Zoom lens and imaging apparatus

Abstract

To provide a zoom lens that has good optical performance even during vibration isolation despite its small size.SOLUTION: A zoom lens L0 comprises a plurality of lens groups consisting of a first lens group L1 having a negative refractive power and a rear group LR including two or more lens groups, which are arranged in order from an object side to an image side, wherein an interval between the adjacent lens groups changes in zooming. The rear group includes an aperture diaphragm SP, and a vibration isolation group LIS having a negative refractive power and moving in a direction orthogonal to an optical axis. The zoom lens has a focus group closer to the object side than the vibration isolation group. When a distance on the optical axis from the aperture diaphragm to an image surface at a wide-angle end is defined as DSPw, and a distance on the optical axis from the aperture diaphragm to a surface on the most object side of the vibration isolation group at the wide-angle end is defined as DISw, a condition of 0.40≤DISw / DSPw≤0.80 is satisfied.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a zoom lens.

Background Art

[0002] As an imaging optical system used in imaging devices such as digital still cameras, video cameras, broadcast cameras, and surveillance cameras, an optical system that is small and lightweight and has high optical performance even when the image blur correction amount is large is required. Patent Document 1 discloses a zoom lens having a subsequent lens group including a first lens group with negative refractive power, a second lens group with positive refractive power, and an anti-shake lens group arranged in order from the object side to the image side. The anti-shake lens group performs OIS that reduces (corrects) image blur caused by camera shake (hereinafter referred to as camera blur) of the imaging device due to hand shake or the like by moving (shifting) in a direction perpendicular to the optical axis. In addition, an imaging element that images a subject image formed by the imaging optical system can perform IIS that corrects image blur by shifting in a direction perpendicular to the optical axis.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a central projection type imaging optical system, the amount of movement of the image point on the image plane due to camera blur is different between the central portion and the peripheral portion of the image plane. In particular, the wider the angle of view of the imaging optical system, the larger the amount of movement of the image point in the peripheral portion compared to the central portion. For this reason, in an ultra-wide-angle zoom lens with an angle of view exceeding 100°, a large amount of image blur remains in the peripheral portion.

[0005] Fig. 2(A) shows the ratio and direction of the movement amount of each image point when image blur (angle blur) causes image blur in the -X direction at the center. Fig. 2(B) shows the amount (image point movement amount) and direction of remaining image blur at each image point in the peripheral part when the image blur at the center shown in Fig. 2(A) is corrected by IIS. As shown in Fig. 2(A), the image point movement amount is larger in the peripheral part than in the center part. Therefore, as shown in Fig. 2(B), a large amount of remaining image blur remains in the peripheral part with respect to the center part where the image blur is well corrected.

[0006] In the zoom lens of Patent Document 1, although the field curvature during anti - shake is corrected, due to the difference in the image point movement amount between the center part and the peripheral part, a large amount of remaining image blur is generated in the peripheral part. Also, in IIS, if the outer diameter of the anti - shake lens group is large, it becomes difficult to miniaturize the zoom lens.

[0007] The present invention provides a zoom lens having good optical performance even during anti - shake while being small, and an imaging device using the same.

Means for Solving the Problems

[0008] The zoom lens according to one aspect of the present invention is composed of a plurality of lens groups including a first lens group with negative refractive power and a rear group including two or more lens groups arranged in order from the object side to the image side, and is a zoom lens in which the interval between adjacent lens groups changes during zooming. The rear group includes a diaphragm and an anti - shake group having negative refractive power and moving in a direction perpendicular to the optical axis. A focus group is provided on the object side of the anti - shake group. When the distance on the optical axis from the diaphragm at the wide - angle end to the image plane is DSPw, and the distance on the optical axis from the diaphragm at the wide - angle end to the most object - side surface of the anti - shake group is DISw, 0.40 ≦ DISw / DSPw ≦ 0.80 It is characterized by satisfying the above conditions. Note that an imaging device or an imaging system having the above zoom lens also constitutes another aspect of the present invention.

Effects of the Invention

[0009] According to the present invention, it is possible to provide a zoom lens that is small in size and has good optical performance even during vibration prevention, and an imaging apparatus using the same.

Brief Description of the Drawings

[0010]

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Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0012] FIGS. 1, 5, 8, 11, 14, 17, and 20 each show a cross section of the zoom lens L0 of Examples 1 to 7 at the wide-angle end and in the infinite-focus state. The zoom lens L0 of each example is used in an imaging apparatus such as a digital video camera, a digital still camera, a camera for silver halide film, a broadcast camera, and a surveillance camera, or an interchangeable lens.

[0013] In each cross-sectional view, the left side is the object side and the right side is the image side. The zoom lens L0 of each example has a plurality of lens groups. A lens group is a collection of one or more lenses that move integrally during zooming (zooming) between the wide-angle end and the telephoto end. That is, the distance between adjacent lens groups changes during zooming. A lens group may include an aperture stop. Also, the wide-angle end and the telephoto end respectively indicate the zoom states of the maximum angle of view (shortest focal length) and the minimum angle of view (longest focal length) when the lens group that moves during zooming is located at both ends of the range where it can move mechanically or under control on the optical axis.

[0014] In each cross-sectional view, Li represents the i-th lens group (where i is a natural number) counted from the object side among the lens groups included in the zoom lens L0. LR is a rear group including two or more lens groups arranged on the image side with respect to the first lens group L1. LIS is an anti-shake group having an anti-shake function of moving (shifting) in a direction perpendicular to the optical axis to correct image blur. Note that the anti-shake group may move in a direction including a direction perpendicular to the optical axis as a component (for example, a rotation direction around the center on the optical axis).

[0015] In each embodiment, the anti-shake group is a collection of one or more lenses in which the distance on the optical axis from the lens surface closest to the object side to the lens surface closest to the image side remains unchanged during zooming. The anti-shake group may be constituted by one lens group or may be constituted as a part of one lens group.

[0016] In the figure, the lens group with a broken-line arrow and "Focus" attached is a focus group that moves from the object side to the image side during focusing from infinity to the closest distance. Note that the focus group may be the whole of one lens group or may be a part of one lens group. LN is the lens group arranged on the most image side among the zoom lens L0.

[0017] Also, SP is the aperture stop, and IP is the image plane. On the image plane IP, an imaging surface of a solid-state imaging device (photoelectric conversion element) such as a CCD sensor or a CMOS sensor or a film surface (photosensitive surface) of a silver halide film is arranged.

[0018] Under the lens group that moves during zooming, the movement locus of the lens group during zooming from the wide-angle end to the telephoto end is indicated by a solid-line arrow. Also, under the lens group that moves during focusing, the movement locus of the lens group during focusing from infinity to the closest distance is indicated by a broken-line arrow.

[0019] The zoom lens L0 of each embodiment is constituted by a plurality of lens groups including a first lens group L1 having a negative refractive power and a rear group LR arranged in order from the object side to the image side.

[0020] The first lens group L1 has three or more negative lenses in order from the object side, and the focus group consists of one positive lens GP.

[0021] The zoom lens L0 of Example 1 and Example 2 is composed of a first lens group L1, a second lens group L2 with positive refractive power, a third lens group L3 with positive refractive power, and a fourth lens group L4 with positive refractive power. The second lens group L2 includes an aperture stop SP. In the zoom lens L0 of Example 1 and Example 2, the second lens group L2, the third lens group L3, and the fourth lens group L4 are included in the rear group LR. When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves along a convex locus toward the image side, and the second lens group L2 and the third lens group L3 move monotonously toward the object side. The fourth lens group L4 is stationary (fixed).

[0022] The zoom lens L0 of Example 3 is composed of a first lens group L1, a second lens group L2 with positive refractive power, a third lens group L3 with positive refractive power, and a fourth lens group L4 with positive refractive power. The second lens group L2 includes an aperture stop SP. In the zoom lens L0 of Example 3, the second lens group L2, the third lens group L3, and the fourth lens group L4 are included in the rear group LR. When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves along a convex locus toward the image side, and the second lens group L2 and the third lens group L3 move monotonously toward the object side. The fourth lens group L4 moves monotonously toward the image side.

[0023] The zoom lens L0 of Example 4 is composed of a first lens group L1, a second lens group L2 with positive refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with negative refractive power, and a fifth lens group L5 with positive refractive power. The second lens group L2 includes an aperture stop SP. In the zoom lens L0 of Example 4, the second lens group L2, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 are included in the rear group LR. When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves along a convex locus toward the image side, and the second lens group L2, the third lens group L3, and the fourth lens group L4 move monotonously toward the object side. The fifth lens group L5 moves monotonously toward the image side.

