Zoom lens, and imaging device and imaging system having the same

Abstract

To provide a zoom lens that has high optical performance in an entire zoom range and is light weight, and an imaging apparatus and an imaging system having the same.SOLUTION: A zoom lens has a first lens group having positive refractive power, a second lens group having negative refractive power, and a subsequent group including a plurality of lens groups, which are arranged in order from an object side to an image side, and in zooming, the first lens group is immovable, and the second lens is movable. The first lens group is composed of a first partial group and a second partial group arranged in an order from the object side to the image side. The first partial group is composed of two positive lenses. The second partial group is composed of one positive lens and one negative lens. A focal distance of the first partial group, a focal distance of the second partial group, a focal distance of the first lens group, and a focal distance of the second lens group are appropriately set respectively.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 recent years, zoom lenses used in image pickup devices have been required to have high optical performance over the entire zoom range while being lightweight. To meet these requirements, zoom lenses have been proposed that have, arranged in order from the object side to the image side, a first lens group with positive refractive power, a second lens group with negative refractive power, and a subsequent group including multiple lens groups (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-325274 [Patent Document 2] Japanese Patent Publication No. 2020-86073 Summary of the Invention [Problem to be solved by the invention]

[0004] Large-aperture telephoto zoom lenses with long focal lengths and small F-numbers tend to have large lens diameters, which can lead to heavy weight. To reduce the weight of a zoom lens, it is effective to increase the positive refractive power of the first lens group and reduce the lens diameters of the subsequent lens groups. However, if the refractive power of the first lens group is too strong, it becomes difficult to correct spherical aberration, axial chromatic aberration, and lateral chromatic aberration, especially at the telephoto end.

[0005] An object of the present invention is to provide a lightweight zoom lens that has high optical performance over the entire zoom range, and an imaging device and imaging system that include the same. [Means for solving the problem]

[0006] A zoom lens according to one aspect of the present invention includes, 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, 3 or more During zooming, the first lens group remains stationary and the second lens group moves. The first lens group is made up of a first subgroup and a second subgroup arranged in this order from the object side to the image side. The first subgroup is made up of two positive lenses, and the second subgroup is made up of one positive lens and one negative lens. The focal length of the first subgroup is f1a, the focal length of the second subgroup is f1b, the focal length of the first lens group is f1, and the focal length of the second lens group is f2. , the focal length of the positive lens arranged on the object side in the first sub-group is f11, and the focal length of the positive lens arranged on the image side in the first sub-group is f12. When -0.45 <f1a / f1b<-0.10 -5.50 <f1 / f2<-3.00 0.50 <f12 / f11<1.00 The present invention is characterized in that the following conditional expression is satisfied: [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a lightweight zoom lens that has high optical performance over the entire zoom range, as well as an imaging device and an imaging system that include the same. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of a zoom lens of Example 1 at a wide-angle end. [Figure 2] 1A, 1B, and 1C are aberration diagrams of Example 1 at the wide-angle end, at the intermediate zoom position, and at the telephoto end. [Figure 3] FIG. 10 is a cross-sectional view of a zoom lens of a second embodiment at the wide-angle end. [Figure 4] 10A, 10B, and 10C are aberration diagrams of Example 2 at the wide-angle end, at the intermediate zoom position, and at the telephoto end. [Figure 5] FIG. 10 is a cross-sectional view of a zoom lens of Example 3 at the wide-angle end. [Figure 6]10A, 10B, and 10C are aberration diagrams of Example 3 at the wide-angle end, at the intermediate zoom position, and at the telephoto end. [Figure 7] FIG. 10 is a cross-sectional view of a zoom lens of Example 4 at the wide-angle end. [Figure 8] 10A, 10B, and 10C are aberration diagrams of Example 4 at the wide-angle end, at the intermediate zoom position, and at the telephoto end. [Figure 9] FIG. 1 is a schematic diagram of an imaging device. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same components, and redundant explanations will be omitted.

[0010] 1, 3, 5, and 7 are cross-sectional views at the wide-angle end of the zoom lenses of Examples 1 to 4, respectively. The zoom lenses of each Example are used in imaging devices such as digital video cameras, digital still cameras, broadcast cameras, silver halide film cameras, and surveillance cameras, as well as optical devices including interchangeable lenses.

[0011] In each cross-sectional view, the left side is the object side and the right side is the image side. The zoom lens of each embodiment is configured with multiple lens groups. In this specification, a lens group refers to a group of lenses that move or remain stationary as a unit during zooming. That is, in the zoom lens of each embodiment, the distance between adjacent lens groups changes during zooming. Note that a lens group may be configured with one lens or multiple lenses. The lens group may also include an aperture stop.

[0012] The zoom lens of each embodiment has, arranged in order from the object side to the image side, a first lens unit L1 with positive refractive power, a second lens unit L2 with negative refractive power, and a subsequent lens unit including a plurality of lens units.

[0013] In each cross-sectional view, Li represents the i-th lens group (i is a natural number) counted from the object side among the lens groups included in the zoom lens.

