Zoom lens and image capturing device

Abstract

To provide a zoom lens which offers high optical performance.SOLUTION: A zoom lens (1a) disclosed herein comprises a first lens group (B1) having negative refractive power, multiple lens groups (B2, B3) having positive refractive power, and a rear group including at least one lens group, arranged in order from the object side to the image side, and is configured such that the distance between each pair of adjacent lens groups changes while zooming from the wide-angle end to the telephoto end, where the multiple lens groups include a first focusing group (F1) and a second focusing group (F2) configured to move while focusing from infinity to a very short distance.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a zoom lens and an imaging apparatus. [Background technology]

[0002] Patent Document 1 discloses a zoom lens that moves the first lens group toward the object side and the second lens group toward the object side during focusing to reduce changes in the angle of view. Patent Document 2 discloses a zoom lens that has two focusing groups, a focusing group and a final lens group within the first lens group, and switches the group that moves during focusing according to the zoom position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-235862 [Patent Document 2] Patent Publication No. 2021-15195 Summary of the Invention [Problem to be solved by the invention]

[0004] In the zoom lens disclosed in Patent Document 1, the correction is made by zooming using a zoom cam, so correction is difficult in a configuration that does not allow motorized zooming, such as an interchangeable lens. In the zoom lens disclosed in Patent Document 2, the lens in the first lens group, which has a large lens diameter and is heavy, is moved, so it is difficult to motorize it and it is also difficult to reduce the change in the angle of view over the entire zoom range. For this reason, it is difficult to realize a zoom lens with high optical performance with the configurations disclosed in Patent Documents 1 and 2.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a zoom lens having high optical performance. [Means for solving the problem]

[0006] A zoom lens according to one aspect of the present invention is a zoom lens comprising, arranged in order from the object side to the image side, a first lens group having negative refractive power, multiple lens groups having positive refractive power, an aperture, and a rear group including at least one lens group, wherein the spacing between adjacent lens groups changes when zooming from the wide-angle end to the telephoto end, and the multiple lens groups include a first focus group and a second focus group that move when focusing from infinity to a close range.

[0007] Other objects and features of the present invention are illustrated in the following examples. Effect of the Invention

[0008] According to the present invention, it is possible to provide a zoom lens having high optical performance. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a zoom lens according to a first embodiment. [Diagram 2] FIG. 11 is a cross-sectional view of a zoom lens according to a second embodiment. [Diagram 3] FIG. 11 is a cross-sectional view of a zoom lens according to a third embodiment. [Figure 4] FIG. 11 is a cross-sectional view of a zoom lens according to a fourth embodiment. [Diagram 5] 4A to 4C are longitudinal aberration diagrams of the zoom lens in Example 1. [Figure 6] 8A to 8C are longitudinal aberration diagrams of the zoom lens in Example 2. [Figure 7] 11A to 11C are longitudinal aberration diagrams of the zoom lens in Example 3. [Figure 8] 13A to 13C are diagrams illustrating longitudinal aberration of the zoom lens in Example 4. [Figure 9] FIG. 2 is a schematic diagram of an image pickup apparatus including the zoom lens of each embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0011] The zoom lens (optical system) of each embodiment is composed of a first lens group B1 having negative refractive power, a plurality of lens groups (positive lens groups) having positive refractive power, an aperture stop (aperture stop) STO, and a rear group including at least one lens group, which are arranged in this order from the object side to the image side. When zooming from the wide-angle end to the telephoto end, the interval between adjacent lens groups changes. The plurality of lens groups (positive lens groups) include a first focus group F1 and a second focus group F2 that move when focusing from infinity to a close distance. That is, the zoom lens of each embodiment performs focusing using two positive lens groups (the first focus group F1 and the second focus group F2) arranged on the object side of the aperture stop STO.

[0012] FIG. 1 is a cross-sectional view of a zoom lens 1a in Example 1. In FIG. 1, the left side indicates the object side, and the right side indicates the image side. The zoom lens 1a is a large-aperture wide-angle zoom lens that is arranged in order from the object side to the image side, and is composed of a first lens group B1 with negative refractive power, a second lens group B2 with positive refractive power, a third lens group B3 with positive refractive power, an aperture stop STO, and a rear group. The lens groups that make up the rear group are arranged in order from the object side to the image side, and are composed of a fourth lens group B4 with negative refractive power, a fifth lens group B5 with positive refractive power, a sixth lens group B6 with negative refractive power, and a seventh lens group B7 with positive refractive power.

[0013] During zooming, the first lens group B1 and the seventh lens group B7 are fixed, and the second lens group B2 to the sixth lens group B6 move toward the object side. The zoom lens 1a of this embodiment has an advantage in terms of dust resistance because the overall length does not change during zooming, with little change in the center of gravity, and also has the characteristics of low zoom torque and easy compatibility with a retrofit electric zoom attachment, making it suitable for use in video shooting.

[0014] During focusing, the second lens group B2 is defined as the first focus group F1, and the third lens group B3 is defined as the second focus group F2, and the first focus group F1 and the second focus group F2 are moved in a direction along the optical axis OA. If the group with higher focus sensitivity during movement is defined as the focus group, and the group with lower focus sensitivity is defined as the floating group, then the focus group in this embodiment is the first focus group F1, and the floating group is the second focus group F2.