[0024] The zoom lens L0 of Example 5 is composed of a first lens group L1, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power, and a fifth lens group L5 with negative refractive power. The second lens group L2 includes an aperture stop SP. In the zoom lens L0 of Example 5, the second lens group L2, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 correspond to the rear group LR. When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves along a locus convex toward the image side, and the second lens group L2, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 move monotonously toward the object side.

[0025] The zoom lens L0 of Example 6 is composed of a first lens group L1, a second lens group L2 with positive refractive power, a third lens group L3 with negative refractive power, a fourth lens group L4 with positive refractive power, a fifth lens group L5 with negative refractive power, and a sixth lens group L6 with positive refractive power. The second lens group L2 includes an aperture stop SP. In the zoom lens L0 of Example 6, the second lens group L2, the third lens group L3, the fourth lens group L4, the fifth lens group L5, and the sixth lens group L6 are included in the rear group LR. When zooming from the wide-angle end to the telephoto end, the first lens group L1 moves along a locus convex toward the image side, and the second lens group L2, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 move monotonously toward the object side. The sixth lens group L6 is stationary.

[0026] The zoom lens L0 of Example 7 is composed of a first lens group L1, a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with positive refractive power, and a fifth lens group L5 with positive refractive power. In the zoom lens L0 of Example 7, the second lens group L2, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 are included in the rear group LR. When zooming from the wide-angle end to the telephoto end, the first lens group L1 and the second lens group L2 move along a locus convex toward the image side, and the third lens group L3 and the fourth lens group L4 move monotonously toward the object side. The fifth lens group L5 is stationary.

[0027] The zoom lenses L0 of Examples 1 to 7 are designed to allow the occurrence of distortion aberration on the premise of correcting distortion aberration by image processing. Therefore, the imaging optical system using the zoom lens L0 has the amount of design distortion aberration that the zoom lens L0 has. And in the imaging device that performs imaging using the imaging optical system, image processing for correcting the amount of design distortion aberration is performed on the acquired imaging image by its image processing unit. It is preferable that a zoom lens or an imaging device as a lens device such as an interchangeable lens has a storage unit that holds correction data used for correcting distortion aberration.

[0028] In the zoom lens that allows the occurrence of distortion aberration in this way, since a lens for correcting distortion aberration becomes unnecessary, miniaturization and weight reduction of the zoom lens become easy. In particular, by correcting distortion aberration by making the effective imaging range (effective image circle diameter) of the imaging element on the wide-angle side smaller than the effective imaging range at the telephoto end, the first lens group L1 can be miniaturized.

[0029] In the zoom lens L0 of each example, a parallel flat plate having substantially no refractive power, such as a low-pass filter or an infrared cut filter, may be arranged between the lens arranged closest to the image side and the image plane IP.

[0030] Figs. 3, 6, 9, 12, 15, 18, and 21 respectively show the longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) at (A) the wide-angle end and (B) the telephoto end in the infinity-focus state of the zoom lenses L0 of numerical examples 1 to 7 corresponding to Examples 1 to 7. In the spherical aberration diagram, Fno is the F-number, and it shows 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, ΔS shows the amount of astigmatism in the sagittal image plane, and ΔM shows 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 lateral chromatic aberration at the g-line. ω is the semi-field angle (°) by paraxial calculation.

[0031] Figures 4, 7, 10, 13, 16, 19, and 22 each show the amount of residual image blur when an angular shake of ±0.4 deg is given to an imaging device having the zoom lens L0 of Examples 1 to 7 and an image sensor that receives an optical image formed by the zoom lens L0. In each figure, the amount of residual image blur in the wide-angle end and infinity focus state of the zoom lens L0 is shown. (A) in each figure shows the direction of image point movement (image blur direction) and the amount of residual image blur for each image height in the direction orthogonal thereto when the image blur at the center of the image plane IP is corrected by OIS alone when the imaging device is tilted. Further, (B) shows the direction of image point movement and the amount of residual image blur for each image height in the direction orthogonal thereto when the image blur at the center is corrected using OIS and IIS at a certain ratio when the imaging device is tilted.

[0032] Next, the characteristic configurations of the zoom lenses L0 of the respective examples will be described. The zoom lens L0 of each example is a so-called negative lead type zoom lens in which the refractive power of the first lens group L1 is negative. The negative lead type zoom lens is particularly effective for widening the angle of the zoom lens. By arranging the focus group near the aperture stop SP, the height of the off-axis light rays incident on the focus group can be reduced, so that it becomes easy to miniaturize the focus group.

[0033] Since the amount of image point movement on the image plane due to camera shake differs between the center and peripheral portions of the image plane, the image blur at the peripheral portion becomes large in a wide-angle zoom lens. Generally, a lens group with a high off-axis light ray height has a large influence on the peripheral portion on the image plane when shifted in a direction orthogonal to the optical axis. For this reason, if the height of the off-axis light rays incident on the anti-shake group is high, it becomes easy to suppress the image blur at the peripheral portion. On the other hand, if the height of the off-axis light rays incident on the anti-shake group is high, the lens diameter of the anti-shake group becomes large. As a result, in order to achieve miniaturization of the anti-shake group and good suppression of image blur at the peripheral portion, it is important to arrange the anti-shake group at an appropriate position.

[0034] Therefore, in the zoom lens L0 of each embodiment, while arranging the focus group LF near the aperture stop SP, the arrangement of the anti-vibration group is appropriately set. Specifically, the zoom lens L0 of each embodiment satisfies the following conditional expression (1).

[0035] 0.40 ≦ DISw / DSPw ≦ 0.80 (1) The conditional expression (1) defines the ratio of the distance DSPw on the optical axis from the aperture stop SP to the image plane at the wide-angle end to the distance DISw on the optical axis from the aperture stop SP to the most object-side surface of the anti-vibration group LIS. By arranging the anti-vibration group LIS at an appropriate position, while reducing the diameter of the anti-vibration group LIS, it becomes easier to arrange the drive units for driving the anti-vibration group LIS and the focus group. If the distance from the aperture stop SP to the anti-vibration group LIS becomes too short such that DISw / DSPw is below the lower limit value of the conditional expression (1), the height of the off-axis light rays incident on the anti-vibration group becomes low, and it becomes difficult to suppress image blur in the peripheral part. Furthermore, since the distance between the focus group LF arranged near the aperture stop SP and the anti-vibration group LIS becomes too short, it becomes difficult to arrange the drive unit for driving the focus group LF and the drive units for driving the anti-vibration group LIS and the focus group. On the other hand, if the distance from the aperture stop SP to the anti-vibration group LIS becomes too long such that DISw / DSPw exceeds the upper limit value of the conditional expression (1), the height of the off-axis light rays incident on the anti-vibration group LIS becomes high. For this reason, it becomes difficult to reduce the diameter of the anti-vibration group LIS, and it becomes difficult to miniaturize the zoom lens L0.

[0036] With the above configuration, a zoom lens having a small size and good optical characteristics can be obtained.

[0037] Also, the zoom lens L0 of each embodiment preferably satisfies at least one of the following conditional expressions (2) to (13).

[0038] 25 ≦ νdGP ≦ 45 (2) 0.48 ≦ DLFw / TLw ≦ 0.65 (3) 0.04 ≦ Skw / TLw ≦ 0.25 (4) -0.45 ≦ fL1 / fLF ≦ -0.15 (5) 0.00 < |fL1 / fLN| ≤ 0.40 (6) 0.50 ≤ |fLN / fLIS| ≤ 1.60 (7) 1.60 ≤ ndGP ≤ 1.91 (8) 35 ≤ νdGIS ≤ 60 (9) 22 ≤ νdG1P ≤ 50 (10) 3.5 ≤ (R1 + R2) / (R1 - R2) ≤ 13.0 (11) -1.60 ≤ Ymax_w / fL1 ≤ -0.40 (12) -20.0 ≤ Dist_w ≤ -8.0 (13) By configuring the focus group LF with a single positive lens GP, the weight of the focus group LF can be reduced. In order to suppress the chromatic aberration variation during focusing, it is important to appropriately set the glass material of the positive lens GP.

[0039] The conditional expression (2) defines the Abbe number νdGP of the positive lens GP with respect to the d-line. When νdGP is below the lower limit value of the conditional expression (2), it becomes difficult to suppress the chromatic aberration variation during focusing. On the other hand, when νdGP exceeds the upper limit value of the conditional expression (2), it becomes difficult to suppress the chromatic aberration variation during focusing.

[0040] In a zoom lens, when the height of the off-axis light ray incident on the lens group is high, the lens diameter becomes large. Therefore, in order to achieve miniaturization and weight reduction of the focus group, it is important to arrange the focus group at a position where the height of the off-axis light ray is low. By arranging the focus group near the aperture stop SP, the height of the off-axis light ray incident on the focus group can be reduced.

