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] The zoom lens has multiple lens groups, and 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 focal length of the third lens group, the focal length of the fourth lens group, 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 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 is small and can efficiently secure a magnification ratio, a zoom lens including first to fifth lens groups having refractive powers of positive, negative, positive, negative, and positive, arranged in order from the object side to the image side, is known.

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 is a zoom lens having a plurality of lens groups, in which the interval between adjacent lens groups changes during zooming, and 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, arranged in order from the object side to the image side. Let the focal length of the third lens group be f3, the focal length of the fourth lens group be f4, the movement amount of the third lens group during zooming from the wide-angle end to the telephoto end be M3, and the movement amount of the fifth lens group during zooming from the wide-angle end to the telephoto end be M5. When the lens groups are located on the image side at the telephoto end with respect to the wide-angle end, M3 and M5 take positive signs. -1.50≦f3 / f4≦-0.90 -20.0≦M3 / M5≦-2.0 It is characterized by satisfying the conditional expressions.

Brief Description of the Drawings

[0005] [Figure 1] It 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 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, and 7 are cross-sectional views of the zoom lenses of Examples 1 to 4, respectively. The zoom lenses of each example are used in imaging devices such as digital video cameras, digital still cameras, broadcast cameras, silver halide film cameras, 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, and 8 are aberration diagrams of the zoom lenses of Examples 1 to 4, 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 for 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. The distortion aberration diagram shows the amount of distortion aberration for the d-line. The chromatic aberration diagram shows the amount of longitudinal chromatic aberration 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 positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with negative refractive power, and a fifth lens group L5 with positive refractive power, 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 lens in each embodiment satisfies the following conditional expression (1).

[0018] -1.50 ≦ f3 / f4 ≦ -0.90 ···(1) Here, f3 is the focal length of the third lens group L3. f4 is the focal length of the fourth lens group L4.

[0019] Conditional expression (1) defines the ratio of the focal length of the third lens group L3 to the focal length of the fourth lens group L4. If it is below the lower limit value of conditional expression (1), it becomes difficult to correct the field curvature throughout the zoom range, which is not preferable. If it exceeds the upper limit value of conditional expression (1), it becomes difficult to correct the spherical aberration and coma aberration at the wide-angle end, which is not preferable.

[0020] Note that the lower limit value of the conditional expression (1) is more preferably set to -1.45, -1.40, -1.35, -1.30, -1.25, -1.20, -1.18, -1.17, -1.16, or -1.15. The upper limit value of the conditional expression (1) is more preferably set to -0.901, -0.902, -0.903, -0.904, -0.905, -0.906, -0.907, -0.908, -0.909, or -0.910.

[0021] Hereinafter, in the zoom lens of each embodiment, a configuration that is preferably satisfied will be described.

[0022] The fourth lens group L4 is preferably a focus lens group that moves along the optical axis during focusing (at the time of focusing). In order to obtain a desired zoom ratio, the third lens group L3 is located closer to the object side than the wide-angle end at the telephoto end, and the fifth lens group L5 is located closer to the image side than the wide-angle end at the telephoto end. Therefore, the distance between the third lens group L3 and the fifth lens group L5 increases at the telephoto end. Therefore, by using the fourth lens group L4 as the focus lens group, even if the refractive power of the fourth lens group L4 is reduced to suppress the focus change during wobbling, it is preferable because it becomes easier to secure a focus stroke for focusing from infinity to the closest distance.

[0023] During zooming, the first lens group L1, which is the heaviest among the plurality of lens groups, and the aperture stop SP are preferably fixed with respect to the image plane. Thereby, generation of drive noise can be suppressed, and for example, it is preferable that the drive noise during zooming is difficult to be recorded during video shooting.

[0024] Hereinafter, conditions that are preferably satisfied by the zoom lens of each embodiment will be described. The zoom lens of each embodiment preferably satisfies one or more of the following conditional expressions (2) to (8).

[0025] -20.0 ≦ M3 / M5 ≦ -2.0 ···(2) 0.30 ≦ f3 / f5 ≦ 1.50 ···(3) 0.0 < |M4 / M5| ≦ 1.2 ···(4) -1.5 ≤ f4 / f5 ≤ -0.5 ···(5) 2.0≦|M3 / M4|≦40.0 ···(6) -9.0 ≤ f1 / f2 ≤ -3.0 ···(7) 0.005 ≤ d12w / d12t ≤ 0.100 ···(8) Here, M3 is the amount of movement of the third lens group L3 when zooming from the wide-angle end to the telephoto end. M4 is the amount of movement of the fourth lens group L4 when zooming from the wide-angle end to the telephoto end. M5 is the amount of movement of the fifth lens group L5 when zooming from the wide-angle end to the telephoto end. M3, M4, and M5 are 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 amount of movement is equal to the difference in the position of each lens group (distance on the optical axis) between the wide-angle end and the telephoto end. f1 is the focal length of the first lens group L1. f2 is the focal length of the second lens group L2. f5 is the focal length of the fifth lens group L5. d12w is the distance on the optical axis from the lens surface closest to the image of the first lens group L1 to the lens surface closest to the object 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 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 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 focal length of the third lens group L3 to the focal length of the fifth lens group L5. If the ratio falls below the lower limit of conditional equation (3), 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 (3), the overall length of the lens tends to become longer in order to secure the desired magnification ratio, which is also undesirable.

