Zoom lens and imaging apparatus having the same

Abstract

To provide a zoom lens that has high optical performance and is small-sized.SOLUTION: A zoom lens has a negative first lens group L1, a positive second lens group L2, a positive third lens group L3, a negative fourth lens group L4, and a positive fifth lens group L5, which are arranged in order from an object side to an image side, in which the interval between the adjacent lens groups changes in zooming. The first lens group L1 and the fourth lens group L4 are immobilized in zooming. In a case where the absolute value of the amount of movement of the second lens group L2 in zooming from a wide-angle end to a telephoto end is defined as M2; the focal length of the entire system at the wide-angle end in infinity focusing is defined as fw; the focal length of the third lens group L3 is defined as f3; and the focal length of the fourth lens group L4 is defined as f4, conditional expressions of 0.45<M2 / fw<4.50 and 0.00<|f3 / f4|<1.70 are satisfied.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a zoom lens, which is suitable for digital video cameras, digital still cameras, broadcast cameras, cameras for silver halide film, surveillance cameras, and the like. [Background technology]

[0002] In a zoom lens used in an image pickup apparatus, if the mass or amount of movement of a lens group that moves during zooming, or the number of lens groups that move, increases, the zoom lens tends to become large.

[0003] Patent Document 1 discloses a zoom lens having, in order from the object side, a negative first lens group, a positive second lens group, a positive third lens group, a negative fourth lens group, and a positive fifth lens group, in which the first lens group and the fourth lens group do not move during zooming. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-078768 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the zoom lens of Patent Document 1 does not adequately correct various aberrations that occur during zooming, and therefore there is a demand for a compact zoom lens with high optical performance.

[0006] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a compact zoom lens having high optical performance. [Means for solving the problem]

[0007] A zoom lens according to one aspect of the present invention has a negative first lens group, a positive second lens group, a positive third lens group, a negative fourth lens group, and a positive fifth lens group arranged in that order from the object side to the image side, and the distance between each of the adjacent lens groups changes during zooming, wherein the first lens group and the fourth lens group do not move during zooming, and when an absolute value of the amount of movement of the second lens group during zooming from the wide-angle end to the telephoto end is M2, a focal length of the entire system when focusing on infinity at the wide-angle end is fw, a focal length of the third lens group is f3, and a focal length of the fourth lens group is f4, 0.45 <M2 / fw<4.50 0.00<|f3 / f4|<1.70 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 compact zoom lens having high optical performance. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a zoom lens L0 according to a first embodiment. [Diagram 2] 3A and 3B are aberration diagrams of the zoom lens L0 according to Example 1 at the wide-angle end and the telephoto end when focused on infinity. [Diagram 3] FIG. 11 is a cross-sectional view of a zoom lens L0 according to a second embodiment. [Figure 4] 13A and 13B are aberration diagrams of the zoom lens L0 according to Example 2 at the wide-angle end and the telephoto end when focused on infinity. [Diagram 5] FIG. 11 is a cross-sectional view of a zoom lens L0 according to a third embodiment. [Figure 6] 13A and 13B are aberration diagrams of the zoom lens L0 according to Example 3 at the wide-angle end and the telephoto end when focused on infinity. [Figure 7] FIG. 11 is a cross-sectional view of a zoom lens L0 according to a fourth embodiment. [Figure 8]13A and 13B are aberration diagrams of the zoom lens L0 according to Example 4 at the wide-angle end and the telephoto end when focused on infinity. [Figure 9] FIG. 1 is a schematic diagram of an imaging device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that the drawings may be drawn at a scale different from the actual scale for convenience. In addition, in each drawing, the same reference numerals are used for the same components, and duplicated explanations will be omitted.

[0011] 1, 3, 5, and 7 are cross-sectional views of the zoom lens L0 at the wide-angle end when focusing at infinity in Examples 1 to 4, respectively. In each figure, the left side is the object side (front side), and the right side is the image side (rear side). The zoom lens L0 of each Example is configured with multiple lenses. The zoom lens L0 according to each Example is configured with multiple lens groups, and the intervals between adjacent lens groups change during zooming. Note that the lens group may be configured with one lens, or may be configured with multiple lenses.

[0012] In each drawing, Li is the i-th lens group (i is a natural number) counted from the object side among the lens groups included in the zoom lens L0.

[0013] In each figure, SP denotes an aperture stop, and IP denotes an image plane. When the zoom lens of each embodiment is used as an imaging optical system for a digital video camera or a digital still camera, the imaging surface of a solid-state imaging element (photoelectric conversion element) is disposed on the image plane IP. A CCD (Charge Coupled Device) sensor, a CMOS (Complementary Metal Oxide Semiconductor) sensor, or the like can be used as the solid-state imaging element. When the zoom lens of each embodiment is used as an imaging optical system for a silver halide film camera, the photosensitive surface of the film is disposed on the image plane IP.

[0014] In each drawing, the solid arrow indicates the trajectory of movement of each lens group during zooming from the wide-angle end to the telephoto end, and the solid arrow is shown below the lens group that moves in the optical axis direction during zooming.

[0015] The dashed arrows in each drawing indicate the locus of movement of each lens group during focusing from infinity to a close distance (close end), and the dashed arrows are shown below the lens groups that move during focusing.

[0016] In the zoom lens L0 of each embodiment, one or more lenses may be decentered so as to include a component perpendicular to the optical axis during image blur correction, thereby providing a function as an anti-vibration optical system. Also, a parallel plate with substantially no refractive power, such as a low-pass filter or an infrared cut filter, may be disposed between the lens disposed closest to the image side and the image plane.

[0017] 2, 4, 6, and 8 are aberration diagrams at the wide-angle end and the telephoto end of the zoom lenses of Examples 1 to 4 when focused on infinity, respectively.

