Zoom lens and imaging apparatus having the same

Abstract

To provide a zoom lens that has high optical performance, a high variable power, and a small size.SOLUTION: A zoom lens consists of 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 subsequent group including three or more lens groups, which are arranged in order from an object side to an image side, and the interval between the adjacent lens groups changes in zooming. In zooming from a wide-angle end to a telephoto end, the first lens group, the third lens group, and all the lens groups included in the subsequent group move to the object side, and the second lens group moves to the image side on a convex locus. The zoom lens satisfies predetermined conditional expressions.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a zoom lens, which is suitable for use in imaging devices such as digital video cameras, digital still cameras, broadcast cameras, and cameras for silver halide film. [Background technology]

[0002] In recent years, imaging optical systems used in imaging apparatuses are required to have high optical performance, a high zoom ratio, and a small size.

[0003] In order to obtain a compact imaging optical system with a high zoom ratio, Patent Document 1 discloses an optical system having six lens groups. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-86537 A Summary of the Invention [Problem to be solved by the invention]

[0005] The zoom lens of Patent Document 1 has a lens group arranged in the following order from the object side to the image side: positive, negative, positive, positive, negative, positive. However, since the refractive power of the second lens group is strong, lateral chromatic aberration at the wide-angle end tends to become large, and the fluctuation of field curvature that occurs during zooming tends to become large.

[0006] SUMMARY OF THE PRESENT EMBODIMENTS An object of the present invention is to provide a zoom lens having high optical performance, a high zoom ratio and a small size. [Means for solving the problem]

[0007] The optical system of the present invention is a zoom lens comprising, in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a subsequent group including three or more lens groups, and in which the spacing between adjacent lens groups changes during zooming. During zooming from the wide-angle end to the telephoto end, the first lens group, the third lens group, and all of the lens groups included in the subsequent group move toward the object side, and the second lens group moves along a locus convex toward the image side. When the focal length of the first lens group is f1, the focal length of the second lens group is f2, and the composite focal length of the subsequent group at the wide-angle end is fr, 3.50 <f1 / |f2|<5.33 0.30 <fr / |f2|<2.30 The present invention is characterized in that the following conditional expression is satisfied: Effect of the Invention

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

[0009] [Figure 1] FIG. 1 is a cross-sectional view of a zoom lens at a wide-angle end according to a first embodiment. [Diagram 2] Aberration diagrams of the zoom lens of Example 1 at (A) the wide-angle end, (B) the zoom intermediate position, and (C) the telephoto end. [Diagram 3] 1 is a cross-sectional view of a zoom lens at a wide-angle end according to a second embodiment of the present invention; [Figure 4] FIG. 13 is aberration diagram of the zoom lens of Example 2 at (A) the wide-angle end, (B) the zoom intermediate position, and (C) the telephoto end. [Diagram 5] 11 is a cross-sectional view of a zoom lens at a wide-angle end according to a third embodiment of the present invention; [Figure 6] FIG. 13 is aberration diagram of the zoom lens of Example 3 at (A) the wide-angle end, (B) the zoom intermediate position, and (C) the telephoto end. [Figure 7] 11 is a cross-sectional view of a zoom lens at a wide-angle end according to a fourth embodiment of the present invention; [Figure 8]FIG. 13 is aberration diagram of the zoom lens of Example 4 at (A) the wide-angle end, (B) the zoom intermediate position, and (C) the telephoto end. [Figure 9] Schematic diagram showing an imaging device DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an optical system and an image pickup apparatus having the same according to the present invention will be described with reference to the accompanying drawings.

[0011] 1, 3, 5, and 7 are cross-sectional views of the zoom lens L0 of Examples 1 to 4. The zoom lens L0 of each Example is a zoom lens used in imaging devices such as digital video cameras, digital still cameras, broadcast cameras, cameras for silver halide film, surveillance cameras, and vehicle-mounted cameras.

[0012] In each lens cross-sectional view, the left side is the object side and the right side is the image side. The zoom lens L0 of each embodiment may be used as a projection lens for a projector, etc. In this case, the left side is the screen side and the right side is the projected image side.

[0013] The zoom lens L0 of each embodiment is composed of a first lens group B1 with positive refractive power, a second lens group B2 with negative refractive power, a third lens group B3 with positive refractive power, and a subsequent group Br including three or more lens groups, arranged in this order from the object side to the image side. The interval between adjacent lens groups changes during zooming. Each lens group may be composed of one lens or multiple lenses. The lens groups may also include an aperture stop.

[0014] The solid arrows shown below each lens cross-sectional view represent the movement locus of each lens group during zooming from the wide-angle end to the telephoto end when focusing on an object at infinity, and the dashed arrows shown below each lens cross-sectional view represent the movement locus of the focus group Bf during zooming from the wide-angle end to the telephoto end when focusing on an object at close range.

[0015] In each lens cross-sectional view, SP is an aperture stop. IP is an image plane, and when the zoom lens of each embodiment is used in a digital still camera or digital video camera, the imaging surface of a solid-state imaging element (photoelectric conversion element) such as a CCD sensor or CMOS sensor is disposed thereon. When the zoom lens of each embodiment is used as the photographing optical system of a silver halide film camera, a photosensitive surface equivalent to the film surface is disposed on the image plane IP.

[0016] 2, 4, 6 and 8 are aberration diagrams of the zoom lenses of Examples 1 to 4 when focused on an object at infinity at the wide-angle end, the intermediate zoom position and the telephoto end, respectively.

[0017] In the spherical aberration diagram, Fno is the F-number, and shows the amount of spherical aberration for the d-line (wavelength 587.6 nm) and g-line (wavelength 435.8 nm). In the astigmatism diagram, S shows the amount of aberration on the sagittal image plane, and M shows the amount of aberration on the meridional image plane. The distortion aberration diagram shows the amount of distortion for the d-line. The chromatic aberration diagram shows the amount of lateral chromatic aberration for the g-line. ω is the half angle of view (°).