[0015] In the zoom lens 1a of this embodiment, when focusing from infinity to a close distance at the wide-angle end, the second lens group B2 (first focus group F1) and the third lens group B3 (second focus group F2) move in different directions. More specifically, when focusing from infinity to a close distance, the second lens group B2 (first focus group F1) moves toward the image side, and the third lens group B3 (second focus group F2) moves toward the object side. Focusing is possible by moving the second lens group B2 toward the image side, but at the same time, a change in focal length occurs and the angle of view changes, so the zoom lens is configured to cancel the change in the angle of view by moving the third lens group B3 toward the object side.

[0016] FIG. 5A shows longitudinal aberration of the zoom lens 1a at the wide-angle end, and FIG. 5B shows longitudinal aberration of the zoom lens 1a at the telephoto end. Good optical performance is obtained from the wide-angle end to the telephoto end.

[0017] In each embodiment, when focusing from infinity to a close distance at the wide-angle end, it is preferable to satisfy the following conditional formula (1), where the movement amount of the first focus unit F1 is mo1w and the movement amount of the second focus unit F2 is mo2w.

[0018] 0.00<|mo2w| / |mo1w|<1.00 …(1) Condition (1) expresses the ratio of the amount of movement of the focus group and the floating group during focusing, and it is preferable to make the amount of movement of the floating group smaller than that of the focus group. If the lower limit of condition (1) is exceeded, the effect of reducing the angle of view fluctuation cannot be obtained, which is undesirable, whereas if the upper limit of condition (1) is exceeded, the zoom movement is restricted and the overall length tends to become long, which is undesirable.

[0019] More preferably, the numerical range of conditional expression (1) is set as shown in the following conditional expression (1a).

[0020] 0.10<|mo2w| / |mo1w|<0.90 …(1a) More preferably, the numerical range of conditional expression (1) is set as in the following conditional expression (1b).

[0021] 0.15<|mo2w| / |mo1w|<0.80 …(1b) Here, the zoom movement amount of the first focus group F1 relative to the first lens group B1 (the movement amount during zooming from the wide-angle end to the telephoto end) is mF1, and the distance from the lens surface closest to the object side in the zoom lens to the image plane img is TTL. In this case, in each embodiment, it is preferable to satisfy the following conditional expression (2).

[0022] 0.00 <movF1 / TTL<0.15 …(2) Conditional formula (2) indicates a preferable range of the relative position of the first focus group F1. By zooming at a position close to the first lens group B1 having a negative refractive power, the first focus group F1 can easily obtain high focus sensitivity while contributing to magnification, and the change in the angle of view when the first focus group F1 moves alone can be reduced. If the lower limit of conditional formula (2) is exceeded, the amount of movement of the first focus group F1 is small, and it is not possible to effectively reduce the spherical aberration fluctuation caused by zooming, which is not preferable. On the other hand, if the upper limit of conditional formula (2) is exceeded, the movement trajectories of the first focus group F1 and the second focus group F2 become closer to each other, which is not preferable because it is difficult to achieve the effect of reducing the change in the angle of view.

[0023] More preferably, the numerical range of conditional expression (2) is set as shown in the following conditional expression (2a).

[0024] 0.02 <movF1 / TTL<0.13 …(2a) More preferably, the numerical range of conditional expression (2) is set as in the following conditional expression (2b).

[0025] 0.03 <movF1 / TTL<0.12 …(2b) In each embodiment, when the composite focal length of the lens group arranged on the object side of the aperture stop STO in the zoom lens is denoted by ff and the composite focal length of the lens group arranged on the image side of the aperture stop STO is denoted by fr, it is preferable that the following conditional expression (3) be satisfied:

[0026] 0.20 <ff / fr<1.00 …(3) Conditional expression (3) expresses the ratio of the focal length of the lens group on the object side of the aperture STO to the focal length of the lens group on the image side. By satisfying conditional expression (3), it is possible to reduce the variation in the angle of view even when the aperture STO is stopped down while disposing the first focus group F1 and the second focus group F2. Exceeding the upper or lower limit of conditional expression (3) is not preferable because the off-axis chief ray is likely to deviate from the center of the aperture, and the variation in the angle of view becomes large due to the effect of the one-sided aperture when the aperture STO is stopped down.

[0027] More preferably, the numerical range of conditional expression (3) is set as in the following conditional expression (3a).

[0028] 0.23 <ff / fr<0.80 …(3a) More preferably, the numerical range of conditional expression (3) is set as in the following conditional expression (3b).

[0029] 0.25 <ff / fr<0.60 …(3b) In each embodiment, when the focal length of the first focus unit F1 is fF1 and the focal length of the second focus unit F2 is fF2, it is preferable to satisfy the following conditional expression (4).

[0030] 0.3 <fF1 / fF2<1.7 …(4) Conditional expression (4) expresses the ratio between the focal length of the first focus group F1 and the focal length of the second focus group F2. By satisfying conditional expression (4), it is possible to obtain the effect of reducing the change in the angle of view caused by zooming and focusing while keeping the overall length small. If the upper limit of conditional expression (4) is exceeded, the focus movement amount of the first focus group F1 becomes too large, which is undesirable as it causes a large fluctuation in the angle of view during focusing. On the other hand, if the lower limit of conditional expression (4) is exceeded, the magnification effect of the second focus group F2 becomes too small, which causes the zoom movement amount to become large and the overall lens length to become long, which is undesirable.

[0031] More preferably, the numerical range of conditional expression (4) is set as in the following conditional expression (4a).

[0032] 0.4 <fF1 / fF2<1.5 …(4a) More preferably, the numerical range of conditional expression (4) is set as in the following conditional expression (4b).