[0018] In each diagram, Fno is the F-number, and ω is the imaging half angle of view (°) determined by paraxial calculation. In the spherical aberration diagrams, the solid line shows spherical aberration at the d-line (wavelength 587.56 nm), and the two-dot chain line shows spherical aberration at the g-line (wavelength 435.835 nm). In the astigmatism diagrams, the solid line shows astigmatism at the d-line on the sagittal image plane, and the dashed line shows astigmatism at the d-line on the meridional image plane. The distortion diagram shows distortion at the d-line. The chromatic aberration diagram shows lateral chromatic aberration at the g-line.

[0019] The characteristic configuration of the zoom lens L0 of each embodiment will be described. The zoom lens L0 of each embodiment is a zoom lens having a negative first lens group L1, a positive second lens group L2, a positive third lens group L3, a negative fourth lens group L4, and a positive fifth lens group L5 arranged in this order from the object side to the image side. Furthermore, the first lens group L1 and the fourth lens group L4 do not move during zooming.

[0020] Next, the conditions that the zoom lens L0 of each embodiment satisfies will be described.

[0021] When the absolute value of the movement amount on the optical axis of the second lens group L2 during zooming from the wide-angle end to the telephoto end is M2, the focal length of the entire system at the wide-angle end when focusing on infinity is fw, the focal length of the third lens group L3 is f3, and the focal length of the fourth lens group L4 is f4, the following conditional expressions (1) and (2) are satisfied. Here, the movement amount of the lens group corresponds to the difference between the position on the optical axis at the wide-angle end and the position on the optical axis at the telephoto end. The sign of the movement amount is positive when it is located closer to the image side at the telephoto end than at the wide-angle end. 0.45 <M2 / fw<4.50 (1) 0.00<|f3 / f4|<1.70 (2)

[0022] Conditional formula (1) defines the relationship between the amount of movement of the second lens group L2 on the optical axis and the focal length at the wide-angle end. If the upper limit of conditional formula (1) is exceeded, the amount of movement of the second lens group L2 becomes too large. As a result, the optical system tends to become large or high-speed zoom operation tends to become difficult. On the other hand, if the lower limit of conditional formula (1) is exceeded, it tends to become difficult to achieve a high zoom ratio.

[0023] Conditional formula (2) defines the relationship between the focal length of the third lens group L3 and the focal length of the fourth lens group L4. If the upper limit of conditional formula (2) is exceeded, the divergence of the light beam in the third lens group L3 becomes too high. As a result, it becomes difficult to reduce the lens diameter of the lens arranged on the image side of the third lens group L3.

[0024] It is more preferable that the numerical ranges of the conditional expressions (1) and (2) be the numerical ranges of the following conditional expressions (1a) and (2a). 0.61 <M2 / fw<3.20 (1a) 0.20<|f3 / f4|<1.39 (2a)

[0025] It is further preferable that the numerical ranges of the conditional expressions (1a) and (2a) be set to the numerical ranges of the following conditional expressions (1b) and (2b). 0.69 <M2 / fw<2.55 (1b) 0.45<|f3 / f4|<1.23 (2b)

[0026] If the lower limit values ​​of the conditional expressions (2a) and (2b) are not reached, the zooming effect of the fourth lens unit L4 decreases, making it difficult to achieve a high zoom ratio.

[0027] Next, conditions that the zoom lens L0 of each embodiment should preferably satisfy will be described.

[0028] In each embodiment, the third lens group L3 has an aperture stop SP, and it is preferable that the aperture stop SP moves integrally with the third lens group L3 during zooming. By adopting such a configuration, it becomes easy to suppress an increase in the lens diameter of each lens group and to suppress the mass of the moving lens group.

[0029] In each embodiment, the first lens unit L1 preferably has three negative lenses. By dispersing the power by the three negative lenses, it becomes easier to correct various aberrations, particularly distortion at the wide-angle end.

[0030] In each embodiment, the fourth lens group L4 preferably has a negative lens with a concave surface facing the object side. By disposing a negative lens with a concave surface facing the object side, it becomes easier to suppress the zoom fluctuation of spherical aberration.

[0031] In each embodiment, the fifth lens group L5 preferably has two positive lenses. By dispersing the power by the two positive lenses, it becomes easier to correct various aberrations, particularly the correction of zoom fluctuations of astigmatism.

[0032] In each embodiment, it is preferable that the second lens group L2 moves during focusing from infinity to a close distance. The movement of the second lens group L2 makes it easier to correct aberrations during focusing, and in particular, makes it easier to correct spherical aberration at the close distance at the telephoto end.

[0033] In each embodiment, it is preferable that the first lens group L1 is fixed relative to the image plane IP during focusing. By making the first lens group L1, which has a large lens diameter and tends to have a large mass, fixed during focusing, the drive mechanism can be simplified.

[0034] It is preferable that the zoom lens L0 of each embodiment satisfy one or more of the following conditional expressions (3) to (15).

[0035] Here, the back focus at the wide-angle end when focusing at infinity is BFw, the focal length of the entire system at the wide-angle end when focusing at infinity is fw, and the focal length of the entire system at the telephoto end when focusing at infinity is ft. The focal length of the first lens group L1 is f1, the focal length of the second lens group L2 is f2, the focal length of the third lens group L3 is f3, the focal length of the fourth lens group L4 is f4, and the focal length of the fifth lens group L5 is f5.