[0041] Conditional expression (3) defines the ratio of the overall optical length TLw at the wide-angle end to the distance DLFw on the optical axis from the most object-side surface of the zoom lens L0 to the most object-side surface of the focus group LF. The overall optical length is the distance on the optical axis from the most object-side lens surface to the image plane IP in the zoom lens L0. When the focus group is positioned on the object side such that DLFw / TLw is below the lower limit value of conditional expression (3), the height of the off-axis light rays incident on the focus group increases, making it difficult to miniaturize the focus group. On the other hand, when the focus group is positioned on the image side such that DLFw / TLw exceeds the upper limit value of conditional expression (3), the height of the off-axis light rays incident on the focus group increases, making it difficult to miniaturize the focus group.

[0042] Conditional expression (4) defines the ratio of the back focus Skw at the wide-angle end to the overall optical length TLw at the wide-angle end. If the back focus SKw becomes too short such that Skw / TLw is below the lower limit value of conditional expression (4), it becomes difficult to arrange optical elements such as a low-pass filter near the imaging element that receives the optical image formed by the zoom lens L0. If the back focus SKw becomes too long such that Skw / TLw exceeds the upper limit value of conditional expression (4), the overall optical length of the zoom lens L0 at the wide-angle end becomes long, making miniaturization difficult.

[0043] Conditional expression (5) defines the ratio of the focal length fL1 of the first lens group L1 to the focal length fLF of the focus group. If the refractive power of the first lens group L1 becomes too weak such that fL1 / fLF is below the lower limit value of conditional expression (5), it becomes difficult to achieve a wide-angle of more than 100° at the wide-angle end. Also, the diameter of the first lens group L1 increases, and the zoom lens becomes larger in the radial direction. On the other hand, if the refractive power of the first lens group L1 becomes too strong such that fL1 / fLF exceeds the upper limit value of conditional expression (5), the asymmetry of the refractive power arrangement of the zoom lens L0 increases, making it difficult to correct the distortion aberration at the wide-angle end.

[0044] The conditional expression (6) defines the ratio between the focal length fL1 of the first lens group L1 and the focal length fLN of the lens group LN disposed on the most image side in the zoom lens L0. By satisfying |fL1 / fLN| with the conditional expression (6), it becomes possible to achieve both miniaturization and high optical performance (high image quality) of the zoom lens L0. If the positive refractive power of the lens group LN becomes too strong such that |fL1 / fLN| falls below the lower limit value of the conditional expression (6), the refractive power arrangement of the retrofocus becomes stronger, so that the asymmetry of the refractive power arrangement of the zoom lens L0 is increased. As a result, it becomes difficult to correct the distortion aberration at the wide-angle end or to shorten the overall length at the wide-angle end. If the negative refractive power of the lens group LN becomes too strong such that |fL1 / fLN| exceeds the upper limit value of the conditional expression (6), it becomes difficult to achieve the refractive power arrangement of the retrofocus, and it becomes difficult to widen the angle of view while securing the back focus at the wide-angle end.

[0045] The conditional expression (7) defines the ratio between the focal length fLN of the lens group LN disposed on the most image side and the focal length fLIS of the anti-shake group LIS. If the refractive power of the anti-shake group LIS becomes too weak such that |fLN / fLIS| falls below the lower limit value of the conditional expression (7), the amount of movement of the anti-shake group LIS during anti-shake increases, making it difficult to miniaturize the zoom lens in the radial direction. If the refractive power of the anti-shake group LIS becomes too strong such that |fLN / fLIS| exceeds the upper limit value of the conditional expression (7), it becomes difficult to suppress the variation of coma aberration and field curvature during anti-shake.

[0046] The conditional expression (8) defines the refractive index ndGP of the positive lens GP constituting the focus group LF with respect to the d-line. If ndGP falls below the lower limit value of the conditional expression (8), the curvature of the positive lens GP increases in order to impart the necessary refractive power to the positive lens GP, making it difficult to suppress the variation of various aberrations such as spherical aberration during focusing. On the other hand, if ndGP exceeds the upper limit value of the conditional expression (8), the curvature of the positive lens GP becomes small, making it difficult to suppress the variation of various aberrations such as spherical aberration during focusing.

[0047] Conditional expression (9) defines the Abbe number νdGIS with respect to the d-line of the negative lens GIS that constitutes the anti-vibration group. When νdGIS is below the lower limit value of conditional expression (9), it becomes difficult to correct the magnification chromatic aberration during anti-vibration. On the other hand, when νdGIS exceeds the upper limit value of conditional expression (9), the refractive index of the negative lens GIS becomes low, and the movement amount of the anti-vibration group LIS during anti-vibration becomes large, making it difficult to miniaturize the zoom lens L0 in the radial direction.

[0048] Conditional expression (10) defines the Abbe number νdG1P with respect to the d-line of the positive lens G1P with the strongest refractive power among at least one positive lens included in the first lens group L1. The refractive power is represented by the reciprocal of the focal length. When νdG1P is below the lower limit value of conditional expression (10), it becomes difficult to correct the magnification chromatic aberration during zooming. When νdG1P exceeds the upper limit value of conditional expression (10), it becomes difficult to correct the axial chromatic aberration during zooming.

[0049] Conditional expression (11) defines the shape of the negative lens GIS that constitutes the anti-vibration group. The negative lens GIS has a meniscus shape with a convex surface facing the object side, suppressing the variation of coma aberration during anti-vibration. R1 is the radius of curvature of the lens surface on the object side of the negative lens GIS, R2 is the radius of curvature of the lens surface on the image side of the negative lens GIS, and (R1 + R2) / (R1 - R2) is the shape factor. When (R1 + R2) / (R1 - R2) is below the lower limit value of conditional expression (11), it becomes difficult to suppress the variation of coma aberration during anti-vibration. Also, when (R1 + R2) / (R1 - R2) exceeds the upper limit value of conditional expression (11), it becomes difficult to suppress the variation of coma aberration during anti-vibration.

[0050] Conditional expression (12) defines the ratio of the maximum effective (imageable) image height Ymax_w at the wide-angle end to the focal length fL1 of the first lens group L1. The maximum image height Ymax_w is the distance from the optical axis of the image point farthest from the optical axis among the image points that can be imaged (received by the imaging element), and here it is the maximum image height considering the magnification change due to the distortion amount. By adjusting the lens and the lens movement mechanism to this maximum image height, it becomes possible to miniaturize and lighten the lens device having the zoom lens L0.

[0051] If the maximum image height becomes too small such that Ymax_w / fL1 is below the lower limit of the conditional expression (12), the angle of view will be narrower than the required angle of view. On the other hand, if the maximum image height becomes too large such that Ymax_w / fL1 exceeds the upper limit of the conditional expression (12), light rays within a range wider than the required angle of view will be focused on the imaging surface. As a result, the lens and the lens moving mechanism will be excessively large, making it difficult to reduce the size and weight.

[0052] The conditional expression (13) defines the amount of distortion Dist_w at the maximum image height Ymax_w in the infinity focus state at the wide-angle end. If Dist_w is below the lower limit of the conditional expression (13), it becomes difficult to suppress image quality degradation in the peripheral part of the image during distortion correction by image processing. On the other hand, if Dist_w exceeds the upper limit of the conditional expression (13), the amount of distortion in the equidistant projection method is too large, resulting in significant degradation of the peripheral image quality during anti-shake operation. Also in OIS, the amount of image blur correction in the peripheral part becomes insufficient.

[0053] Assuming the ideal image height in the central projection method is y and the actual image height is yp, the amount of distortion Dist_w [%] at an arbitrary image height at the wide-angle end can be expressed as follows.

[0054] Dist_w [%] = ((yp - y) / y1) × 100 The ideal image height y in the central projection method is defined as follows using the focal length f of the zoom lens L0 and the half angle of view θi of the actual light rays at an arbitrary image height.

[0055] y = ftanθi Also, the ideal image height y can be expressed as follows using the focal length f of the zoom lens L0 and the half angle of view θ of the actual light rays at the maximum image height.

[0056] y1 = ftanθ Note that it is more preferable if the numerical ranges of the conditional expressions (1) to (13) are as follows.

[0057] 0.42 ≦ DISw / DSPw ≦ 0.70 (1a) 27 ≦ νdGP ≦ 43 (2a) 0.49 ≤ DLFw / TLw ≤ 0.60 (3a) 0.05 ≤ Skw / TLw ≤ 0.20 (4a) -0.40 ≤ fL1 / fLF ≤ -0.17 (5a) 0.00 < |fL1 / fLN| ≤ 0.35 (6a) 0.60 ≤ |fLN / fLIS| ≤ 1.50 (7a) 1.63 ≤ ndGP ≤ 1.89 (8a) 37 ≤ νdGIS ≤ 55 (9a) 25 ≤ νdG1P ≤ 45 (10a) 4.0 ≤ (R1 + R2) / (R1 - R2) ≤ 11.0 (11a) -1.40 ≤ Ymax_w / fL1 ≤ -0.60 (12a) -16.0 ≤ Dist_w ≤ -9.0 (13a) Also, the numerical ranges of the conditional expressions (1) to (13) are more preferably as follows.

