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

Abstract

To provide a zoom lens that is small-sized and has good optical characteristics, and an imaging apparatus and an imaging system having the same.SOLUTION: A zoom lens L0 is composed of a first lens group L1 having a positive refractive power, a second lens group L2 having a positive refractive power, and a rear group LR including one or more lens groups, which are arranged in order from an object side. The first lens group includes three or more negative lenses arranged in order from the object side. The second lens group is composed of one positive lens that moves from the object side to an image side in focusing from infinity to a close range. The total optical length TLw of the zoom lens at a wide angle end, the distance D2w on an optical axis from a lens surface on the most object side in the zoom lens to a lens surface on the most object side in the second lens group at the wide angle end, and the Abbe number νdGP to the d-line of the positive lens satisfy predetermined conditional expressions.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a zoom lens, which is suitable for imaging devices using solid-state imaging elements such as digital still cameras, video cameras, broadcast cameras, and surveillance cameras, or imaging devices such as cameras using silver halide photographic film. [Background technology]

[0002] Zoom lenses used in imaging devices are required to have a wide angle of view, be small in size, and have good optical characteristics. As a zoom lens with a wide angle of view, a so-called negative lead type zoom lens in which a lens group with negative refractive power is arranged closest to the object is known.

[0003] Patent Document 1 discloses a zoom lens including, arranged in order from the object side to the image side, a first lens group with negative refractive power, 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. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-134806 A Summary of the Invention [Problem to be solved by the invention]

[0005] Negative lead type zoom lenses are characterized by the fact that it is relatively easy to achieve a wide angle of view and a long back focus. However, negative lead type zoom lenses tend to have an asymmetric lens configuration with respect to the aperture stop. This makes it difficult to correct various aberrations, for example, it is difficult to suppress aberration fluctuations during focusing, and it is very difficult to achieve high optical performance.

[0006] In particular, in an inner focus type where focusing is performed using a small, lightweight lens group that is closer to the image than the first lens group in order to perform high-speed focusing, there is a tendency for aberration fluctuations to increase during focusing.

[0007] In the zoom lens described in Patent Document 1, aberration fluctuation during focusing is suppressed, but the size of the focus lens group is insufficient.

[0008] In order to realize good optical performance while reducing the diameter of the focus lens group, it is important to appropriately set the position of the focus lens group and the power arrangement of each lens group.

[0009] The present invention provides a zoom lens that is small in size and has good optical characteristics, and an imaging device and an imaging system that include the same. [Means for solving the problem]

[0010] A zoom lens according to one aspect of the present invention includes, arranged in order from an object side to an image side, a first lens group having negative refractive power, and a second lens group having positive refractive power; 2 It contains more than one lens group. Positive refractive power overall rear group and, a zoom lens in which a distance between adjacent lens groups changes during zooming, the first lens group includes three or more negative lenses arranged in order from the object side to the image side, and the second lens group includes one positive lens that moves from the object side to the image side during focusing from infinity to a close distance, wherein TLw is the total optical length of the zoom lens at a wide-angle end, D2w is the distance on the optical axis from the lens surface of the zoom lens closest to the object side at the wide-angle end to the lens surface of the second lens group closest to the object side, and νdGP is the Abbe number of the positive lens with respect to the d-line, 0.48 <D2w / TLw<0.65 25<νdGP ≦38.26 The present invention is characterized in that the following conditional expression is satisfied:

[0011] Other objects and features of the present invention will be described in the following embodiments. Effect of the Invention

[0012] According to the present invention, it is possible to provide a zoom lens that is small in size and has good optical characteristics, and an imaging device and an imaging system that include the same. [Brief description of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view of a zoom lens according to a first embodiment. [Diagram 2] 4A to 4C are aberration diagrams of the zoom lens of Example 1. [Diagram 3] FIG. 11 is a cross-sectional view of a zoom lens according to a second embodiment. [Figure 4] 8A to 8C are aberration diagrams of the zoom lens of Example 2. [Diagram 5] FIG. 11 is a cross-sectional view of a zoom lens according to a third embodiment. [Figure 6] 11A to 11C are aberration diagrams of the zoom lens of Example 3. [Figure 7] FIG. 11 is a cross-sectional view of a zoom lens according to a fourth embodiment. [Figure 8] 11A to 11C are aberration diagrams of the zoom lens of Example 4. [Figure 9] FIG. 11 is a cross-sectional view of a zoom lens according to a fifth embodiment. [Figure 10] 13A to 13C are aberration diagrams of the zoom lens of Example 5. [Figure 11] FIG. 13 is a cross-sectional view of a zoom lens according to a sixth embodiment. [Figure 12] 13A to 13C are aberration diagrams of the zoom lens of Example 6. [Figure 13] FIG. 1 is a schematic diagram of an imaging device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a zoom lens and an image pickup apparatus having the same according to the present invention will be described with reference to the accompanying drawings.