[0036] Also, the absolute value of the movement amount on the optical axis of the third lens group L3 during zooming from the wide-angle end to the telephoto end is M3, and the absolute value of the movement amount on the optical axis of the fifth lens group L5 during zooming from the wide-angle end to the telephoto end is M5. The composite lateral magnification of the second lens group L2 and the third lens group L3 at the wide-angle end is βFw, and the composite lateral magnification of the second lens group L2 and the third lens group L3 at the telephoto end is βFt. The composite lateral magnification of the lens group arranged closer to the image side than the third lens group L3 at the wide-angle end is βRw, and the composite lateral magnification of the lens group arranged closer to the image side than the third lens group L3 at the telephoto end is βRt. The distance on the optical axis from the aperture stop SP to the surface of the fourth lens group closest to the object is DSPL4t. 0.30 <BFw / fw<3.10 (3) 0.60<|f1 / fw|<3.60 (4) 2.00 <f2 / fw<12.10 (5) 1.00 <f3 / fw<7.60 (6) 1.00<|f4 / fw|<7.60 (7) 0.90 <f5 / fw<5.90 (8) 0.30<|f1 / f5|<1.60 (9) 0.20<|f1 / f4|<1.30 (10) 0.40 <M3 / fw<3.80 (11) 0.20 <M5 / fw<2.10 (12) 0.70<βFt / βFw<4.10 (13) 0.50<βRt / βRw<2.10 (14) 0.20 <DSPL4t / ft<1.50 (15)

[0037] Conditional formula (3) specifies the relationship between the back focal length at the wide-angle end and the focal length of the entire system. If the upper limit of conditional formula (3) is exceeded, the entire system tends to become large. On the other hand, if the lower limit of conditional formula (3) is not reached, the height of the off-axis ray in the fifth lens unit L5 increases, which tends to increase the lens diameter.

[0038] Conditional formula (4) defines the relationship between the focal length of the first lens unit L1 and the focal length of the entire system at the wide-angle end. If the upper limit of conditional formula (4) is exceeded, the lens diameter of the front lens tends to become large. On the other hand, if the lower limit of conditional formula (4) is not reached, it tends to be difficult to correct distortion at the wide-angle end.

[0039] Conditional formula (5) specifies the relationship between the focal length of the second lens group L2 and the focal length of the entire system at the wide-angle end. If the upper limit of conditional formula (5) is exceeded, the lens diameter of the lens arranged on the image side of the second lens group L2 tends to become large. On the other hand, if the lower limit of conditional formula (5) is exceeded, it tends to become difficult to correct spherical aberration at the telephoto end.

[0040] Conditional formula (6) specifies the relationship between the focal length of the third lens group L3 and the focal length of the entire system at the wide-angle end. If the upper limit of conditional formula (6) is exceeded, the lens diameter of the lens arranged on the image side of the third lens group L3 tends to become large. On the other hand, if the lower limit of conditional formula (6) is exceeded, it tends to become difficult to correct spherical aberration at the telephoto end.

[0041] Conditional expression (7) defines the relationship between the focal length of the fourth lens group L4 and the focal length of the entire system at the wide-angle end. If the upper limit of conditional expression (7) is exceeded, it becomes difficult to correct spherical aberration at the telephoto end. On the other hand, if the lower limit of conditional expression (7) is not reached, the lens diameter of the lens located closer to the image side than the fourth lens group L4 tends to become large.

[0042] Conditional expression (8) defines the relationship between the focal length of the fifth lens unit L5 and the focal length of the entire system at the wide-angle end. If the upper limit of conditional expression (8) is exceeded, the Petzval sum will not be sufficiently corrected, making it difficult to correct curvature of field. On the other hand, if the lower limit of conditional expression (8) is exceeded, it will be difficult to correct astigmatism at the wide-angle end.

[0043] Conditional expression (9) defines the relationship between the focal length of the first lens group L1 and the focal length of the fifth lens group L5. If the upper limit of conditional expression (9) is exceeded, the Petzval sum will be overcorrected. As a result, it will tend to be difficult to correct the curvature of field. On the other hand, if the lower limit of conditional expression (9) is exceeded, the Petzval sum will be undercorrected. As a result, it will tend to be difficult to correct the curvature of field.

[0044] Conditional expression (10) defines the relationship between the focal length of the first lens group L1 and the focal length of the fourth lens group L4. If the upper limit of conditional expression (10) is exceeded, the front lens diameter tends to become large. On the other hand, if the lower limit of conditional expression (10) is exceeded, it tends to become difficult to correct distortion at the wide-angle end.

[0045] Conditional expression (11) defines the relationship between the amount of movement of the third lens unit L3 on the optical axis during zooming from the wide-angle end to the telephoto end and the focal length of the entire system at the wide-angle end. If the upper limit of conditional expression (11) is exceeded, the optical system tends to become large. On the other hand, if the lower limit of conditional expression (11) is exceeded, it tends to become difficult to achieve a high zoom ratio.

[0046] Conditional expression (12) defines the relationship between the amount of movement of the fifth lens unit L5 on the optical axis during zooming from the wide-angle end to the telephoto end and the focal length of the entire system at the wide-angle end. If the upper limit of conditional expression (12) is exceeded, the optical system tends to become large. On the other hand, if the lower limit of conditional expression (12) is exceeded, it tends to become difficult to achieve a high zoom ratio.

[0047] Conditional expression (13) defines the ratio of the composite lateral magnifications of the second lens group L2 and the third lens group L3 at the telephoto end and the wide-angle end. If the upper limit of conditional expression (13) is exceeded, it becomes difficult to suppress the zoom fluctuation of the coma aberration generated in the second lens group L2 and the third lens group L3. On the other hand, if the lower limit of conditional expression (13) is not reached, it becomes difficult to achieve a high zoom ratio.

[0048] Conditional expression (14) specifies the ratio of composite lateral magnifications of the lens groups arranged closer to the image side than the third lens group L3 at the telephoto end and the wide-angle end. If the upper limit of conditional expression (14) is exceeded, it becomes difficult to suppress zoom fluctuations of astigmatism that occurs in the lens groups arranged closer to the image side than the third lens group L3. On the other hand, if the lower limit of conditional expression (14) is exceeded, it becomes difficult to achieve a high zoom ratio.