[0028] Conditional equation (4) specifies the ratio of the amount of movement of the fourth lens group L4 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. Exceeding the upper limit of conditional equation (4) is undesirable because it becomes difficult to secure a sufficient focus stroke.

[0029] Conditional equation (5) specifies the ratio of the focal length of the fourth lens group L4 to the focal length of the fifth lens group L5. If the ratio falls below the lower limit of conditional equation (5), it becomes difficult to secure a sufficient focus stroke or the overall length of the lens tends to increase, which is undesirable. If the ratio exceeds the upper limit of conditional equation (5), it becomes difficult to keep the focus change during wobbling within the depth of field, which is also undesirable.

[0030] Conditional equation (6) 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 fourth lens group L4 during zooming from the wide-angle end to the telephoto end. If the ratio falls below the lower limit of conditional equation (6), it becomes difficult to secure a focus stroke or the overall length of the lens tends to increase, which is undesirable. If the ratio exceeds the upper limit of conditional equation (6), the overall length of the lens tends to increase, which is also undesirable.

[0031] Conditional equation (7) specifies the ratio of the focal length of the first lens group L1 to the focal length of the second lens group. If the upper limit of conditional equation (7) is exceeded, the overall length of the lens tends to become longer in order to secure the desired magnification ratio, which is undesirable. If the lower limit of conditional equation (7) is exceeded, it becomes difficult to correct the field curvature at the wide-angle end, which is also undesirable.

[0032] Conditional equation (8) 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 (8), 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 (8), the front element diameter tends to increase when widening the angle, which is undesirable.

[0033] Furthermore, it is more preferable that the lower limit of condition (2) be set to -19.95, -19.90, -19.80, -19.85, -19.70, -19.75, -19.60, -19.65, -19.55, or -19.50. It is more preferable that the upper limit of condition (2) be set to -2.10, -2.20, -2.30, -2.40, -2.50, -2.60, -2.70, -2.80, -2.85, or -2.90.

[0034] Furthermore, it is more preferable that the lower limit of conditional expression (3) be set to 0.32, 0.34, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, or 0.43. It is more preferable that the upper limit of conditional expression (3) be set to 1.45, 1.40, 1.35, 1.30, 1.25, 1.20, 1.16, 1.14, 1.12, or 1.10.

[0035] Furthermore, it is more preferable that the upper limit of conditional expression (4) be set to 1.16, 1.12, 1.08, 1.04, 1.00, 0.96, 0.92, 0.90, 0.89, or 0.88.

[0036] Furthermore, it is more preferable that the lower limit of conditional expression (5) be set to -1.45, -1.40, -1.35, -1.30, -1.25, -1.20, -1.16, -1.14, -1.12, or -1.10. It is more preferable that the upper limit of conditional expression (5) be set to -0.55, -0.60, -0.65, -0.70, -0.75, -0.78, -0.80, -0.82, -0.84, or -0.86.

[0037] Furthermore, it is more preferable that the lower limit of conditional expression (6) be set to 2.2, 2.4, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, or 3.3. It is more preferable that the upper limit of conditional expression (6) be set to 39.0, 38.0, 37.5, 37.0, 36.5, 36.0, 35.5, 35.0, 34.5, or 34.0.

[0038] Furthermore, it is more preferable that the lower limit of conditional expression (7) be set to -8.75, -8.50, -8.25, -8.00, -7.75, -7.50, -7.25, -7.00, -6.75, or -6.50. It is more preferable that the upper limit of conditional expression (7) be set to -3.20, -3.40, -3.60, -3.80, -4.00, -4.10, -4.20, -4.30, -4.40, or -4.50.

[0039] Furthermore, it is more preferable that the lower limit of conditional expression (8) 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 conditional expression (8) be set to 0.095, 0.090, 0.085, 0.082, 0.080, 0.078, 0.076, 0.074, 0.072, or 0.070.

[0040] Next, we will describe the zoom lenses of each embodiment in detail.

[0041] 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. 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.

[0042] The numerical values ​​corresponding to Examples 1 to 4 are shown below.

[0043] 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.

