Zoom lens and imaging device having the same

Abstract

To provide a zoom lens that is smaller than conventional lenses, offers higher magnification, and has better optical performance. [Solution] A zoom lens having multiple lens groups, wherein the spacing between adjacent lens groups changes during zooming, the multiple lens groups consist of a first lens group with positive refractive power, a second lens group with negative refractive power, an intermediate lens group composed of one or two lens groups with positive refractive power, a rear lens group with negative refractive power, and a final lens group with positive refractive power, arranged in order from the object side to the image side, and the focal length of the second lens group, the focal length of the intermediate lens group at the telephoto end, the lateral magnification of the second lens group at the wide-angle end, the lateral magnification of the second lens group at the telephoto end, the lateral magnification of the intermediate lens group at the wide-angle end, and the lateral magnification of the intermediate lens group at the telephoto end are each appropriately set.

Description

Technical Field

[0001] The present invention relates to a zoom lens and an imaging device having the same.

Background Art

[0002] Conventionally, as a zoom lens that can efficiently secure a small size and a magnification ratio, there is known a zoom lens composed of first to fifth lens groups having positive, negative, positive, negative, and positive refractive powers, which are arranged in order from the object side to the image side.

Summary of the Invention

Problems to be Solved by the Invention

[0003] A zoom lens that is smaller, has a higher magnification, and has better optical performance than conventional ones is desired.

Means for Solving the Problems

[0004] A zoom lens according to one aspect of the present invention has a plurality of lens groups, and is a zoom lens in which the interval between adjacent lens groups changes during zooming. The plurality of lens groups include a first lens group having a positive refractive power, a second lens group having a negative refractive power, an intermediate lens group composed of one or two lens groups having a positive refractive power, a rear lens group having a negative refractive power, and a final lens group having a positive refractive power, which are arranged in order from the object side to the image side. When the focal length of the second lens group is f2, the focal length of the intermediate lens group at the telephoto end is fMt, the lateral magnification of the second lens group at the wide-angle end is β2w, the lateral magnification of the second lens group at the telephoto end is β2t, the lateral magnification of the intermediate lens group at the wide-angle end is βMw, and the lateral magnification of the intermediate lens group at the telephoto end is βMt, -0.5≦f2 / fMt≦-0.1 15.0≦(β2t / β2w)×(βMt / βMw)≦35.0 It is characterized by satisfying the conditional expression.

Brief Description of the Drawings

[0005] [Figure 1]This is a cross-sectional view of the zoom lens of Example 1. [Figure 2] These are aberration diagrams for Example 1 at (a) the wide-angle end, (b) the intermediate focal length, and (c) the telephoto end. [Figure 3] This is a cross-sectional view of the zoom lens of Example 2. [Figure 4] These are aberration diagrams for Example 2 at (a) the wide-angle end, (b) the intermediate focal length, and (c) the telephoto end. [Figure 5] This is a cross-sectional view of the zoom lens of Example 3. [Figure 6] These are aberration diagrams for Example 3 at (a) the wide-angle end, (b) the intermediate focal length, and (c) the telephoto end. [Figure 7] This is a cross-sectional view of the zoom lens of Example 4. [Figure 8] These are aberration diagrams for Example 4 at (a) the wide-angle end, (b) the intermediate focal length, and (c) the telephoto end. [Figure 9] This is a cross-sectional view of the zoom lens of Example 5. [Figure 10] These are aberration diagrams for Example 5 at (a) the wide-angle end, (b) the intermediate focal length, and (c) the telephoto end. [Figure 11] This is a schematic diagram of the imaging device. [Modes for carrying out the invention]

[0006] The embodiments of the present invention will be described in detail below with reference to the drawings. In each figure, the same reference numeral is used for identical components, and redundant explanations are omitted.

[0007] Figures 1, 3, 5, 7, and 9 are cross-sectional views of the zoom lenses of Examples 1 to 5, 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, surveillance cameras, and in-vehicle cameras.

[0008] In each cross-sectional view, the left side is the object side and the right side is the image side. Note that the zoom lens in each embodiment may also be used as a projection lens for a projector or the like. In this case, the left side is the screen side and the right side is the projected image side.

[0009] Each embodiment of the zoom lens is composed of multiple lens groups. In this specification, a lens group is a collection of lenses that move or remain stationary as a whole during zooming (magnification). That is, in each embodiment of the zoom lens, the distance between adjacent lens groups changes during zooming. A lens group may consist of a single lens or multiple lenses. Furthermore, a lens group may include an aperture diaphragm.

[0010] In each cross-sectional view, Li represents the i-th lens group (where i is a natural number) from the object side among the lens groups included in the zoom lens.

[0011] SP is the aperture diaphragm. I is the image plane, and when the zoom lens of each embodiment is used as the shooting optical system of a digital still camera or digital video camera, the imaging surface of an image sensor (photoelectric conversion element) such as a CCD sensor or CMOS sensor is placed on it. When the zoom lens of each embodiment is used as the shooting optical system of a silver halide film camera, a photosensitive surface corresponding to the film plane is placed on the image plane I. P is a glass block such as a faceplate or low-pass filter of a CCD sensor.

[0012] In each embodiment, when zooming from the wide-angle end to the telephoto end, each lens group is moved as shown by the arrows. The solid and dotted arrows represent the movement trajectories when focusing on an object at infinity and a nearby object, respectively.

[0013] Figures 2, 4, 6, 8, and 10 are aberration diagrams of the zoom lenses of Examples 1 to 5, respectively. In each aberration diagram, (a) is the aberration diagram at the wide-angle end, (b) is the aberration diagram at the intermediate focal length, and (c) is the aberration diagram at the telephoto end.