[0058] 0.45 ≤ DISw / DSPw ≤ 0.60 (1b) 28 ≤ νdGP ≤ 40 (2b) 0.50 ≤ DLFw / TLw ≤ 0.55 (3b) 0.06 ≤ Skw / TLw ≤ 0.15 (4b) -0.38 ≤ fL1 / fLF ≤ -0.20 (5b) 0.00 < |fL1 / fLN| ≤ 0.33 (6b) 0.70 ≤ |fLN / fLIS| ≤ 1.40 (7b) 1.65 ≤ ndGP ≤ 1.87 (8b) 39 ≤ νdGIS ≤ 50 (9b) 28 ≤ νdG1P ≤ 42 (10b) 4.5 ≤ (R1 + R2) / (R1 - R2) ≤ 9.0 (11b) -1.20 ≤ Ymax_w / fL1 ≤ -0.70 (12b) -14.0 ≤ Dist_w ≤ -10.0 (13b) Next, the preferable configurations satisfied by the zoom lenses of the respective examples will be described.

[0059] The first lens group L1 has three or more negative lenses in order from the object side. This makes it possible to ensure sufficient wide-angle conversion (for example, an angle of view of 100° or more at the wide-angle end). Further, the first lens group L1 preferably has four or more negative lenses and at least one positive lens. This also makes it possible to ensure a sufficient magnification ratio (for example, about 2 times) while ensuring sufficient wide-angle conversion.

[0060] Also, the aperture stop SP is preferably arranged on the object side of the focus group and moves monotonously toward the object side during zooming from the wide-angle end to the telephoto end. This facilitates miniaturization of the aperture stop SP.

[0061] Further, the rear group LR preferably has three or more lens groups in which the distance between adjacent lens groups changes during zooming. This also makes it possible to achieve a sufficient magnification ratio (for example, about 2 times).

[0062] Also, the lens group LN arranged closest to the image side in the zoom lens L0 is preferably composed of three or fewer lenses. This makes it possible to miniaturize the zoom lens L0.

[0063] Also, at the wide-angle end, the distance between the first lens group L1 and the second lens group L2 is preferably the largest among the distances between all the lens groups included in the zoom lens L0. This results in a strong retrofocus configuration at the wide-angle end and also makes it possible to achieve a sufficient magnification ratio (for example, about 2 times) while achieving wide-angle conversion.

[0064] Also, when performing OIS by shifting the anti-shake group LIS, it is preferable to also shift the imaging element to perform IIS. By combining OIS and IIS, it becomes easy to suppress image blur in the peripheral part.

[0065] Next, Numerical Examples 1 to 7 are shown. In the surface data of each numerical example, the surface number m indicates the order of the surface when counted from the object side. r is the radius of curvature of the m-th surface, and d (mm) indicates the axial interval (distance on the optical axis) between the m-th surface and the (m + 1)-th surface. Also, nd is the refractive index with respect to the d-line of the optical material between the m-th surface and the (m + 1)-th surface, and νd indicates the Abbe number of the optical material. The Abbe number νd is defined as, when the refractive indices at the d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm) of the Fraunhofer lines are Nd, NF, and NC, νd=(Nd - 1) / (NF - NC) represented by

[0066] In each numerical example, d, focal length (mm), F-number, and half angle (°) are all values in the infinity-focus state of the zoom lens L0. The back focus is the distance on the optical axis from the final lens surface, which is the most image-side lens surface of the zoom lens, to the paraxial image plane, expressed in terms of the air-equivalent length. The overall lens length is the length obtained by adding the back focus to the distance on the optical axis from the frontmost lens surface, which is the most object-side lens surface of the zoom lens L0, to the final lens surface.