[0018] Next, the characteristic configuration of the zoom lens of each embodiment will be described.

[0019] In the zoom lens L0 of each embodiment, the refractive power of the first lens group B1 is positive and the refractive power of the second lens group B2 is negative, so that the principal point is located on the object side and the overall lens length (the distance on the optical axis from the lens surface closest to the object side of the zoom lens L0 to the image plane) is shortened. In addition, the refractive power of the third lens group B3 is positive, so that the longitudinal chromatic aberration occurring in the second lens group B2, particularly at the telephoto end, is suppressed. Furthermore, by disposing a trailing group Br including three or more lens groups, fluctuations in various aberrations occurring during zooming are suppressed while maintaining a high zoom ratio.

[0020] In addition, when zooming from the wide-angle end to the telephoto end, the first lens group B1 moves toward the object side, thereby shortening the overall lens length at the wide-angle end. Furthermore, all lens groups included in the third lens group B3 and the subsequent group Br move toward the object side, thereby preventing a large change in the air space between adjacent lens groups. As a result, it is possible to prevent the height from the optical axis of the on-axis marginal rays and the height from the optical axis of the off-axis rays incident on each lens group at the telephoto end from increasing, and it is possible to reduce the diameter of the lenses arranged in each lens group.

[0021] Furthermore, during zooming from the wide-angle end to the telephoto end, the second lens unit B2 moves along a locus that is convex toward the image side, thereby reducing the amount of field curvature at the intermediate zoom position.

[0022] Moreover, the zoom lens L0 in each embodiment is configured to satisfy the following conditional expressions. 3.50 <f1 / |f2|<5.33···(1) 0.30 <fr / |f2|<2.30···(2)

[0023] Here, f1 is the focal length of the first lens unit B1, f2 is the focal length of the second lens unit B2, and fr is the composite focal length of the subsequent lens unit Br at the wide-angle end.

[0024] Conditions (1) and (2) are intended to correct various aberrations, achieve a high zoom ratio, and achieve compactness.

[0025] If the refractive power of the second lens group B2 becomes too strong, exceeding the upper limit of conditional expression (1), it becomes difficult to correct lateral chromatic aberration, particularly at the wide-angle end, and fluctuations in field curvature that occur during zooming. If the refractive power of the second lens group B2 becomes too weak, falling below the lower limit of conditional expression (1), the amount of movement of the second lens group B2 during zooming becomes large in order to obtain a high zoom ratio. As a result, the overall lens length becomes long, which is undesirable.

[0026] If the refractive power of the subsequent lens unit Br becomes too weak, exceeding the upper limit of conditional expression (2), it becomes difficult to suppress the spherical aberration and axial chromatic aberration that occur in the second lens unit B2, particularly at the telephoto end. If the refractive power of the subsequent lens unit Br becomes too strong, falling below the lower limit of conditional expression (2), the principal point of the entire system is located on the image side. As a result, the overall lens length becomes long, which is undesirable.

[0027] With the above configuration, it is possible to realize a zoom lens that has high optical performance, a high zoom ratio, and a small size.

[0028] It is preferable that at least one of the upper limit and the lower limit of the numerical range of either condition (1) or (2) satisfies the numerical value of the following condition (1a) or (2a). 3.70 <f1 / |f2|<5.33···(1a) 0.60 <fr / |f2|<2.20···(2a)

[0029] It is even more preferable that at least one of the upper limit and the lower limit of the numerical range of either conditional formula (1) or (2) satisfies the range of the following conditional formula (1b) or (2b). 4.00 <f1 / |f2|<5.32···(1b) 1.00 <fr / |f2|<2.10···(2b)

[0030] Next, a preferred configuration of the zoom lens L0 in each embodiment will be described.

[0031] The first lens group B1 is preferably composed of one lens, which makes it possible to reduce the thickness of the first lens group B1 in the optical axis direction and shorten the overall lens length.

[0032] The second lens unit B2 is preferably made up of four lenses, which can suppress fluctuations in curvature of field that occur particularly during zooming.

[0033] The third lens group B3 is preferably composed of a positive lens, a positive lens, and a negative lens arranged in that order from the object side to the image side, so that the principal point of the third lens group B3 can be arranged on the object side, and the overall lens length can be shortened.

[0034] The rear group Br preferably has a focus group Bf that moves during focusing. Since the height from the optical axis of off-axis rays passing through the lenses in the rear group Br is relatively low, the radial size of the focus group Bf can be made small.

[0035] Furthermore, it is preferable that at least one lens group arranged closer to the image side than the focus group Bf has at least one negative lens and at least one positive lens. By arranging a negative lens and a positive lens closer to the image side than the focus group Bf, fluctuations in lateral chromatic aberration that occurs during focusing can be suppressed.

[0036] Moreover, it is preferable that the focus group Bf is composed of one lens, which makes it possible to reduce the thickness of the focus group in the optical axis direction.

[0037] Moreover, the rear group Br has a lens group Bp2 having positive refractive power arranged adjacent to the focus group Bf on the object side, and it is preferable that the lens group Bp2 has the strongest refractive power among the lens groups arranged in the rear group Br. As a result, the focus group Bf can be arranged at a position where the height from the optical axis is low with respect to off-axial rays, and the radial size of the focus group Bf can be reduced.

[0038] Next, the conditional expressions that are preferably satisfied in the zoom lens L0 of each embodiment will be described.