[0014] In the spherical aberration diagram, Fno is the F-number, showing the amount of spherical aberration with respect to the d-line (wavelength 587.6 nm) and the g-line (wavelength 435.8 nm). In the astigmatism diagram, S represents the amount of astigmatism in the sagittal image plane, and M represents the amount of astigmatism in the meridional image plane. In the distortion aberration diagram, it shows the amount of distortion aberration with respect to the d-line. In the chromatic aberration diagram, it shows the amount of chromatic aberration at the g-line. ω is the imaging semi-field angle [°].

[0015] Hereinafter, the characteristic configurations of the zoom lenses in each embodiment will be described.

[0016] The zoom lenses of each embodiment have a plurality of lens groups. The plurality of lens groups are composed of a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, an intermediate lens group composed of one or two lens groups with positive refractive power, a rear lens group with negative refractive power, and a final lens group with positive refractive power, which are arranged in order from the object side to the image side. With such a configuration, the zoom lens can be made small.

[0017] The zoom lenses of each embodiment satisfy the following conditional expression (1).

[0018] -0.5 ≦ f2 / fMt ≦ -0.1 ···(1) Here, f2 is the focal length of the second lens group L2. fMt is the focal length of the intermediate lens group at the telephoto end.

[0019] Conditional expression (1) defines the ratio of the focal length of the second lens group L2 to the focal length of the intermediate lens group at the telephoto end. If it is below the lower limit value of conditional expression (1), it is not preferable because the overall length of the lens and the front lens diameter tend to increase to ensure the desired magnification ratio. If it exceeds the upper limit value of conditional expression (1), it becomes difficult to correct the curvature of the image plane throughout the zoom range, which is not preferable.

[0020] Furthermore, it is more preferable that the lower limit of conditional expression (1) be set to -0.498, -0.496, -0.494, -0.492, -0.491, -0.490, -0.489, -0.488, -0.487, or -0.486. It is more preferable that the upper limit of conditional expression (1) be set to -0.120, -0.140, -0.160, -0.180, -1.190, -0.200, -0.210, -0.220, -0.230, or -0.240.

[0021] The following describes the preferred configurations for each embodiment of the zoom lens.

[0022] It is preferable that the intermediate lens group moves toward the object when zooming from the wide-angle end to the telephoto end. This is preferable because it makes it easier to maintain the magnification ratio and also suppresses an increase in the front lens diameter.

[0023] When zooming, it is preferable that the heaviest of the multiple lens groups, the first lens group L1 and the aperture diaphragm SP, be fixed to the image plane. This suppresses the generation of drive noise, which is preferable because, for example, drive noise during zoom changes is less likely to be recorded when shooting video.

[0024] The following describes the conditions that the zoom lenses of each embodiment preferably satisfy. The zoom lenses of each embodiment preferably satisfy one or more of the following conditional formulas (2) to (9).

[0025] 15.0≦(β2t / β2w)×(βMt / βMw)≦35.0 (2) -7.0 ≤ f1 / f2 ≤ -4.5 ···(3) 1.1 ≤ f1 / fMt ≤ 3.7 ···(4) -3.5 ≤ f1 / fR ≤ -0.5 ···(5) 0.1 ≤ f² / fR ≤ 0.8 ···(6) -1.6 ≤ fMt / fR ≤ -0.2 ···(7) 26.0 ≤ νd1min ≤ 45.0 ···(8) 0.005 ≤ d12w / d12t ≤ 0.100 ···(9) Here, β2w is the lateral magnification of the second lens group L2 at the wide-angle end. β2t is the lateral magnification of the second lens group L2 at the telephoto end. βMw is the lateral magnification of the intermediate lens group at the wide-angle end. βMt is the lateral magnification of the intermediate lens group at the telephoto end. f1 is the focal length of the first lens group L1. fR is the focal length of the rear lens group. νd1min is the smallest Abbe number among the lenses included in the first lens group L1. d12w is the distance along the optical axis from the image-side lens surface of the first lens group L1 to the object-side lens surface of the second lens group L2 at the wide-angle end. d12t is the distance along the optical axis from the image-side lens surface of the first lens group L1 to the object-side lens surface of the second lens group L2 at the telephoto end.

[0026] Conditional equation (2) specifies the product of the lateral magnification ratio at the wide-angle and telephoto ends of the second lens group L2 and the lateral magnification ratio at the wide-angle and telephoto ends of the intermediate lens group. If the value falls below the lower limit of conditional equation (2), it becomes difficult to secure the desired magnification ratio, which is undesirable. If the value exceeds the upper limit of conditional equation (2), it becomes difficult to correct field curvature and coma aberration across the entire zoom range, which is also undesirable.

[0027] Conditional equation (3) specifies the ratio of the focal length of the first lens group L1 to the focal length of the second lens group L2. If the ratio falls below the lower limit of conditional equation (3), it becomes difficult to correct field curvature at the wide-angle end, which is undesirable. If the ratio exceeds the upper limit of conditional equation (3), the overall length of the lens becomes longer in order to secure the desired magnification ratio, which is also undesirable.

[0028] Conditional equation (4) specifies the ratio of the focal length of the first lens group L1 to the focal length of the intermediate lens group at the telephoto end. If the ratio falls below the lower limit of conditional equation (4), it becomes difficult to correct spherical aberration and coma aberration at the telephoto end, which is undesirable. If the ratio exceeds the upper limit of conditional equation (4), the overall length of the lens becomes longer in order to secure the desired magnification ratio, which is also undesirable.