[0014] Additionally, SP denotes an aperture stop. IP denotes an image plane, on which the imaging surface of a solid-state imaging element (photoelectric conversion element) such as a CCD sensor or CMOS sensor is placed when the zoom lens of each embodiment is used as the imaging optical system of a digital still camera or digital video camera. When the zoom lens of each embodiment is used as the imaging optical system of a silver halide film camera, a photosensitive surface equivalent to the film surface is placed on the image plane IP.

[0015] In the zoom lens of each embodiment, each lens group moves in the direction of the solid arrow when zooming from the wide-angle end to the telephoto end, and in the zoom lens of each embodiment, each lens group moves in the direction of the dotted arrow when focusing from an object at infinity to an object at a close distance.

[0016] Furthermore, in the zoom lens of each embodiment, the optical image on the image plane can be displaced by moving a lens group with positive refractive power, or a part of the lens group, that is arranged closer to the image side than the aperture stop SP, in a direction that includes a component perpendicular to the optical axis. Utilizing this, when vibrations such as camera shake are applied to a zoom lens used as an imaging optical system, image blur on the image plane can be corrected.

[0017] Figures 2(A), 4(A), 6(A), and 8(A) are aberration diagrams at the wide-angle ends of the zoom lenses of Examples 1 to 4, respectively. Figures 2(B), 4(B), 6(B), and 8(B) are aberration diagrams at the intermediate zoom positions of the zoom lenses of Examples 1 to 4, respectively. Figures 2(C), 4(C), 6(C), and 8(C) are aberration diagrams at the telephoto ends of the zoom lenses of Examples 1 to 4, respectively.

[0018] 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, ΔS shows the amount of astigmatism on the sagittal image plane, and ΔM shows the amount of astigmatism on the meridional image plane. In the distortion diagram, the amount of distortion for the d-line is shown. In the chromatic aberration diagram, the amount of chromatic aberration for the g-line is shown. ω is the half angle of view (degrees).

[0019] Next, the characteristic configuration of the zoom lens of each embodiment will be described.

[0020] During zooming, the first lens unit L1 remains stationary, and the second lens unit L2 moves.

[0021] The first lens group L1 is made up of a first subgroup 1a and a second subgroup 1b, which are arranged in this order from the object side to the image side.

[0022] The first subgroup 1a is composed of two positive lenses. The first subgroup 1a, which is positioned closest to the object, is required to appropriately converge the axial light beam at the telephoto end in order to reduce the lens diameters of the lens groups positioned closer to the image than the first subgroup 1a. In this case, the first subgroup 1a needs to have strong positive refractive power. However, it is difficult to reduce aberrations such as spherical aberration and axial chromatic aberration at the telephoto end with a single positive lens, so multiple lenses are required. However, if the first subgroup 1a contains three or more lenses, the aforementioned aberrations can be suppressed, but the weight of the first subgroup 1a increases, which is undesirable. To achieve convergence of the axial light beam, suppression of aberrations, and a lightweight first subgroup 1a, it is preferable to configure the first subgroup 1a with two positive lenses.

[0023] The second sub-group 1b is composed of one positive lens and one negative lens. In order to effectively correct various aberrations generated in the first sub-group 1a, it is preferable that the second sub-group 1b has a negative lens. In order to effectively correct various aberrations while not impairing the effect of the first sub-group 1a in converging the axial light beam, it is preferable that the second sub-group 1b has weak negative refractive power. In order to achieve a lightweight second sub-group 1b while satisfying these conditions, it is preferable that the second sub-group 1b be composed of one positive lens and one negative lens.

[0024] The zoom lens of each embodiment satisfies the following conditional expressions (1) and (2).

[0025] -0.45 <f1a / f1b<-0.10 (1) -5.50 <f1 / f2<-3.00 (2) Here, f1a is the focal length of the first sub-group 1a, f1b is the focal length of the second sub-group 1b, f1 is the focal length of the first lens group L1, and f2 is the focal length of the second lens group L2.

[0026] Conditional expression (1) defines the ratio between the focal length of the first sub-group 1a and the focal length of the second sub-group 1b in order to reduce the weight of the second sub-group 1b and to effectively correct spherical aberration, axial chromatic aberration, and lateral chromatic aberration at the telephoto end. If the focal length of the first sub-group 1a becomes longer below the lower limit of conditional expression (1), the axial light beam incident on the second sub-group 1b cannot be sufficiently converged, the lens diameter of the second sub-group 1b becomes larger, and it becomes difficult to reduce the weight of the second sub-group 1b, which is undesirable. If the focal length of the first sub-group 1a becomes shorter above the upper limit of conditional expression (1), it becomes difficult to correct spherical aberration, axial chromatic aberration, and lateral chromatic aberration at the telephoto end, which is also undesirable.