[0044] 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 the distance along the optical axis from the object-side lens surface of the lens closest to the object among the optically powerful lenses to the paraxial image plane, expressed as the air-equivalent length (length excluding optical block G). "BF" is the back focus, and is the distance along the optical axis from the image-side lens surface of the lens closest to the image among the optically powerful lenses to the paraxial image plane, expressed as the air-equivalent length.

[0045] 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.

[0046]

number

[0047] This is expressed as follows. Note that "e±XX" in each aspherical coefficient is "×10± XX This means "[...]". For aspherical coefficients where no specific numerical value is given, it is 0.

[0048] [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 40.612 0.80 1.99868 29.3 2 25.745 5.23 1.59522 67.7 3 952.053 0.11 4 26.994 2.67 1.59522 67.7 5 114.495 (variable) 6 176.269 0.45 2.05090 26.9 7 7.823 2.67 8 -170.688 0.55 2.05090 26.9 9 53.888 0.77 10 -33.147 2.75 1.92286 18.9 11 -8.631 0.54 1.90525 35.0 12 47.848 0.11 13 20.115 1.56 1.92286 18.9 14 272.011 (variable) 15 (aperture) ∞ (variable) 16* 10.306 5.15 1.76802 49.2 17* -633.805 0.11 18 19.656 0.55 2.00100 29.1 19 8.813 5.37 20 17.960 4.34 1.62280 57.0 21 -10.521 0.53 2.05090 26.9 22 -18.970 (variable) 23 61.083 2.13 1.95906 17.5 24 -16.887 0.54 2.05090 26.9 25 16.335 (Variable) 26 13.593 3.62 1.77250 49.6 27 -18.028 0.56 1.92286 18.9 28 -79.969 (variable) 29 ∞ 0.88 1.51633 64.1 30 ∞ 1.00 Image plane ∞ Aspherical data Page 16 K =-2.56954e-01 A 4=-2.62754e-05 Page 17 K = 0.00000e+00 A 4= 5.66685e-05 Various data Zoom ratio 21.46 Wide-angle, Medium, Telephoto Focal length 3.81 26.24 81.67 F-number 1.85 3.44 4.12 Half-angle [°] 39.83 6.98 2.25 Image height 2.82 3.20 3.20 Lens length 99.86 99.86 99.86 BF 8.55 8.16 7.99 d 5 0.74 18.62 26.28 d14 26.48 8.60 0.94 d15 14.87 3.50 3.86 d22 0.50 12.55 11.91 d25 7.59 7.31 7.76 d28 6.97 6.58 6.41 Zoom lens group data Group starting plane focal length 1 1 40.16 2 6 -6.36 4 16 17.65 5 23 -18.97 6 26 16.81 [Numerical Example 4] Unit: mm Surface data Face number rd nd νd 1 103.265 1.77 1.92286 18.9 2 52.157 4.00 1.75500 52.3 3 142.066 0.26 4 65.640 2.26 1.83481 42.7 5 112.942 0.26 6 41.558 3.63 1.80400 46.5 7 107.235 (variable) 8 231.557 0.90 2.00100 29.1 9 12.682 3.86 10 -5771.418 0.91 1.96300 24.1 11 162.941 1.27 12 -36.703 1.27 1.95906 17.5 13 -28.544 0.91 1.83481 42.7 14 36.286 0.27 15 27.777 3.03 1.92286 18.9 16 -112.289 (variable) 17 (aperture) ∞ (variable) 18* 16.112 3.60 1.58313 59.4 19* -117.613 3.99 20 -93.637 0.91 1.75500 52.3 21 17.331 0.89 22 25.112 3.88 1.48749 70.2 23 -26.836 0.78 24* 21.790 4.80 1.49700 81.5 25 -21.393 0.90 1.95906 17.5 26 -29.977 (variable) 27 -107.066 0.90 1.89190 37.1 28 -115.075 0.90 1.75500 52.3 29 20.039 (Variable) 30* 37.607 3.78 1.49700 81.5 31 -44.892 0.91 1.95375 32.3 32 -51.236 (variable) 33 ∞ 2.73 1.51633 64.1 34 ∞ 1.00 Image plane ∞ Aspherical data Side 18 K = 0.00000e+00 A 4=-1.92139e-05 Page 19 K = 0.00000e+00 A 4= 4.14133e-06 A 6= 6.56750e-08 Page 24 K =-3.50535e+00 A 4= 2.38315e-05 A 6=-2.70182e-08 Page 30 K = 7.36314e+00 A 4=-1.94153e-05 A 6= 2.38991e-08 A 8=-7.76031e-10 Various data Zoom ratio 4.35 Wide-angle, Medium, Telephoto Focal length 12.71 36.34 55.31 F-number 4.12 4.12 4.12 Half-angle [°] 40.35 16.43 10.82 Image height 9.35 10.74 10.74 Lens length 114.72 114.72 114.72 BF 21.83 21.48 21.33 d 7 1.54 15.96 22.14 d16 24.66 10.24 4.05 d17 10.11 1.83 1.84 d26 2.19 7.84 10.22 d29 3.55 6.53 4.29 d32 19.03 18.68 18.53 Zoom lens group data Group starting plane focal length 1 1 56.72 2 8 -12.26 4 18 20.18 5 27 -22.17 6 30 46.85 The various values ​​in each numerical example are summarized in Table 1 below.

