 97.16 97.16
BF 5.90 8.82 11.39

d 5 0.70 16.54 40.01
d11 35.17 14.90 1.16
d18 13.91 15.42 3.12
d21 3.19 6.11 8.68
d23 0.50 0.50 0.50

Entrance pupil position 23.99 65.75 374.74
Exit pupil position 41.53 33.97 -144.27
Front principal point position 27.34 75.32 404.94
Rear principal point position -2.62 -7.26 -42.43

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 62.00 15.48 1.57 -7.32
2 6 -7.00 10.65 2.48 -5.30
3 12 20.10 10.10 5.69 -3.36
4 19 16.83 4.05 0.51 -1.78
5 22 ∞ 3.41 1.11 -1.11

Single lens Data lens Start surface Focal length
1 1 -97.76
2 2 64.14
3 4 87.94
4 6 -14.08
5 8 -8.90
6 10 17.17
7 13 13.25
8 15 -21.99
9 17 43.43
10 19 7.82
11 20 -13.39
12 22 0.00


[Numerical Example 4]

Unit mm

Surface data surface number rd nd vd
1 76.088 1.50 1.84666 23.9
2 44.151 9.40 1.69680 55.5
3 311.742 0.18
4 41.572 5.80 1.69680 55.5
5 84.164 (variable)
6 39.655 0.70 1.88300 40.8
7 9.976 3.20
8 22.686 0.85 2.00 330 28.3
9 11.590 4.50
10 -14.208 0.90 1.48701 70.2
11 12.787 0.82
12 17.858 2.00 1.92286 18.9
13 321.161 (variable)
14 * 12.638 2.80 1.58313 59.4
15 * -19.725 1.30
16 (Aperture) ∞ 2.20
17 -23.476 0.60 1.76182 26.5
18 20.918 1.00
19 * -22.847 2.80 1.58313 59.4
20 -9.758 (variable)
21 19.608 2.80 1.83400 37.2
22 -8.809 0.55 1.92286 18.9
23 -25.515 (variable)
24 ∞ 3.41 1.54400 60.0
25 ∞ (variable)
Image plane ∞

Aspheric data 14th surface
K = 2.48999e-001 A 4 = -5.43882e-005 A 6 = -1.71945e-007 A 8 = 2.45456e-008

15th page
K = -6.24301e + 000 A 4 = 3.28488e-005 A 6 = 2.04654e-007 A 8 = 2.37793e-008

19th page
K = -7.63606e-001 A 4 = -1.17194e-004

Various data Zoom ratio 11.80

Wide angle Medium Telephoto focal length 2.97 8.35 35.01
F number 1.85 2.73 3.00
Angle of View 41.66 17.55 4.31
Image height 2.64 2.64 2.64
Total lens length 104.28 104.28 104.28
BF 5.20 9.46 13.07

d 5 0.68 19.99 42.94
d13 41.16 14.32 0.89
d20 12.14 15.59 2.27
d23 2.48 6.56 10.36
d25 0.50 0.50 0.50

Entrance pupil position 25.18 78.08 363.78
Exit pupil position 59.72 33.64 -40.40
Front principal point position 28.30 88.52 368.83
Rear principal point position -2.47 -7.85 -34.51

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear principal point position
1 1 70.00 16.88 0.90 -8.86
2 6 -6.80 12.97 2.46 -8.08
3 14 20.79 10.70 1.60 -8.45
4 21 15.02 3.35 0.76 -1.12
5 24 ∞ 3.41 1.11 -1.11

Single lens Data lens Start surface Focal length
1 1 -126.97
2 2 72.77
3 4 111.65
4 6 -15.26
5 8 -24.56
6 10 -13.67
7 12 20.42
8 14 13.64
9 17 -14.44
10 19 27.07
11 21 7.63
12 22 -14.81
13 24 0.00

L1: First lens group L2: Second lens group L3: Third lens group L4: Fourth lens group SP: Aperture or light amount adjusting device GB: Glass block IP: Image plane d: d line g: g line Fno: F Number ω: Half angle of view ΔS: Sagittal image plane ΔM: Meridional image plane

Claims (6)

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 positive refractive power in order from the object side. ,
During zooming, the second lens group moves to the image side, the third lens group moves so as to have a convex locus on the object side, and the fourth lens group is a zoom lens that moves on the optical axis. ,
A zoom lens satisfying the following conditional expression:
13.0 <f1 / fw <26.0 (1)
2.6 <M3 / fw <5.5 (2)
fw: focal length at the wide-angle end of the entire system f1: focal length of the first lens group M3: amount of movement in the optical axis direction with respect to the wide-angle end when the third lens group is located closest to the object side during zooming The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
5.0 <f3 / fw <7.7 (3)
f3: focal length of the third lens unit The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
1.0 <f4 / √ (fw · ft) <1.8 (4)
ft: focal length at the telephoto end of the entire system f4: focal length of the fourth lens unit   4. The zoom lens according to claim 1, wherein the third lens group includes a stop, and the zoom moves together with the third lens group during zooming. 5.   An image pickup apparatus comprising: the zoom lens according to claim 1; and an image pickup device that receives an image formed by the zoom lens. 6. The zoom lens according to claim 1, wherein an aberration is corrected by an electric correction unit.