[0029] Conditional equation (5) specifies the ratio of the focal length of the first lens group L1 to the focal length of the rear lens group. If the ratio falls below the lower limit of conditional equation (5), the overall length of the lens becomes longer in order to secure the desired magnification ratio, which is undesirable. If the ratio exceeds the upper limit of conditional equation (5), it becomes difficult to correct spherical aberration at the telephoto end, which is also undesirable.

[0030] Conditional equation (6) specifies the ratio of the focal length of the second lens group L2 to the focal length of the rear lens group. If the ratio falls below the lower limit of conditional equation (6), it becomes difficult to suppress the variation in field curvature during zooming, which is undesirable. If the ratio exceeds the upper limit of conditional equation (6), the overall length of the lens becomes longer in order to secure the desired magnification ratio, which is also undesirable.

[0031] Conditional equation (7) specifies the ratio of the focal length of the intermediate lens group to the focal length of the rear lens group at the telephoto end. If the ratio falls below the lower limit of conditional equation (7), it becomes difficult to correct field curvature throughout the entire zoom range, which is undesirable. If the ratio exceeds the upper limit of conditional equation (7), it becomes difficult to correct spherical aberration and coma aberration at the wide-angle end, which is also undesirable.

[0032] Conditional equation (8) specifies the smallest Abbe number among the lenses included in the first lens group L1. If the value falls below the lower limit of conditional equation (8), chromatic aberration correction at the telephoto end tends to be overcorrected on the short wavelength side, which is undesirable. If the value exceeds the upper limit of conditional equation (8), chromatic aberration correction at the telephoto end becomes difficult, which is also undesirable.

[0033] Conditional equation (9) defines the ratio of the distance along the optical axis from the image-side lens surface of the first lens group L1 to the object-side lens surface of the second lens group L2 at the wide-angle and telephoto ends. If the value falls below the lower limit of conditional equation (9), the overall length of the lens tends to increase, or the arrangement of the members that hold the second lens group L2 becomes difficult, which is undesirable. If the value exceeds the upper limit of conditional equation (9), the front element diameter tends to increase when widening the angle, which is undesirable.

[0034] Furthermore, it is more preferable that the lower limit of condition (2) be set to 15.2, 15.4, 15.6, 15.8, 16.0, 16.2, 16.4, 16.6, 16.8, or 17.0. It is more preferable that the upper limit of condition (2) be set to 34.0, 33.0, 32.0, 31.0, 30.0, 29.0, 28.5, 28.0, 27.5, or 27.0.

[0035] Furthermore, it is more preferable that the lower limit of conditional expression (3) be set to -6.95, -6.90, -6.85, -6.80, -6.75, -6.70, -6.65, -6.62, -6.60, or -6.58. It is more preferable that the upper limit of conditional expression (3) be set to -4.60, -4.70, -4.80, -4.90, -5.00, -5.10, -5.20, -5.25, -5.30, or -5.32.

[0036] Furthermore, it is more preferable that the lower limit of conditional expression (4) be set to 1.15, 1.18, 1.20, 1.22, 1.24, 1.26, 1.28, 1.30, 1.32, or 1.34. It is more preferable that the upper limit of conditional expression (4) be set to 3.65, 3.60, 3.55, 3.50, 3.45, 3.40, 3.35, 3.30, 3.25, or 3.20.

[0037] Furthermore, it is more preferable that the lower limit of conditional expression (5) be set to -3.45, -3.40, -3.35, -3.30, -3.25, -3.20, -3.16, -3.14, -3.12, or -3.10. It is more preferable that the upper limit of conditional expression (5) be set to -0.51, -0.52, -0.53, -0.54, -0.55, -0.56, -0.57, -0.58, or -0.59.

[0038] Furthermore, it is more preferable that the lower limit of condition expression (6) be set to 0.101, 0.102, 0.103, 0.104, 0.105, 0.106, or 0.107. It is more preferable that the upper limit of condition expression (6) be set to 0.75, 0.70, 0.66, 0.64, 0.62, 0.60, 0.58, 0.56, 0.54, or 0.51.

[0039] Furthermore, it is more preferable that the lower limit of conditional expression (7) be set to -1.55, -1.50, -1.45, -1.40, -1.35, -1.30, -1.25, -1.20, or -1.15. It is more preferable that the upper limit of conditional expression (7) be set to -0.23, -0.26, -0.29, -0.31, -0.33, -0.35, -0.37, -0.39, -0.41, or -0.43.

[0040] Furthermore, it is more preferable that the lower limit of conditional expression (8) be set to 26.3, 26.6, 26.9, 27.2, 27.5, 27.8, 28.1, 28.3, 28.4, or 28.5. It is more preferable that the upper limit of conditional expression (8) be set to 44.5, 44.0, 43.5, 43.0, 42.5, 42.2, 41.9, 41.6, 41.3, or 41.0.

[0041] Furthermore, it is more preferable that the lower limit of condition expression (9) be set to 0.007, 0.009, 0.010, 0.011, 0.012, 0.014, 0.016, 0.018, 0.019, or 0.020. It is more preferable that the upper limit of condition expression (9) be set to 0.090, 0.080, 0.070, 0.060, 0.050, 0.045, 0.040, 0.037, 0.034, or 0.032.

[0042] Next, we will describe the zoom lenses of each embodiment in detail.