[0067] Also, when the optical surface has an aspherical shape, an asterisk (*) is attached to the right of the surface number. The aspherical shape is expressed as, when X is the displacement amount from the vertex of the surface in the optical axis direction, h is the height from the optical axis in the direction perpendicular to the optical axis, R is the paraxial radius of curvature, K is the conic constant, and A4, A6, A8, A10, A12 are the aspherical coefficients of each order, X=(h 2 / R) / [1 + [1 - (1 + K)(h / R) 2 1 / 2 +A4×h 4 +A6×h 6 +A8×h 8 +A10×h 10 +A12×h 12 +A14×h 14 represented by. In the conic constant and aspherical coefficients, "e±XX" means "×10± XX ". [Numerical Example 1] Unit: mm ​ Surface data Surface numbers r d nd νd 1* 37.000 3.00 1.58313 59.4 2* 17.814 12.20 3 52.582 1.23 1.91082 35.2 4 17.849 5.54 5 30.037 1.15 1.59282 68.6 6 18.728 9.86 7 -28.561 1.10 1.43875 94.7 8 33.065 4.99 1.88300 40.8 9 -88.917 (variable) 10 (aperture) ∞ (variable) 11 76.538 1.86 1.72047 34.7 12 -170.686 (variable) 13 21.263 0.69 1.80810 22.8 14 10.223 4.67 1.67300 38.3 15 101.506 0.80 16 -48.763 0.55 1.88300 40.8 17 13.497 2.73 1.92286 20.9 18 39.963 0.35 19 19.540 5.55 1.49700 81.5 20* -31.043 0.15 21 18.566 0.64 2.05090 26.9 22 11.089 7.99 1.49700 81.5 23 -43.632 0.35 24 22.204 0.90 1.88300 40.8 25 16.576 5.56 26* -26.667 1.90 1.85400 40.4 27* -55.445 (variable) 28 -497.495 7.36 1.49700 81.5 29 -33.423 (variable) Image plane ∞ Aspherical data First surface K = 0.00000e+00 A 4= 2.59429e-06 A 6=-2.61399e-08 A 8= 5.21697e-11 A10=-5.59197e-14 A12= 3.27515e-17 A14=-8.57311e-21 Second surface K =-8.76022e-01 A 4= 9.21103e-06 A 6=-3.58438e-08 A 8=-4.52147e-11 A10= 2.92832e-13 A12=-4.25258e-16 A14= 2.03592e-19 Twentieth surface K = 0.00000e+00 A 4= 2.45229e-05 A 6=-3.72036e-08 A 8=-1.08800e-09 A10= 1.03970e-11 A12=-1.91023e-14 Twenty-sixth surface K = 0.00000e+00 A 4= 1.66615e-04 A 6=-1.90317e-06 A 8= 1.23230e-08 A10=-9.41453e-11 A12= 4.39584e-13 Twenty-seventh surface K = 0.00000e+00 A 4= 1.69532e-04 A 6=-1.38711e-06 A 8= 4.53596e-09 A10=-6.87436e-12 A12= 2.41668e-14 Various data Zoom ratio 1.88 Wide angle Middle Telephoto Focal length 10.33 15.00 19.39 F number 4.08 4.08 4.12 Half field angle (°) 61.36 55.26 48.13 Image height 18.92 21.64 21.64 Overall lens length 128.82 122.35 123.27 BF 12.13 12.13 12.13 d 9 24.06 9.31 2.42 d10 3.18 3.92 3.78 d12 4.97 4.23 4.37 d27 3.36 11.64 19.44 d29 12.13 12.13 12.13 Lens group data Group Start surface Focal length 1 1 -19.37 2 11 73.58 3 13 49.46 4 28 71.72 [Numerical example 2] Unit mm Surface data Surface number r d nd νd 1* 36.964 2.00 1.76450 49.1 2* 17.381 12.97 3 38.540 1.00 1.83400 37.2 4 17.838 8.18 5 35.542 1.00 1.49700 81.5 6 17.493 9.44 7 -32.408 0.80 1.43875 94.7 8 29.388 4.33 1.88300 40.8 9 -153.902 (Variable) 10 (Aperture) ∞ (Variable) 11 60.063 1.50 1.77047 29.7 12 4073.289 (variable) 13 24.469 0.50 1.80810 22.8 14 10.086 6.29 1.80610 33.3 15 65.185 0.67 16 -92.079 0.50 2.00100 29.1 17 10.799 3.89 1.86966 20.0 18 60.938 0.10 19 18.584 4.65 1.43875 94.7 20* -29.965 0.10 21 16.998 0.50 2.05090 26.9 22 11.071 6.27 1.43875 94.7 23 -72.227 4.03 24 21.999 0.90 1.88300 40.8 25 16.878 5.45 26* -21.844 1.20 1.85400 40.4 27* -29.304 (variable) 28 -242.542 7.32 1.49700 81.5 29 -31.336 (variable) Image plane ∞ Aspherical data First surface K = 0.00000e+00 A 4=-5.05120e-07 A 6=-2.59180e-08 A 8= 5.64585e-11 A10=-6.28825e-14 A12= 3.59492e-17 A14=-8.73398e-21 Second surface K =-8.50179e-01 A 4= 6.50619e-06 A 6=-3.67327e-08 A 8=-4.18782e-11 A10 = 3.45919e-13 A12 = -5.82222e-16 A14 = 3.42039e-19 The 20th surface K = 0.00000e+00 A4 = 1.88217e-05 A6 = -1.07644e-07 A8 = -8.81979e-10 A10 = 3.51547e-12 A12 = 2.13797e-14 The 26th surface K = 0.00000e+00 A4 = 1.99287e-04 A6 = -1.86752e-06 A8 = 9.76715e-09 A10 = -7.11283e-11 A12 = 4.03250e-13 The 27th surface K = 0.00000e+00 A4 = 2.02967e-04 A6 = -1.31168e-06 A8 = 1.15301e-09 A10 = 2.03422e-11 A12 = -3.00629e-14 Various data Zoom ratio 1.94 Wide angle, medium, telephoto Focal length 9.20, 16.04, 17.90 F-number 4.08, 4.08, 4.12 Half field angle (°) 64.04, 53.45, 50.40 Image height 18.90, 21.64, 21.64 Overall lens length 125.26, 118.57, 119.35 BF 10.50, 10.50, 10.50 d9 24.00, 4.83, 2.21 d10 2.10, 3.01, 3.07 d12 4.14, 3.23, 3.17 d27 0.93, 13.41, 16.81 d29 10.50, 10.50, 10.50 Lens group data Group starting surface Focal length 1 1 -17.03 2 11 79.11 3 13 42.64 4 28 71.58 [Numerical example 3] Unit: mm Surface data Surface number r d nd νd 1* 34.540 2.00 1.76450 49.1 2* 17.538 12.00 3 27.845 1.00 2.05090 26.9 4 17.335 12.15 5 -102.534 1.00 1.49700 81.5 6 24.557 4.63 7 -163.874 1.40 1.83400 37.2 8 -79.091 0.80 1.43875 94.7 9 23.675 5.93 1.88300 40.8 10 685.207 (Variable) 11 (Aperture) ∞ (Variable) 12 73.782 1.50 1.85025 30.1 13 -353.985 (Variable) 14 22.242 0.50 1.96300 24.1 15 10.175 6.30 1.88300 40.8 16 40.767 0.92 17 -465.076 0.50 1.91082 35.2 18 10.734 4.46 1.86966 20.0 19 30.913 0.10 20 17.320 4.70 1.43875 94.7 21* -61.628 0.10 22 17.378 0.50 2.05090 26.9 23 11.257 7.57 1.43875 94.7 24 -32.482 1.49 25 27.690 0.90 1.88300 40.8 26 20.124 5.98 27* -29.240 1.20 1.85400 40.4 28* -43.741 (variable) 29 -130.532 6.39 1.49700 81.5 30 -34.115 (variable) Image plane ∞ Aspherical data First surface K = 0.00000e+00 A 4=-5.58771e-07 A 6=-1.77995e-08 A 8= 4.41109e-11 A10=-6.23317e-14 A12= 4.47696e-17 A14=-1.40227e-20 Second surface K =-8.15972e-01 A 4= 8.81718e-06 A 6=-1.49702e-08 A 8=-1.54936e-11 A10= 2.29531e-13 A12=-5.29361e-16 A14= 3.75849e-19 Twenty-first surface K = 0.00000e+00 A 4= 1.85120e-05 A 6=-1.09055e-07 A 8= 4.00606e-10 A10=-1.62869e-11 A12= 9.72903e-14 Twenty-seventh surface K = 0.00000e+00 A 4= 3.73139e-05 A 6=-5.43373e-07 A 8= 2.13025e-09 A10=-2.57230e-11 A12= 1.92965e-13 Twenty-eighth surface K = 0.00000e+00 A4 = 5.07750e-05 A6 = -4.00620e-07 A8 = 1.66532e-10 A10 = 4.59683e-12 A12 = 8.96637e-15 Various data Zoom ratio 2.12 Wide angle, Medium, Telephoto Focal length 11.30 16.61 23.90 F-number 4.08 4.08 4.12 Half field angle (°) 59.29 52.49 42.15 Image height 19.02 21.64 21.64 Overall lens length 129.79 125.70 129.33 BF 14.54 12.80 10.54 d10 24.00 10.61 2.20 d11 2.10 2.30 2.09 d13 3.77 3.57 3.78 d28 1.36 12.39 26.70 d30 14.54 12.80 10.54 Lens group data Group, Starting surface, Focal length 1 1 -19.47 2 12 71.93 3 14 53.25 4 29 90.93 [Numerical example 4] Unit: mm Surface data Surface number, r, d, nd, νd 1* 35.655 2.00 1.55332 71.7 2* 18.553 10.14 3 43.354 1.00 1.96300 24.1 4 18.994 9.15 5 54.034 1.00 1.59270 35.3 6 26.677 8.97 7 -33.675 0.80 1.49700 81.5 8 35.482 6.14 1.85883 30.0 9 -84.554 (variable) 10 (aperture) ∞ (variable) 11 123.998 1.70 1.85025 30.1 12 -234.488 (variable) 13* 26.749 1.00 1.80810 22.8 14 13.432 7.73 1.80610 40.7 15 83.403 0.67 16 495.726 0.50 2.00100 29.1 17 13.374 4.37 1.94594 18.0 18 28.803 0.10 19 18.829 6.49 1.43875 94.7 20* -34.371 0.10 21 16.112 0.50 2.05090 26.9 22 11.216 8.27 1.43875 94.7 23 373.115 (variable) 24 31.589 0.90 1.88300 40.8 25 20.666 4.64 26* -27.639 1.20 1.80400 46.5 27* -31.668 (variable) 28 -110.630 1.00 1.80610 33.3 29 -432.539 6.50 1.59282 68.6 30 -34.154 (variable) Image plane ∞ Aspherical data First surface K = 0.00000e+00 A 4= 