[0049] Conditional formula (15) specifies the relationship between the distance from the aperture stop SP to the object side of the fourth lens group L4 and the focal length of the entire system at the telephoto end. If the upper limit of conditional formula (15) is exceeded, the height of off-axis rays in the fifth lens group L5 at the telephoto end increases, which tends to increase the lens diameter. On the other hand, if the lower limit of conditional formula (15) is exceeded, the height of on-axis rays in the fourth lens group L4 at the telephoto end increases, which tends to make it difficult to correct spherical aberration occurring in the fourth lens group L4.

[0050] It is more preferable that the numerical ranges of the conditional expressions (3) to (15) be within the ranges of the following conditional expressions (3a) to (15a). 0.45 <BFw / fw<2.31 (3a) 0.90<|f1 / fw|<2.70 (4a) 3.03 <f2 / fw<9.08 (5a) 1.54 <f3 / fw<5.70 (6a) 1.48<|f4 / fw|<5.71 (7a) 1.36 <f5 / fw<4.44 (8a) 0.42<|f1 / f5|<1.20 (9a) 0.30<|f1 / f4|<0.97 (10a) 0.57 <M3 / fw<2.84 (11a) 0.31 <M5 / fw<1.57 (12a) 1.08<βFt / βFw<3.07 (13a) 0.74<βRt / βRw<1.58 (14a) 0.33 <DSPL4t / ft<1.13 (15a)

[0051] It is more preferable that the numerical ranges of the conditional expressions (3) to (15) be within the numerical ranges of the following conditional expressions (3b) to (15b). 0.52 <BFw / fw<1.92 (3b) 1.05<|f1 / fw|<2.25 (4b) 3.54 <f2 / fw<7.57 (5b) 1.81 <f3 / fw<4.75 (6b) 1.72<|f4 / fw|<4.76 (7b) 1.59 <f5 / fw<3.71 (8b) 0.48<|f1 / f5|<1.00 (9b) 0.35<|f1 / f4|<0.80 (10b) 0.66 <M3 / fw<2.36 (11b) 0.37 <M5 / fw<1.30 (12b) 1.27<βFt / βFw<2.55 (13b) 0.86<βRt / βRw<1.32 (14b) 0.40 <DSPL4t / ft<0.95 (15b)

[0052] [Example 1] The zoom lens L0 in this embodiment is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with negative refractive power, and a fifth lens group L5 with positive refractive power, arranged in that order from the object side to the image side.

[0053] The first lens group L1 and the fourth lens group L4 do not move with respect to the image plane IP during zooming from the wide-angle end to the telephoto end. The second lens group L2, the third lens group L3, and the fifth lens group L5 move toward the object side during zooming from the wide-angle end to the telephoto end. Furthermore, the second lens group L2 moves toward the image side during focusing from infinity to a close distance.

[0054] The first lens group L1 consists of three negative lenses and one positive lens. The fourth lens group L4 has a negative lens with its concave surface facing the object side. The fifth lens group L5 consists of, from the object side to the image side, a positive lens, a meniscus-shaped negative lens with its convex surface facing the image side, and another meniscus-shaped negative lens with its convex surface facing the object side.

[0055] [Example 2] The zoom lens L0 in this embodiment is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with negative refractive power, a fifth lens group L5 with positive refractive power, and a sixth lens group L6 with positive refractive power, arranged in that order from the object side to the image side.

[0056] The first lens group L1, the fourth lens group L4, and the sixth lens group L6 do not move with respect to the image plane IP during zooming from the wide-angle end to the telephoto end. The second lens group L2, the third lens group L3, and the fifth lens group L5 move toward the object side during zooming from the wide-angle end to the telephoto end. The fifth lens group L5 is composed of, in order from the object side to the image side, a positive lens with a meniscus shape with a convex surface facing the image side, a negative lens with a meniscus shape with a convex surface facing the object side, a positive lens, and a negative lens.

[0057] [Example 3] The lens group configuration of the zoom lens L0 in this embodiment is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with negative refractive power, a fifth lens group L5 with positive refractive power, and a sixth lens group L6 with negative refractive power, arranged in this order from the object side to the image side. The fifth lens group L5 in this embodiment is composed of, in this order from the object side to the image side, a positive lens on the image side, a negative lens in a meniscus shape with a convex surface facing the object side, a positive lens, and a negative lens in a meniscus shape with a convex surface facing the image side.

[0058] [Example 4] The configuration of the lens groups of the zoom lens L0 in this embodiment is the same as that in embodiment 2. The fifth lens group L5 in this embodiment is composed of, in order from the object side to the image side, a positive lens on the image side, a negative lens in a meniscus shape with a convex surface facing the object side, a positive lens in a meniscus shape with a convex surface facing the object side, and a negative lens in a meniscus shape with a convex surface facing the image side. Furthermore, during focusing from infinity to a close distance, the second lens group L2 moves to the image side, and the third lens group L3 moves to the object side.

[0059] Numerical examples 1 to 4 corresponding to the first to fourth embodiments are shown below.

[0060] In the surface data of each numerical example, r represents the radius of curvature of each optical surface, and d (mm) represents the axial distance (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. The Abbe number νd of a certain material is a value defined by the following formula, where Nd, NF, NC, and Ng are the refractive indices at the d-line (587.6 nm), F-line (486.1 nm), C-line (656.3 nm), and g-line (wavelength 435.8 nm) of the Fraunhofer lines. νd=(Nd-1) / (NF-NC)

[0061] In each numerical example, d, focal length (mm), F-number, and half angle of view (°) are all values ​​when the zoom lens L0 of each example is focused on an object at infinity. The back focus BF is the distance from the final lens surface to the image surface. The total optical length is the sum of the back focus and the distance from the first lens surface to the final lens surface. The lens group is not limited to being composed of multiple lenses, and may be composed of a single lens.

