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 distance between adjacent lens groups changes during zooming, the multiple lens groups are arranged in order from the object side to the image side, consisting of a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with negative refractive power, and a fifth lens group with positive refractive power, the second lens group comprises five or more lenses, and the amount of movement of the second lens group during zooming from the wide-angle end to the telephoto end, the amount of movement of the third lens group during zooming from the wide-angle end to the telephoto end, and the amount of movement of the fifth lens group during zooming from the wide-angle end to the telephoto end are set appropriately.

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 capable of efficiently securing a magnification ratio in a small size, there is known a zoom lens including 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] There is a desire for a zoom lens that is smaller than conventional ones, has a high magnification, and has good optical performance.

Means for Solving the Problems

[0004] A zoom lens according to one aspect of the present invention is a zoom lens having a plurality of lens groups, in which an 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, 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 order from the object side to the image side. The second lens group includes five or more lenses. When the movement amount of the second lens group during zooming from the wide-angle end to the telephoto end is M2, the movement amount of the third lens group during zooming from the wide-angle end to the telephoto end is M3, and the movement amount of the fifth lens group during zooming from the wide-angle end to the telephoto end is M5, and M2, M3, and M5 take positive signs when the lens groups are located on the image side at the telephoto end with respect to the wide-angle end, -20.0≦M3 / M5≦-2.6 -6.0≦M2 / M3≦-1.5 It is characterized by satisfying the conditional expressions.

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, and it shows the spherical aberration amounts for the d-line (wavelength 587.6 nm) and the g-line (wavelength 435.8 nm). In the astigmatism diagram, S shows the astigmatism amount in the sagittal image plane, and M shows the astigmatism amount in the meridional image plane. In the distortion aberration diagram, it shows the distortion aberration amount for the d-line. In the chromatic aberration diagram, it shows the chromatic aberration amount for 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 plurality of lens groups of the zoom lens in each embodiment are composed of a first lens group L1 with a positive refractive power, a second lens group with a negative refractive power, a third lens group L3 with a positive refractive power, a fourth lens group L4 with a negative refractive power, and a fifth lens group L5 with a 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 second lens group L2 includes five or more lenses. Thereby, it is possible to suppress fluctuations in field curvature and longitudinal chromatic aberration during zooming.

[0018] The zoom lens in each embodiment satisfies the following conditional expression (1).

[0019] -20.0 ≦ M3 / M5 ≦ -2.6 ···(1) Here, M3 is the movement amount of the third lens group L3 during zooming from the wide-angle end to the telephoto end. M5 is the movement amount of the fifth lens group L5 during zooming from the wide-angle end to the telephoto end. M3 and M5 are given positive signs when the lens group is located on the image side at the telephoto end with respect to the wide-angle end. Note that the absolute value of the movement amount is equal to the difference in the positions of each lens group (distance on the optical axis) between the wide-angle end and the telephoto end.

[0020] Conditional equation (1) specifies the ratio of the amount of movement of the third lens group L3 during zooming from the wide-angle end to the telephoto end to the amount of movement of the fifth lens group L5 during zooming from the wide-angle end to the telephoto end. If the ratio falls below the lower limit of conditional equation (1), the diameter of the third lens group L3 tends to increase, which is undesirable. If the ratio exceeds the upper limit of conditional equation (1), it becomes difficult to secure back focus, which is also undesirable.

[0021] Furthermore, it is more preferable that the lower limit of condition (1) be set to -19.96, -19.92, -19.88, -19.85, -19.82, -19.79, -19.78, -19.77, -19.76, or -19.75. It is more preferable that the upper limit of condition (1) be set to -2.650, -2.700, -2.750, -2.780, -2.810, -2.840, -2.870, -2.900, -2.905, or -2.910.

[0022] The following describes the preferred configurations for each embodiment of the zoom lens.

[0023] The second lens group L2 preferably comprises two or more positive lenses. Since the second lens group L2 has negative refractive power, it is preferable to have a larger number of negative lenses. However, to correct chromatic aberration, it is effective to use positive lenses made of materials with a smaller Abbe number than the negative lenses. By providing two or more positive lenses, the range of materials that can be used for the positive lenses is increased, making it easier to suppress fluctuations in chromatic aberration during zooming.

[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 (11).