[0039] It is preferable that the zoom lens L0 of each embodiment satisfies one or more of the following conditional expressions. 1.34 <f3 / |f2|<4.26···(3) 1.31 <f1 / ft<2.81···(4) 0.66<|f2| / fw<1.41 (5) 1.14 <Lt / ft<2.49···(6) 1.52 <Lw / fr<4.10···(7) 0.50 <fs / f3<1.85···(8) 1.00<|ff / f2|<2.74···(9) 0.75<|ff| / fr<1.81···(10) 3.50 <f1 / fp2<7.19···(11) 1.35 <f3 / fp2<5.26···(12)

[0040] Here, f3 is the focal length of the third lens group B3. ft is the focal length of the entire system at the telephoto end, and fw is the focal length of the entire system at the wide-angle end. Lt is the distance on the optical axis from the lens surface closest to the object to the lens surface closest to the image at the telephoto end. Lw is the distance on the optical axis from the lens surface closest to the object to the lens surface closest to the image at the wide-angle end.

[0041] fs is the focal length of the positive lens having an aspherical shape arranged in the third lens group B3. ff is the focal length of the focus group Bf in the subsequent group Br. fp2 is the focal length of the lens group Bp2 having the strongest refractive power among the lens groups having positive refractive power arranged in the subsequent group Br. Note that when the third lens group B3 includes multiple positive lenses having an aspherical shape, the focal length of the positive lens having the strongest refractive power is taken as fs.

[0042] Next, the technical meanings of the above-mentioned conditional expressions (3) to (12) will be explained.

[0043] If the refractive power of the third lens group B3 becomes too weak by exceeding the upper limit of conditional expression (3), the amount of movement of the third lens group B3 during zooming becomes large, and the overall lens length becomes long. If the refractive power of the third lens group B3 becomes too strong by falling below the lower limit of conditional expression (3), it becomes difficult to correct spherical aberration over the entire zoom range.

[0044] If the refractive power of the first lens unit B1 becomes too weak by exceeding the upper limit of conditional expression (4), the amount of movement of the first lens unit B1 during zooming becomes large, and the overall lens length becomes long. If the refractive power of the first lens unit B1 becomes too strong by falling below the lower limit of conditional expression (4), it becomes difficult to correct spherical aberration, particularly at the telephoto end.

[0045] If the refractive power of the second lens unit B2 becomes too weak by exceeding the upper limit of conditional expression (5), the amount of movement of the second lens unit B2 during zooming becomes large, and the overall lens length becomes long. If the refractive power of the second lens unit B2 becomes too strong by falling below the lower limit of conditional expression (5), it becomes difficult to correct the variation in field curvature that occurs during zooming.

[0046] If the upper limit of conditional expression (6) is exceeded, the overall lens length at the telephoto end becomes too long, whereas if the lower limit of conditional expression (6) is not reached and the overall lens length at the telephoto end becomes too short, the refractive power of the first lens unit B1 in particular becomes too strong, making it difficult to correct spherical aberration at the telephoto end.

[0047] If the upper limit of conditional expression (7) is exceeded, the overall lens length at the wide-angle end becomes too long, whereas if the lower limit of conditional expression (7) is not reached and the overall lens length at the wide-angle end becomes too short, the refractive power of the first lens unit B1 in particular becomes too strong, making it difficult to correct spherical aberration at the telephoto end.

[0048] If the refractive power of the aspherical positive lens in the third lens group B3 becomes too weak, exceeding the upper limit of conditional expression (8), it becomes difficult to strengthen the refractive power of the third lens group B3 within an appropriate range, and the overall lens length becomes long. If the refractive power of the aspherical positive lens in the third lens group B3 becomes too strong, falling below the lower limit of conditional expression (8), it becomes difficult to correct spherical aberration, particularly at the telephoto end.

[0049] If the refractive power of the focus group Bf becomes too weak, exceeding the upper limit of conditional expression (9), the amount of movement of the focus group Bf during focusing becomes large, and the space required for movement becomes large, resulting in a long overall lens length. If the refractive power of the focus group Bf becomes too strong, falling below the lower limit of conditional expression (9), it becomes difficult to correct curvature of field, particularly at the wide-angle end.

[0050] If the refractive power of the succeeding unit Br becomes too strong, exceeding the upper limit of condition (10), the principal point of the entire system will be located on the image side, resulting in a long overall lens length. If the refractive power of the focus unit Bf becomes too strong, falling below the lower limit of condition (10), it will be difficult to correct curvature of field, particularly at the wide-angle end.

[0051] If the upper limit of conditional expression (11) is exceeded and the refractive power of the lens unit Bp2, which has the strongest refractive power among the lens units having positive refractive power arranged in the subsequent unit Br, becomes too strong, it becomes difficult to correct coma aberration and curvature of field in particular. If the lower limit of conditional expression (11) is exceeded and the refractive power of the first lens unit B1 becomes too strong, it becomes difficult to correct spherical aberration, especially at the telephoto end.

[0052] If the upper limit of conditional expression (12) is exceeded and the refractive power of the lens unit Bp2, which has the strongest refractive power among the lens units having positive refractive power arranged in the subsequent unit Br, becomes too strong, it becomes difficult to correct coma aberration and curvature of field in particular. If the lower limit of conditional expression (12) is exceeded and the refractive power of the third lens unit B3 becomes too strong, it becomes difficult to correct spherical aberration, especially at the wide-angle end.

[0053] It is more preferable to set at least one of the upper and lower limits of the conditional expressions (3) to (12) to the following numerical ranges. 1.53 <f3 / |f2|<3.93···(3a) 1.49 <f1 / ft<2.59···(4a) 0.75<|f2| / fw<1.30 (5a) 1.30 <Lt / ft<2.30···(6a) 1.74 <Lw / fr<3.78···(7a) 0.57 <fs / f3<1.71···(8a) 1.15<|ff / f2|<2.53···(9a) 0.86<|ff| / fr<1.67···(10a) 4.01 <f1 / fp2<6.64···(11a) 1.55 <f3 / fp2<4.85···(12a)

[0054] Moreover, it is more preferable to set at least one of the upper and lower limits of the conditional expressions (3) to (12) to the following numerical ranges. 1.81 <f3 / |f2|<3.44···(3b) 1.77 <f1 / ft<2.27···(4b) 0.89<|f2| / fw<1.14 (5b) 1.55 <Lt / ft<2.01···(6b) 2.07 <Lw / fr<3.31···(7b) 0.68 <fs / f3<1.49···(8b) 1.36<|ff / f2|<2.22···(9b) 1.02<|ff| / fr<1.47···(10b) 4.76 <f1 / fp2<5.81···(11b) 1.84 <f3 / fp2<4.25···(12b)

[0055] Next, the configuration of the zoom lens L0 in each embodiment will be described in detail.