[0043] The zoom lenses of Examples 1 to 4 consist of a first lens group L1, a second lens group L2, a third lens group L3, a fourth lens group L4, and a fifth lens group L5, arranged sequentially from the object side to the image side, with refractive powers of positive, negative, positive, negative, and positive. In Examples 1 to 4, the third lens group L3 corresponds to the intermediate group, the fourth lens group L4 to the rear lens group, and the fifth lens group L5 to the final lens group. During zooming, the first lens group L1 is fixed relative to the image plane, while the second lens group L2, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 move along the optical axis. Furthermore, image stabilization can be performed by moving the entire third lens group L3 or a part of the third lens group L3 with a component perpendicular to the optical axis.

[0044] The zoom lens of Example 5 consists of a first lens group L1, second lens group L2, third lens group L3, fourth lens group L4, fifth lens group L5, and sixth lens group L6, arranged sequentially from the object side to the image side, with refractive powers of positive, negative, positive, positive, positive, and positive. In Example 5, the third lens group L3 and fourth lens group L4 correspond to intermediate groups, the fifth lens group L5 to the rear lens group, and the sixth lens group L6 to the final lens group. During zooming, the first lens group L1 is fixed relative to the image plane, while the second lens group L2, third lens group L3, fourth lens group L4, fifth lens group L5, and sixth lens group L6 move along the optical axis. Furthermore, image stabilization can be performed by moving the entire third lens group L3, a part of the third lens group L3, or the entire fourth lens group L4 with a component perpendicular to the optical axis.

[0045] The numerical values ​​corresponding to Examples 1 to 5 are shown below.

[0046] In the surface data for each numerical example, r represents the radius of curvature of each optical surface, and d (mm) represents the on-axial spacing (distance along the optical axis) between the m-th surface and the (m+1)-th surface. Here, m is the surface number counted from the light incidence side. Furthermore, nd represents the refractive index of each optical element with respect to the d-line, and νd represents the Abbe number of each optical element with respect to the d-line. Note that the Abbe number νd of a certain material is given by Nd, NF, and NC, respectively, when the refractive indices at the Fraunhofer lines d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm) are Nd, NF, and NC. νd = (Nd-1) / (NF-NC) It is represented as follows.

[0047] In each numerical example, d, focal length (mm), F-number, and half-angle of view [°] are all values ​​when the zoom lens of each example is focused on an object at infinity. The half-angle of view is a value obtained by ray tracing. "Lens length" is expressed as the distance along the optical axis from the lens surface closest to the object among the optically powerful lens surfaces to the paraxial image plane, expressed as the air-equivalent length (length excluding optical block G). "BF" is the back focus, expressed as the distance along the optical axis from the lens surface closest to the image among the optically powerful lens surfaces to the paraxial image plane, expressed as the air-equivalent length.

[0048] Furthermore, if the optical surface is aspherical, the sign * is added to the right of the surface number. The aspherical shape is defined as follows, where X is the displacement from the surface vertex in the optical axis direction, h is the height from the optical axis perpendicular to the optical axis, R is the paraaxial radius of curvature, k is the cone constant, and A4, A6, A8, and A10 are the aspherical coefficients of their respective orders.

[0049]

number

[0050] This is expressed as follows. Note that "e±XX" in each aspherical coefficient is "×10± XX It means "...".