[0025] -6.0 ≤ M2 / M3 ≤ -1.5 ···(2) 6.5 ≤ M2 / M5 ≤ 51.3 ···(3) 0.2 ≤ d45w / bkw ≤ 1.1 ···(4) 2.0 ≤ f1 / f3 ≤ 3.7 ···(5) 0.3 ≤ f2 / f4 ≤ 0.6 ···(6) -1.3 ≤ f3 / f4 ≤ -0.8 ···(7) -3.5 ≤ f1 / f4 ≤ -1.8 ···(8) 1.65 ≤ Nd2min ≤ 2.15 ···(9) 26.0 ≤ νd1min ≤ 45.0 ···(10) 0.005 ≤ d12w / d12t ≤ 0.100 ···(11) Here, M2 is the amount of movement of the second lens group L2 during zooming from the wide-angle end to the telephoto end. M2 is positive when the lens group is positioned on the image side at the telephoto end relative to the wide-angle end. The absolute value of the movement is equal to the difference in position of the second lens group L2 at the wide-angle end and the telephoto end (distance along the optical axis). d45w is the distance along the optical axis from the lens surface on the image side of the fourth lens group L4 to the lens surface on the object side of the fifth lens group L5 at the wide-angle end. bkw is the back focus at the wide-angle end. If there is a glass block or the like in the back focus area, the value excluding the glass block is used. f1 is the focal length of the first lens group L1. f2 is the focal length of the second lens group L2. f3 is the focal length of the third lens group L3. f4 is the focal length of the fourth lens group L4. Nd2min is the lowest refractive index among the lenses included in the second lens group L2. 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) defines the ratio of the amount of movement of the second lens group L2 during zooming from the wide-angle end to the telephoto end to the amount of movement of the third lens group L3 during zooming from the wide-angle end to the telephoto end. If the value falls below the lower limit of conditional equation (2), the overall length of the lens and the diameter of the front element tend to increase in order to secure the desired zoom ratio, which is undesirable. If the value exceeds the upper limit of conditional equation (2), it becomes difficult to secure the desired zoom ratio, or the diameter of the third lens group L3 tends to increase, which is undesirable.

[0027] Conditional equation (3) specifies the ratio of the amount of movement of the second lens group L2 during zooming from the wide-angle end to the telephoto end to the amount of movement of the fifth lens group L5 during zooming from the wide-angle end to the telephoto end. If the value falls below the lower limit of conditional equation (3), it becomes difficult to secure the desired magnification ratio or to secure the back focus, which is undesirable. If the value exceeds the upper limit of conditional equation (3), the overall length of the lens tends to become longer, which is undesirable.

[0028] Conditional equation (4) defines the ratio of the distance along the optical axis from the image-side lens surface of the fourth lens group L4 to the object-side lens surface of the fifth lens group L5 at the wide-angle end to the back focus at the wide-angle end. If the value falls below the lower limit of conditional equation (4), it becomes difficult to arrange the members that hold the fourth lens group L4 and the fifth lens group L5, which is undesirable. If the value exceeds the upper limit of conditional equation (4), it becomes difficult to secure back focus at the telephoto end, which is undesirable.

[0029] Conditional equation (5) specifies the ratio of the focal length of the first lens group L1 to the focal length of the third lens group L3. If the ratio falls below the lower limit of conditional equation (5), 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 (5), it becomes difficult to correct spherical aberration and coma aberration at the wide-angle 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 fourth lens group L4. 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 third lens group L3 to the focal length of the fourth lens group L4. If the ratio falls below the lower limit of conditional equation (7), it becomes difficult to correct field curvature across 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 ratio of the focal length of the first lens group L1 to the focal length of the fourth lens group L4. If the ratio falls below the lower limit of conditional equation (8), 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 (8), it becomes difficult to correct spherical aberration at the telephoto end, which is also undesirable.

[0033] Condition (9) specifies the lowest refractive index among the lenses included in the second lens group L2. If the refractive index falls below the lower limit of condition (9), it becomes difficult to suppress the increase in the front lens diameter and the fluctuation of field curvature during zooming, which is undesirable. If the refractive index exceeds the upper limit of condition (9), it becomes difficult to select the appropriate material, which is also undesirable.

[0034] Conditional equation (10) 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 (10), 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 (10), chromatic aberration correction at the telephoto end becomes difficult, which is also undesirable. 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.