[0056] [Example 1] The zoom lens L0 of the first embodiment is composed of, arranged in order from the object side to the image side, a first lens group B1 with positive refractive power, a second lens group B2 with negative refractive power, a third lens group B3 with positive refractive power, and a rear group Br. The rear group Br is composed of, arranged in order from the object side to the image side, 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 negative refractive power. By appropriately arranging the lens groups with positive refractive power and the lens groups with negative refractive power, various aberrations are well corrected throughout the entire zoom range.

[0057] The second lens group B2 is composed of four lenses arranged in that order from the object side to the image side: a negative lens, a negative lens, a positive lens, and a negative lens. By configuring the second lens group B2 with four lenses and arranging a positive lens, fluctuations in lateral chromatic aberration that occurs in the second lens group B2 during zooming are suppressed.

[0058] In addition, in order to reduce the thickness in the optical axis direction and the size in the radial direction of the groups that move during focusing, the sixth lens group B6, which is composed of one negative lens, moves toward the image side during focusing from infinity to a close distance. Furthermore, the single negative lens that constitutes the sixth lens group B6 has a meniscus shape with its convex surface facing the object side. By making the meniscus shape with its convex surface facing the object side, it is possible to suppress the fluctuation of spherical aberration that occurs during focusing.

[0059] Moreover, the aperture diaphragm that determines Fno is disposed closest to the object side of the third lens group B3. By disposing the aperture diaphragm closest to the object side of the third lens group B3, which has a relatively small diameter, the diameter of the aperture diaphragm can be made small.

[0060] [Example 2] The zoom lens L0 of the second embodiment is composed of, arranged in order from the object side to the image side, a first lens group B1 with positive refractive power, a second lens group B2 with negative refractive power, a third lens group B3 with positive refractive power, and a rear group Br. The rear group Br is composed of, arranged in order from the object side to the image side, a fourth lens group B4 with positive refractive power, a fifth lens group B5 with negative refractive power, and a sixth lens group B6 with negative refractive power.

[0061] In the zoom lens L0 of the second embodiment, the number of lens groups in the rear group Br is reduced compared to the first embodiment, thereby making it easier to suppress relative decentering between the lens groups that occurs during zooming and to ensure high optical performance.

[0062] [Example 3] The zoom lens L0 of the third embodiment is composed of, arranged in order from the object side to the image side, a first lens group B1 with positive refractive power, a second lens group B2 with negative refractive power, a third lens group B3 with positive refractive power, and a rear group Br. The rear group Br is composed of, arranged in order from the object side to the image side, a fourth lens group B4 with positive refractive power, a fifth lens group B5 with negative refractive power, and a sixth lens group B6 with positive refractive power.

[0063] In the zoom lens L0 of Example 3, the refractive power of the sixth lens group B6, which is disposed adjacent to the object side of the fifth lens group B5, which has a negative refractive power compared to Example 2, is made positive, making it easier to suppress lateral chromatic aberration generated in the fifth lens group B5.

[0064] [Example 4] The zoom lens L0 of the fourth embodiment is composed of, arranged in order from the object side to the image side, a first lens group B1 with positive refractive power, a second lens group B2 with negative refractive power, a third lens group B3 with positive refractive power, and a rear group Br. The rear group Br is composed of, arranged in order from the object side to the image side, 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, a seventh lens group B7 with negative refractive power, and an eighth lens group B8 with positive refractive power.

[0065] In the zoom lens L0 of the fourth embodiment, by having an eighth lens group B8 having positive refractive power arranged adjacent to the seventh lens group B7 having negative refractive power on the image side, fluctuations in field curvature that occur during zooming are suppressed.

[0066] Numerical examples 1 to 4 corresponding to the first to fourth embodiments, respectively, are shown below.

[0067] In the surface data of each numerical example, r represents the radius of curvature of each optical surface, and d (mm) represents the axial spacing (distance on the optical axis) between the mth surface and the (m+1)th surface. Here, m is the surface number counted from the light incident side. In addition, nd represents the refractive index of each optical member with respect to the d-line, and νd represents the Abbe number of the optical member. Note that the Abbe number νd of a certain material is given by the following, where Nd, NF, and NC are the refractive indices at the d-line (wavelength 587.6 nm), F-line (wavelength 486.1 nm), C-line (wavelength 656.3 nm), and g-line (wavelength 435.8 nm): νd=(Nd-1) / (NF-NC) It is expressed as:

[0068] The two surfaces closest to the image correspond to glass blocks (GB). The aspheric shape is such that the X axis is in the direction of the optical axis, the H axis is perpendicular to the optical axis, the light travels in the positive direction, R is the paraxial radius of curvature, K is the conic constant, and A4, A6, A8, A10, and A12 are the aspheric coefficients.

[0069]

number

[0070] The symbol * denotes a surface with an aspheric shape. "ex" is 10 -x Ba is the back focus, which indicates the distance from the final lens surface to the image surface in air equivalent. Wide angle indicates the wide angle end, intermediate indicates the intermediate position of the zoom, and telephoto indicates the telephoto end. Furthermore, the surface with surface number 1 is a virtual surface, and the configuration is not limited to including virtual surfaces, and may be deleted.