8.84489e-07 A 6=-1.74958e-08 A 8= 4.77183e-11 A10=-6.77556e-14 A12= 5.30183e-17 A14=-1.85401e-20 Second side K =-9.16996e-01 A 4= 9.24051e-06 A 6=-2.08874e-08 A 8= 6.43752e-11 A10=-1.33742e-13 A12= 3.26127e-16 A14=-3.48263e-19 Thirteenth side K = 0.00000e+00 A 4=-3.08173e-06 A 6=-9.07213e-09 A 8= 3.76703e-11 A10=-9.38527e-14 Twentieth side K = 0.00000e+00 A 4= 1.39904e-05 A 6= 6.25811e-09 A 8=-8.77158e-10 A10= 1.49936e-11 A12=-6.74357e-14 Twenty-sixth side K = 0.00000e+00 A 4= 1.02392e-04 A 6=-1.86870e-07 A 8=-5.03914e-09 A10= 3.67314e-11 A12=-3.01596e-14 Twenty-seventh side K = 0.00000e+00 A 4= 1.16632e-04 A 6=-1.10396e-08 A 8=-7.02472e-09 A10= 5.73923e-11 A12=-1.51353e-13 Various data Zoom ratio 1.95 Wide angle, medium, telephoto Focal length 11.30 14.97 22.00 F number 2.89 2.89 2.89 Half field angle (°) 59.44 55.32 44.52 Image height 19.14 21.64 21.64 Overall lens length 137.35 129.65 125.58 BF 13.50 12.41 10.50 d 9 29.39 16.54 3.44 d10 2.10 2.10 2.53 d12 4.88 4.88 4.45 d23 1.00 2.19 4.27 d27 1.61 6.66 15.52 d30 13.50 12.41 10.50 Lens group data Group Starting surface Focal length 1 1 -20.99 2 11 95.60 3 13 33.35 4 24 -57.66 5 28 89.95 [Numerical example 5] Unit mm Surface data Surface number r d nd νd 1* 36.363 1.60 1.76450 49.1 2* 15.487 6.54 3 27.280 1.00 2.05090 26.9 4 18.536 6.70 5 32.793 1.00 1.49700 81.5 6 17.362 10.47 7 -34.260 0.80 1.43875 94.7 8 34.586 3.94 1.90525 35.0 9 -201.854 (Variable) 10 (Diaphragm) ∞ (Variable) 11 51.209 1.50 1.67300 38.3 12 -111.251 (Variable) 13 -61.646 0.80 2.00100 29.1 14 -204.214 (Variable) 15 19.146 0.50 2.05090 26.9 16 10.112 4.75 1.80610 40.7 17 152.402 0.35 18 -367.791 0.50 1.91082 35.2 19 11.324 2.84 1.89286 20.4 20 31.987 0.10 21 17.704 4.27 1.43875 94.7 22* -54.171 0.10 23 18.960 0.50 2.05090 26.9 24 11.500 8.01 1.43875 94.7 25 -21.312 0.49 26 21.333 1.00 1.83481 42.7 27 16.304 (Variable) 28* -24.186 1.20 1.85400 40.4 29* -41.948 (Variable) Image plane ∞ Aspherical data First surface K = 0.00000e+00 A 4=-7.44158e-06 A 6= 2.17599e-08 A 8=-4.81867e-11 A10= 6.22617e-14 A12=-4.40517e-17 A14= 1.19690e-20 Second surface K =-8.72295e-01 A 4= 5.42531e-07 A 6= 9.78315e-09 A 8= 1.72802e-10 A10 = -9.18661e-13, A12 = 2.12915e-15, A14 = -1.99953e-18 The 22nd surface K = 0.00000e+00, A4 = 3.62847e-05, A6 = -2.63477e-07, A8 = 1.92638e-09 A10 = -6.70834e-11, A12 = 4.52971e-13 The 28th surface K = 0.00000e+00, A4 = 1.17855e-04, A6 = -1.63605e-06, A8 = 9.00680e-09 A10 = -6.51152e-11, A12 = 3.38027e-13 The 29th surface K = 0.00000e+00, A4 = 1.30738e-04, A6 = -1.32589e-06, A8 = 4.36587e-09 A10 = -2.34452e-12, A12 = 1.29797e-14 Various data Zoom ratio 1.90 Wide angle, medium, telephoto Focal length 10.30, 16.00, 19.60 F-number 4.08, 4.08, 4.12 Half field angle (°) 61.86, 53.52, 47.83 Image height 19.26, 21.64, 21.64 Overall lens length 114.35, 105.41, 104.44 BF 14.75, 21.84, 26.22 d9 24.50, 7.84, 2.10 d10 2.10, 2.82, 3.40 d12 3.35, 3.32, 3.17 d14 2.03, 1.34, 0.91 d27 8.66, 9.29, 9.68 d29 14.75 21.84 26.22 Lens group data Group start surface Focal length 1 1 -18.06 2 11 52.30 3 13 -88.46 4 15 27.53 5 28 -69.03 [Numerical example 6] Unit: mm Surface data Surface number r d nd νd 1* 36.245 2.00 1.76450 49.1 2* 18.260 13.76 3 36.879 1.00 1.95375 32.3 4 18.000 10.79 5 53.599 1.00 1.49700 81.5 6 21.569 8.03 7 -31.559 0.80 1.43875 94.7 8 31.309 4.96 1.88300 40.8 9 -94.449 (Variable) 10 (Aperture) ∞ (Variable) 11 53.950 1.50 1.66565 35.6 12 -175.277 (Variable) 13 268.814 0.80 1.61772 49.8 14 56.472 (Variable) 15 22.881 0.50 1.96300 24.1 16 10.376 5.45 1.90043 37.4 17 94.514 0.58 18 -137.963 0.50 1.95375 32.3 19 10.860 3.42 1.86966 20.0 20 34.673 0.10 21 17.287 5.79 1.43875 94.7 22* -61.411 0.10 23 16.219 0.50 2.05090 26.9 24 11.080 8.94 1.43875 94.7 25 -31.009 0.50 26 20.448 1.00 1.83481 42.7 27 15.800 (Variable) 28* -15.305 1.20 1.85400 40.4 29* -22.734 (Variable) 30 -116.151 6.84 1.49700 81.5 31 -29.679 (Variable) Image plane ∞ Aspherical data First surface K = 0.00000e+00 A 4= 3.92202e-08 A 6=-2.69648e-08 A 8= 6.09684e-11 A10=-7.05373e-14 A12= 4.15238e-17 A14=-1.05285e-20 Second surface K =-8.62038e-01 A 4= 8.10669e-06 A 6=-3.15674e-08 A 8=-3.37489e-11 A10= 3.31967e-13 A12=-5.81678e-16 A14= 3.32304e-19 Twenty-second surface K = 0.00000e+00 A 4= 2.23580e-05 A 6=-1.43420e-07 A 8= 1.13126e-09 A10=-2.96786e-11 A12= 1.87767e-13 Twenty-eighth surface K = 0.00000e+00 A 4= 1.89068e-04 A 6=-1.82499e-06 A 8= 8.70129e-09 A10=-5.29084e-11 A12= 3.77732e-13 The 29th surface K = 0.00000e+00 A 4= 1.81235e-04 A 6=-1.41031e-06 A 8= 3.38789e-09 A10= 1.58728e-11 A12=-5.28155e-14 Various data Zoom ratio 1.92 Wide angle, middle, telephoto Focal length 10.30 15.22 19.80 F number 2.89 3.50 4.12 Half field angle (°) 61.76 54.87 47.54 Image height 19.18 21.64 21.64 Overall lens length 132.94 126.11 127.01 BF 11.35 11.35 11.35 d 9 24.44 9.22 2.28 d10 2.17 2.34 2.10 d12 3.85 4.20 4.93 d14 2.01 1.49 1.00 d27 7.87 7.76 7.66 d29 1.19 9.69 17.64 d31 11.35 11.35 11.35 Lens group data Group, starting surface, focal length 1 1 -19.36 2 11 62.14 3 13 -115.90 4 15 30.94 5 28 -59.25 6 30 78.16 [Numerical Example 7] Unit: mm Surface data Surface number r d nd νd 1* 40.468 3.00 1.58313 59.4 2* 18.279 10.33 3 41.125 1.23 1.91082 35.2 4 18.235 7.50 5 34.985 1.15 1.59282 68.6 6 18.756 9.56 7 -34.618 1.10 1.43875 94.7 8 29.346 5.41 1.88300 40.8 9 -90.407 (variable) 10 -56.739 1.00 1.76385 48.5 11 -112.660 (variable) 12 (aperture) ∞ (variable) 13 63.090 1.59 1.72047 34.7 14 -227.320 (variable) 15 21.699 0.69 1.80810 22.8 16 10.106 5.14 1.67300 38.3 17 121.574 0.70 18 -51.133 0.55 1.88300 40.8 19 13.133 2.71 1.92286 20.9 20 38.530 0.35 21 19.973 5.25 1.49700 81.5 22* -31.304 0.15 23 18.415 0.64 2.05090 26.9 24 11.103 8.58 1.49700 81.5 25 -41.834 0.35 26 22.000 0.90 1.88300 40.8 27 16.493 5.28 28* -23.968 1.90 1.85400 40.4 29* -43.861 (Variable) 30 -345.096 6.53 1.49700 81.5 31 -35.363 (Variable) Image plane ∞ Aspherical data First surface K = 0.00000e+00 A 4= 9.61528e-06 A 6=-3.60704e-08 A 8= 5.97941e-11 A10=-5.54186e-14 A12= 2.90939e-17 A14=-6.66932e-21 Second surface K =-1.23054e+00 A 4= 2.50795e-05 A 6=-3.04254e-08 A 8=-9.21626e-11 A10= 3.40025e-13 A12=-3.47266e-16 A14= 9.28758e-20 Twenty-second surface K = 0.00000e+00 A 4= 2.19912e-05 A 6=-6.02422e-08 A 8=-9.31268e-10 A10= 8.72477e-12 A12=-1.88516e-14 Twenty-eighth surface K = 0.00000e+00 A 4= 1.68018e-04 A 6=-1.88198e-06 A 8= 1.28345e-08 A10=-9.75590e-11 A12= 4.53596e-13 Twenty-ninth surface K = 0.00000e+00 A 4= 1.65677e-04 A 6=-1.34196e-06 A 8= 4.55621e-09 A10 = -6.90232e-12 A12 = 1.71906e-14 Various data Zoom ratio 1.88 Wide angle, intermediate, telephoto Focal length 10.33, 15.00, 19.39 F-number 4.08, 4.08, 4.12 Half field angle (°) 61.35, 55.27, 48.13 Image height 18.90, 21.64, 21.64 Overall lens length 128.34, 123.04, 124.10 BF 12.36, 12.36, 12.36 d 9, 3.98, 2.86, 1.10 d11 18.86, 6.19, 1.20 d12 3.18, 4.32, 4.18 d14 4.50, 3.36, 3.50 d29 3.86, 12.35, 20.15 d31 12.36, 12.36, 12.36 Lens group data Group, starting surface, focal length 1, 1, -24.89 2, 10, -150.81 3, 13, 68.70 4, 15, 47.71 5, 30, 78.73 The values related to the above conditional expressions (1) to (13) in each numerical example are summarized in Table 1.