[0035] Conditional equation (11) 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 (11), 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 (11), the front element diameter tends to increase when widening the angle, which is undesirable.

[0036] Furthermore, it is more preferable that the lower limit of conditional expression (2) be set to -5.60, -5.20, -4.80, -4.70, -4.60, -4.50, -4.40, -4.30, -4.20, or -4.10. It is more preferable that the upper limit of conditional expression (2) be set to -1.60, -1.70, -1.80, -1.90, -2.00, -2.10, -2.15, -2.20, -2.25, or -2.30.

[0037] Furthermore, it is more preferable that the lower limit of condition (3) be set to 6.60, 6.70, 6.80, 6.90, 6.95, 7.00, 7.05, 7.10, 7.15, or 7.20. It is more preferable that the upper limit of condition (3) be set to 51.0, 50.0, 49.0, 48.0, 47.6, 47.3, 47.0, 46.9, 46.8, or 46.7.

[0038] Furthermore, it is more preferable that the lower limit of conditional expression (4) be set to 0.205, 0.210, 0.215, 0.220, 0.225, 0.227, 0.229, 0.231, 0.233, or 0.235. It is more preferable that the upper limit of conditional expression (4) be set to 1.050, 1.030, 1.010, 1.000, 0.990, 0.980, 0.975, 0.970, 0.965, or 0.960.

[0039] Furthermore, it is more preferable that the lower limit of conditional expression (5) be set to 2.05, 2.10, 2.15, 2.20, 2.25, or 2.27. It is more preferable that the upper limit of conditional expression (5) be set to 3.65, 3.60, 3.55, 3.50, 3.45, 3.43, 3.41, 3.39, 3.37, or 3.35.

[0040] Furthermore, it is more preferable that the lower limit of condition expression (6) be set to 0.301, 0.303, 0.305, 0.307, 0.309, 0.311, 0.312, 0.313, 0.314, or 0.315. It is more preferable that the upper limit of condition expression (6) be set to 0.590, 0.580, 0.570, 0.560, 0.550, 0.540, 0.530, 0.520, 0.515, or 0.510.

[0041] Furthermore, it is more preferable that the lower limit of conditional expression (7) be set to -1.29, -1.27, -1.25, -1.23, -1.21, -1.19, -1.18, -1.17, -1.16, or -1.15. It is more preferable that the upper limit of conditional expression (7) be set to -0.810, -0.820, -0.830, -0.840, -0.845, -0.850, -0.855, -0.860, -0.865, or -0.870.

[0042] Furthermore, it is more preferable that the lower limit of conditional expression (8) be set to -3.45, -3.40, -3.36, -3.33, -3.30, -3.27, -3.24, -3.21, -3.18, or -3.15. It is more preferable that the upper limit of conditional expression (8) be set to -1.820, -1.840, -1.860, -1.880, -1.900, -1.920, -1.940, -1.960, -1.980, or -1.990.

[0043] Furthermore, it is more preferable that the lower limit of condition expression (9) be set to 1.660, 1.665, 1.670, 1.675, 1.680, 1.685, 1.690, 1.694, or 1.696. It is more preferable that the upper limit of condition expression (9) be set to 2.10, 2.05, 2.00, 1.98, 1.97, 1.96, 1.95, 1.94, 1.93, or 1.92.

[0044] Furthermore, it is more preferable that the lower limit of condition expression (10) 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 condition expression (10) be set to 44.5, 44.0, 43.5, 43.0, 42.5, 42.2, 41.9, 41.6, 41.3, or 41.0.

[0045] Furthermore, it is more preferable that the lower limit of condition expression (11) 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 (11) be set to 0.090, 0.080, 0.070, 0.060, 0.050, 0.045, 0.040, 0.035, 0.031, or 0.029.

[0046] Next, we will describe the zoom lenses of each embodiment in detail.

[0047] In Examples 1 to 4, 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, and fifth lens group L5 move along the optical axis. During focusing, the fourth lens group L4 also moves 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.

[0048] In Example 5, during zooming, the first lens group L1, the second lens group L2, the third lens group L3, and the fifth lens group L5 move along the optical axis, while the fourth lens group L4 is fixed relative to the image plane. During focusing, the fifth lens group L5 also moves 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.

[0049] In each embodiment, the second lens group L2 consists of a negative lens, a negative lens, a cemented lens of a positive lens and a negative lens, and a positive lens, arranged in order from the object side to the image side.