[0033] 0.5 <fF1 / fF2<1.3 …(4b) In a typical wide-angle zoom, the first lens group B1 is moved to perform image point correction by extending the entire lens. However, if the first lens group B1 is fixed, the image point correction function is reduced, so it is preferable to place a negative lens group and a positive lens group that moves from the image side to the object side during magnification change on the image side of the aperture stop STO, and to change the spacing between each lens group during zooming.

[0034] In each embodiment, in order to reduce the overall length, it is preferable to arrange a lens group with positive refractive power closest to the image side of the zoom lens (lens group constituting the rear group). In each embodiment, it is preferable to satisfy the following conditional formula (5), where BFw is the air-equivalent length of the back focus at the wide-angle end and fw is the focal length of the zoom lens at the wide-angle end.

[0035] 0.2 <BFw / fw<2.0 …(5) Condition (5) shows the relationship of the back focus to the focal length. If the upper limit of condition (5) is exceeded, the back focus becomes too long relative to the focal length, and the overall length becomes too long, which is not preferable. On the other hand, if the lower limit of condition (5) is exceeded, the back focus becomes too short, and the lens and the lens barrel tend to interfere with the sensor, which is not preferable.

[0036] More preferably, the numerical range of conditional expression (5) is set as in the following conditional expression (5a).

[0037] 0.5 <BFw / fw<1.5 …(5a) More preferably, the numerical range of conditional expression (5) is set as in the following conditional expression (5b).

[0038] 0.8 <BFw / fw<1.3 …(5b) Fig. 2 is a cross-sectional view of a zoom lens 1b in Example 2. In Fig. 2, the left side indicates the object side, and the right side indicates the image side. The zoom lens 1b is a large-aperture wide-angle zoom lens that is composed of, in order from the object side to the image side, a first lens group B1 with negative refractive power, a second lens group B2 with positive refractive power, a third lens group B3 with positive refractive power, a fourth lens group B4 with positive refractive power, an aperture stop STO, and a rear group. The lens groups that make up the rear group are composed of a fifth lens group B5 with negative refractive power, a sixth lens group B6 with positive refractive power, and a seventh lens group B7 with positive refractive power, arranged in order from the object side to the image side.

[0039] The zoom lens 1b of this embodiment is a type in which the focal length range of wide angle and telephoto is expanded compared to the zoom lens 1a of the first embodiment, and the change in the angle of view caused by focusing is reduced even when the focal length range is expanded. In addition, the second lens group B2 is a focus group (first focus group F1), and the third lens group B3 is a floating group (second focus group F2), and the variator section is divided and assigned to variable magnification and floating, respectively. This makes it possible to reduce the weight of the focus movement group and reduce zoom fluctuations.

[0040] During zooming, both the first focus group F1 and the second focus group F2 move toward the object side, as in the first embodiment. During focusing from infinity to close range, in the range from the wide-angle end to the intermediate zoom position, the first focus group F1 moves toward the image side, and the second focus group F2 moves toward the object side, as in the first embodiment, so that the angle of view fluctuation can be suppressed. At the telephoto end, in order to ensure close distances and shorten the overall length, both the first focus group F1 and the second focus group F2 move toward the image side. At this time, the change in the angle of view at the telephoto end is not zero, but is a sufficiently small amount, and at the wide-angle end where the change in the angle of view is easily noticeable, it is possible to correct it to a value close to zero.

[0041] FIG. 3 is a cross-sectional view of a zoom lens 1c in Example 3. In FIG. 3, the left side indicates the object side, and the right side indicates the image side. The zoom lens 1c is a large-aperture wide-angle zoom lens that is composed of, in order from the object side to the image side, a first lens group B1 with negative refractive power, a second lens group B2 with positive refractive power, a third lens group B3 with positive refractive power, a fourth lens group B4 with positive refractive power, an aperture stop STO, and a rear group. The second lens group B2 is the first focus group F1, and the fourth lens group B4 is the second focus group F2. The lens groups that constitute the rear group are composed of, in order from the object side to the image side, a fifth lens group B5 with negative refractive power, a sixth lens group B6 with positive refractive power, a seventh lens group B7 with negative refractive power, and an eighth lens group B8 with positive refractive power. The zoom lens 1c of this embodiment has a much wider focal length range at the wide-angle end than the zoom lens 1a of the first embodiment, and reduces the change in the angle of view that accompanies focusing even when the angle is widened.

[0042] FIG. 4 is a cross-sectional view of a zoom lens 1d in Example 4. In FIG. 4, the left side indicates the object side, and the right side indicates the image side. The zoom lens 1d is a large-aperture wide-angle zoom lens consisting of a first lens group B1 with negative refractive power, a second lens group B2 with positive refractive power, a third lens group B3 with positive refractive power, an aperture stop STO, and a rear group, which are arranged in this order from the object side to the image side. The lens groups constituting the rear group consist of a fourth lens group B4 with negative refractive power, a fifth lens group B5 with positive refractive power, a sixth lens group B6 with negative refractive power, and a seventh lens group B7 with positive refractive power, which are arranged in this order from the object side to the image side. The zoom lens 1d in this example is a type in which the focal length range of the wide angle and telephoto is expanded compared to the zoom lens 1a in Example 1, and the change in the angle of view caused by focusing is reduced even when the focal length range is expanded.