[0015] 1, 3, 5, 7, 9, and 11 are cross-sectional views of the zoom lens L0 of Examples 1 to 6 when focused on infinity at the wide-angle end (infinity focused state). The zoom lens L0 of each Example is used in imaging devices such as digital video cameras, digital still cameras, broadcast cameras, silver halide cameras, and surveillance cameras, as well as optical devices including interchangeable lenses.

[0016] 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 embodiment is configured to have multiple lens groups. In this specification, a lens group is a component of the zoom lens L0 that is configured from one or more lenses. In the zoom lens L0 of each embodiment, the distance between adjacent lens groups changes when zooming from the wide-angle end to the telephoto end. The lens groups may also include an aperture stop.

[0017] In each cross-sectional view, Li represents the i-th lens group (i is a natural number) counted from the object side among the lens groups included in the zoom lens L0. LR is a rear group including all lens groups arranged on the image side of the second lens group L2. LIS refers to a subgroup (anti-vibration group) having a function of correcting image blur (anti-vibration function) by moving in a direction including a component perpendicular to the optical axis. In this specification, a subgroup refers to a group of one or more lenses whose construction length (the distance from the lens surface closest to the object side to the lens surface closest to the image side of the subgroup) remains unchanged during zooming. In other words, a subgroup can be one lens group or a part of one lens group. LN is a lens group arranged on the image side.

[0018] Additionally, SP is an aperture stop. IP is an image plane, and when the zoom lens L0 of each embodiment is used as the photographing optical system of a digital still camera or digital video camera, the imaging surface of a solid-state imaging element (photoelectric conversion element) such as a CCD sensor or CMOS sensor is disposed thereon. When the zoom lens L0 of each embodiment is used as the photographing optical system of a silver halide film camera, a photosensitive surface equivalent to the film surface is disposed on the image plane IP.

[0019] The solid arrows in each lens cross-sectional view are simplified representations of the movement locus of each lens group during zooming from the wide-angle end to the telephoto end. In this specification, the wide-angle end and the telephoto end refer to the zoom positions when each lens group is located at both ends of the range in which it can move mechanically along the optical axis. The dashed arrows in each lens cross-sectional view are simplified representations of the movement locus of each lens group during focusing from infinity to a close distance.

[0020] The zoom lens L0 in each embodiment is composed of, arranged in order from the object side to the image side, a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, and a rear group LR including one or more lens groups. The rear group LR includes all lens groups arranged on the image side of the second lens group L2.

[0021] The first lens group L1 includes three or more negative lenses arranged in order from the object side to the image side. The second lens group L2 includes one positive lens GP, which moves from the object side to the image side during focusing from infinity to a close distance.

[0022] The zoom lens L0 of the first and second embodiments is composed of a first lens group L1, a second lens group L2, a third lens group L3 having a positive refractive power, and a fourth lens group L4 having a positive refractive power, which are arranged in this order from the object side. In the zoom lens L0 of the first and second embodiments, the third lens group L3 and the fourth lens group L4 correspond to the rear group LR. During zooming from the wide-angle end to the telephoto end, the first lens group L1 moves along a convex locus toward the image side, the second lens group L2 and the third lens group L3 move monotonically toward the object side, and the fourth lens group L4 is fixed. Here, the convex locus of the lens group A toward the image side means that, with respect to the amount of movement of the lens group A from the wide-angle end when focusing on infinity, the case where the lens group A moves toward the image side is a positive value, and the amount of movement is maximum in the intermediate region during zooming.