[0051] [Numerical Example 1] Unit: mm Surface data Face number rd nd νd 1 309.071 1.75 1.85150 40.8 2 45.294 6.82 1.49700 81.5 3 -257.207 0.15 4 66.298 3.13 1.49700 81.5 5 594.924 0.13 6 43.810 4.05 1.59522 67.7 7 827.908 (variable) 8 -293.352 0.85 1.89190 37.1 9 13.328 3.03 10 156.589 0.70 2.05090 26.9 11 29.902 3.01 12 -21.463 1.75 1.85478 24.8 13 -14.611 0.70 1.72916 54.7 14 10250.684 0.11 15 48.072 2.49 1.89286 20.4 16 -58.604 (variable) 17 (aperture) ∞ (variable) 18* 17.225 4.55 1.58313 59.4 19* -59.610 5.35 20 25.947 0.70 1.96300 24.1 21 15.035 4.76 22 23.907 4.04 1.49700 81.5 23 -13.597 0.70 1.90525 35.0 24 -22.045 (variable) 25 329.166 1.40 1.89286 20.4 26 -32.452 0.60 1.83481 42.7 27 16.723 (Variable) 28 72.392 4.75 1.51742 52.4 29 -12.353 0.70 2.05090 26.9 30 -26.471 1.70 31 -70.539 2.83 1.62004 36.3 32 -18.298 (variable) 33 ∞ 1.93 1.51633 64.1 34 ∞ 1.00 Image plane ∞ Aspherical data Side 18 K = 0.00000e+00 A 4=-1.66504e-05 A 6=-2.89555e-08 A 8= 1.24059e-10 A10=-8.64505e-13 Page 19 K = 0.00000e+00 A 4= 2.09321e-05 A 6=-4.11374e-08 A 8= 2.65954e-10 A10=-8.83687e-13 Various data Zoom ratio 21.55 Wide-angle, Medium, Telephoto Focal length 8.30 60.16 178.89 F-numbers: 2.88, 4.90, 5.77 Half-angle [°] 40.48 6.51 2.21 Image height 6.25 7.05 7.05 Lens length 146.29 146.29 146.29 BF 19.54 14.22 14.04 d 7 1.07 29.02 41.00 d16 41.60 13.65 1.67 d17 16.94 0.96 0.90 d24 1.80 16.54 13.03 d27 4.61 11.17 14.91 d32 17.27 11.94 11.77 Zoom lens group data Group starting plane focal length 1 1 59.64 2 8 -11.15 4 18 24.18 5 25 -22.10 6 28 34.33 [Numerical Example 2] Unit: mm Surface data Face number rd nd νd 1 97.607 1.89 1.89190 37.1 2 45.764 6.68 1.49700 81.5 3 1545.305 0.17 4 65.113 2.89 1.49700 81.5 5 203.279 0.17 6 44.761 4.47 1.49700 81.5 7 732.754 (variable) 8 -222.514 0.92 1.89190 37.1 9 13.464 4.12 10 -148.355 0.73 1.89190 37.1 11 63.470 2.05 12 -30.371 1.56 1.89286 20.4 13 -19.848 0.74 1.69680 55.5 14 64.516 0.17 15 33.680 2.30 1.89286 20.4 16 -365.582 (variable) 17 (aperture) ∞ (variable) 18* 14.774 5.02 1.58313 59.4 19* -175.511 3.90 20 61.390 1.07 1.89190 37.1 21 11.942 0.69 22 13.683 3.38 1.51633 64.1 23 -125.765 4.05 24 28.191 3.02 1.48749 70.2 25 -19.276 0.60 2.00100 29.1 26 -29.914 (variable) 27 1127.760 1.55 1.95906 17.5 28 -24.565 0.60 1.90366 31.3 29 17.931 (Variable) 30 26.854 5.11 1.48749 70.2 31 -17.721 0.72 1.90366 31.3 32 -25.908 (variable) 33 ∞ 1.84 1.51633 64.1 34 ∞ 1.00 Image plane ∞ Aspherical data Side 18 K = 0.00000e+00 A 4=-1.36811e-05 Page 19 K = 0.00000e+00 A 4= 2.07566e-05 A 6= 3.65077e-08 Various data Zoom ratio 24.59 Wide-angle, Medium, Telephoto Focal length 8.34 63.32 205.12 F-numbers: 2.88, 4.90, 5.77 Half-angle [°] 40.08 6.23 1.93 Image height 6.13 7.05 7.05 Lens length 149.51 149.51 149.51 BF 19.28 15.67 14.12 d 7 1.21 30.12 42.51 d16 43.02 14.10 1.71 d17 18.53 1.25 1.10 d26 1.61 17.56 14.65 d29 7.30 12.25 16.86 d32 17.07 13.46 11.90 Zoom lens group data Group starting plane focal length 1 1 64.10 2 8 -10.69 4 18 24.28 5 27 -21.18 6 30 34.62 [Numerical Example 3] Unit: mm Surface data Face number rd nd νd 1 39.929 0.84 2.00480 29.0 2 25.787 5.19 1.59522 67.7 3 862.615 0.11 4 27.285 2.61 1.59522 67.7 5 110.003 (variable) 6 164.147 0.46 2.05090 26.9 7 7.773 2.67 8 -268.311 0.55 2.05090 26.9 9 47.204 0.87 10 -29.366 2.49 1.92286 18.9 11 -9.058 0.55 1.90525 35.0 12 45.873 0.11 13 20.840 1.71 1.92286 18.9 14 -244.990 (variable) 15 (aperture) ∞ (variable) 16* 10.166 4.89 1.76802 49.2 17* 685.546 0.24 18 19.007 0.56 2.00100 29.1 19 8.607 4.92 20 18.013 4.27 1.62280 57.0 21 -10.562 0.53 2.05090 26.9 22 -19.017 (variable) 23 62.906 2.08 1.95906 17.5 24 -17.033 0.52 2.05090 26.9 25 17.406 (Variable) 26 13.496 3.71 1.77250 49.6 27 -17.539 0.55 1.92286 18.9 28 -84.085 (variable) 29 ∞ 0.88 1.51633 64.1 30 ∞ 1.00 Image plane ∞ Aspherical data Page 16 K =-2.76224e-01 A 4=-2.34922e-05 Page 17 K = 0.00000e+00 A 4= 4.86811e-05 Various data Zoom ratio 21.63 Wide-angle, Medium, Telephoto Focal length 3.81 26.40 82.34 F-number 1.85 3.44 4.12 Half-angle [°] 39.83 6.94 2.24 Image height 2.82 3.20 3.20 Lens length 99.73 99.73 99.73 BF 8.54 8.16 7.99 d 5 0.74 18.78 26.51 d14 26.55 8.51 0.78 d15 14.79 3.49 3.88 d22 0.49 13.09 11.78 d25 8.19 7.28 8.35 d28 6.96 6.58 6.41 Zoom lens group data Group starting plane focal length 1 1 40.39 2 6 -6.48 4 16 17.77 5 23 -20.28 6 26 16.89 [Numerical Example 4] Unit: mm Surface data Face number rd nd νd 1 33.371 1.00 1.85025 30.1 2 21.372 4.25 1.49700 81.5 3 88.744 0.10 4 30.386 2.14 1.49700 81.5 5 96.936 0.10 6 25.316 2.40 1.59522 67.7 7 100.767 (variable) 8 ∞ 0.60 2.05090 26.9 9 7.162 2.30 10 -56.485 0.50 2.05090 26.9 11 37.662 1.02 12 -17.619 1.71 1.85478 24.8 13 -9.063 0.70 1.88300 40.8 14 71.894 0.10 15 27.476 1.71 1.95906 17.5 16 -28.101 (variable) 17 (aperture) ∞ (variable) 18* 9.466 5.95 1.58313 59.4 19* -54.869 0.10 20 24.236 0.50 1.88300 40.8 21 8.686 9.90 22 21.210 5.36 1.49700 81.5 23 -10.748 0.50 2.05090 26.9 24 -14.630 (variable) 25 896.133 0.92 1.95906 17.5 26 -50.642 0.40 1.95375 32.3 27 48.150 (Variable) 28 -62.933 1.94 1.49700 81.5 29 -13.282 0.50 2.05090 26.9 30 -26.911 0.10 31 21.247 2.23 1.53172 48.8 32 -30.450 (variable) 33 ∞ 0.88 1.51633 64.1 34 ∞ 1.00 Image plane ∞ Aspherical data Side 18 K = 0.00000e+00 A 4=-8.61196e-05 A 6= 3.26653e-08 A 8=-1.37238e-08 A10=-1.93560e-11 Page 19 K = 0.00000e+00 A 4= 7.72554e-05 A 6= 1.10521e-06 A 8=-4.04116e-08 A10= 4.25888e-10 Various data Zoom ratio 19.91 Wide-angle, Medium, Telephoto Focal length 4.11 26.87 81.77 F-number 1.85 3.44 4.12 Half-angle [°] 37.98 6.81 2.24 Image height 2.84 3.20 3.20 Lens length 110.43 110.43 110.43 BF 11.14 8.85 8.79 d 7 0.60 13.79 19.45 d16 23.13 9.94 4.28 d17 19.94 3.28 3.09 d24 2.18 20.09 12.78 d27 6.42 7.46 15.02 d32 9.56 7.27 7.21 Zoom lens group data Group starting plane focal length 1 1 31.82 2 8 -5.81 4 18 23.65 5 25 -53.71 6 28 30 31 [Numerical Example 5] Unit: mm Surface data Face number rd nd νd 1 97.786 1.00 1.89190 37.1 2 45.429 6.19 1.49700 81.5 3 786.767 0.10 4 52.226 4.01 1.49700 81.5 5 329.218 0.10 6 42.530 3.85 1.49700 81.5 7 185.513 (variable) 8 ∞ 0.60 2.05090 26.9 9 9.664 2.58 10 104.927 0.50 2.00100 29.1 11 44.205 1.46 12 -24.396 1.53 1.95906 17.5 13 -13.230 0.75 2.00100 29.1 14 69.742 0.10 15 28.525 2.47 1.95906 17.5 16 -39.421 (variable) 17 (aperture) ∞ (variable) 18* 8.722 6.18 1.58313 59.4 19* -35.096 0.10 20 -240.161 0.70 1.56732 42.8 21 7.250 (Variable) 22 12.766 4.45 1.49700 81.5 23 -9.134 0.50 2.00100 29.1 24 -14.229 (variable) 25 -48.866 0.95 1.95906 17.5 26 -17.186 0.40 1.71736 29.5 27 19.261 (Variable) 28 15.064 1.76 1.49700 81.5 29 -80.147 (variable) 30 ∞ 1.84 1.51633 64.1 31 ∞ 1.00 Image plane ∞ Aspherical data Side 18 K = 0.00000e+00 A 4=-7.44399e-05 A 6=-6.93936e-07 A 8=-9.78937e-09 A10=-5.13832e-11 Page 19 K = 0.00000e+00 A 4= 1.25482e-04 A 6=-1.02500e-06 A 8= 1.53308e-09 A10= 3.23692e-10 Various data Zoom ratio 35.06 Wide-angle, Medium, Telephoto Focal length 4.16 28.70 145.67 F-number 1.85 3.44 4.12 Half-angle [°] 37.79 6.39 1.25 Image height 2.84 3.20 3.20 Lens length 119.87 119.87 119.87 BF 9.48 13.70 8.00 d 7 1.00 31.00 43.86 d16 44.44 14.44 1.58 d17 12.94 3.38 3.31 d21 5.59 4.70 4.04 d24 2.52 6.15 3.08 d27 3.61 6.22 15.72 d29 7.27 11.48 5.79 Zoom lens group data Group starting plane focal length 1 1 59.95 2 8 -9.14 4 18 43.66 5 22 19.04 6 25 -23.22 7 28 25.67 The various values ​​in each numerical example are summarized in Table 1 below.