[0027] Conditional expression (2) defines the ratio between the focal length of the first lens group L1 and the focal length of the second lens group L2 in order to achieve both lightweight and high optical performance for the zoom lens. If the focal length of the first lens group L1 becomes longer than the lower limit of conditional expression (2), the lens diameters of the second lens group L2 and subsequent lens groups located closer to the image than the first lens group L1 become larger, making it difficult to reduce the weight of the zoom lens, which is undesirable. Also, if the focal length of the second lens group L2 becomes shorter than the lower limit of conditional expression (2), it becomes difficult to correct off-axis aberrations such as coma and curvature of field at the wide-angle end, which is undesirable. If the focal length of the first lens group L1 becomes shorter than the upper limit of conditional expression (2), it becomes difficult to correct axial chromatic aberrations and chromatic aberrations of magnification at the telephoto end, which is undesirable. Furthermore, if the focal length of the second lens unit L2 becomes long beyond the upper limit of conditional expression (2), the overall length of the zoom lens becomes long, which is undesirable as it results in the zoom lens becoming large.

[0028] It is preferable that the numerical ranges of the conditional expressions (1) and (2) be set to the numerical ranges of the following conditional expressions (1a) and (2a).

[0029] -0.42 <f1a / f1b<-0.15 (1a) -4.80 <f1 / f2<-3.15 (2a) It is more preferable that the numerical ranges of the conditional expressions (1) and (2) be set to the numerical ranges of the following conditional expressions (1b) and (2b).

[0030] -0.39 <f1a / f1b<-0.20 (1b) -4.00 <f1 / f2<-3.30 (2b) Next, conditions that the zoom lens of each embodiment should preferably satisfy will be described. The zoom lens of each embodiment should preferably satisfy one or more of the following conditional expressions (3) to (8).

[0031] 0.60 <f1 / ft<1.10 (3) 0.05 <D1ab / D1<0.25 (4) 0.50 <f12 / f11<1.00 (5) 0.20 <M2 / ft<0.35 (6) 75<νd1ave<100 (7) -0.90 <f2 / fw<-0.50 (8) Here, ft is the focal length of the zoom lens at the telephoto end. D1ab is the axial distance from the lens surface of the first lens group L1 closest to the image to the lens surface of the second lens group L1 closest to the object. D1 is the axial distance from the lens surface of the first lens group L1 closest to the object to the lens surface of the first lens group L1 closest to the image. f11 is the focal length of the positive lens L11 located on the object side in the first lens group L1. f12 is the focal length of the positive lens L12 located on the image side in the first lens group L1. M2 is the movement amount of the second lens group L2 during zooming from the wide-angle end to the telephoto end, with movement toward the image side being positive. νd1ave is the average Abbe number at the d-line of all positive lenses included in the first lens group L1. fw is the focal length of the zoom lens at the wide-angle end.

[0032] Conditional expression (3) defines the ratio between the focal length of the first lens unit L1 and the focal length of the zoom lens at the telephoto end in order to achieve both a reduction in the overall length of the zoom lens and correction of spherical aberration, axial chromatic aberration, and lateral chromatic aberration at the telephoto end. If the focal length of the first lens unit L1 becomes short below the lower limit of conditional expression (3), it becomes difficult to correct spherical aberration, axial chromatic aberration, and lateral chromatic aberration at the telephoto end, which is undesirable. If the focal length of the first lens unit L1 becomes long above the upper limit of conditional expression (3), the overall length of the zoom lens becomes long, which is undesirable because the zoom lens becomes large.

[0033] Conditional expression (4) defines the arrangement of the first and second sub-groups 1a and 1b to achieve both a reduction in the weight of the second sub-group 1b and correction of spherical aberration, axial chromatic aberration, and lateral chromatic aberration at the telephoto end. If the distance from the lens surface of the first sub-group 1a closest to the image to the lens surface of the second sub-group 1b closest to the object becomes short, falling below the lower limit of conditional expression (4), the axial light beam incident on the second sub-group 1b cannot be sufficiently converged. As a result, the lens diameter of the second sub-group 1b becomes large, making it difficult to reduce the weight of the second sub-group 1b, which is undesirable. If the distance from the lens surface of the first sub-group 1a closest to the image to the lens surface of the second sub-group 1b closest to the object becomes long, exceeding the upper limit of conditional expression (4), making it difficult to correct spherical aberration, axial chromatic aberration, and lateral chromatic aberration at the telephoto end, which is undesirable.

[0034] Conditional expression (5) defines the ratio between the focal length of the positive lens L11 and the focal length of the positive lens L12 in order to effectively correct spherical aberration and axial chromatic aberration at the telephoto end. If the focal length of the positive lens L12 becomes shorter below the lower limit of conditional expression (5), it becomes difficult to correct spherical aberration and axial chromatic aberration at the telephoto end, which is undesirable. If the focal length of the positive lens L11 becomes shorter above the upper limit of conditional expression (5), it becomes difficult to correct spherical aberration and axial chromatic aberration at the telephoto end, which is undesirable.