[0023] The zoom lens L0 of the third embodiment is composed of, in order from the object side, a first lens group L1, a second lens group L2, a third lens group L3 with positive refractive power, and a fourth lens group L4 with positive refractive power. In the zoom lens L0 of the third embodiment, the third lens group L3 and the fourth lens group L4 correspond to the rear group LR. During zooming from the wide-angle end to the telephoto end, the first lens group L1 moves along a convex locus toward the image side, the second lens group L2 and the third lens group L3 move monotonically toward the object side, and the fourth lens group L4 moves monotonically toward the image side.

[0024] The zoom lens L0 of Example 4 is composed of a first lens group L1, a second lens group L2, 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, arranged in that order from the object side. In the zoom lens L0 of Example 4, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 correspond to the rear group LR. During zooming from the wide-angle end to the telephoto end, the first lens group L1 moves along a convex locus toward the image side, the second lens group L2, the third lens group L3, and the fourth lens group L4 move monotonically toward the object side, and the fifth lens group L5 moves monotonically toward the image side.

[0025] The zoom lens L0 of the fifth embodiment is composed of, in order from the object side, a first lens group L1, a second lens group L2, 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. In the zoom lens L0 of the fifth embodiment, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 correspond to the rear group LR. During 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, the fourth lens group L4, and the fifth lens group L5 move monotonically toward the object side.

[0026] The zoom lens L0 of the sixth embodiment is composed of a first lens group L1, a second lens group L2, 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, arranged in this order from the object side. In the zoom lens L0 of the sixth embodiment, the third lens group L3, the fourth lens group L4, the fifth lens group L5, and the sixth lens group L6 correspond to the rear group LR. During zooming from the wide-angle end to the telephoto end, the first lens group L1 moves along a convex locus toward the image side, the second lens group L2, the third lens group L3, the fourth lens group L4, and the fifth lens group L5 move monotonically toward the object side, and the sixth lens group L6 is fixed.

[0027] Here, the zoom lens L0 of the first to sixth embodiments is designed to allow the occurrence of distortion. Assuming the use of electronic aberration correction technology resulting from recent technological developments, this image processing technology can correct image distortion caused by distortion. For this reason, imaging optical systems having these zoom lenses L0 store design values ​​(distortion correction data) of the amount of distortion of the zoom lens L0 in their storage units. An electronic image captured using the imaging optical system is corrected by image processing in an arbitrary image processing unit (for example, a CPU attached to an imaging device such as a camera body) using the design value of the amount of distortion.

[0028] In a zoom lens that allows for the occurrence of distortion, a lens for correcting distortion is not necessary, which makes it easy to make the zoom lens smaller and lighter.

[0029] In particular, by making the effective imaging range (effective image circle diameter) of the image sensor at the wide-angle end smaller than the effective imaging range (effective image circle diameter) at the telephoto end and correcting the distortion aberration, it contributes to reducing the diameter of the front lens.

[0030] In the zoom lens L0 of each embodiment, some lenses or some lens groups may be decentered in parallel in a direction perpendicular to the optical axis during image blur correction to provide a function as an anti-vibration optical system. Also, a parallel plate having substantially no refractive power, such as a low-pass filter or an infrared cut filter, may be disposed between the lens disposed closest to the image side and the image surface IP. In other words, the rear group LR may include a parallel plate on the image side of the lens disposed closest to the image side.

[0031] 2, 4, 6, 8, 10, and 12 are aberration diagrams of the zoom lens L0 of Examples 1 to 6. Each aberration diagram is an aberration diagram when focused at infinity, where (A) is an aberration diagram at the wide-angle end, (B) is an aberration diagram at a middle zoom position, and (C) is an aberration diagram at the telephoto end.

[0032] In the spherical aberration diagram, Fno is the F-number, and shows the amount of spherical aberration for the d-line (wavelength 587.6 nm) and g-line (wavelength 435.8 nm). In the astigmatism diagram, ΔS shows the amount of astigmatism on the sagittal image plane, and ΔM shows the amount of astigmatism on the meridional image plane. In the distortion diagram, the amount of distortion for the d-line is shown. In the chromatic aberration diagram, the amount of chromatic aberration for the g-line is shown. ω is the imaging half angle of view (°), which is the angle of view calculated by paraxial calculation.