[0050] The numerical values ​​corresponding to Examples 1 to 5 are shown below.

[0051] 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.

[0052] 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.

[0053] 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.

[0054]

number

[0055] This is expressed as follows. Note that "e±XX" in each aspherical coefficient is "×10± XX It means "...".

[0056] [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 43.948 1.10 1.95375 32.3 2 27.892 5.74 1.49700 81.5 3 -1562.702 0.11 4 28.777 3.02 1.59522 67.7 5 147.462 (variable) 6 111.289 0.58 2.05090 26.9 7 8.104 3.06 8 104.748 0.57 2.05090 26.9 9 50.778 0.66 10 -74.218 3.83 1.92286 18.9 11 -8.715 0.57 1.91650 31.6 12 34.155 0.11 13 15.560 1.50 1.92286 18.9 14 33.405 (Variable) 15 (aperture) ∞ (variable) 16* 9.301 4.30 1.76802 49.2 17* -301.531 0.14 18 23.002 0.57 1.95375 32.3 19 8.076 4.47 20 16.991 4.50 1.69680 55.5 21 -9.671 0.57 2.05090 26.9 22 -19.365 (variable) 23 -451.387 1.62 1.95906 17.5 24 -15.277 0.55 1.91650 31.6 25 14.608 (Variable) 26 12.495 3.60 1.77250 49.6 27 -17.926 0.57 1.92286 18.9 28 -142.527 (variable) 29 ∞ 0.88 1.51633 64.1 30 ∞ 1.00 Image plane ∞ Aspherical data Page 16 K =-2.31862e-01 A 4=-3.38139e-05 Page 17 K = 0.00000e+00 A 4= 7.22194e-05 Various data Zoom ratio 21.65 Wide-angle, Medium, Telephoto Focal length 3.80 27.19 82.22 F-number 1.85 3.44 4.12 Half-angle [°] 40.09 6.79 2.25 Image height 2.82 3.20 3.20 Lens length 99.61 99.61 99.61 BF 9.04 8.34 8.04 d 5 0.65 21.43 30.33 d14 20.47 6.90 2.27 d15 21.27 4.34 2.38 d22 0.62 10.18 8.03 d25 5.82 6.67 6.82 d28 7.46 6.76 6.46 Zoom lens group data Group starting plane focal length 1 1 45.23 2 6 -6.92 4 16 16.13 5 23 -16.08 6 26 16.65 [Numerical Example 5] Unit: mm Surface data Face number rd nd νd 1 53.444 1.40 1.90525 35.0 2 30.883 6.25 1.49700 81.5 3 -566.919 0.11 4 30.701 3.85 1.52841 76.5 5 204.366 (variable) 6 375.602 0.62 1.88300 40.8 7 7.921 2.64 8 33.025 0.52 2.05090 26.9 9 17.689 1.60 10 -36.968 2.34 1.92286 18.9 11 -11.046 0.54 2.00100 29.1 12 53.067 0.11 13 20.504 1.96 1.92286 18.9 14 -306.888 (variable) 15 (aperture) ∞ 2.95 16* 13.339 3.18 1.72903 54.0 17* -102.456 1.89 18 15.783 0.56 1.68893 31.1 19 9.449 3.79 20 29.182 2.63 1.69680 55.5 21 -12.583 0.59 1.89286 20.4 22 -26.691 (variable) 23 189.422 1.67 1.95906 17.5 24 -14.288 0.56 2.00069 25.5 25 16.050 (Variable) 26 15.982 3.38 1.80400 46.5 27 -13.276 0.58 2.05090 26.9 28 -32.115 (variable) 29 ∞ 0.88 1.51633 64.1 30 ∞ 1.00 Image plane ∞ Aspherical data Page 16 K = 3.62388e-02 A 4=-2.53227e-05 Page 17 K = 0.00000e+00 A 4= 5.27956e-05 Various data Zoom ratio 23.51 Wide-angle, Medium, Telephoto Focal length 3.79 15.43 89.12 F-number 1.85 3.44 4.12 Half-angle [°] 40.07 11.67 2.05 Image height 2.82 3.20 3.20 Lens length: 99.69 98.06 106.89 BF 8.91 10.16 7.92 d 5 0.86 19.10 36.44 d14 37.74 11.43 1.95 d22 0.50 6.95 7.92 d25 7.96 6.71 8.95 d28 7.33 8.58 6.34 Zoom lens group data Group starting plane focal length 1 1 52.43 2 6 -7.05 3 15 15.76 4 23 -16.70 5 26 15.93 The various values ​​in each numerical example are summarized in Table 1 below.