[0049] [Table 1]

[0050] [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 9.

[0051] In Figure 9, 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 4. 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.

[0052] 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 possesses good optical performance.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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. Let f3 be the focal length of the third lens group, f4 be the focal length of the fourth lens group, M3 be the amount of movement of the third lens group during zooming from the wide-angle end to the telephoto end, and M5 be 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. -1.50 ≤ f3 / f4 ≤ -0.90 -20.0 ≤ M3 / M5 ≤ -2.0 A zoom lens characterized by satisfying the following conditional equation. (Configuration 2) When the focal length of the fifth lens group is f5, 0.30 ≤ f3 / f5 ≤ 1.50 A zoom lens according to configuration 1, characterized in that it satisfies the following condition. (Composition 3) The zoom lens according to configuration 1 or 2, characterized in that the fourth lens group moves during focusing. (Composition 4) When the amount of movement of the fourth lens group during zooming from the wide-angle end to the telephoto end is denoted as M4, 0.0 < |M4 / M5| ≤ 1.2 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 fifth lens group is f5, -1.5 ≤ f4 / f5 ≤ -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 amount of movement of the fourth lens group during zooming from the wide-angle end to the telephoto end is denoted as M4, 2.0 ≤ |M3 / M4| ≤ 40.0 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 first lens group is f1 and the focal length of the second lens group is f2, -9.0 ≤ f1 / f2 ≤ -3.0 A zoom lens according to any one of configurations 1 to 6, characterized by satisfying the following conditional expression. (Composition 8) 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 7 that satisfies the following condition. (Composition 9) A zoom lens according to any one of configurations 1 to 8, 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 10) It further has an aperture diaphragm, The zoom lens according to any one of configurations 1 to 9, characterized in that the aperture diaphragm is fixed to the image plane when zooming. (Composition 11) 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. When the focal length of the third lens group is f3 and the focal length of the fourth lens group is f4, -1.50 ≤ f3 / f4 ≤ -0.90 A zoom lens characterized by satisfying the following conditional equation. (Composition 12) An imaging device characterized by comprising a zoom lens described in any one of configurations 1 to 11, and an image sensor that receives the image formed by the zoom lens. (Composition 13) 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 14) The imaging system according to configuration 13, 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 15) The imaging system according to configuration 13 or 14, characterized in that the control unit is configured separately from the zoom lens and has an operating section for operating the zoom lens. (Composition 16) An imaging system according to any one of configurations 13 to 15, characterized in that it has a display unit that displays information regarding the zoom of the zoom lens.

[0057] 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]

[0058] 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 focal length of the third lens group is f3, the focal length of the fourth lens group is f4, 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. -1.50 ≤ f3 / f4 ≤ -0.90 -20.0 ≤ M3 / M5 ≤ -2.0 A zoom lens characterized by satisfying the following conditional equation.

2. When the focal length of the fifth lens group is f5, 0.30 ≤ f3 / f5 ≤ 1.50 The zoom lens according to claim 1, characterized in that it satisfies the following condition.

3. The zoom lens according to claim 1 or 2, characterized in that the fourth lens group moves during focusing.

4. When the amount of movement of the fourth lens group during zooming from the wide-angle end to the telephoto end is denoted as M4, 0.0<|M4 / M5|≦1.2 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 fifth lens group is f5, -1.5 ≤ f4 / f5 ≤ -0.5 A zoom lens according to claim 1 or 2, characterized in that it satisfies the following conditional expression.

6. When the amount of movement of the fourth lens group during zooming from the wide-angle end to the telephoto end is denoted as M4, 2.0≦|M3 / M4|≦40.0 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 first lens group is f1 and the focal length of the second lens group is f2, -9.0 ≤ f1 / f2 ≤ -3.0 A zoom lens according to claim 1 or 2, characterized in that it satisfies the following conditional expression.

8. 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.

9. 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.

10. 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.

11. 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. When the focal length of the third lens group is f3 and the focal length of the fourth lens group is f4, -1.50 ≤ f3 / f4 ≤ -0.90 A zoom lens characterized by satisfying the following conditional equation.

12. 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.

13. 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.

14. The imaging system according to claim 13, 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.

15. The imaging system according to claim 13, characterized in that the control unit is configured separately from the zoom lens and has an operating section for operating the zoom lens.

16. The imaging system according to claim 13, characterized in that it has a display unit that displays information regarding the zoom of the zoom lens.

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