[0033] Next, the characteristic configuration of the zoom lens L0 of each embodiment will be described.

[0034] The zoom lens L0 of each embodiment is composed of a first lens group L1 with negative refractive power, a second lens group L2 with positive refractive power, and a rear group LR including one or more lens groups, which are arranged in this order from the object side to the image side. The zoom lens L0 of each embodiment 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 known as a configuration that is particularly effective for making the zoom lens have a wide angle. In addition, the first lens group L1 includes three or more negative lenses arranged in this order from the object side to the image side, which makes it possible to ensure a sufficient wide angle (for example, an angle of view of 100° or more at the wide angle end) in each embodiment.

[0035] Moreover, the second lens group L2 is composed of one positive lens GP, and the positive lens GP moves from the object side to the image side during focusing from infinity to a close distance. In a zoom lens, if the height of the off-axis light rays incident on the lens group is high, the lens diameter becomes large. Therefore, in order to realize a compact and lightweight focus lens group, it is important to arrange the focus lens group at a position where the height of the off-axis light rays is low. By arranging the second lens group L2, which is the focus lens group, near the aperture stop SP, it is possible to lower the height of the off-axis light rays incident on the focus lens group. Furthermore, by configuring the focus lens group with one positive lens GP, it is possible to reduce the weight of the focus lens group. In order to suppress the chromatic aberration fluctuation during focusing, it is important to appropriately select the glass material of the positive lens GP.

[0036] Therefore, in the zoom lens L0 of each embodiment, the arrangement of the focus lens group and the glass material of the focus lens group are appropriately set. Specifically, the zoom lens L0 of each embodiment satisfies the following conditional expressions (1) and (2).

[0037] 0.48 <D2w / TLw<0.65 ··· (1) 25<νdGP<45 (2) Here, TLw is the total optical length of the zoom lens L0 at the wide-angle end. The total optical length is the distance on the optical axis from the lens surface closest to the object in the zoom lens L0 to the image plane IP. D2w is the distance on the optical axis from the lens surface closest to the object in the zoom lens L0 at the wide-angle end to the lens surface closest to the object in the second lens group L2. νdGP is the Abbe number for the d-line of the positive lens GP.

[0038] Conditional formula (1) specifies the ratio of the total optical length TLw at the wide-angle end to the distance D2w on the optical axis from the lens surface closest to the object at the wide-angle end to the lens surface closest to the object of the second lens group L2. If the lower limit of conditional formula (1) is not satisfied and the second lens group L2 becomes too close to the object side, the height of off-axis light rays incident on the second lens group L2 becomes high, making it difficult to reduce the size of the focus lens group. On the other hand, if the upper limit of conditional formula (1) is exceeded and the second lens group L2 becomes too close to the image side, the height of off-axis light rays incident on the second lens group L2 becomes high, making it difficult to reduce the size of the focus lens group.

[0039] Conditional formula (2) specifies the Abbe number νdGP for the d-line of the positive lens GP. If the Abbe number is below the lower limit of conditional formula (2) and becomes too small, it becomes difficult to suppress the chromatic aberration fluctuation during focusing. On the other hand, if the Abbe number is above the upper limit of conditional formula (2) and becomes too large, it becomes difficult to suppress the chromatic aberration fluctuation during focusing.

[0040] With the above configuration, a zoom lens L0 that is small in size and has good optical characteristics is obtained.

[0041] Moreover, it is preferable that the zoom lens L0 of each embodiment satisfies one or more of the following conditional expressions (3) to (13).

[0042] 0.35 <DISw / DSPw<0.80 ··· (3) 0.04 <Skw / TLw<0.25 ··· (4) -0.45 <fL1 / fL2<-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) Here, DSPw is the distance on the optical axis from the aperture stop SP to the image plane IP at the wide-angle end. DISw is the distance on the optical axis from the aperture stop SP to the lens surface of the image-side image-proof group LIS at the wide-angle end. Skw is the back focus of the zoom lens L0 at the wide-angle end. fL1 is the focal length of the first lens group L1. fL2 is the focal length of the second lens group L2. fLN is the focal length of the lens group arranged closest to the image side in the zoom lens L0. fLIS is the focal length of the image-proof group LIS. ndGP is the refractive index of the positive lens GP, which is the focus lens group, at the d-line. νdGIS is the Abbe number at the d-line of the negative lens GIS that constitutes the image-proof group LIS. νdG1P is the Abbe number at the d-line of the positive lens G1P, which has the strongest refractive power among the positive lenses included in the first lens group L1. R1 is the radius of curvature of the lens surface at 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. Ymax_w is the maximum image height when focusing on infinity at the wide-angle end. Dist_w is the amount of distortion at the maximum image height Ymax_w when focusing on infinity at the wide-angle end.