[0057] [Table 1]

[0058] [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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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, a third lens group with positive refractive power, a fourth lens group with negative refractive power, and a fifth lens group with positive refractive power, arranged in order from the object side to the image side. The second lens group comprises five or more lenses, M2 is the amount of movement of the second lens group when zooming from the wide-angle end to the telephoto end, M3 is the amount of movement of the third lens group when zooming from the wide-angle end to the telephoto end, and M5 is the amount of movement of the fifth lens group when zooming from the wide-angle end to the telephoto end. M2, M3, and M5 take a positive sign when the lens group is positioned on the image side at the telephoto end relative to the wide-angle end. -20.0 ≤ M3 / M5 ≤ -2.6 -6.0 ≤ M2 / M3 ≤ -1.5 A zoom lens characterized by satisfying the following conditional equation. (Configuration 2) The zoom lens according to configuration 1, characterized in that the second lens group comprises two or more positive lenses. (Composition 3) 6.5 ≤ M2 / M5 ≤ 51.3 A zoom lens according to configuration 1 or 2, characterized by satisfying the following conditional expression. (Composition 4) When the distance along the optical axis from the image-side lens surface of the fourth lens group to the object-side lens surface of the fifth lens group at the wide-angle end is d45w, and the back focus at the wide-angle end is bkw, 0.2 ≤ d45w / bkw ≤ 1.1 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 third lens group is f3, 2.0 ≤ f1 / f3 ≤ 3.7 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 second lens group is f2 and the focal length of the fourth lens group is f4, 0.3 ≤ f2 / f4 ≤ 0.6 A zoom lens described in any one of configurations 1 to 5 that satisfies the following condition. (Composition 7) When the focal length of the third lens group is f3 and the focal length of the fourth lens group is f4, -1.3 ≤ f3 / f4 ≤ -0.8 A zoom lens described in any one of configurations 1 to 6 that satisfies the following condition. (Composition 8) When the focal length of the first lens group is f1 and the focal length of the fourth lens group is f4, -3.5 ≤ f1 / f4 ≤ -1.8 A zoom lens described in any one of configurations 1 to 7 that satisfies the following condition. (Composition 9) When the lowest refractive index among the lenses included in the second lens group is Nd2min, 1.65 ≤ Nd2min ≤ 2.15 A zoom lens described in any one of configurations 1 to 8 that satisfies the following condition. (Composition 10) 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 9 that satisfies the following condition. (Composition 11) 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 10 that satisfies the following condition. (Composition 12) A zoom lens according to any one of configurations 1 to 11, characterized in that, when zooming, the first lens group is fixed with respect to the image plane, and the second lens group, the third lens group, the fourth lens group, and the fifth lens group move. (Composition 13) A zoom lens according to any one of configurations 1 to 11, characterized in that, during zooming, the first lens group, the second lens group, the third lens group, and the fifth lens group move, and the fourth lens group is fixed with respect to the image plane. (Composition 14) The zoom lens according to any one of configurations 1 to 13, characterized in that the second lens group consists of a negative lens, a negative lens, a cemented lens of a positive lens and a negative lens, and a positive lens, arranged in order from the object side to the image side. (Composition 15) 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, a third lens group with positive refractive power, a fourth lens group with negative refractive power, and a fifth lens group with positive refractive power, arranged in order from the object side to the image side. The second lens group comprises five or more lenses, The amount of movement of the third lens group during zooming from the wide-angle end to the telephoto end is M3, and the amount of movement of the fifth lens group during zooming from the wide-angle end to the telephoto end is M5. M3 and M5 take a positive sign when the lens group is positioned on the image side at the telephoto end relative to the wide-angle end. -20.0 ≤ M3 / M5 ≤ -2.6 A zoom lens characterized by satisfying the following conditional equation. (Composition 16) An imaging device characterized by comprising a zoom lens described in any one of configurations 1 to 15, and an image sensor that receives the image formed by the zoom lens. (Composition 17) An imaging system characterized by comprising a zoom lens described in any one of configurations 1 to 15, and a control unit that controls the zoom lens during zooming. (Composition 18) The imaging system according to configuration 17, 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 19) The imaging system according to configuration 17 or 18, characterized in that the control unit is configured separately from the zoom lens and has an operating section for operating the zoom lens. (Composition 20) An imaging system according to any one of configurations 17 to 19, characterized in that it has a display unit that displays information regarding the zoom of the zoom lens.