[0052] [Table 1]

[0053] [Imaging device] Next, an embodiment of a video camera using the zoom lens of the present invention as the imaging optical system will be described with reference to Figure 11.

[0054] In Figure 11, 10 is the video camera body, and 11 is the imaging optical system composed of one of the zoom lenses described in Examples 1 to 5. 12 is an image sensor such as a CCD that receives the subject image formed by the imaging optical system 11 and converts it into photoelectric light. 13 is a recording means for recording the subject image received by the image sensor 12, and 14 is a viewfinder for observing the subject image displayed on an unshown display element. The display element is composed of a liquid crystal panel or the like, and displays the subject image formed on the image sensor 12.

[0055] Thus, by applying the zoom lens of the present invention to an imaging device such as a video camera, it is possible to obtain an imaging device that is compact, has high magnification, and has good optical performance.

[0056] Furthermore, by using an electronic image sensor such as a CCD for the image sensor 12, the output image can be further improved in quality by electronically correcting aberrations. [Imaging System] Furthermore, 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 blur correction. At this time, the control unit does not need to be integrated with the zoom lens; the control unit may be configured separately from the zoom lens. For example, a control unit (control device) located far away from the drive unit that drives each lens of the zoom lens may be configured to include a transmission unit that sends control signals (commands) for controlling the zoom lens. With such a control unit, the zoom lens can be remotely operated.