[0043] Conditional formula (3) specifies the ratio of the distance DSPw on the optical axis from the aperture stop SP to the image plane IP at the wide-angle end to the distance DISw on the optical axis from the aperture stop SP to the lens surface of the vibration-proof group LIS closest to the object at the wide-angle end. By arranging the vibration-proof group LIS at an appropriate position, it becomes easy to arrange the drive unit for driving the vibration-proof group LIS and the focus lens group while making the diameter of the vibration-proof group LIS small. If the distance from the aperture stop SP to the vibration-proof group LIS becomes too short below the lower limit of conditional formula (3), the distance between the focus lens group arranged near the aperture stop SP and the vibration-proof group LIS becomes too short. Therefore, it becomes difficult to arrange the drive unit for driving the focus lens group and the drive unit for driving the vibration-proof group LIS and the focus lens group. On the other hand, if the distance from the aperture stop SP to the vibration-proof group LIS becomes too long above the upper limit of conditional formula (3), the height of the off-axis light rays incident on the vibration-proof group LIS becomes high. This makes it difficult to reduce the diameter of the vibration isolation group LIS, and therefore makes it difficult to reduce the size of the zoom lens L0.

[0044] Conditional formula (4) specifies the ratio of the back focal length Skw at the wide-angle end to the total optical length TLw at the wide-angle end. If the back focal length Skw is too short, falling below the lower limit of conditional formula (4), it becomes difficult to place an optical element such as a low-pass filter near an image sensor that photoelectrically converts an optical image formed by the zoom lens L0. On the other hand, if the back focal length Skw is too long, exceeding the upper limit of conditional formula (4), the total optical length of the zoom lens L0 at the wide-angle end becomes too long, making it difficult to reduce the size.

[0045] Conditional formula (5) defines the ratio of the focal length fL1 of the first lens group L1 to the focal length fL2 of the second lens group L2. If the refractive power of the first lens group L1 is too weak, as a result of falling below the lower limit of conditional formula (5), it becomes difficult to achieve a wide angle of view exceeding 100° at the wide-angle end. In addition, the front lens diameter becomes large, and the lens outer diameter becomes large. On the other hand, if the refractive power of the first lens group L1 is too strong, as a result of exceeding the upper limit of conditional formula (5), the asymmetry of the refractive power arrangement of the zoom lens L0 becomes stronger, and it becomes difficult to correct distortion at the wide-angle end.

[0046] Conditional expression (6) specifies the ratio of the focal length fL1 of the first lens group L1 to the focal length fLN of the lens group LN arranged closest to the image side. By satisfying conditional expression (6), it is possible to achieve both compactness and high image quality of the zoom lens L0. If the positive refractive power of the lens group LN becomes too strong below the lower limit of conditional expression (6), the retrofocus refractive power arrangement becomes strong. This increases the asymmetry of the refractive power arrangement of the zoom lens L0, making it difficult to correct distortion at the wide-angle end. In addition, it becomes difficult to shorten the overall lens length at the wide-angle end. On the other hand, if the negative refractive power of the lens group LN becomes too strong above the upper limit of conditional expression (6), it becomes difficult to achieve the retrofocus refractive power arrangement. This makes it difficult to widen the imaging angle of view while ensuring the back focus at the wide-angle end.

[0047] Conditional formula (7) specifies the ratio of the focal length fLN of the lens group LN arranged closest to the image to the focal length fLIS of the vibration-reduction group LIS. If the refractive power of the vibration-reduction group LIS becomes too weak as a result of falling below the lower limit of conditional formula (7), the amount of movement of the vibration-reduction group LIS during vibration reduction becomes too large, making it difficult to reduce the outer diameter of the lens. On the other hand, if the refractive power of the vibration-reduction group LIS becomes too strong as a result of exceeding the upper limit of conditional formula (7), it becomes difficult to suppress fluctuations in coma aberration and field curvature during vibration reduction.