[0065] 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 gist. [Explanation of Symbols]

[0066] 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, a third lens group with positive refractive power, a fourth lens group with negative refractive power, and a fifth lens group with positive refractive power, arranged in order from the object side to the image side. The second lens group comprises five or more lenses, M2 is the amount of movement of the second lens group when zooming from the wide-angle end to the telephoto end, M3 is the amount of movement of the third lens group when zooming from the wide-angle end to the telephoto end, and M5 is the amount of movement of the fifth lens group when zooming from the wide-angle end to the telephoto end. M2, M3, and M5 take a positive sign when the lens group is positioned on the image side at the telephoto end relative to the wide-angle end. -20.0 ≤ M3 / M5 ≤ -2.6 -6.0 ≤ M2 / M3 ≤ -1.5 A zoom lens characterized by satisfying the following conditional equation.

2. The zoom lens according to claim 1, characterized in that the second lens group comprises two or more positive lenses.

3. 6.5 ≤ M2 / M5 ≤ 51.3 A zoom lens according to claim 1 or 2, characterized in that it satisfies the following conditional expression.

4. When the distance along the optical axis from the image-side lens surface of the fourth lens group to the object-side lens surface of the fifth lens group at the wide-angle end is d45w, and the back focus at the wide-angle end is bkW, 0.2 ≤ d45w / bkw ≤ 1.1 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 third lens group is f3, 2.0 ≤ f1 / f3 ≤ 3.7 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 second lens group is f2 and the focal length of the fourth lens group is f4, 0.3 ≤ f² / f⁴ ≤ 0.6 A zoom lens according to claim 1 or 2 that satisfies the following condition.

7. When the focal length of the third lens group is f3 and the focal length of the fourth lens group is f4, -1.3 ≤ f3 / f4 ≤ -0.8 A zoom lens according to claim 1 or 2 that satisfies the following condition.

8. When the focal length of the first lens group is f1 and the focal length of the fourth lens group is f4, -3.5 ≤ f1 / f4 ≤ -1.8 A zoom lens according to claim 1 or 2 that satisfies the following condition.

9. When the lowest refractive index among the lenses included in the second lens group is Nd2min, 1.65 ≤ Nd2min ≤ 2.15 A zoom lens according to claim 1 or 2 that satisfies the following condition.

10. 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.

11. 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.

12. The zoom lens according to claim 1 or 2, characterized in that, when zooming, the first lens group is fixed with respect to the image plane, and the second lens group, the third lens group, the fourth lens group, and the fifth lens group move.

13. The zoom lens according to claim 1 or 2, characterized in that, during zooming, the first lens group, the second lens group, the third lens group, and the fifth lens group move, and the fourth lens group is fixed with respect to the image plane.

14. The zoom lens according to claim 1 or 2, characterized in that the second lens group consists of a negative lens, a negative lens, a cemented lens of a positive lens and a negative lens, and a positive lens, arranged in order from the object side to the image side.

15. 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, a third lens group with positive refractive power, a fourth lens group with negative refractive power, and a fifth lens group with positive refractive power, arranged in order from the object side to the image side. The second lens group comprises five or more lenses, M3 is the amount of movement of the third lens group during zooming from the wide-angle end to the telephoto end, and M5 is the amount of movement of the fifth lens group during zooming from the wide-angle end to the telephoto end. M3 and M5 take a positive sign when the lens group is positioned on the image side at the telephoto end relative to the wide-angle end. -20.0 ≤ M3 / M5 ≤ -2.6 A zoom lens characterized by satisfying the following conditional equation.

16. 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.

17. 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.

18. The imaging system according to claim 17, 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.

19. The imaging system according to claim 17, characterized in that the control unit is configured separately from the zoom lens and has an operating section for operating the zoom lens.

20. The imaging system according to claim 17, characterized in that it has a display unit that displays information regarding the zoom of the zoom lens.

Images