[0043] 5, 6, 7, and 8 are longitudinal aberration diagrams showing the imaging performance of the zoom lenses 1a to 1d of Examples 1 to 4. In each aberration diagram, (A) shows the aberration diagram at the wide-angle end, and (B) shows the aberration diagram at the telephoto end, and from the left, the diagrams show the spherical aberration, the astigmatism, and the distortion aberration. In the spherical aberration, the solid line shows the aberration of the d-line (587.56 nm), the dashed line shows the aberration of the f-line (486.13 nm), the rough dashed line shows the aberration of the C-line (656.27 nm), and the two-dot chain line shows the aberration of the g-line (435.83 nm). The scale of the horizontal axis is the defocus amount, and is −0.4 to +0.4 [mm]. In the astigmatism diagram, the solid line shows the curvature of field of the sagittal image plane, and the dotted line shows the curvature of field of the meridional image plane. The horizontal axis is the same as the spherical aberration. For distortion, the horizontal axis scale is -15 to +15%.

[0044] Numerical Examples 1 to 4 corresponding to Examples 1 to 4 will be described below. In each numerical example, the surface number is the number given to each lens surface in order from the magnification side. r is the radius of curvature of each lens surface (mm), d is the surface spacing (mm), and the surface spacing in parentheses indicates the group spacing. nd and vd are the refractive index and Abbe number of the glass material for the d line (587.56 nm).

[0045] A lens surface with an asterisk (*) to the right of the surface number indicates that it has an aspheric shape according to the following function, and its coefficients are shown in the numerical examples: y is the radial coordinate when the vertex of the lens surface is used as the reference, and x is the optical axis coordinate when the vertex of the lens surface is used as the reference.

[0046] x=(y 2 / R) / [1+{1-(1+K)(y 2 / R 2 )} 1 / 2 ]+Ay 4 +By 6 +Cy 8 +Dy 10 +Fy 12 In the various data tables, the focal length and F-number (aperture value) are listed as values ​​for an object distance of infinity. The image height indicates the paraxial image height and the real image height, respectively, and here it is assumed that image distortion due to distortion aberration is corrected by processing the captured image. The total lens length indicates the distance from the first lens surface to the image position. BF indicates the back focus, which is the distance from the lens with refractive power located closest to the image side to the image plane IP, and if there is an element with no refractive power such as a flat plate between them, it is the air equivalent length calculated excluding this. In the interval data, OBJ indicates the object distance, which is expressed here as the distance from the object position to the image plane IP.