[0048] Conditional formula (8) specifies the refractive index ndGP for the d-line of the positive lens GP in the focus lens group. If the refractive index of the positive lens GP is too low, below the lower limit of conditional formula (8), the curvature of the positive lens GP becomes tight in order to give the positive lens GP the necessary refractive power. This makes it difficult to suppress the fluctuation of various aberrations, including astigmatism, during focusing. On the other hand, if the refractive index of the positive lens GP is too high, above the upper limit of conditional formula (8), the curvature of the positive lens GP becomes loose, making it difficult to suppress the fluctuation of various aberrations, including spherical aberration, during focusing.

[0049] Conditional formula (9) specifies the Abbe number νdGIS for the d-line of the negative lens GIS constituting the image stabilization group LIS. If the Abbe number of the negative lens GIS becomes too small below the lower limit of conditional formula (9), it becomes difficult to correct chromatic aberration of magnification during image stabilization. On the other hand, if the Abbe number of the negative lens GIS becomes too large above the upper limit of conditional formula (9), the refractive index of the negative lens GIS becomes low, the amount of movement of the image stabilization group LIS during image stabilization becomes too large, and it becomes difficult to reduce the lens outer diameter.

[0050] Conditional formula (10) specifies the Abbe number νdG1P for the d-line of the positive lens G1P that has the strongest refractive power among the positive lenses included in the first lens group L1. Here, the refractive power is expressed as the reciprocal of the focal length, and strong refractive power means that the value of the reciprocal of the focal length is large. If the Abbe number of the positive lens G1P is too small below the lower limit of conditional formula (10), it becomes difficult to correct lateral chromatic aberration during zooming. On the other hand, if the Abbe number of the positive lens G1P is too large above the upper limit of conditional formula (10), it becomes difficult to correct axial chromatic aberration during zooming.

[0051] Conditional expression (11) specifies the shape of the negative lens GIS that constitutes the image stabilization lens group. The negative lens GIS has a meniscus shape with a convex surface facing the object side, and suppresses the fluctuation of coma aberration during image stabilization. If the lower limit of conditional expression (11) is exceeded, it becomes difficult to suppress the fluctuation of coma aberration during image stabilization. On the other hand, if the upper limit of conditional expression (11) is exceeded, it becomes difficult to suppress the fluctuation of coma aberration during image stabilization.

[0052] Conditional formula (12) specifies the ratio between the maximum image height Ymax_w that can be photographed at the wide-angle end and the focal length fL1 of the first lens group L1. The maximum image height Ymax_w is the distance from the optical axis to the image point that is farthest from the optical axis among the image points that can be photographed, and is the maximum image height taking into consideration the change in magnification due to the amount of distortion. By making the mechanical mechanism and optical system matched to this maximum image height, it is effective in making the optical system and the lens device small and lightweight. If the maximum image height is below the lower limit of conditional formula (12) and becomes too small, the angle of view becomes narrower than the desired angle of view. On the other hand, if the maximum image height is above the upper limit of conditional formula (12) and becomes too large, a light beam in a range wider than the desired angle of view is imaged on the imaging surface, so that the mechanical mechanism and the optical system become excessively large, making it difficult to make them small and lightweight.

[0053] Conditional expression (13) specifies the amount of distortion Dist_w at the maximum image height Ymax_w when focusing at infinity at the wide-angle end. If the amount of distortion Dist_w falls below the lower limit of conditional expression (13) and becomes too large, it becomes difficult to suppress deterioration of peripheral image quality during electronic distortion correction. On the other hand, if the amount of distortion Dist_w exceeds the upper limit of conditional expression (13) and becomes too small, the amount of distortion in the equidistant projection method becomes too large, resulting in significant deterioration of peripheral image quality during image blur correction. Also, the amount of correction of image blur in the peripheral areas becomes insufficient during lens shift image stabilization.