[0071] [Numerical Example 1] Unit: mm Surface Data Surface number rd nd νd 1∞1.60 2 71.698 7.40 1.49700 81.7 3 -1074.771 (variable) 4 95.769 1.60 1.89190 37.1 5 22.455 7.05 6 -369.959 1.25 1.60311 60.6 7 22.126 7.00 1.90366 31.3 8 412.508 4.86 9 -36.457 1.00 1.85150 40.8 10 -89.252 (variable) 11 (Aperture) ∞ 0.65 12 43.928 3.45 2.00100 29.1 13 -750.000 2.40 14* 106.432 3.70 1.58313 59.4 15* -70.798 2.33 16 -41.445 1.20 1.77047 29.7 17 220.269 (variable) 18 ∞ 1.20 1.85478 24.8 19 28.842 6.10 1.49700 81.7 20 -56.203 (variable) 21* 55.622 3.80 1.58313 59.4 22* -248.880 0.20 23 69.909 7.75 1.59522 67.7 24 -31.690 (variable) 25 71.379 1.10 1.61340 44.3 26 23.380 (variable) 27 -53.964 1.30 1.74400 44.8 28 43.097 4.80 1.92286 20.9 29 -750.000 (variable) 30 ∞ 2.00 1.54400 66.3 31 ∞ (variable) Image plane ∞ Aspheric Data Side 14 K = 0.00000e+00 A 4=-5.91734e-06 A 6=-1.25922e-08 A 8=-6.96192e-11 A10=-1.24634e-13 A12= 3.32938e-16 Page 15 K = 0.00000e+00 A 4=-2.81431e-06 A 6=-1.15888e-08 A 8=-1.20810e-10 A10= 3.67743e-13 A12=-6.62375e-16 Page 21 K = 0.00000e+00 A 4=-2.16306e-06 A 6=-3.51669e-08 A 8= 3.80997e-12 A10=-8.02806e-13 A12= 7.68937e-16 Page 22 K = 0.00000e+00 A 4= 1.35282e-05 A 6=-2.86368e-08 A 8= 3.89958e-11 A10=-1.08816e-12 A12= 1.83610e-15 Various data Zoom ratio 2.36 Wide Angle Mid-Telephoto Focal length 28.80 49.00 67.90 F-number 2.88 2.88 2.92 Half angle of view 34.93 23.82 17.67 Image height 21.64 21.64 21.64 Lens length 132.38 144.25 158.83 Ba 15.39 26.31 34.87 d 3 0.85 15.70 26.56 d10 21.64 7.73 2.90 d17 4.86 2.83 2.01 d20 2.00 4.04 4.86 d24 3.22 3.12 2.00 d26 12.68 12.78 13.90 d29 13.00 23.93 32.48 d31 1.09 1.09 1.09 Zoom lens group data Group starting plane focal length B1 2 135.53 B2 4 -27.10 B3 11 51.68 B4 18 -321.04 B5 21 26.75 B6 25 -57.18 B7 27 -120.17 GB30∞

[0072] [Numerical Example 2] Unit: mm Surface Data Surface number rd nd νd 1∞1.60 2 64.109 7.17 1.49700 81.5 3 4538.818 (variable) 4 110.231 1.80 1.59522 67.7 5 21.806 8.58 6 -146.659 1.50 1.61340 44.3 7 25.001 4.89 2.00100 29.1 8 94.515 4.46 9 -42.715 1.30 1.53775 74.7 10 -130.569 (variable) 11(Aperture) ∞ 1.80 12 33.675 2.98 1.59522 67.7 13 92.568 2.87 14* 75.661 3.74 1.58313 59.4 15* -96.472 3.66 16 -28.115 1.22 1.77047 29.7 17 -80.146 (variable) 18* 57.289 5.74 1.58313 59.4 19* -37.418 0.26 20 956.173 1.40 1.85478 24.8 21 71.298 7.39 1.59522 67.7 22 -29.436 (variable) 23 102.308 1.00 1.78470 26.3 24 27.735 (variable) 25 -323.671 1.60 1.75500 52.3 26 27.770 5.39 1.92286 20.9 27 135.653 (variable) 28∞2.001.5440066.3 29 ∞ (variable) Image plane ∞ Aspheric Data Side 14 K = 0.00000e+00 A 4=-4.99308e-06 A 6= 9.56563e-11 A 8= 2.28657e-11 A10= 6.19341e-13 Page 15 K = 0.00000e+00 A 4=-3.09477e-06 A 6= 9.21828e-09 A 8=-7.68728e-11 A10= 9.48917e-13 Page 18 K = 0.00000e+00 A 4=-5.65839e-06 A 6= 5.09383e-08 A 8= 9.98074e-11 A10=-5.71949e-13 A12= 2.69551e-15 Page 19 K = 0.00000e+00 A 4= 2.10447e-05 A 6= 4.37658e-08 A 8= 9.78884e-11 A10=-3.21204e-13 A12= 2.51468e-15 Various data Zoom ratio 2.39 Wide Angle Mid-Telephoto Focal length 28.80 49.00 68.80 F-number 2.88 2.88 2.88 Half angle of view 34.92 23.68 17.46 Image height 21.64 21.64 21.64 Lens length 127.13 138.45 151.03 Ba 15.39 27.19 37.02 d 3 0.85 14.36 23.61 d10 17.85 6.94 2.00 d17 7.91 4.82 3.27 d22 7.33 4.02 2.00 d24 7.45 10.76 12.79 d27 13.00 24.80 34.63 d29 1.09 1.09 1.09 Zoom lens group data Group starting plane focal length B1 2 130.77 B2 4 -31.26 B3 11 102.51 B4 18 25.35 B5 23 -48.78 B6 25 -330.93 GB28∞