[0035] Conditional expression (6) defines the ratio between the amount of movement of the second lens unit L2 during zooming and the focal length of the zoom lens at the telephoto end in order to shorten the overall length of the zoom lens and effectively correct axial chromatic aberration at the telephoto end. If the lower limit of conditional expression (6) is not met and the amount of movement of the second lens unit L2 during zooming becomes small, the refractive power of the second lens unit L2 becomes too strong to obtain a sufficient magnification ratio, making it difficult to correct axial chromatic aberration at the telephoto end, which is undesirable. If the upper limit of conditional expression (6) is exceeded and the amount of movement of the second lens unit L2 during zooming becomes large, the zoom lens becomes large, which is also undesirable.

[0036] Conditional expression (7) specifies the average Abbe number at the d-line of all positive lenses included in the first lens group L1 to effectively correct longitudinal chromatic aberration and lateral chromatic aberration at the telephoto end. If the average Abbe number at the d-line of all positive lenses included in the first lens group L1 falls below the lower limit of conditional expression (7) and becomes small, it becomes difficult to correct longitudinal chromatic aberration and lateral chromatic aberration at the telephoto end, which is undesirable. If the average Abbe number at the d-line of all positive lenses included in the first lens group L1 exceeds the upper limit of conditional expression (7), it becomes possible to effectively correct longitudinal chromatic aberration and lateral chromatic aberration at the telephoto end. However, with currently available glass materials, the refractive index becomes too small, making it difficult to correct spherical aberration at the telephoto end, which is undesirable.

[0037] Conditional expression (8) defines the ratio between the focal length of the second lens unit L2 and the focal length of the zoom lens at the wide-angle end in order to achieve both a reduction in the weight of the second lens unit L2 and correction of off-axis aberrations such as coma and field curvature at the wide-angle end. If the focal length of the second lens unit L2 becomes longer by falling below the lower limit of conditional expression (8), the lens diameter of the second lens unit L2 becomes larger, making it difficult to reduce the weight of the second lens unit L2, which is undesirable. If the focal length of the second lens unit L2 becomes shorter by exceeding the upper limit of conditional expression (8), it is undesirable because it makes it difficult to correct off-axis aberrations such as coma and field curvature at the wide-angle end.

[0038] It is preferable that the numerical ranges of the conditional expressions (3) to (8) be set to the numerical ranges of the following conditional expressions (3a) to (8a).

[0039] 0.70 <f1 / ft<1.00 (3a) 0.10 <D1ab / D1<0.23 (4a) 0.58 <f11 / f12<0.92 (5a) 0.23 <M2 / ft<0.32 (6a) 78<νd1ave<95 (7a) -0.82 <f2 / fw<-0.58 (8a) It is more preferable that the numerical ranges of the conditional expressions (3) to (8) be the numerical ranges of the following conditional expressions (3b) to (8b).

[0040] 0.80 <f1 / ft<0.96 (3b) 0.15 <D1ab / D1<0.21 (4b) 0.66 <f11 / f12<0.85 (5b) 0.25 <M2 / ft<0.30 (6b) 81<νd1ave<90 (7b) -0.75 <f2 / fw<-0.65 (8b) Next, the zoom lens of each embodiment will be described in detail.

[0041] The zoom lens of Example 1 is a seven-group zoom lens, with subsequent groups arranged in order from the object side to the image side, including the third lens group L3 to the seventh lens group L7, each having positive, positive, negative, negative, and positive refractive powers. In the zoom lens of Example 1, during zooming from the wide-angle end to the telephoto end, the second lens group L2 moves toward the image side, the third lens group L3 moves toward the object side, the fifth lens group L5 moves toward the object side along a locus convex toward the image side, and the sixth lens group L6 moves toward the image side. The first lens group L1, the fourth lens group L4, and the seventh lens group L7 do not move during zooming. In the zoom lens of Example 1, focusing is performed by the fifth lens group L5 and the sixth lens group L6 moving along different loci. Specifically, during focusing from an object at infinity to a close-up object, the fifth lens group L5 and the sixth lens group L6 move toward the image side.

[0042] The zoom lens of Example 2 is a five-group zoom lens, with subsequent groups arranged in order from the object side to the image side, and consisting of a third lens group L3 to a fifth lens group L5 with positive, negative, and positive refractive powers. In the zoom lens of Example 2, when zooming from the wide-angle end to the telephoto end, the second lens group L2 moves toward the image side, and the fourth lens group L4 moves toward the object side. The first lens group L1, the third lens group L3, and the fifth lens group L5 do not move during zooming. In the zoom lens of Example 2, focusing is performed by moving the fourth lens group L4. Specifically, when focusing from an object at infinity to a close-up object, the fourth lens group L4 moves toward the image side.