[0047] (Numerical Example 1) Unit: mm Surface Data BS EA R d glass nd v OBJ 1 1 52.86 54.8041 2.5000 SLAH89 1.85150 40.78 2 41.91 26.1910 6.3000 3 41.61 51.1936 2.3000 LLAL15 1.69304 52.93 4* 35.96 19.9502 12.4800 5* 30.92 237.3916 2.6000 SLAH95 1.90366 31.34 6 29.83 194.7316 7.3300 7 28.00 -32.1785 1.6000 SFPM2 1.59522 67.73 8 28.89 38.5920 5.6000 SNBH56 1.85478 24.80 9 29.06 -336.2204 (7.1775) 2 10 29.32 125.4790 1.5000 SNPH5 1.85896 22.73 11 29.15 42.9695 7.3000 SBSM14 1.60311 60.64 12 29.35 -47.4609 (16.9373) 3 13 29.25 29.6448 1.5000 TAFD55 2.00100 29.13 14 27.96 22.2226 8.2000 SNSL3 1.51823 58.90 15 27.68 -132.5812 (2.1766) 4 s16 17.00 Unlimited 3.8300 17 22.90 -49.8744 1.2000 SLAH89 1.85150 40.78 18 23.30 50.5772 4.0000 EFDS1W 1.92286 20.88 19 23.54 -498.2846 (9.9588) 5 20 25.22 24.6944 6.2000 SFPM2 1.59522 67.73 21 24.99 -325.3047 0.2000 22 24.58 42.0763 1.5000 SLAH60 1.83400 37.16 23 22.82 15.3362 8.4000 SFPM2 1.59522 67.73 24 22.65 -78.8115 0.7800 25 22.38 -105.2701 5.0000 SNSL36 1.51742 52.43 26 22.18 -18.4462 1.0000 NBFD29 1.77047 29.74 27 22.77 -2176.5164 (6.5370) 6 28* 23.73 -110.7182 1.8000 LLAH85V 1.85400 40.38 29* 25.66 205.5464 (1.2000) 7 30 38.21 120.0000 4.1000 EFDS1W 1.92286 20.88 31 38.57 -397.3916 17.1928 IMG Aspheric Data Surface 4 r = 1.99502e+01 K = -5.52483e-01 A = -7.91035e-06 B = -1.38810e-08 C = 4.17072e-12 D = -6.21938e-14 E = -2.32811e-16 F = 2.86624e-19 Surface 5 r = 2.37392e+02 K = 0.00000e+00 A = -5.84004e-06 B = -9.83163e-09 C = 9.77778e-12 D = -1.48934e-13 E = 6.43223e-17 F = 0.00000e+00 Surface 28 r = -1.10718e+02 K = 0.00000e+00 A = -1.05024e-04 B = 2.69301e-07 C = -3.07723e-10 D = 2.81210e-13 E = -6.41624e-15 F = 0.00000e+00 Surface 29 r = 2.05546e+02 K = 0.00000e+00 A = -8.35550e-05 B = 3.38827e-07 C = -5.37040e-10 D = 0.00000e+00 E = 0.00000e+00 F = 0.00000e+00 Various data Wide-angle end Mid-range Telephoto end Focal length 16.40 24.00 30.00 F-number 2.88 2.88 2.88 Angle of view 52.84 42.03 35.80 Paraxial image height 21.64 21.64 21.64 Real image height 18.61 20.70 21.42 TTL 158.40 158.40 158.40 BF 17.19 17.19 17.19 Interval Data Wide-angle Mid-range Telephoto Wide-angle Mid-range Telephoto Object distance Infinity Infinity Infinity 280mm 350mm 400mm d9 7.1775 1.7780 1.2000 9.2819 3.4208 2.5694 d12 16.9373 11.0189 2.0000 14.1369 9.0421 0.3000 d15 2.1766 11.0862 16.5829 2.8726 11.4201 16.9136 d19 9.9588 2.8758 1.0000 9.9588 2.8758 1.0000 d27 6.5370 5.1470 4.2451 6.5370 5.1470 4.2451 d29 1.2000 12.0813 18.9592 1.2000 12.0813 18.9592 Zoom lens group data Group starting plane focal length B1 1 -17.4381 B2 10 74.0295 B3 13 61.9737 B4 16 -72.9207 B5 20 40.8428 B6 28 -84.0399 B7 30 100.2545 (Numerical Example 2) Unit: mm Surface Data BS EA R d glass nd v OBJ 1 1 59.38 66.1424 2.5000 SLAH89 1.85150 40.78 2 46.80 29.2487 5.6000 3 46.39 45.0000 2.3000 SBAL42 1.58313 59.37 4* 41.06 20.5649 5.6000 5* 40.18 42.6792 2.2000 SLAH92 1.89190 37.13 6 36.13 28.8740 10.4000 7 36.00 -48.6042 1.6000 SFPM2 1.59522 67.73 8 37.64 40.3631 5.4000 SNBH56 1.85478 24.80 9 37.63 165.7629 0.2000 10 37.91 76.9297 4.5000 SNBH8 1.72047 34.71 11 37.67 1093.7021 (19.6727) 2 12 33.89 113.1330 1.2000 SNBH56 1.85478 24.80 13 33.42 40.7656 7.5000 SBSM28 1.61772 49.81 14 33.38 -67.7799 (12.5960) 3 15 31.61 43.8442 4.3500 SFPM2 1.59522 67.73 16 30.83 108.8785 (1.0000) 4 17 30.43 40.9083 1.2000 TAFD55 2.00100 29.13 18 29.17 24.2681 9.0000 SBSL7 1.51633 64.14 19 28.99 -73.6596 (5.8827) 5 s20 14.76 infinite 2.0000 21 21.91 -56.2465 1.2000 SLAH65V 1.80400 46.58 22 21.95 226.2022 1.6800 23 21.98 -51.0367 1.2000 SLAH66 1.77250 49.60 24 23.21 41.1961 3.9500 EFDS1W 1.92286 20.88 25 23.79 -189.1545 (13.1305) 6 26 27.71 27.7185 1.5000 TAFD55W 2.00100 29.13 27 27.03 21.1557 8.6000 SFPM3 1.53775 74.70 28 27.51 -83.7891 0.2000 29 28.03 