[0073] [Numerical Example 3] Unit: mm Surface Data Surface number rd nd νd 1∞1.60 2 69.090 7.40 1.49700 81.5 3 -803.300 (variable) 4 121.485 1.80 1.59522 67.7 5 22.418 8.77 6 -134.878 1.50 1.61340 44.3 7 26.095 4.63 2.00100 29.1 8 103.970 4.45 9 -39.791 1.30 1.53775 74.7 10 -136.339 (variable) 11(Aperture) ∞ 1.80 12 31.872 3.21 1.59522 67.7 13 95.837 2.80 14* 74.280 3.64 1.58313 59.4 15* -111.093 3.73 16 -28.556 1.33 1.77047 29.7 17 -84.332 (variable) 18* 58.568 5.63 1.58313 59.4 19* -37.260 0.78 20 1434.050 1.40 1.85478 24.8 21 75.530 7.14 1.59522 67.7 22 -29.651 (variable) 23 139.647 1.00 1.78470 26.3 24 27.157 (variable) 25 -3733.823 1.60 1.75500 52.3 26 29.164 5.85 1.92286 20.9 27 204.217 (variable) 28∞2.001.5440066.3 29 ∞ (variable) Image plane ∞ Aspheric Data Page 14 K = 0.00000e+00 A 4=-5.32077e-06 A 6= 7.65017e-09 A 8=-4.96809e-11 A10= 1.19886e-12 Page 15 K = 0.00000e+00 A 4=-4.15343e-06 A 6= 2.86367e-08 A 8=-2.46191e-10 A10= 1.83092e-12 Side 18 K = 0.00000e+00 A 4=-7.75733e-06 A 6= 7.82802e-08 A 8=-5.68650e-11 A10=-5.97309e-15 A12= 2.47205e-15 Page 19 K = 0.00000e+00 A 4= 1.98553e-05 A 6= 5.79944e-08 A 8= 4.92930e-11 A10=-1.42165e-13 A12= 2.87702e-15 Various data Zoom ratio 2.39 Wide Angle Mid-Telephoto Focal length 28.80 50.00 68.80 F-number 2.88 2.88 2.88 Half angle of view 34.92 23.26 17.46 Image height 21.64 21.64 21.64 Lens length 127.13 139.11 151.03 Ba 15.39 27.80 37.28 d 3 0.85 14.97 23.52 d10 18.11 6.72 2.00 d17 6.55 3.38 2.00 d22 7.69 4.67 2.88 d24 7.19 10.21 12.00 d27 13.00 25.41 34.89 d29 1.09 1.09 1.09 Zoom lens group data Group starting plane focal length B1 2 128.37 B2 4 -30.04 B3 11 95.30 B4 18 25.64 B5 23 -43.13 B6 25 900.00 GB28∞

[0074] [Numerical Example 4] Unit: mm Surface Data Surface number rd nd νd 1∞1.60 2 79.594 7.59 1.49700 81.7 3 -835.318 (variable) 4 73.280 1.60 1.89190 37.1 5 21.548 7.37 6 -369.959 1.25 1.60311 60.6 7 21.168 6.95 1.90366 31.3 8 289.158 4.06 9 -36.165 1.00 1.85150 40.8 10 -91.177 (variable) 11 (Aperture) ∞ 0.60 12 44.013 3.47 2.00100 29.1 13 -750.000 2.36 14* 107.718 3.73 1.58313 59.4 15* -69.983 2.47 16 -39.067 1.20 1.77047 29.7 17 199.294 (variable) 18 ∞ 1.20 1.85478 24.8 19 29.445 6.20 1.49700 81.7 20 -54.091 (variable) 21* 54.923 4.13 1.58313 59.4 22* -150.167 0.20 23 75.662 6.75 1.59522 67.7 24 -33.194 (variable) 25 83.342 1.10 1.61340 44.3 26 24.485 (variable) 27 -41.988 1.30 1.74400 44.8 28 59.444 3.71 1.92286 20.9 29 -750.000 (variable) 30 150.000 3.00 2.00100 29.1 31 -1033.371 (variable) 32∞2.00 1.54400 66.3 33 ∞ (variable) Image plane ∞ Aspheric Data Page 14 K = 0.00000e+00 A 4=-4.20525e-06 A 6=-3.82772e-08 A 8= 2.77210e-10 A10=-1.84598e-12 A12= 4.13300e-15 Page 15 K = 0.00000e+00 A 4=-7.76915e-07 A 6=-4.58293e-08 A 8= 3.25378e-10 A10=-1.82949e-12 A12= 3.89584e-15 Page 21 K = 0.00000e+00 A 4=-4.04521e-06 A 6=-3.55365e-08 A 8= 3.62232e-11 A10=-4.52586e-13 A12=-5.35347e-16 Page 22 K = 0.00000e+00 A 4= 9.66538e-06 A 6=-2.63857e-08 A 8= 2.80285e-11 A10=-5.56106e-13 A12= 1.71401e-16 Various data Zoom ratio 2.36 Wide Angle Mid-Telephoto Focal length 28.80 49.00 67.90 F-number 2.88 2.88 2.88 Half angle of view 34.93 23.82 17.67 Image height 21.64 21.64 21.64 Lens length 133.93 147.58 164.79 Ba 15.39 26.87 33.17 d 3 0.93 17.37 29.29 d10 21.92 7.63 3.07 d17 4.14 2.68 2.05 d20 2.00 3.46 4.09 d24 3.31 3.13 2.00 d26 12.42 12.60 13.73 d29 1.00 1.00 4.55 d31 13.00 24.49 30.79 d33 1.09 1.09 1.09 Zoom lens group data Group starting plane focal length B1 2 146.62 B2 4 -27.63 B3 11 54.59 B4 18 -400.00 B5 21 26.50 B6 25 -56.93 B7 27 -74.69 B8 30 131.02 GB32∞

[0075] The table below gives various values ​​for each example.