[0062] Furthermore, if the optical surface is aspheric, a * symbol is added to the right of the surface number. The aspheric shape can be expressed by the following formula, where X is the displacement from the apex of the surface in the optical axis direction, h is the height from the optical axis in a direction perpendicular to the optical axis, R is the paraxial radius of curvature, K is the conic constant, and A4, A6, A8, A10, and A12 are aspheric coefficients of each order. Note that "e±XX" in each aspheric coefficient is expressed as "×10 ±XX " It means. x=(h 2 / R) / [1+{1-(1+K)(h / R) 2} 1 / 2 ]+A4×h 4 +A6×h 6 +A8×h 8 +A10×h 10 +A12×h 12

[0063] [Numerical Example 1] Unit: mm Surface Data Surface number rd nd νd 1 50.138 1.50 2.00100 29.1 2 22.570 7.45 3 116.355 1.30 1.59282 68.6 4 35.489 4.98 5 -173.357 1.20 1.49700 81.5 6 27.379 5.78 1.91082 35.2 7 103.647 (variable) 8 -67.008 1.00 1.85478 24.8 9 55.824 0.36 10 64.927 4.72 1.95375 32.3 11* -46.353 (variable) 12 30.945 1.00 1.90366 31.3 13 22.207 6.69 1.59522 67.7 14* -195.735 1.37 15 (Aperture) ∞ (Variable) 16* -31.517 0.80 1.61340 44.3 17 27.386 2.64 1.92286 20.9 18 80.449 (variable) 19 30.011 5.74 1.49700 81.5 20 -31.783 0.45 21 44.726 6.67 1.49700 81.5 22 -20.853 0.80 2.05090 26.9 23 -44.250 1.33 24* 70.402 1.20 1.88202 37.2 25* 27.013 (variable) Image plane ∞ Aspheric Data Page 11 K=0.00000e+00 A4=-2.12988e-07 A6=-1.38481e-09 A8=-2.96618e-12 Page 14 K=0.00000e+00 A4=2.70462e-08 A6=5.91799e-10 A8=6.68411e-12 Page 16 K=0.00000e+00 A4=-6.84993e-07 A6=-1.21471e-08 A8=-2.80284e-11 Page 24 K=0.00000e+00 A4=-3.85359e-05 A6=1.24853e-07 A8=-2.07298e-10 Page 25 K=-9.43177e+00 A4= 3.62160e-05 A6=-1.14770e-07 A8=1.04700e-09 A10=-3.45970e-12 A12=2.70504e-15 Various data Zoom ratio 1.88 Wide Angle Mid-Telephoto Focal length 20.61 29.26 38.72 F-number 2.90 2.90 2.90 Half angle of view 43.64 36.48 29.19 Image height 19.65 21.64 21.64 Lens total length 130.70 130.70 130.70 BF 31.45 36.15 40.28 d 7 21.33 7.98 3.07 d11 6.72 11.43 7.70 d15 4.29 12.93 21.57 d18 9.91 5.21 1.08 d25 31.45 36.15 40.28 Lens Group Data Group starting plane focal length 1 1 -30.24 2 8 119.72 3 12 54.58 4 16 -50.60 5 19 37.67

[0064] [Numerical Example 2] Unit: mm Surface Data Surface number rd nd νd 1 45.404 1.50 2.00100 29.1 2 19.584 7.30 3 198.185 1.30 1.59282 68.6 4 39.571 3.87 5 -113.867 1.20 1.49700 81.5 6 24.514 5.38 1.91082 35.2 7 95.965 (variable) 8 -76.671 1.00 1.85478 24.8 9 84.843 4.45 1.85150 40.8 10 -41.739 (variable) 11 25.047 1.00 1.83481 42.7 12 15.346 8.52 1.59522 67.7 13* -99.784 1.03 14 (Aperture) ∞ (Variable) 15 -35.351 0.80 1.80400 46.5 16 31.393 1.99 1.92286 20.9 17 165.712 (variable) 18 -1029.479 2.83 1.49700 81.5 19 -25.457 0.15 20 17.370 1.20 1.91082 35.2 21 13.009 8.31 1.49700 81.5 22 -36.445 0.84 23* -69.710 2.00 1.85400 40.4 24* 26.620 (variable) 25 -422.142 7.40 1.48749 70.2 26 -28.946 2.42 27 -59.052 1.00 1.98612 16.5 28 -201.430 (variable) Image plane ∞ Aspheric Data Page 13 K=0.00000e+00 A4= 2.39150e-07 A6=2.26158e-09 A8=-6.83170e-11 Page 23 K=0.00000e+00 A4=-8.65880e-06 A6=-1.40706e-07 A8=8.04703e-10 Page 24 K=-2.07769e+00 A4= 3.72658e-05 A6=-1.22272e-07 A8= 6.54331e-10 A10=-7.63019e-13 A12= 2.70504e-15 Various data Zoom ratio 2.35 Wide Angle Mid-Telephoto Focal length 20.61 33.00 48.39 F-number 4.10 4.10 4.10 Half angle of view 43.69 33.25 24.09 Image height 19.69 21.64 21.64 Lens length 133.51 133.51 133.51 BF 12.18 12.18 12.18 d 7 23.75 7.98 2.59 d10 5.04 10.63 5.84 d14 2.60 12.78 22.96 d17 11.66 6.30 1.05 d24 12.78 18.14 23.39 d28 12.18 12.18 12.18 Lens Group Data Group starting plane focal length 1 1 -25.64 2 8 101.18 3 11 42.95 4 15 -40.56 5 18 45.08 6 25 229.11