53.7544 5.5000 SFPM2 1.59522 67.73 30 27.80 -85.3802 0.2000 31 26.86 60.1813 5.2000 SFPL51 1.49700 81.54 32 26.24 -44.3572 1.0000 NBFD29 1.77047 29.74 33 25.27 46.9107 3.4300 34* 25.30 116.1760 1.8000 LLAH85V 1.85400 40.38 35* 26.45 50.0000 (1.5000) 7 36 36.65 120.0000 4.5500 SNSL36 1.51742 52.43 37 37.17 -153.1252 (20.0054) IMG Aspheric Data Surface 4 r = 2.05649e+01 K = -6.38630e-01 A = -8.16907e-06 B = -1.97414e-09 C = -4.67214e-11 D = 9.01843e-14 E = -2.35851e-16 F = 1.72266e-19 Surface 5 r = 4.26792e+01 K = 0.00000e+00 A = -5.17486e-06 B = -3.03735e-09 C = -1.14335e-11 D = -5.94349e-15 E = 0.00000e+00 F = 0.00000e+00 Surface 34 r = 1.16176e+02 K = 0.00000e+00 A = -1.04238e-04 B = 2.17055e-07 C = -7.97888e-11 D = 1.39933e-13 E = -1.27150e-15 F = 0.00000e+00 Surface 35 r = 5.00000e+01 K = 0.00000e+00 A = -9.17868e-05 B = 2.94581e-07 C = -2.71975e-10 D = 0.00000e+00 E = 0.00000e+00 F = 0.00000e+00 Various data Wide-angle end Mid-range Telephoto end Focal length 15.40 24.00 34.50 F-number 2.88 2.88 2.88 Angle of view 54.55 42.03 32.09 Paraxial image height 21.64 21.64 21.64 Real image height 18.61 21.26 22.06 TTL 179.35 179.35 179.35 BF 20.01 17.65 25.54 Interval Data Wide-angle Mid-range Telephoto Wide-angle Mid-range Telephoto Object distance Infinity Infinity Infinity 280mm 350mm 400mm d11 19.6727 5.1155 1.0000 23.2631 7.8710 3.1338 d14 12.5960 15.4151 2.0000 6.9721 12.3169 0.3000 d16 1.0000 1.0000 6.7950 3.0334 1.3426 6.3616 d19 5.8827 13.2865 19.7386 5.8827 13.2865 19.7386 d25 13.1305 6.1448 1.2000 13.1305 6.1448 1.2000 d35 1.5000 15.1705 17.5168 1.5000 15.1705 17.5168 d37 20.0054 17.6548 25.5365 20.0054 17.6548 25.5365 Zoom lens group data Group starting plane focal length B1 1 -20.9626 B2 12 92.9094 B3 15 120.3173 B4 17 86.9686 B5 20 -41.2219 B6 26 41.7900 B7 36 130.7674 (Numerical Example 3) Unit: mm Surface Data BS EA R d glass nd v OBJ 1 1 52.09 59.2027 2.5000 SLAH89 1.85150 40.78 2 40.35 25.2169 5.0500 3 39.96 40.0000 2.5000 SLAH65V 1.80400 46.58 4* 34.25 18.0788 13.2500 5* 29.09 -138.6637 2.5000 TAFD25 1.90366 31.31 6 28.38 1829.7489 3.6500 7 28.03 -40.1475 1.4000 SFPM2 1.59522 67.73 8 28.57 36.3384 5.1000 SNBH56 1.85478 24.80 9 28.47 -689.0235 (8.8779) 2 10 27.46 63.6216 1.5000 SNPH5 1.85896 22.73 11 26.98 36.5502 6.6000 SFSL5 1.48749 70.24 12 27.12 -45.8745 (11.4346) 3 13 27.54 38.3060 3.6000 SFPL51 1.49700 81.54 14 27.33 98.2355 (1.3653) 4 15 27.55 40.0573 1.5000 TAFD55 2.00100 29.13 16 26.55 23.7272 7.3500 STIL2 1.54072 47.23 17 26.49 -69.6732 (2.0280) 5 s18 15.67 Infinite 3.6200 19 21.23 -51.0515 1.2000 TAFD30 1.88300 40.80 20 22.05 36.9523 4.1000 EFDS1W 1.92286 20.88 21 22.74 742.6839 (14.8364) 6 22 26.80 24.8694 6.8200 SFPM2 1.59522 67.73 23 26.47 -218.3764 0.2000 24 25.75 31.3592 1.5000 SLAH88 1.91650 31.60 25 23.55 15.2512 8.1000 SFPM2 1.59522 67.73 26 23.06 992.4468 1.4500 27 22.84 -110.8411 5.8000 SBAL12 1.53996 59.46 28 22.63 -16.6080 1.0000 NBFD29 1.77047 29.74 29 23.50 -301.5408 (5.0672) 7 30* 24.37 -534.6150 1.8000 LLAH85V 1.85400 40.38 31* 26.16 120.0000 (1.2000) 8 32 35.37 236.2095 3.6500 EFDS1W 1.92286 20.88 33 36.00 -164.5918 (13.9496) IMG Aspheric Data Surface 4 r = 1.80788e+01 K = -2.08409e-01 A = -1.40681e-05 B = -3.21992e-08 C = -1.45149e-11 D = -3.21578e-13 E = 3.99325e-16 F = -2.03118e-18 Surface 5 r = -1.38664e+02 K = 0.00000e+00 A = -7.94693e-06 B = -1.84773e-08 C = 3.72751e-11 D = -3.91728e-13 E = 2.17993e-16 F = 0.00000e+00 Surface 30 r = -5.34615e+02 K = 0.00000e+00 A = -9.84401e-05 B = 2.34528e-07 C = -5.20812e-10 D = 3.27435e-12 E = -1.52726e-14 F = 0.00000e+00 Surface 31 r = 1.20000e+02 K = 0.00000e+00 A = -7.53437e-05 B = 2.65764e-07 C = -1.51236e-10 D = -6.71234e-13 E = 0.00000e+00 F = 0.00000e+00 Various data Wide-angle end Mid-range Telephoto end Focal length 14.42 20.00 27.40 