[0068] [Table 1]

[0069] [Imaging device] FIG. 23 shows an outline of an imaging device (digital still camera) 10 using the zoom lens of each embodiment as an imaging optical system. The imaging device 10 includes a camera body 13, an imaging optical system 11, and an imaging element 12 that photoelectrically converts (images) an optical image formed by the imaging optical system 11.

[0070] Since the imaging device 10 has an imaging optical system 11 that is small and has good optical characteristics, a high-quality imaging image can be obtained. At this time, by electrically correcting various aberrations such as distortion aberration and chromatic aberration in the imaging image by an image processing unit (not shown) in the imaging device 10, the output image can also be made of high quality.

[0071] Note that the zoom lens L0 of each of the above-described embodiments is not limited to the digital still camera shown in FIG. 23, and can be used in various optical devices such as a camera for silver salt film, a video camera, and a telescope. [Imaging System] Note that an imaging system (surveillance camera system) including the zoom lens L0 of each embodiment and a control unit that controls the zoom lens L0 may be configured. In this case, the control unit can control the zoom lens L0 so that each lens group moves as described above during zooming, focusing, and image blur correction. At this time, the control unit does not necessarily have to be configured integrally with the zoom lens L0, and the control unit may be configured separately from the zoom lens L0. For example, a configuration may be adopted in which a control unit (control device) disposed remotely from a drive unit that drives each lens group of the zoom lens L0 includes a transmission unit that sends a control signal (command) for controlling the zoom lens L0. According to such a control unit, the zoom lens L0 can be remotely operated.

[0072] Further, a configuration may be adopted in which an operation unit such as a controller and buttons for remotely operating the zoom lens L0 is provided in the control unit, and the zoom lens L0 is controlled in response to an input to the operation unit by the user. For example, an enlargement button and a reduction button may be provided as the operation unit. In this case, when the user presses the enlargement button, the magnification of the zoom lens L0 increases, and when the user presses the reduction button, the magnification of the zoom lens L0 decreases. A signal may be sent from the control unit to the drive unit of the zoom lens L0 accordingly.

[0073] Further, the imaging system may have a display unit such as a liquid crystal panel that displays information (movement state) regarding the zooming of the zoom lens L0. Information regarding the zooming of the zoom lens L0 is, for example, the zoom magnification (zoom state) or the movement amount (movement state) of each lens group. In this case, while viewing the information regarding the zooming of the zoom lens L0 shown on the display unit, the user can remotely operate the zoom lens L0 via the operation unit. At this time, the display unit and the operation unit may be integrated by adopting, for example, a touch panel.

[0074] The above embodiments include the following configurations.

[0075] (Configuration 1) A zoom lens configured by a plurality of lens groups including a first lens group having a negative refractive power and a rear group including two or more lens groups, which are arranged in order from the object side to the image side, and in which the distance between adjacent lens groups changes during zooming, wherein the rear group includes a diaphragm and an anti-vibration group having a negative refractive power and moving in a direction orthogonal to the optical axis, has a focus group on the object side of the anti-vibration group, when the distance on the optical axis from the diaphragm at the wide-angle end to the image plane is DSPw and the distance on the optical axis from the diaphragm at the wide-angle end to the most object-side surface of the anti-vibration group is DISw, 0.40 ≦ DISw / DSPw ≦ 0.80 A zoom lens characterized by satisfying the above conditions. (Configuration 2) The focus group includes a positive lens, when the Abbe number of the positive lens with respect to the d-line is νdGP, 25 ≦ νdGP ≦ 45 The zoom lens according to Configuration 1, characterized by satisfying the condition. (Configuration 3) When the overall optical length at the wide-angle end of the zoom lens is TLw and the distance on the optical axis from the most object-side surface of the zoom lens to the most object-side surface of the focus group is DLFw, the zoom lens according to Configuration 1 or 2, characterized by satisfying the following conditional expression.

[0076] 0.48 ≦ DLFw / TLw ≦ 0.65 The zoom lens according to Configuration 1, characterized by satisfying the condition. (Configuration 4) When the back focus at the wide-angle end of the zoom lens is Skw and the overall optical length TLw at the wide-angle end of the zoom lens, 0.04 ≦ Skw / TLw ≦ 0.25 The zoom lens according to any one of Configurations 1 to 3, characterized by satisfying the condition. (Configuration 5) When the focal length of the first lens group is fL1 and the focal length of the second lens group is fLF, -0.45 ≦ fL1 / fLF ≦ -0.15 The zoom lens according to any one of Configurations 1 to 4, characterized by satisfying the condition. (Configuration 6) When the focal length of the first lens group is fL1 and the focal length of the lens group arranged most on the image side in the zoom lens is fLN, 0.00 < |fL1 / fLN| ≦ 0.40 The zoom lens according to any one of Configurations 1 to 5, characterized by satisfying the condition. (Configuration 7) When the focal length of the lens group arranged most on the image side in the zoom lens is fLN and the focal length of the anti-vibration group is fLIS, 0.50 ≦ |fLN / fLIS| ≦ 1.60 The zoom lens according to any one of Configurations 1 to 6, characterized by satisfying the condition. (Configuration 8) The focus group includes a positive lens, When the refractive index of the positive lens with respect to the d-line is ndGP, 1.60 ≦ ndGP ≦ 1.91 The zoom lens according to any one of Configurations 1 to 7, characterized by satisfying the condition. (Configuration 9) The anti-vibration group includes a negative lens, When the Abbe number of the negative lens with respect to the d-line is νdGIS, 35 ≦ νdGIS ≦ 60 The zoom lens according to any one of Configurations 1 to 8, characterized by satisfying the condition. (Configuration 10) The first lens group includes at least one positive lens, When the Abbe number of the positive lens with the strongest refractive power among the at least one positive lens with respect to the d-line is νdG1P, 22 ≦ νdG1P ≦ 50 The zoom lens according to any one of Configurations 1 to 9, characterized by satisfying the condition. (Configuration 11) The anti-vibration group includes a negative lens, the negative lens has a meniscus shape with a convex surface facing the object side, when the radius of curvature of the object-side surface of the negative lens is R1 and the radius of curvature of the image-side surface of the negative lens is R2, 3.5 ≦ (R1 + R2) / (R1 - R2) ≦ 13.0 The zoom lens according to any one of Configurations 1 to 10, characterized by satisfying the condition. (Configuration 12) When the maximum image height in the wide-angle end and the infinity focus state is Ymax_w and the focal length of the first lens group is fL1, -1.60 ≦ Ymax_w / fL1 ≦ -0.40 The zoom lens according to any one of Configurations 1 to 11, characterized by satisfying the condition. (Configuration 13) When the distortion amount at the maximum image height in the wide-angle end and the infinity focus state is Dist_w, -20 ≦ Dist_w ≦ -8.0 The zoom lens according to any one of Configurations 1 to 12, characterized by satisfying the condition. (Configuration 14) The zoom lens according to any one of Configurations 1 to 13, characterized by having a storage unit that holds correction data used for correcting the distortion aberration of the zoom lens. (Configuration 15) The zoom lens according to any one of Configurations 1 to 14, characterized in that the first lens group has four or more negative lenses and at least one positive lens. (Configuration 16) The zoom lens according to any one of Configurations 1 to 15, characterized in that the first lens group moves during zooming. (Configuration 17) The zoom lens according to any one of Configurations 1 to 16, characterized in that the lens group arranged closest to the image side in the zoom lens has three or fewer lenses. (Configuration 18) At the wide-angle end, the distance between the first lens group and the second lens group is the largest among the distances between all the lens groups included in the zoom lens. The zoom lens according to any one of Configurations 1 to 17, characterized by this. (Configuration 19) The rear group has three or more lens groups whose distances change during zooming. The zoom lens according to any one of Configurations 1 to 18, characterized by this. (Configuration 20) The lens group arranged closest to the image side in the zoom lens is stationary during zooming. The zoom lens according to any one of Configurations 1 to 19, characterized by this. (Configuration 21) The aperture stop is arranged on the object side of the focus group. The zoom lens according to any one of Configurations 1 to 20, characterized by this. (Configuration 22) The two or more lens groups included in the rear group are composed of a second lens group with positive refractive power, a third lens group with positive refractive power, and a fourth lens group with positive refractive power, which are arranged in order from the object side to the image side. The zoom lens according to any one of Configurations 1 to 21, characterized in that. (Configuration 23) The two or more lens groups included in the rear group are composed of a second lens group with positive 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, which are arranged in order from the object side to the image side. The zoom lens according to any one of Configurations 1 to 22, characterized in that. (Configuration 24) The two or more lens groups included in the rear group are composed of a second lens group with positive refractive power, a third lens group with negative refractive power, a fourth lens group with positive refractive power, and a fifth lens group with negative refractive power, which are arranged in order from the object side to the image side. The zoom lens according to any one of Configurations 1 to 23, characterized in that. (Configuration 25) The two or more lens groups included in the rear group are composed of a second lens group with positive refractive power, a third lens group with negative refractive power, a fourth lens group with positive refractive power, a fifth lens group with negative refractive power, and a sixth lens group with positive refractive power, which are arranged in order from the object side to the image side. The zoom lens according to any one of Configurations 1 to 24, characterized in that. (Configuration 26) The two or more lens groups included in the rear group are composed of a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with negative refractive power, a fifth lens group with negative refractive power, and a sixth lens group with positive refractive power, which are arranged in order from the object side to the image side. The zoom lens according to any one of Configurations 1 to 25, characterized in that. (Configuration 27) The zoom lens according to any one of Configurations 1 to 26, and An imaging device having an imaging element that receives an optical image formed by the zoom lens. (Configuration 28) The imaging device according to Configuration 27, characterized in that the effective image circle diameter on the imaging element at the wide-angle end is smaller than the effective image circle diameter at the telephoto end. (Configuration 29) The imaging device according to Configuration 27 or 28, wherein the imaging element moves in a direction perpendicular to the optical axis together with the anti-vibration group. (Configuration 30) A zoom lens according to any one of Configurations 1 to 26, and an imaging system comprising a control unit for controlling the zoom lens during zooming. (Configuration 31) The imaging system according to Configuration 30, wherein the control unit is configured separately from the zoom lens and has a transmission unit for transmitting a control signal for controlling the zoom lens. (Configuration 32) The imaging system according to Configuration 30 or 31, wherein the control unit is configured separately from the zoom lens and has an operation unit for operating the zoom lens. (Configuration 33) The imaging system according to any one of Configurations 30 to 32, further comprising a display unit for displaying information regarding zooming of the zoom lens.