[0043] The zoom lens of Example 3 is a seven-group zoom lens, with subsequent groups arranged in order from the object side to the image side, including the third lens group L3 to the seventh lens group L7, each having positive, negative, positive, negative, and positive refractive powers. In the zoom lens of Example 3, during zooming from the wide-angle end to the telephoto end, the second lens group L2 moves toward the image side, the third lens group L3 and the fourth lens group L4 move toward the object side, and the sixth lens group L6 moves toward the object side along a locus convex toward the image side. The first lens group L1, the fifth lens group L5, and the seventh lens group L7 do not move during zooming. In the zoom lens of Example 3, focusing is performed by moving the sixth lens group L6. Specifically, during focusing from an object at infinity to a close-up object, the sixth lens group L6 moves toward the image side.

[0044] The zoom lens of Example 4 is a six-group zoom lens consisting of a third lens group L3 to a sixth lens group L6, with subsequent groups arranged in order from the object side to the image side, and each group having positive, negative, negative, and positive refractive powers. In the zoom lens of Example 4, during zooming from the wide-angle end to the telephoto end, the second lens group L2 moves toward the image side, the fourth lens group L4 moves toward the object side along a locus convex toward the image side, and the fifth lens group L5 moves toward the image side. The first lens group L1, the third lens group L3, and the sixth lens group L6 do not move during zooming. In the zoom lens of Example 4, focusing is performed by moving the fourth lens group L4 and the fifth lens group L5 along different loci. Specifically, during focusing from an object at infinity to a close-up object, the fourth lens group L4 and the fifth lens group L5 move toward the image side.

[0045] In the zoom lens of each embodiment, the second lens unit L2 is composed of, in order from the object side to the image side, a negative lens, a negative lens, a positive lens, and a negative lens. This configuration makes it possible to obtain sufficient negative refractive power while effectively correcting coma and field curvature at the wide-angle end, and also makes it possible to reduce the weight of the second lens unit L2.

[0046] In the zoom lens of each embodiment, the aperture stop SP is disposed between the third lens unit L3 and the fourth lens unit L4, or within the third lens unit L3.

[0047] During focusing, at least one lens group other than the fourth lens group L4 to the sixth lens group L6 may be moved.

[0048] 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. Furthermore, nd represents the refractive index of each optical element with respect to the d-line, and vd represents the Abbe number of the optical element. Note that the Abbe number vd of a certain material is given by the following equation, where Nd, NF, and NC are the refractive indices at the d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm) of the Fraunhofer lines: νd=(Nd-1) / (NF-NC) It is expressed as:

[0049] In each numerical example, d, focal length (mm), F-number, and half angle of view (degrees) are all values ​​when the zoom lens of each example is focused on an object at infinity. "Back focus" is the distance on the optical axis from the final lens surface (the lens surface closest to the image) to the paraxial image plane, expressed as an air-equivalent length. "Total lens length" is the distance on the optical axis from the frontmost lens surface (the lens surface closest to the object) to the final lens surface, plus the back focus.