[0057] Alternatively, the control unit may be equipped with an operating section such as a controller or buttons for remotely operating the zoom lens, thereby enabling a configuration that controls the zoom lens in response to user input to the operating section. For example, the operating section may include a zoom-in button and a zoom-out button. In this case, the control unit should be configured to send a signal to the zoom lens drive unit so that when the user presses the zoom-in button, the magnification of the zoom lens increases, and when the user presses the zoom-out button, the magnification of the zoom lens decreases.

[0058] Furthermore, the imaging system may have a display unit, such as an LCD panel, that displays information (movement status) related to the zoom of the zoom lens. This information could include, for example, the zoom magnification (zoom status) or the amount of movement of each lens group (movement status). In this case, the user can remotely operate the zoom lens via the control unit while viewing the zoom information displayed on the display unit. The display unit and the control unit may be integrated by, for example, using a touch panel.

[0059] This embodiment includes the following configuration. (Composition 1) A zoom lens having multiple lens groups, wherein the distance between adjacent lens groups changes during zooming, The aforementioned group of lenses consists of a first lens group with positive refractive power, a second lens group with negative refractive power, an intermediate lens group composed of one or two lens groups with positive refractive power, a rear lens group with negative refractive power, and a final lens group with positive refractive power, arranged in order from the object side to the image side. When the focal length of the second lens group is f2, the focal length of the intermediate lens group at the telephoto end is fMt, the lateral magnification of the second lens group at the wide-angle end is β2w, the lateral magnification of the second lens group at the telephoto end is β2t, the lateral magnification of the intermediate lens group at the wide-angle end is βMw, and the lateral magnification of the intermediate lens group at the telephoto end is βMt, -0.5 ≤ f2 / fMt ≤ -0.1 15.0≦(β2t / β2w)*(βMt / βMw)≦35.0 A zoom lens characterized by satisfying the following conditional equation. (Configuration 2) The zoom lens according to configuration 1, characterized in that the intermediate lens group moves toward the object when zooming from the wide-angle end to the telephoto end. (Composition 3) When the focal length of the first lens group is f1, -7.0 ≤ f1 / f2 ≤ -4.5 A zoom lens according to configuration 1 or 2, characterized by satisfying the following conditional expression. (Composition 4) When the focal length of the first lens group is f1, 1.1 ≤ f1 / fMt ≤ 3.7 A zoom lens according to any one of configurations 1 to 3, characterized by satisfying the following conditional expression. (Composition 5) When the focal length of the first lens group is f1 and the focal length of the rear lens group is fR, -3.5 ≤ f1 / fR ≤ -0.5 A zoom lens according to any one of configurations 1 to 4, characterized by satisfying the following conditional expression. (Composition 6) When the focal length of the rear lens group is fR, 0.1 ≤ f² / fR ≤ 0.8 A zoom lens according to any one of configurations 1 to 5, characterized by satisfying the following conditional expression. (Composition 7) When the focal length of the rear lens group is fR, -1.6 ≤ fMt / fR ≤ -0.2 A zoom lens according to any one of configurations 1 to 6, characterized by satisfying the following conditional expression. (Composition 8) When the smallest Abbe number among the lenses included in the first lens group is denoted as νd1min, 26.0 ≤ νd1min ≤ 45.0 A zoom lens described in any one of configurations 1 to 7 that satisfies the following condition. (Composition 9) When d12w is the distance along the optical axis from the image-side lens surface of the first lens group to the object-side lens surface of the second lens group at the wide-angle end, and d12t is the distance along the optical axis from the image-side lens surface of the first lens group to the object-side lens surface of the second lens group at the telephoto end, 0.005 ≤ d12w / d12t ≤ 0.100 A zoom lens described in any one of configurations 1 to 8 that satisfies the following condition. (Composition 10) A zoom lens according to any one of configurations 1 to 9, characterized in that, when zooming, the first lens group is fixed with respect to the image plane, and the second lens group, the intermediate lens group, the rear lens group, and the final lens group move. (Composition 11) It further has an aperture diaphragm, The zoom lens according to any one of configurations 1 to 10, characterized in that the aperture diaphragm is fixed to the image plane when zooming. (Composition 12) The zoom lens according to any one of configurations 1 to 11, characterized in that the plurality of lens groups consist of the first lens group, the second lens group, the third lens group with positive refractive power, the fourth lens group with negative refractive power, and the fifth lens group with positive refractive power, arranged in order from the object side to the image side. (Composition 13) The zoom lens according to any one of configurations 1 to 11, characterized in that the plurality of lens groups consist of the first lens group, the second lens group, the third lens group with positive refractive power, the fourth lens group with positive refractive power, the fifth lens group with negative refractive power, and the sixth lens group with positive refractive power, arranged in order from the object side to the image side. (Composition 14) A zoom lens having multiple lens groups, wherein the distance between adjacent lens groups changes during zooming, The aforementioned group of lenses consists of a first lens group with positive refractive power, a second lens group with negative refractive power, an intermediate lens group composed of one or two lens groups with positive refractive power, a rear lens group with negative refractive power, and a final lens group with positive refractive power, arranged in order from the object side to the image side. When the focal length of the second lens group is f2 and the focal length of the intermediate lens group at the telephoto end is fMt, -0.5 ≤ f2 / fMt ≤ -0.1 A zoom lens characterized by satisfying the following conditional equation. (Composition 15) An imaging device characterized by comprising a zoom lens described in any one of configurations 1 to 14, and an image sensor that receives the image formed by the zoom lens. (Composition 16) An imaging system characterized by comprising a zoom lens as described in configuration 1 or 2, and a control unit that controls the zoom lens during zooming. (Composition 17) The imaging system according to configuration 16, characterized in that the control unit is configured separately from the zoom lens and has a transmitting unit that transmits control signals for controlling the zoom lens. (Composition 18) The imaging system according to configuration 16 or 17, characterized in that the control unit is configured separately from the zoom lens and has an operating section for operating the zoom lens. (Composition 19) An imaging system according to any one of configurations 16 to 18, characterized in that it has a display unit that displays information regarding the zoom of the zoom lens.