F-number 2.88 2.88 2.88 Angle of view 56.31 47.25 38.30 Paraxial image height 21.64 21.64 21.64 Real image height 18.61 20.71 22.06 TTL 154.50 154.50 154.50 BF 13.95 15.21 18.90 Interval Data Wide-angle Mid-range Telephoto Wide-angle Mid-range Telephoto Object distance Infinity Infinity Infinity 280mm 350mm 400mm d9 8.8779 1.7644 1.0000 10.8108 3.2406 2.3866 d12 11.4346 13.0911 2.9539 8.0026 10.8666 0.3000 d14 1.3653 1.0000 1.7878 2.8645 1.7482 3.0552 d17 2.0280 7.8507 17.9639 2.0280 7.8507 17.9639 d21 14.8364 6.2452 1.0000 14.8364 6.2452 1.0000 d29 5.0672 5.5077 3.8729 5.0672 5.5077 3.8729 d31 1.2000 8.0916 11.2788 1.2000 8.0916 11.2788 d33 13.9496 15.2083 18.9010 13.9496 15.2083 18.9010 Zoom lens group data Group starting plane focal length B1 1 -14.6826 B2 10 72.4807 B3 13 123.8691 B4 15 74.9138 B5 18 -57.1268 B6 22 39.5804 B7 30 -114.6116 B8 32 105.5706 (Numerical Example 4) Unit: mm Surface Data BS EA R d glass nd v OBJ 1 1 56.89 59.6831 2.5000 SLAH88 1.91650 31.60 2 45.16 28.2244 4.7300 3 44.80 40.0000 2.3000 SLAL14 1.69680 55.53 4* 38.15 20.3201 6.8000 5* 37.91 50.3556 2.3000 SLAH93 1.90525 35.04 6 34.83 30.2873 8.9300 7 34.71 -63.0516 1.6000 SLAL12Q 1.67790 55.35 8 36.14 34.5393 7.1000 SNBH56 1.85478 24.80 9 36.20 261.3543 0.2000 10 36.49 75.4467 3.4000 STIH53 1.84666 23.78 11 36.15 133.6277 (12.5565) 2 12 35.80 55.1695 1.5000 SNPH5 1.85896 22.73 13 34.79 30.7739 8.9000 SNBH5 1.65412 39.68 14 34.81 -98.4237 (26.3663) 3 15 33.36 41.3530 1.5000 TAFD55 2.00100 29.13 16 31.98 27.8439 9.8000 SFSL5 1.48749 70.24 17 31.80 -57.2376 (2.0000) 4 s18 16.77 Unlimited 2.0000 19 25.17 23.6438 3.0500 SFPM3 1.53775 74.70 20 24.05 29.2192 4.5700 21 23.96 -42.1852 1.2000 SLAH92 1.89190 37.13 22 24.47 31.1615 4.2000 EFDS1W 1.92286 20.88 23 24.64 260.9278 (9.4139) 5 24 25.93 34.6788 1.5000 SLAH95 1.90366 31.34 25 25.52 20.8116 8.1000 SFPM3 1.53775 74.70 26 26.50 -71.9648 0.2000 27 29.04 30.8001 8.2000 SFPM2 1.59522 67.73 28 28.76 -51.2140 (1.6134) 6 29 26.90 -229.5965 3.7000 SNPH5 1.85896 22.73 30 26.33 -51.2136 1.0000 NBFD29 1.77047 29.74 31 24.98 38.1643 4.1000 32* 24.99 -331.2751 1.8000 LLAH85V 1.85400 40.38 33* 26.02 110.0000 (1.2000) 7 34 37.67 135.8342 4.6000 STIL2 1.54072 47.23 35 38.21 -150.8802 (16.7700) IMG Aspheric Data Surface 4 r = 2.03201e+01 K = -4.40911e-01 A = -2.49618e-06 B = -5.16534e-09 C = 2.15461e-11 D = -1.41245e-13 E = 3.48943e-16 F = -3.74156e-19 Surface 5 r = 5.03556e+01 K = 0.00000e+00 A = -2.25139e-06 B = 1.90669e-10 C = -6.15158e-12 D = 1.79381e-14 E = -2.26347e-17 F = 0.00000e+00 Surface 32 r = -3.31275e+02 K = 0.00000e+00 A = -1.21024e-04 B = 3.97839e-07 C = 2.86516e-10 D = -2.67375e-12 E = 2.31235e-15 F = 0.00000e+00 Surface 33 r = 1.10000e+02 K = 0.00000e+00 A = -1.00095e-04 B = 5.14427e-07 C = -6.10752e-10 D = 0.00000e+00 E = 0.00000e+00 F = 0.00000e+00 Various data Wide-angle end Mid-range Telephoto end Focal length 15.40 24.00 34.50 F-number 2.88 2.88 2.88 Angle of view 54.55 42.03 32.09 Paraxial image height 21.64 21.64 21.64 Real image height 18.61 21.04 22.06 TTL 179.70 179.70 179.70 BF 16.77 19.64 20.70 Interval Data Wide-angle Mid-range Telephoto Wide-angle Mid-range Telephoto Object distance Infinity Infinity Infinity 280mm 350mm 400mm d11 12.5565 1.2363 1.0000 14.9466 3.0633 2.2964 d14 26.3663 18.3489 2.0000 23.5414 16.7524 2.6901 d17 2.0000 12.7636 20.0679 2.4348 12.5331 18.0814 d23 9.4139 4.2982 1.2000 9.4139 4.2982 1.2000 d28 1.6134 1.9397 1.2000 1.6134 1.9397 1.2000 d33 1.2000 11.6882 23.7548 1.2000 11.6882 23.7548 d35 16.7700 19.6446 20.6962 16.7700 19.6446 20.6962 Zoom lens group data Group starting plane focal length B1 1 -17.6659 B2 12 65.6278 B3 15 70.8286 B4 18 -58.7680 B5 24 23.4941 B6 29 -29.4723 B7 34 132.9449 Table 1 shows the values ​​of the conditional expressions in each embodiment.