[0065] [Numerical Example 3] Unit: mm Surface Data Surface number rd nd νd 1 41.061 1.50 1.76385 48.5 2 18.670 2.76 3* 18.742 2.00 1.58313 59.4 4* 10.437 9.13 5 -149.551 1.20 1.49700 81.5 6 18.547 4.44 1.73037 32.2 7 54.644 (variable) 8 71.685 1.00 2.05090 26.9 9 35.420 2.84 1.60311 60.6 10 -43.164 (variable) 11 21.461 1.00 1.85478 24.8 12 14.791 3.77 1.58313 59.4 13* -100.111 1.27 14 (Aperture) ∞ (Variable) 15 -30.974 0.80 1.69680 55.5 16 55.570 1.32 1.89286 20.4 17 341.623 (variable) 18 19.862 7.09 1.49700 81.5 19 -28.852 0.15 20 625.638 1.20 1.91082 35.2 21 61.772 4.06 1.49700 81.5 22 -43.596 1.27 23* -43.206 1.50 1.85400 40.4 24* 330.721 (variable) 25 150.000 3.35 1.48749 70.2 26* -124.136 4.44 27 -40.000 1.00 1.84666 23.8 28 -100.000 (variable) Image plane ∞ Aspheric Data 3rd page K=0.00000e+00 A4=2.80228e-05 A6=-5.08742e-07 A8=1.42896e-09 A10=-2.05137e-12 Side 4 K=-2.17472e+00 A4= 2.22288e-04 A6=-1.24383e-06 A8= 3.19583e-09 A10=-2.83819e-12 Page 13 K=0.00000e+00 A4=-9.42621e-06 A6=-7.89365e-09 A8= 4.25537e-10 Page 23 K=0.00000e+00 A4=-2.15677e-04 A6=1.29960e-06 A8=-3.41698e-09 Page 24 K=-3.17793e+03 A4=-1.35576e-04 A6=1.45714e-06 A8=-4.52525e-09 A10=5.21835e-12 A12=2.70504e-15 Page 26 K=0.00000e+00 A4=-1.19997e-05 A6=6.59284e-10 Various data Zoom ratio 1.86 Wide Angle Mid-Telephoto Focal length 15.47 22.61 28.82 F-number 4.10 4.10 4.10 Half angle of view 52.36 43.74 36.90 Image height 20.06 21.64 21.64 Lens length 97.47 97.47 97.47 BF 11.75 11.75 11.75 d 7 13.88 4.32 1.84 d10 2.46 6.27 3.00 d14 1.91 7.65 13.39 d17 9.18 3.72 0.97 d24 1.20 6.66 9.41 d28 11.75 11.75 11.75 Lens Group Data Group starting plane focal length 1 1 -18.56 2 8 62.78 3 11 36.69 4 15 -46.28 5 18 34.63 6 25 -200.19

[0066] [Numerical Example 4] Unit: mm Surface Data Surface number rd nd νd 1* 104.446 1.50 1.76450 49.1 2 17.760 6.57 3 130.913 0.90 1.59282 68.6 4 28.342 3.64 5 4587.402 0.90 1.49700 81.5 6 22.267 5.15 1.90525 35.0 7 86.995 (variable) 8 164.349 0.80 1.85478 24.8 9 32.649 0.46 10 43.922 3.69 1.80400 46.5 11* -51.454 (variable) 12 32.570 0.80 1.84666 23.8 13 23.789 4.09 1.59522 67.7 14* -98.723 1.47 15 (Aperture) ∞ (Variable) 16* -28.645 0.80 1.61340 44.3 17 28.022 1.86 1.92286 20.9 18 86.197 (variable) 19 15.506 6.28 1.49700 81.5 20 -100.043 0.15 21 28.845 0.80 2.00100 29.1 22 17.606 6.67 1.49700 81.5 23 56.231 2.83 24* -274.936 1.20 1.95150 29.8 25* 65.639 (variable) 26 -120.000 3.66 1.48749 70.2 27 -28.829 (variable) Image plane ∞ Aspheric Data Front page K=0.00000e+00 A4=4.84168e-06 A6=-4.90718e-09 A8=4.34450e-12 Page 11 K=0.00000e+00 A4=-4.65434e-06 A6=-5.76280e-10 A8=-8.53780e-11 Page 14 K=0.00000e+00 A4=-1.53451e-06 A6=4.72698e-09 A8=-4.93209e-12 Page 16 K=0.00000e+00 A4=3.85293e-06 A6= 2.09562e-08 A8=-1.71228e-10 Page 24 K=0.00000e+00 A4=-5.03054e-04 A6= 2.71124e-06 A8=-3.90281e-09 Page 25 K=-1.28237e+02 A4=-3.64939e-04 A6=3.18192e-06 A8=-3.10274e-09 A10=-5.42651e-11 A12=4.25542e-13 Various data Zoom ratio 2.75 Wide Angle Mid-Telephoto Focal length 12.37 23.99 33.97 F-number 2.35 3.03 3.60 Half angle of view 44.47 29.74 21.96 Image height 12.14 13.71 13.70 Lens length 113.77 113.77 113.77 BF 11.50 11.50 11.50 d 7 25.21 4.23 1.66 d11 3.73 13.04 3.94 d15 2.53 14.20 25.87 d18 13.96 4.43 1.10 d25 2.64 12.16 15.49 d27 11.50 11.50 11.50 Lens Group Data Group starting plane focal length 1 1 -22.31 2 8 74.95 3 12 47.02 4 16 -47.22 5 19 36.74 6 26 76.83

[0067] [Table 1]

[0068] [Imaging device] Next, an embodiment of a digital still camera (imaging device) using the zoom lens L0 of the present invention as an imaging optical system will be described with reference to Fig. 9. In Fig. 9, 10 denotes a camera body, and 11 denotes an imaging optical system constituted by any of the zoom lenses of Examples 1 to 4. 12 denotes a solid-state imaging element (photoelectric conversion element) such as a CCD sensor or CMOS sensor that is built into the camera body 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 return mirror, or a so-called mirrorless camera having no quick return mirror.