[0076] [Table 1]

[0077] [Imaging device] Next, an embodiment of a digital still camera (imaging device) using the zoom lens of the present invention as an imaging optical system will be described with reference to Fig. 9. In Fig. 9, 11 denotes an imaging optical system constituted by any of the zoom lenses described in Examples 1 to 4. 12 denotes an imaging element (photoelectric conversion element) such as a CCD sensor or CMOS sensor that is built into a camera body 10 and receives an optical image formed by the imaging optical system 11 and photoelectrically converts it. The camera body 10 may be a so-called single-lens reflex camera having a quick-turn mirror, or a so-called mirrorless camera having no quick-turn mirror.

[0078] In this way, by applying the zoom lens L0 of the present invention to an imaging device such as a digital still camera, it is possible to obtain a high-resolution image with a wide angle of view.

[0079] The disclosure of each embodiment includes the following configuration.

[0080] (Configuration 1) A zoom lens comprising, in order from the object side to the image side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a subsequent group including three or more lens groups, in which the spacing between adjacent lens groups changes during zooming, during zooming from the wide-angle end to the telephoto end, all of the lens groups included in the first lens group, the third lens group, and the subsequent lens group move toward the object side, and the second lens group moves along a locus convex toward the image side, Let f1 be the focal length of the first lens group, f2 be the focal length of the second lens group, and fr be the composite focal length of the subsequent lens group at the wide-angle end. 3.50 <f1 / |f2|<5.33 0.30 <fr / |f2|<2.30 A zoom lens characterized by satisfying the following conditional expressions:

[0081] (Configuration 2) When the focal length of the third lens group is f3, 1.34 <f3 / |f2|<4.26 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

[0082] (Configuration 3) When the focal length of the entire system at the telephoto end is ft, 1.31 <f1 / ft<2.81 3. The zoom lens according to configuration 1 or 2, wherein the following condition is satisfied:

[0083] (Configuration 4) When the focal length of the entire system at the wide-angle end is fw, 0.66<|f2| / fw<1.41 4. The zoom lens according to any one of configurations 1 to 3, which satisfies the following conditional expression:

[0084] (Configuration 5) Let Lt be the distance on the optical axis from the lens surface closest to the object at the telephoto end to the lens surface closest to the image at the telephoto end, and ft be the focal length of the entire system at the telephoto end. 1.14 <Lt / ft<2.49 5. The zoom lens according to any one of configurations 1 to 4, which satisfies the following condition:

[0085] (Configuration 6) Let Lw be the distance on the optical axis from the lens surface closest to the object to the lens surface closest to the image at the wide-angle end. 1.52 <Lw / fr<4.10 6. The zoom lens according to any one of configurations 1 to 5, wherein the following condition is satisfied:

[0086] (Configuration 7) The third lens group includes a positive lens having an aspheric shape. When the focal length of the positive lens is fs and the focal length of the third lens group is f3, 0.50 <fs / f3<1.85 7. The zoom lens according to any one of configurations 1 to 6, wherein the following condition is satisfied:

[0087] (Configuration 8) 8. The zoom lens according to any one of configurations 1 to 7, wherein the subsequent group has a focus group that moves during focusing.

[0088] (Configuration 9) 9. The zoom lens according to configuration 8, wherein the focus group is made up of one lens.

[0089] (Configuration 10) 10. The zoom lens according to configuration 8 or 9, wherein the subsequent group has at least one lens group on the image side of the focus group, and the lens group has one or more negative lenses and one or more positive lenses.

[0090] (Configuration 11) When the focal length of the focus group is ff, 1.00<|ff / f2|<2.74 11. The zoom lens according to any one of configurations 8 to 10, which satisfies the following condition:

[0091] (Configuration 12) When the focal length of the focus group is ff, 0.75<|ff| / fr<1.81 12. The zoom lens according to any one of configurations 8 to 11, wherein the following condition is satisfied:

[0092] (Configuration 13) A zoom lens according to any one of configurations 8 to 12, characterized in that, among the lens groups having positive refractive power arranged in the subsequent group, the lens group having the strongest refractive power is arranged adjacent to the object side of the focus group.

[0093] (Configuration 14) Let fp2 be the focal length of the lens group having the strongest refractive power among the lens groups having positive refractive power arranged in the subsequent group. 3.50 <f1 / fp2<7.19 14. The zoom lens according to any one of configurations 1 to 13, wherein the following condition is satisfied:

[0094] (Configuration 15) Let fp2 be the focal length of the lens group having the strongest refractive power among the lens groups having positive refractive power arranged in the subsequent group, and let f3 be the focal length of the third lens group. 1.35 <f3 / fp2<5.26 15. The zoom lens according to any one of configurations 1 to 14, wherein the following condition is satisfied:

[0095] (Configuration 16) The zoom lens according to any one of configurations 1 to 15, wherein the first lens group is composed of one lens.

[0096] (Configuration 17) The zoom lens according to any one of configurations 1 to 16, wherein the second lens group is made up of four lenses.

[0097] (Configuration 18) The zoom lens according to any one of configurations 1 to 17, wherein the third lens group is composed of a positive lens, a positive lens, and a negative lens arranged in this order from the object side to the image side.

[0098] (Configuration 19) The zoom lens according to any one of configurations 1 to 18, wherein the subsequent group consists of, arranged in order from the object side to the image side, a fourth lens group having negative refractive power, a fifth lens group having positive refractive power, a sixth lens group having negative refractive power, and a seventh lens group having negative refractive power.

[0099] (Configuration 20) The zoom lens according to any one of configurations 1 to 18, wherein the subsequent group consists of, arranged in order from the object side to the image side, a fourth lens group having positive refractive power, a fifth lens group having negative refractive power, and a sixth lens group having negative refractive power.