[0077] Each of the embodiments described above is merely a representative example, and various modifications and changes can be made to each embodiment when implementing the present invention.

Description of Reference Numerals

[0078] L0 Zoom lens L1 First lens group L2 Second lens group L3 Third lens group L4 Fourth lens group L5 Fifth lens group L6 Sixth lens group LR Rear group LIS Anti-vibration group LN Lens group disposed closest to the image side

Claims

1. A zoom lens system comprising a plurality of lens groups, arranged in order from the object side to the image side, including a first lens group having negative refractive power and a rear group including three or more lens groups, wherein the spacing between adjacent lens groups changes during zooming, the first lens group has two or more negative lenses arranged successively in order from the object side to the image side, the rear group includes an aperture stop and a vibration-proof group having negative refractive power that moves in a direction perpendicular to the optical axis; a focus group on the object side of the image stabilization group, When the distance on the optical axis from the aperture stop to the image plane at the wide-angle end is DSPw, and the distance on the optical axis from the aperture stop to the surface of the image stabilization group closest to the object at the wide-angle end is DISw, 0.40≦DISw / DSPw≦0.80 A zoom lens characterized by satisfying the following conditions:

2. the focus group includes a positive lens; When the Abbe number of the positive lens with respect to the d-line is νdGP, 25≦νdGP≦45 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

3. When the total optical length of the zoom lens at the wide-angle end is TLw, and the distance on the optical axis from the surface of the zoom lens closest to the object side to the surface of the focus group closest to the object side is DLFw, 0.48≦DLFw / TLw≦0.65 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

4. When the back focus at the wide-angle end of the zoom lens is Skw and the total optical length at the wide-angle end of the zoom lens is TLw, 0.04≦Skw / TLw≦0.25 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

5. A second lens group is arranged closest to the object side among the lens groups included in the rear group, When the focal length of the first lens group is fL1 and the focal length of the second lens group is fLF, −0.45≦fL1 / fLF≦−0.15 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

6. When the focal length of the first lens group is fL1 and the focal length of the lens group arranged closest to the image side in the zoom lens is fLN, 0.00<|fL1 / fLN|≦0.40 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

7. When the focal length of the lens group arranged closest to the image side in the zoom lens is fLN and the focal length of the image stabilization group is fLIS, 0.50≦|fLN / fLIS|≦1.60 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

8. the focus group includes a positive lens; When the refractive index of the positive lens for the d-line is ndGP, 1.60≦ndGP≦1.91 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

9. the image stabilization group includes a negative lens; When the Abbe number of the negative lens with respect to the d-line is νdGIS, 35≦νdGIS≦60 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

10. the first lens group includes at least one positive lens; When the Abbe number for the d-line of the positive lens having the strongest refractive power among the at least one positive lens is νdG1P, 22≦νdG1P≦50 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

11. The image stabilization group includes a negative lens, and the negative lens has a meniscus shape with a convex surface facing the object side. When the radius of curvature of the object side surface of the negative lens is R1 and the radius of curvature of the image side surface of the negative lens is R2, 3.5≦(R1+R2) / (R1-R2)≦13.0 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

12. When the maximum image height at the wide-angle end and in the infinity focused state is Ymax_w and the focal length of the first lens group is fL1, -1.60≦Ymax_w / fL1≦-0.40 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

13. When the amount of distortion at the wide-angle end and at the maximum image height in the infinity focused state is Dist_w, −20≦Dist_w≦−8.0 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

14. 2. The zoom lens according to claim 1, further comprising a storage unit for storing correction data used to correct distortion of the zoom lens.

15. 2. The zoom lens according to claim 1, wherein the first lens group comprises four or more negative lenses and at least one positive lens.

16. 2. The zoom lens according to claim 1, wherein the first lens group moves during zooming.

17. 2. The zoom lens according to claim 1, wherein the lens group arranged closest to the image side in the zoom lens has three or less lenses.

18. A second lens group is disposed closest to the object side among the lens groups included in the rear group, 2. The zoom lens according to claim 1, wherein at the wide-angle end, the distance between the first lens group and the second lens group is the largest among the distances between all the lens groups included in the zoom lens.

19. 2. The zoom lens according to claim 1, wherein the rear group has three or more lens groups whose spacing changes during zooming.

20. 2. The zoom lens according to claim 1, wherein the lens group arranged closest to the image side in the zoom lens does not move during zooming.

21. 2. The zoom lens according to claim 1, wherein the aperture stop is disposed closer to the object side than the focus group.

22. 2. The zoom lens according to claim 1, wherein the two or more lens groups included in the rear group consist of, in order from the object side to the image side, a second lens group having positive refractive power, a third lens group having positive refractive power, and a fourth lens group having positive refractive power.

23. 2. The zoom lens according to claim 1, wherein the two or more lens groups included in the rear group consist of, arranged in order from the object side to the image side, a second lens group with positive 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.

24. 2. The zoom lens according to claim 1, wherein the two or more lens groups included in the rear group consist of, arranged in order from the object side to the image side, a second lens group with positive refractive power, a third lens group with negative refractive power, a fourth lens group with positive refractive power, and a fifth lens group with negative refractive power.

25. 2. The zoom lens according to claim 1, wherein the two or more lens groups included in the rear group consist of, arranged in order from the object side to the image side, a second lens group with positive refractive power, a third lens group with negative refractive power, a fourth lens group with positive refractive power, a fifth lens group with negative refractive power, and a sixth lens group with positive refractive power.

26. 2. The zoom lens according to claim 1, wherein the two or more lens groups included in the rear group consist of, arranged in order from the object side to the image side, a second lens group with negative refractive power, a third lens group with positive refractive power, a fourth lens group with positive refractive power, and a fifth lens group with positive refractive power.

27. a zoom lens according to any one of claims 1 to 26; and an image sensor that receives an optical image formed by the zoom lens.

28. 28. The image pickup apparatus according to claim 27, wherein an effective image circle diameter on the image pickup element at a wide-angle end is smaller than an effective image circle diameter at a telephoto end.

29. 28. The imaging apparatus according to claim 27, wherein the imaging element moves together with the vibration isolation group in a direction perpendicular to the optical axis.

30. a zoom lens according to any one of claims 1 to 26; and a control unit that controls the zoom lens during zooming.

31. 31. The imaging system according to claim 30, wherein the control unit is configured as a separate unit from the zoom lens and includes a transmission unit that transmits a control signal for controlling the zoom lens.

32. 31. The imaging system according to claim 30, wherein the control unit is configured as a separate unit from the zoom lens and has an operation unit for operating the zoom lens.

33. 31. The imaging system according to claim 30, further comprising a display unit that displays information related to the zoom of the zoom lens.

Images