[0048] [Table 1]

[0049] Table 2 shows the angle of view (degrees) in each example.

[0050] [Table 2]

[0051] Table 3 shows the fold change (%) for each example.

[0052] [Table 3]

[0053] (Imaging device) Next, an imaging device 200 equipped with a zoom lens of each embodiment will be described with reference to FIG. 9. FIG. 9 is a schematic diagram of the imaging device 200. In FIG. 9, 50 is a camera body, and 100 is a lens device equipped with a zoom lens of each embodiment. 60 is an imaging element (photoelectric conversion element) such as a CMOS sensor or a CCD sensor that is built into the camera body 50 and receives an optical image formed by the zoom lens of the lens device 100 and photoelectrically converts it. The camera body 50 may be either a so-called single-lens reflex camera having a quick-turn mirror, or a so-called mirrorless camera having no quick-turn mirror. The zoom lens of each embodiment can be applied not only to digital still cameras, but also to other imaging devices such as video cameras.

[0054] The zoom lens of each embodiment has little aberration fluctuation during zooming, provides high optical performance over the entire object distance range, and has little change in the angle of view during focusing. Therefore, according to each embodiment, it is possible to provide a zoom lens and an image pickup apparatus having high optical performance.

[0055] The disclosure of each embodiment includes the following configuration. (Configuration 1) A zoom lens including, in order from an object side to an image side, a first lens group having negative refractive power, a plurality of lens groups having positive refractive power, an aperture stop, and a rear group including at least one lens group, When zooming from the wide-angle end to the telephoto end, the spacing between adjacent lens groups changes. A zoom lens, wherein the plurality of lens groups include a first focus group and a second focus group that move during focusing from infinity to a close range. (Configuration 2) 2. The zoom lens according to configuration 1, wherein, during focusing from infinity to a close distance at the wide-angle end, the first focus group and the second focus group move in different directions from each other. (Configuration 3) The zoom lens according to configuration 2, wherein, during focusing from infinity to a close distance at the wide-angle end, the first focus group moves toward the image side, and the second focus group moves toward the object side. (Configuration 4) When focusing from infinity to a close distance at the wide-angle end, the amount of movement of the first focus group is defined as mo1w and the amount of movement of the second focus group is defined as mo2w. 0.00<|mo2w| / |mo1w|<1.00 4. The zoom lens according to any one of the configurations 1 to 3, wherein the following condition is satisfied: (Configuration 5) Let mF1 be the amount of zoom movement of the first focus group relative to the first lens group, and TTL be the distance from the lens surface closest to the object side in the zoom lens to an image plane. 0.00 <movF1 / TTL<0.15 5. The zoom lens according to any one of the first to fourth aspects, wherein the following condition is satisfied: (Configuration 6) In the zoom lens, let ff be the composite focal length of the lens group arranged on the object side of the aperture and fr be the composite focal length of the lens group arranged on the image side of the aperture. 0.20 <ff / fr<1.00 6. The zoom lens according to any one of configurations 1 to 5, wherein the following condition is satisfied: (Configuration 7) When the focal length of the first focus group is fF1 and the focal length of the second focus group is fF2, 0.3 <fF1 / fF2<1.7 7. The zoom lens according to any one of configurations 1 to 6, wherein the following condition is satisfied: (Configuration 8) When zooming from the wide-angle end to the telephoto end, the first lens group is fixed with respect to an image plane; 8. The zoom lens according to any one of configurations 1 to 7, wherein the first focus group and the second focus group move toward the object side. (Configuration 9) 9. The zoom lens according to any one of configurations 1 to 8, wherein the lens group constituting the rear group has a negative lens group and a positive lens group that moves from the image side to the object side during magnification variation. (Configuration 10) the lens group constituting the rear group includes a lens group having a positive refractive power that is disposed closest to the image side, When the air-equivalent length of the back focus at the wide-angle end is BFw and the focal length of the zoom lens at the wide-angle end is fw, 0.2 <BFw / fw<2.0 10. The zoom lens according to any one of configurations 1 to 9, wherein the following condition is satisfied: (Configuration 11) 11. An imaging device comprising the zoom lens according to any one of configurations 1 to 10 and an imaging element.

[0056] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention.

[0057] For example, a lens group having a weak refractive power may be further disposed on the object side or image side of the zoom lens of each embodiment. [Explanation of symbols]

[0058] 1a, 1b, 1c, 1d Zoom Lenses B1 First lens group B2 2nd lens group B3 3rd lens group B4, B5, B6, B7, B8 rear group F1 First focus group F2 Second focus group

Claims

1. A zoom lens including, in order from an object side to an image side, a first lens group having negative refractive power, a plurality of lens groups having positive refractive power, a stop, and a rear group including at least one lens group, When zooming from the wide-angle end to the telephoto end, the spacing between adjacent lens groups changes.

1. A zoom lens, wherein the plurality of lens groups include a first focus group and a second focus group that move during focusing from infinity to a close range.

2. 2. The zoom lens according to claim 1, wherein, during focusing from infinity to a close distance at the wide-angle end, the first focus group and the second focus group move in different directions from each other.

3. 3. The zoom lens according to claim 2, wherein, during focusing from infinity to a close distance at the wide-angle end, the first focus unit moves toward the image side, and the second focus unit moves toward the object side.

4. When focusing from infinity to a close distance at the wide-angle end, the amount of movement of the first focus group is defined as mo1w and the amount of movement of the second focus group is defined as mo2w, 0.00<|mo2w| / |mo1w|<1.00 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

5. Let mF1 be the amount of zoom movement of the first focus group relative to the first lens group, and TTL be the distance from the lens surface closest to the object side in the zoom lens to an image plane. 0.00<movF1 / TTL<0.15 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

6. In the zoom lens, when a composite focal length of a lens group arranged on the object side of the aperture is ff and a composite focal length of a lens group arranged on the image side of the aperture is fr, 0.20<ff / fr<1.00 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

7. When the focal length of the first focus group is fF1 and the focal length of the second focus group is fF2, 0.3<fF1 / fF2<1.7 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

8. When zooming from the wide-angle end to the telephoto end, the first lens group is fixed with respect to an image plane, 2. The zoom lens according to claim 1, wherein the first focus group and the second focus group move toward the object side.

9. 2. The zoom lens according to claim 1, wherein the lens group constituting the rear group includes a negative lens group and a positive lens group that moves from the image side to the object side during zooming.

10. the lens group constituting the rear group includes a lens group having a positive refractive power that is disposed closest to the image side, When the air-equivalent length of the back focus at the wide-angle end is BFw and the focal length of the zoom lens at the wide-angle end is fw, 0.2<BFw / fw<2.0 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

11. An imaging device comprising: the zoom lens according to claim 1 ; and an imaging element.

Images