[0100] (Configuration 21) The zoom lens according to any one of configurations 1 to 18, wherein the subsequent group consists of, arranged in order from the object side to the image side, a fourth lens group having positive refractive power, a fifth lens group having negative refractive power, and a sixth lens group having positive refractive power.

[0101] (Configuration 22) The zoom lens according to any one of configurations 1 to 18, characterized in that the subsequent group consists of, arranged in order from the object side to the image side, a fourth lens group with negative refractive power, a fifth lens group with positive refractive power, a sixth lens group with negative refractive power, a seventh lens group with negative refractive power, and a seventh lens group with positive refractive power.

[0102] (Configuration 23) A zoom lens according to any one of configurations 1 to 22, an imaging device having an image sensor for receiving an image formed by the zoom lens;

[0103] Although the preferred embodiments and examples of the present invention have been described above, the present invention is not limited to these embodiments and examples, and various combinations, modifications, and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0104] L0 Zoom Lens B1 First lens group B2 2nd lens group B3 3rd lens group Br Successor group

Claims

1. A zoom lens comprising, arranged in order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a subsequent group including three or more lens groups, wherein the spacing between adjacent lens groups changes during zooming, during zooming from the wide-angle end to the telephoto end, all lens groups included in the first lens group, the third lens group, and the subsequent lens group move toward the object side, and the second lens group moves along a locus convex toward the image side, When the focal length of the first lens group is f1, the focal length of the second lens group is f2, the composite focal length of the subsequent lens group at the wide-angle end is fr, and the focal length of the third lens group is f3, 3.50<f1 / |f2|<5.33 0.30<fr / |f2|<2.30 1.34<f3 / |f2|<4.26 A zoom lens characterized by satisfying the following conditional expressions:

2. When the focal length of the entire system at the telephoto end is ft, 1.31<f1 / ft<2.81 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

3. When the focal length of the entire system at the wide-angle end is fw, 0.66<|f2| / fw<1.41 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

4. When the distance on the optical axis from the lens surface closest to the object side to the lens surface closest to the image side at the telephoto end is Lt and the focal length of the entire system at the telephoto end is ft, 1.14<Lt / ft<2.49 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

5. When the distance on the optical axis from the lens surface closest to the object to the lens surface closest to the image at the wide-angle end is Lw, 1.52<Lw / fr<4.10 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

6. The third lens group includes a positive lens having an aspherical shape. When the focal length of the positive lens is fs and the focal length of the third lens group is f3, 0.50<fs / f3<1.85 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

7. 2. The zoom lens according to claim 1, wherein the subsequent lens group includes a focus lens group that moves during focusing.

8. 8. The zoom lens according to claim 7, wherein the focus group consists of one lens.

9. 8. The zoom lens according to claim 7, wherein the subsequent group has at least one lens group located closer to the image side than the focus group, and the lens group has at least one negative lens and at least one positive lens.

10. When the focal length of the focus group is ff, 1.00<|ff / f2|<2.74 8. The zoom lens according to claim 7, wherein the following condition is satisfied:

11. When the focal length of the focus group is ff, 0.75<|ff| / fr<1.81 8. The zoom lens according to claim 7, wherein the following condition is satisfied:

12. 8. The zoom lens according to claim 7, wherein the lens group having the strongest refractive power among the lens groups having positive refractive power arranged in the subsequent group is arranged adjacent to the focus group on the object side.

13. When the focal length of the lens group with the strongest refractive power among the lens groups with positive refractive power arranged in the subsequent group is fp2, 3.50<f1 / fp2<7.19 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

14. When the focal length of the lens group having the strongest refractive power among the lens groups having positive refractive power arranged in the subsequent group is fp2 and the focal length of the third lens group is f3, 1.35<f3 / fp2<5.26 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

15. 2. The zoom lens according to claim 1, wherein the first lens group consists of one lens.

16. 2. The zoom lens according to claim 1, wherein the second lens group is made up of four lenses.

17. 2. The zoom lens according to claim 1, wherein the third lens group comprises, in order from the object side to the image side, a positive lens, a positive lens, and a negative lens.

18. 2. The zoom lens according to claim 1, wherein the subsequent lens group comprises, arranged in order from the object side to the image side, a fourth lens group having negative refractive power, a fifth lens group having positive refractive power, a sixth lens group having negative refractive power, and a seventh lens group having negative refractive power.

19. 2. The zoom lens according to claim 1, wherein the subsequent lens group comprises, arranged in order from the object side to the image side, a fourth lens group having a positive refractive power, a fifth lens group having a negative refractive power, and a sixth lens group having a negative refractive power.

20. 2. The zoom lens according to claim 1, wherein the subsequent lens group comprises, arranged in order from the object side to the image side, a fourth lens group having a positive refractive power, a fifth lens group having a negative refractive power, and a sixth lens group having a positive refractive power.

21. 2. The zoom lens according to claim 1, wherein the subsequent lens group comprises, arranged in order from the object side to the image side, a fourth lens group having negative refractive power, a fifth lens group having positive refractive power, a sixth lens group having negative refractive power, a seventh lens group having negative refractive power, and a seventh lens group having positive refractive power.

22. When the focal length of the entire system at the telephoto end is ft, 1.31<f1 / ft<2.81 22. The zoom lens according to claim 3, wherein the following condition is satisfied:

23. When the focal length of the entire system at the wide-angle end is fw, 0.66<|f2| / fw<1.41 22. The zoom lens according to claim 4, wherein the following condition is satisfied:

24. When the focal length of the entire system at the telephoto end is ft and the focal length of the entire system at the wide-angle end is fw, 1.31<f1 / ft<2.81 0.66<|f2| / fw<1.41 22. The zoom lens according to claim 4, wherein the following condition is satisfied:

25. A zoom lens according to any one of claims 1 to 21; an imaging device having an imaging element that receives an image formed by the zoom lens;

Images