[0050] [Numerical Example 1] Unit: mm Surface Data Surface number rd nd νd 1 435.360 8.41 1.48749 70.2 2 -570.557 1.00 3 144.875 11.51 1.43875 94.7 4 3213.208 8.50 5 113.847 13.56 1.49700 81.5 6 -847.524 2.70 1.61340 44.3 7 107.418 (variable) 8 3163.839 2.00 1.59270 35.3 9 57.405 8.36 10 -101.612 1.80 1.49700 81.5 11 161.066 0.30 12 100.360 6.63 1.85478 24.8 13 -264.182 2.39 14 -115.832 1.80 1.69680 55.5 15 491.399 (variable) 16 249.103 5.99 1.49700 81.5 17 -128.650 0.50 18 129.745 9.76 1.49700 81.5 19 -74.540 2.00 1.67300 38.3 20 -1333.860 0.50 21 54.405 7.50 1.49700 81.5 22 433.835 (variable) 23 (Aperture) ∞ 10.28 24 -148.769 1.60 1.51633 64.1 25 69.371 9.58 26 1901.045 4.10 1.85478 24.8 27 -96.905 2.00 28 5198.592 1.60 1.90366 31.3 29 59.212 3.83 30 70.488 1.80 1.80810 22.8 31 44.138 6.84 1.59282 68.6 32 -205.857 0.30 33 71.584 2.85 1.80400 46.5 34 163.001 1.50 35 41.273 2.29 1.83481 42.7 36 51.514 (variable) 37 224.893 3.05 1.80810 22.8 38 -149.874 1.50 1.77250 49.6 39 46.152 (variable) 40 52.870 1.80 1.49700 81.5 41 37.091 (variable) 42 90.301 9.64 1.58313 59.4 43* -88.102 9.39 44 -67.820 1.60 1.76182 26.5 45 -155.784 31.93 Image plane ∞ Aspheric data Page 43 K = 0.00000e+00 A 4=-1.36103e-06 A 6=-1.88328e-10 A 8= 1.14944e-13 A10=-5.86480e-18 Various data Zoom ratio 2.83 Wide-angle Mid-range Telephoto Focal length 103.00 166.42 292.00 F-number 2.90 2.91 2.91 Half angle of view (degrees) 11.86 7.41 4.24 Image height 21.64 21.64 21.64 Lens total length 333.61 333.61 333.61 BF 31.93 31.93 31.93 d 7 6.68 43.95 81.22 d15 77.53 39.27 1.00 d22 2.93 3.93 4.93 d36 3.63 7.01 3.60 d39 8.11 5.49 9.73 d41 32.06 31.28 30.45 Zoom lens group data Group starting plane focal length 1 1 247.39 2 8 -69.85 3 16 65.43 4 23 136.41 5 37 -78.41 6 40 -259.90 7 42 133.85 First lens group Sub-lens group data Group starting plane focal length 1a 1 206.52 1b 5 -826.03 Single lens data Lens starting surface focal length 1 1 507.94 2 3 345.40 3 5 202.89 4 6 -155.25 [Numerical Example 2] Unit: mm Surface Data Surface number rd nd νd 1 357.911 9.12 1.48749 70.2 2 -634.182 1.00 3 150.018 11.39 1.43875 94.7 4 1917.212 8.00 5 152.149 8.96 1.43875 94.7 6 940.309 1.00 7 2744.842 3.80 1.65412 39.7 8 150.564 (variable) 9 136.590 2.00 1.59270 35.3 10 47.115 9.29 11 -133.963 1.80 1.49700 81.5 12 130.618 0.30 13 71.551 6.90 1.85478 24.8 14 3712.290 2.97 15 -121.136 1.80 1.76385 48.5 16 280.220 (variable) 17 126.302 5.43 1.53775 74.7 18 -382.910 0.50 19 78.163 6.65 1.49700 81.5 20 -1358.820 0.50 21 92.143 9.10 1.49700 81.5 22 -102.484 2.20 1.67300 38.3 23 491.679 5.15 24 (Aperture) ∞ 3.90 25 -159.232 2.00 1.61340 44.3 26 148.675 8.20 27 -203.299 3.19 1.89286 20.4 28 -85.684 0.30 29 -657.804 1.50 1.80610 33.3 30 63.951 3.79 31 103.288 1.80 1.89286 20.4 32 54.282 6.49 1.69680 55.5 33 -312.910 0.30 34 88.252 3.45 1.85150 40.8 35 468.597 1.50 36 51.674 3.07 1.72916 54.7 37 87.793 (variable) 38 342.082 3.41 1.89286 20.4 39 -96.736 1.50 1.85150 40.8 40 45.657 (variable) 41 -255.883 2.00 1.48749 70.2 42 57.060 6.57 43 113.451 4.43 1.71736 29.5 44 -1269.534 1.00 45 66.805 10.89 1.53775 74.7 46 -77.597 12.89 47 -143.456 2.00 1.92286 18.9 48 575.681 34.04 Image plane ∞ Various data Zoom ratio 2.83 Wide-angle Mid-range Telephoto Focal length 103.00 166.66 292.00 F-number 2.91 2.91 2.91 Half angle of view (degrees) 11.86 7.40 4.24 Image height 21.64 21.64 21.64 Lens total length 350.00 350.00 350.00 BF 34.04 34.04 34.04 d 8 9.64 51.41 93.55 d16 84.91 43.14 1.00 d37 3.00 7.45 8.19 d40 36.36 31.91 31.17 Zoom lens group data Group starting plane focal length 1 1 279.79 2 9 -73.63 3 17 63.84 4 38 -64.60 5 41 171.50 First lens group Sub-lens group data Group starting plane focal length 1a 1 208.29 1b 5 -636.76 Single lens data Lens starting surface focal length 1 1 470.74 2 3 370.22 3 5 412.29 4 7 -243.68 [Numerical Example 3] Unit: mm Surface Data Surface number rd nd νd 1 