[0069] In this way, by applying the zoom lens of the present invention to an imaging device such as a digital still camera, it is possible to obtain an imaging device with a small lens.

[0070] [Imaging system] An imaging system (surveillance camera system) may be configured that includes the zoom lens L0 according to any one of the first to fourth embodiments and a control unit that controls the zoom lens. In this case, the control unit can control the zoom lens so that each lens group moves as described above during zooming, focusing, and image blur correction.

[0071] In this case, the control unit does not need to be configured integrally with the zoom lens, and may be configured separately from the zoom lens. For example, a control unit (control device) disposed far away from a drive unit that drives each lens of the zoom lens may include a transmission unit that transmits a control signal (command) for controlling the zoom lens. With such a control unit, the zoom lens can be remotely operated.

[0072] In addition, the control unit may be provided with an operation unit such as a controller or buttons for remotely operating the zoom lens, so that the zoom lens is controlled in response to a user's input to the operation unit. For example, a zoom-in button and a zoom-out button may be provided as the operation unit. In this case, the control unit may be configured to send a signal to a drive unit for the zoom lens so that the magnification of the zoom lens increases when the user presses the zoom-in button, and decreases when the user presses the zoom-out button.

[0073] The imaging system may also have a display unit such as a liquid crystal panel that displays information (movement state) related to the zoom of the zoom lens. The information related to the zoom of the zoom lens is, for example, the zoom magnification (zoom state) and the movement amount (movement state) of each lens group. In this case, the user can remotely operate the zoom lens via the operation unit while viewing the information related to the zoom of the zoom lens displayed on the display unit. In this case, the display unit and the operation unit may be integrated by adopting, for example, a touch panel.

[0074] 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.

[0075] The embodiments of the present invention include the following configurations.

[0076] [Configuration 1] A zoom lens having a first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having positive refractive power, a fourth lens group having negative refractive power, and a fifth lens group having positive refractive power, which are arranged in this order from the object side to the image side, and in which the distance between adjacent lens groups changes during zooming, the first lens group and the fourth lens group do not move during zooming, Let M2 be the absolute value of the amount of movement of the second lens group on the optical axis during zooming from the wide-angle end to the telephoto end, fw be the focal length of the entire system at the wide-angle end when focusing on infinity, f3 be the focal length of the third lens group, and f4 be the focal length of the fourth lens group. 0.45 <M2 / fw<4.50 0.00<|f3 / f4|<1.70 A zoom lens characterized by satisfying the following conditional expressions:

[0077] [Configuration 2] the zoom lens has an aperture stop; Let DSPL4t be the distance on the optical axis from the aperture stop to the surface of the fourth lens group closest to the object, and ft be the focal length of the entire system at the telephoto end when focused on infinity. 0.20 <DSPL4t / ft<1.50 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

[0078] [Configuration 3] When a composite lateral magnification of the second lens group and the third lens group at a wide-angle end is βFw, and a composite lateral magnification of the second lens group and the third lens group at a telephoto end is βFt, 0.70<βFt / βFw<4.10 3. The zoom lens according to claim 1, wherein the following condition is satisfied:

[0079] [Configuration 4] When the back focus at the wide-angle end when focusing at infinity is BFw, 0.30 <BFw / fw<3.10 4. The zoom lens according to any one of the configurations 1 to 3, which satisfies the following conditional expression:

[0080] [Configuration 5] When the focal length of the first lens group is f1, 0.60<|f1 / fw|<3.60 5. The zoom lens according to any one of the configurations 1 to 4, which satisfies the following conditional expression:

[0081] [Configuration 6] When the focal length of the second lens group is f2, 2.00 <f2 / fw<12.10 6. The zoom lens according to any one of configurations 1 to 5, which satisfies the following conditional expression:

[0082] [Configuration 7] 1.00 <f3 / fw<7.60 7. The zoom lens according to any one of the configurations 1 to 6, which satisfies the following conditional expression:

[0083] [Configuration 8] 1.00<|f4 / fw|<7.60 8. The zoom lens according to any one of configurations 1 to 7, wherein the following condition is satisfied:

[0084] [Configuration 9] When the focal length of the fifth lens group is f5, 0.90 <f5 / fw<5.90 9. The zoom lens according to any one of the configurations 1 to 8, which satisfies the following conditional expression:

[0085] [Configuration 10] When the focal length of the first lens group is f1 and the focal length of the fifth lens group is f5, 0.30<|f1 / f5|<1.60 10. The zoom lens according to any one of configurations 1 to 9, which satisfies the following conditional expression:

[0086] [Configuration 11] When the focal length of the first lens group is f1, 0.20<|f1 / f4|<1.30 11. The zoom lens according to any one of configurations 1 to 10, which satisfies the following conditional expression:

[0087] [Configuration 12] When the absolute value of the amount of movement of the third lens group on the optical axis during zooming from the wide-angle end to the telephoto end is M3, 0.40 <M3 / fw<3.80 12. The zoom lens according to any one of the configurations 1 to 11, wherein the following condition is satisfied:

[0088] [Configuration 13] When the absolute value of the amount of movement of the fifth lens group on the optical axis during zooming from the wide-angle end to the telephoto end is M5, 0.20 <M5 / fw<2.10 13. The zoom lens according to any one of configurations 1 to 12, wherein the following condition is satisfied:

[0089] [Configuration 14] Let βRw be the composite lateral magnification of the lens group arranged closer to the image side than the third lens group at the wide-angle end, and βRt be the composite lateral magnification of the lens group arranged closer to the image side than the third lens group at the telephoto end. 0.50<βRt / βRw<2.10 14. The zoom lens according to any one of configurations 1 to 13, wherein the following condition is satisfied:

[0090] [Configuration 15] the third lens group has an aperture stop; 15. The zoom lens according to any one of configurations 1 to 14, wherein the third lens group and the aperture stop move integrally during zooming.