[0060] Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of its essence. [Explanation of Symbols]

[0061] L1 First lens group L2 Second lens group L3 Third lens group L4 4th lens group L5 5th lens group

Claims

1. A zoom lens having multiple lens groups, wherein the distance between adjacent lens groups changes during zooming, The aforementioned group of lenses consists of a first lens group with positive refractive power, a second lens group with negative refractive power, an intermediate lens group composed of one or two lens groups with positive refractive power, a rear lens group with negative refractive power, and a final lens group with positive refractive power, arranged in order from the object side to the image side. When the focal length of the second lens group is f2, the focal length of the intermediate lens group at the telephoto end is fMt, the lateral magnification of the second lens group at the wide-angle end is β2w, the lateral magnification of the second lens group at the telephoto end is β2t, the lateral magnification of the intermediate lens group at the wide-angle end is βMw, and the lateral magnification of the intermediate lens group at the telephoto end is βMt, -0.5 ≤ f² / fMt ≤ -0.1 15.0≦(β2t / β2w)×(βMt / βMw)≦35.0 A zoom lens characterized by satisfying the following condition.

2. The zoom lens according to claim 1, characterized in that the intermediate lens group moves toward the object when zooming from the wide-angle end to the telephoto end.

3. When the focal length of the first lens group is f1, -7.0 ≤ f1 / f2 ≤ -4.5 A zoom lens according to claim 1 or 2, characterized in that it satisfies the following conditional expression.

4. When the focal length of the first lens group is f1, 1.1 ≤ f1 / fMt ≤ 3.7 A zoom lens according to claim 1 or 2, characterized in that it satisfies the following conditional expression.

5. When the focal length of the first lens group is f1 and the focal length of the rear lens group is fR, -3.5 ≤ f1 / fR ≤ -0.5 A zoom lens according to claim 1 or 2, characterized in that it satisfies the following conditional expression.

6. When the focal length of the rear lens group is fR, 0.1 ≤ f² / fR ≤ 0.8 A zoom lens according to claim 1 or 2, characterized in that it satisfies the following conditional expression.

7. When the focal length of the rear lens group is fR, -1.6 ≤ fMt / fR ≤ -0.2 A zoom lens according to claim 1 or 2, characterized in that it satisfies the following conditional expression.

8. When the smallest Abbe number among the lenses included in the first lens group is denoted as νd1min, 26.0 ≤ νd1min ≤ 45.0 A zoom lens according to claim 1 or 2 that satisfies the following condition.

9. When d12w is the distance along the optical axis from the image-side lens surface of the first lens group to the object-side lens surface of the second lens group at the wide-angle end, and d12t is the distance along the optical axis from the image-side lens surface of the first lens group to the object-side lens surface of the second lens group at the telephoto end, 0.005 ≤ d12w / d12t ≤ 0.100 A zoom lens according to claim 1 or 2 that satisfies the following condition.

10. The zoom lens according to claim 1 or 2, characterized in that, during zooming, the first lens group is fixed with respect to the image plane, and the second lens group, the intermediate lens group, the rear lens group, and the final lens group move.

11. It further has an aperture diaphragm, The zoom lens according to claim 1 or 2, characterized in that the aperture diaphragm is fixed to the image plane when zooming.

12. The zoom lens according to claim 1 or 2, characterized in that the plurality of lens groups consist of the first lens group, the second lens group, the third lens group with positive refractive power, the fourth lens group with negative refractive power, and the fifth lens group with positive refractive power, arranged in order from the object side to the image side.

13. The zoom lens according to claim 1 or 2, characterized in that the plurality of lens groups consist of the first lens group, the second lens group, the third lens group with positive refractive power, the fourth lens group with positive refractive power, the fifth lens group with negative refractive power, and the sixth lens group with positive refractive power, arranged in order from the object side to the image side.

14. A zoom lens having multiple lens groups, wherein the distance between adjacent lens groups changes during zooming, The aforementioned group of lenses consists of a first lens group with positive refractive power, a second lens group with negative refractive power, an intermediate lens group composed of one or two lens groups with positive refractive power, a rear lens group with negative refractive power, and a final lens group with positive refractive power, arranged in order from the object side to the image side. When the focal length of the second lens group is f2 and the focal length of the intermediate lens group at the telephoto end is fMt, -0.5 ≤ f² / fMt ≤ -0.1 A zoom lens characterized by satisfying the following condition.

15. An imaging device characterized by comprising a zoom lens according to claim 1 or 2, and an image sensor that receives light from an image formed by the zoom lens.

16. An imaging system characterized by comprising a zoom lens according to claim 1 or 2, and a control unit that controls the zoom lens during zooming.

17. The imaging system according to claim 16, characterized in that the control unit is configured separately from the zoom lens and has a transmitting unit that transmits control signals for controlling the zoom lens.

18. The imaging system according to claim 16, characterized in that the control unit is configured separately from the zoom lens and has an operating section for operating the zoom lens.

19. The imaging system according to claim 16, characterized in that it has a display unit that displays information regarding the zoom of the zoom lens.

Images