276.211 10.69 1.49700 81.5 2 -518.352 0.50 3 115.331 12.94 1.43875 94.7 4 972.244 10.00 5 2084.057 2.70 1.61340 44.3 6 97.100 1.00 7 103.768 10.69 1.48749 70.2 8 488.045 (variable) 9 165.489 2.00 1.59270 35.3 10 46.079 8.98 11 -129.707 1.80 1.49700 81.5 12 98.898 0.30 13 71.730 6.43 1.85478 24.8 14 1868.000 3.46 15 -98.768 1.80 1.72916 54.7 16 5343.346 (variable) 17 110.371 6.49 1.49700 81.5 18 -239.050 0.50 19 111.257 9.72 1.49700 81.5 20 -77.123 2.00 1.67003 47.2 21 -3139.749 0.50 22 56.291 7.77 1.49700 81.5 23 1259.545 2.61 24 (Aperture) ∞ (Variable) 25 -197.808 1.60 1.51633 64.1 26 88.977 5.71 27 -197.618 2.92 1.84666 23.8 28 -95.782 0.30 29 496.082 1.60 1.80100 35.0 30 48.826 (variable) 31 69.734 1.80 1.80810 22.8 32 43.354 7.12 1.59282 68.6 33 -222.407 0.30 34 90.771 2.83 1.88300 40.8 35 276.166 1.50 36 39.982 2.69 1.75500 52.3 37 54.702 (variable) 38 304.669 3.39 1.80810 22.8 39 -87.105 1.50 1.78590 44.2 40 41.289 (variable) 41 99.492 1.80 1.49700 81.5 42 49.560 15.59 43 68.599 11.00 1.58313 59.4 44* -86.039 13.62 45 -42.027 1.80 1.80518 25.4 46 -60.096 31.58 Image plane ∞ Aspheric data Page 44 K = 0.00000e+00 A 4=-1.63430e-06 A 6=-3.85253e-10 A 8= 1.42947e-13 A10=-2.55937e-17 Various data Zoom ratio 2.83 Wide-angle Mid-range Telephoto Focal length 103.00 166.61 291.00 F-number 2.91 2.91 2.91 Half angle of view (degrees) 11.86 7.40 4.25 Image height 21.64 21.64 21.64 Lens total length 331.70 331.70 331.70 BF 31.58 31.58 31.58 d 8 5.53 41.98 78.75 d16 77.22 39.38 1.20 d24 7.48 7.74 8.01 d30 3.71 4.84 5.97 d37 3.68 7.39 5.47 d40 22.55 18.84 20.76 Zoom lens group data Group starting plane focal length 1 1 242.51 2 9 -67.36 3 17 60.18 4 25 -51.69 5 31 47.95 6 38 -62.55 7 41 162.50 First lens group Sub-lens group data Group starting plane focal length 1a 1 164.54 1b 5 -432.99 Single lens data Lens starting surface focal length 1 1 364.19 2 3 296.88 3 5 -166.12 4 7 267.90 [Numerical Example 4] Unit: mm Surface Data Surface number rd nd νd 1 318.412 9.60 1.48749 70.2 2 -861.108 0.50 3 150.245 12.24 1.43387 95.1 4 9401.300 7.00 5 111.079 14.21 1.49700 81.5 6 -1731.157 0.20 7 -1429.819 2.40 1.61340 44.3 8 100.324 (variable) 9 -6502.891 1.80 1.58144 40.8 10 58.931 7.68 11 -110.449 1.60 1.49700 81.5 12 198.706 0.30 13 101.587 5.82 1.85478 24.8 14 -370.711 1.60 15 -131.451 1.60 1.76385 48.5 16 885.349 (variable) 17 139.669 5.94 1.49700 81.5 18 -250.111 0.50 19 79.286 9.55 1.49700 81.5 20 -110.681 1.80 1.78590 44.2 21 168.957 0.50 22 67.931 6.88 1.49700 81.5 23 8851.483 3.89 24 (Aperture) ∞ 17.94 25 18059.683 4.63 1.84666 23.8 26 -78.373 1.50 1.72342 38.0 27 50.231 3.73 28 86.093 1.50 1.89286 20.4 29 49.267 6.22 1.72916 54.7 30 -265.136 0.30 31 77.830 2.83 1.80400 46.5 32 190.511 1.50 33 38.860 2.83 1.65160 58.5 34 55.133 (variable) 35 334.840 2.79 1.89286 20.4 36 -158.150 1.50 1.77250 49.6 37 46.681 (variable) 38 57.104 1.50 1.75500 52.3 39 39.022 (variable) 40 74.395 11.11 1.58313 59.4 41* -70.264 8.49 42 -46.660 1.40 1.64769 33.8 43 -141.783 35.45 Image plane ∞ Aspheric data Page 41 K = 0.00000e+00 A 4=-1.73775e-06 A 6= 1.43818e-10 A 8=-1.24546e-12 A10= 1.73713e-15 A12=-5.94146e-19 Various data Zoom ratio 2.86 Wide-angle Mid-range Telephoto Focal length 103.00 167.33 295.00 F-number 2.90 2.91 2.91 Half angle of view (degrees) 11.86 7.37 4.19 Image height 21.64 21.64 21.64 Lens total length 328.58 328.58 328.58 BF 35.45 35.45 35.45 d 8 5.83 46.30 87.14 d16 82.31 41.84 1.00 d34 6.72 9.37 4.67 d37 5.01 4.20 9.54 d39 27.90 26.05 25.41 Zoom lens group data Group starting plane focal length 1 1 256.11 2 9 -75.32 3 17 64.55 4 35 -76.86 5 38 -169.27 6 40 123.41 First lens group Sub-lens group data Group starting plane focal length 1a 1 203.91 1b 5 -680.08 Single lens data Lens starting surface focal length 1 1 478.12 2 3 351.77 3 5 210.56 4 7 -152.74 The various values ​​in each numerical example are summarized in Table 1 below.