[0091] [Configuration 16] 16. The zoom lens according to any one of configurations 1 to 15, wherein the second lens group moves during focusing from infinity to a close distance.

[0092] [Configuration 17] 17. The zoom lens according to any one of configurations 1 to 16, wherein the first lens group is stationary during focusing from infinity to a close distance.

[0093] [Configuration 18] 18. The zoom lens according to any one of configurations 1 to 17, wherein the first lens group has three negative lenses.

[0094] [Configuration 19] 19. The zoom lens according to any one of configurations 1 to 18, wherein the fourth lens group has a negative lens with a concave surface facing the object side.

[0095] [Configuration 20] 20. The zoom lens according to any one of configurations 1 to 19, wherein the fifth lens group has two positive lenses.

[0096] [Configuration 21] 21. An imaging device comprising: the zoom lens according to any one of configurations 1 to 20; and an imaging element that receives an image formed by the zoom lens.

Claims

1. A zoom lens having a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a positive refractive power, a fourth lens group having a negative refractive power, and a fifth lens group having a positive refractive power, which are arranged in this order from an object side to an image side, and in which the distance between adjacent lens groups changes during zooming, the first lens group and the fourth lens group do not move during zooming, Let M2 be the absolute value of the amount of movement of the second lens group on the optical axis during zooming from the wide-angle end to the telephoto end, fw be the focal length of the entire system at the wide-angle end when focusing on infinity, f3 be the focal length of the third lens group, and f4 be the focal length of the fourth lens group. 0.45<M2 / fw<4.50 0.00<|f3 / f4|<1.70 A zoom lens characterized by satisfying the following conditional expressions:

2. the zoom lens has an aperture stop; Let DSPL4t be the distance on the optical axis from the aperture stop to the surface of the fourth lens group closest to the object, and ft be the focal length of the entire system at the telephoto end when focused on infinity. 0.20<DSPL4t / ft<1.50 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

3. When a composite lateral magnification of the second lens group and the third lens group at a wide-angle end is βFw, and a composite lateral magnification of the second lens group and the third lens group at a telephoto end is βFt, 0.70<βFt / βFw<4.10 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

4. When the back focus at the wide-angle end when focusing at infinity is BFw, 0.30<BFw / fw<3.10 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

5. When the focal length of the first lens group is f1, 0.60<|f1 / fw|<3.60 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

6. When the focal length of the second lens group is f2, 2.00<f2 / fw<12.10 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

7. 1.00<f3 / fw<7.60 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

8. 1.00<|f4 / fw|<7.60 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

9. When the focal length of the fifth lens group is f5, 0.90<f5 / fw<5.90 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

10. When the focal length of the first lens group is f1 and the focal length of the fifth lens group is f5, 0.30<|f1 / f5|<1.60 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

11. When the focal length of the first lens group is f1, 0.20<|f1 / f4|<1.30 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

12. When the absolute value of the amount of movement of the third lens group on the optical axis during zooming from the wide-angle end to the telephoto end is M3, 0.40<M3 / fw<3.80 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

13. When the absolute value of the amount of movement of the fifth lens unit on the optical axis during zooming from the wide-angle end to the telephoto end is M5, 0.20<M5 / fw<2.10 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

14. When the composite lateral magnification of the lens group arranged closer to the image side than the third lens group at the wide-angle end is βRw, and the composite lateral magnification of the lens group arranged closer to the image side than the third lens group at the telephoto end is βRt, 0.50<βRt / βRw<2.10 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

15. the third lens group has an aperture stop; 2. The zoom lens according to claim 1, wherein the third lens group and the aperture stop move together during zooming.

16. 2. The zoom lens according to claim 1, wherein the second lens group moves during focusing from infinity to a close distance.

17. 2. The zoom lens according to claim 1, wherein the first lens group remains stationary during focusing from infinity to a close distance.

18. 2. The zoom lens according to claim 1, wherein the first lens group comprises three negative lenses.

19. 2. The zoom lens according to claim 1, wherein the fourth lens group has a negative lens having a concave surface facing the object side.

20. 2. The zoom lens according to claim 1, wherein the fifth lens group comprises two positive lenses.

21. the zoom lens has an aperture stop; Let DSPL4t be the distance on the optical axis from the aperture stop to the surface of the fourth lens group closest to the object, and ft be the focal length of the entire system at the telephoto end when focused on infinity. 0.20<DSPL4t / ft<1.50 21. The zoom lens according to claim 3, wherein the following condition is satisfied:

22. When a composite lateral magnification of the second lens group and the third lens group at a wide-angle end is βFw, and a composite lateral magnification of the second lens group and the third lens group at a telephoto end is βFt, 0.70<βFt / βFw<4.10 21. The zoom lens according to claim 4, wherein the following condition is satisfied:

23. the zoom lens has an aperture stop; Let DSPL4t be the distance on the optical axis from the aperture stop to the surface of the fourth lens group closest to the object, and ft be the focal length of the entire system at the telephoto end when focused on infinity. 0.20<DSPL4t / ft<1.50 23. The zoom lens according to claim 22, wherein the following condition is satisfied:

24. 21. An imaging apparatus comprising: the zoom lens according to claim 1; and an imaging element that receives an image formed by the zoom lens.

Images