[0051] [Table 1]

[0052] [Imaging device] Next, an embodiment of a digital still camera (imaging device) using the zoom lens of each embodiment 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 described in Embodiments 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 and photoelectrically converts an optical image formed by the imaging optical system 11. 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.

[0053] In this way, by applying the zoom lens of each embodiment to an imaging device such as a digital still camera, an imaging device with a small lens can be obtained. [Imaging system] An imaging system (surveillance camera system) may be configured that includes the zoom lens of each embodiment 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 stabilization. In this case, the control unit does not need to be configured integrally with the zoom lens; the control unit may be configured separately from the zoom lens. For example, a control unit (control device) located far from the drive units that drive each lens of the zoom lens may include a transmission unit that sends control signals (commands) to control the zoom lens. Such a control unit allows the zoom lens to be remotely controlled.

[0054] Alternatively, the control unit may be provided with an operation unit such as a controller or buttons for remotely operating the zoom lens, thereby controlling the zoom lens in response to user input to the operation unit. For example, the operation unit may be provided with a zoom-in button and a zoom-out button. In this case, the control unit may be configured to send a signal to a zoom lens driver so that the zoom magnification increases when the user presses the zoom-in button, and decreases when the user presses the zoom-out button.

[0055] 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. Information related to the zoom of the zoom lens includes, for example, the zoom magnification (zoom state) and the amount of movement (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 using, for example, a touch panel.

[0056] 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]

[0057] L1 First lens group L2 Second lens group 1a 1st subgroup 1b second subgroup

Claims

1. the first lens group having a positive refractive power, the second lens group having a negative refractive power, and a subsequent group including three or more lens groups, which are arranged in this order from the object side to the image side, and the first lens group does not move during zooming, and the second lens group moves; the first lens group is made up of a first subgroup and a second subgroup, which are arranged in this order from the object side to the image side, the first sub-group is composed of two positive lenses, the second sub-lens group is composed of one positive lens and one negative lens, When the focal length of the first subgroup is f1a, the focal length of the second subgroup is f1b, the focal length of the first lens group is f1, the focal length of the second lens group is f2, the focal length of the positive lens arranged on the object side in the first subgroup is f11, and the focal length of the positive lens arranged on the image side in the first subgroup is f12, -0.45<f1a / f1b<-0.10 -5.50<f1 / f2<-3.00 0.50<f12 / f11<1.00 A zoom lens characterized by satisfying the following conditional expressions:

2. When the focal length of the zoom lens at the telephoto end is ft, 0.60<f1 / ft<1.10 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

3. When the distance on the optical axis from the lens surface of the first lens group closest to the image side to the lens surface of the second lens group closest to the object side is D1ab, and the distance on the optical axis from the lens surface of the first lens group closest to the object side to the lens surface of the first lens group closest to the image side is D1, 0.05<D1ab / D1<0.25 3. The zoom lens according to claim 1, wherein the following condition is satisfied:

4. When the movement toward the image side is defined as positive, and the movement amount of the second lens unit during zooming from the wide-angle end to the telephoto end is defined as M2, 0.20<M2 / ft<0.35 4. The zoom lens according to claim 1, wherein the following condition is satisfied:

5. When the average value of the Abbe numbers at the d-line of all the positive lenses included in the first lens group is νd1ave, 75<νd1ave<100 5. The zoom lens according to claim 1, wherein the following condition is satisfied:

6. When the focal length of the zoom lens at the wide-angle end is fw, -0.90<f2 / fw<-0.50 6. The zoom lens according to claim 1, wherein the following condition is satisfied:

7. the subsequent lens group includes an aperture stop and a lens group having positive refractive power that is disposed closer to the image side than the aperture stop, 7. The zoom lens according to claim 1, wherein the lens group with positive refractive power or a part of the lens group moves in a direction including a component perpendicular to the optical axis during image blur correction.

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

9. 8. 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 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.

10. 8. The zoom lens according to claim 1, wherein the subsequent lens group consists of, arranged in order from the object side to the image side, a third lens group having a positive refractive power, a fourth lens group having a negative refractive power, a fifth lens group having a positive refractive power, a sixth lens group having a negative refractive power, and a seventh lens group having a positive refractive power.

11. 8. 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 third lens group having a positive refractive power, a fourth lens group having a negative refractive power, a fifth lens group having a negative refractive power, and a sixth lens group having a positive refractive power.

12. 8. The zoom lens according to claim 1, wherein the second lens group consists of a negative lens, a negative lens, a positive lens, and a negative lens arranged in this order from the object side to the image side.

13. A zoom lens according to any one of claims 1 to 12; and an image sensor that receives an image formed by the zoom lens.

14. 13. An imaging system comprising: the zoom lens according to claim 1; and a control unit that controls the zoom lens during zooming.

15. 15. The imaging system according to claim 14, wherein the control unit is configured as a separate unit from the zoom lens and includes a transmission unit that transmits a control signal for controlling the zoom lens.

16. 16. The imaging system according to claim 14, wherein the control unit is configured as a separate unit from the zoom lens, and has an operation unit for operating the zoom lens.

17. 17. The imaging system according to claim 14, further comprising a display unit that displays information related to the zoom of the zoom lens.

Images