[0054] Here, the amount of distortion is defined as follows: In an optical system, if the ideal image height in the central projection method is y and the real 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:

[0055] Dist_w[%]=((yp-y) / y1)×100 Here, the ideal image height y in the central projection method is a value defined as follows using the total focal length f of the optical system and the half angle of view θi of the actual light ray at an arbitrary image height.

[0056] y=ftanθi Furthermore, at the maximum image height, the ideal image height y can be expressed as follows, using the total focal length f of the optical system and the half angle of view θ of the actual light ray at the maximum image height.

[0057] y1=ftanθ It is more preferable that the numerical ranges of the conditional expressions (1) to (13) be the numerical ranges of the following conditional expressions (3a) to (13a).

[0058] 0.49 <D2w / TLw<0.60 ··· (1a) 27<νdGP<43 (2a) 0.38 <DISw / DSPw<0.70 ··· (3a) 0.05 <Skw / TLw<0.20 ··· (4a) -0.40 <fL1 / fL2<-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) It is further preferable that the numerical ranges of the conditional expressions (1) to (13) be within the numerical ranges of the following conditional expressions (1b) to (13b).

[0059] 0.50 <D2w / TLw<0.55 ··· (1b) 28<νdGP<40 (2b) 0.41 <DISw / DSPw<0.60 ··· (3b) 0.06 <Skw / TLw<0.15 ··· (4b) -0.38 <fL1 / fL2<-0.20 ··· (5b) 0.00<|fL1 / fLN|<0.30 (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<-0.80 ··· (12b) -14.0 <Dist_w<-10.0 ··· (13b) Next, the configuration that is preferably satisfied in the zoom lens L0 of each embodiment will be described.

[0060] The first lens group L1 preferably includes four or more negative lenses and at least one positive lens. The first lens group L1 is preferably movable during zooming. Of the intervals between adjacent lens groups in the zoom lens L0, the interval between the first lens group L1 and the second lens group L2 is preferably maximum at the wide-angle end. This makes it possible to achieve a sufficient wide-angle (for example, an angle of view of 100° or more at the wide-angle end) while also achieving a sufficient zoom ratio (for example, about 2x).

[0061] It is also preferable that the aperture stop SP is disposed on the object side of the second lens unit L2 and that the aperture stop SP monotonically moves toward the object side during zooming from the wide-angle end to the telephoto end, which makes it easy to make the aperture stop SP compact.

[0062] It is also preferable that the rear group LR includes two or more lens groups in which the spacing between adjacent lens groups changes during zooming, which makes it possible to achieve a sufficient zoom ratio (for example, about 2x).

[0063] Moreover, it is preferable that the lens group LN arranged closest to the image side is composed of three lenses or less, which allows the zoom lens L0 to be made compact.

[0064] Moreover, it is preferable that the lens group LN arranged closest to the image side in the zoom lens L0 is fixed during zooming.

[0065] Numerical examples 1 to 6 corresponding to the first to sixth embodiments, respectively, are given below.

[0066] In the surface data of each numerical example, r represents the radius of curvature of each optical surface, and d (mm) represents the axial spacing (distance on the optical axis) between the mth surface and the (m+1)th surface. Here, m is the surface number counted from the light incident side. Additionally, nd represents the refractive index of each optical member with respect to the d-line, and νd represents the Abbe number of the optical member. The Abbe number νd of a certain material is given by the following, 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, respectively: νd=(Nd-1) / (NF-NC) It is expressed as:

[0067] In each numerical example, d, focal length (mm), F-number, and half angle of view (°) are all values ​​when the zoom lens L0 of each example is focused on an object at infinity. "Back focus BF" is the distance on the optical axis from the final lens surface (the lens surface closest to the image) to the paraxial image surface expressed as an air-equivalent length. "Total lens length" is the distance on the optical axis from the foremost lens surface (the lens surface closest to the object) of the zoom lens L0 to the final surface plus the back focus. The term "lens group" is not limited to cases where the lens group is composed of multiple lenses, but also includes cases where the lens group is composed of a single lens.

[0068] If the optical surface is aspheric, a * symbol is added to the right of the surface number. The aspheric shape is expressed as follows, where X is the displacement from the apex 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, and A12 are the aspheric coefficients of each order: X = (h 2 / R) / [1+[1-(1+K)(h / R) 2 ] 1 / 2 ]+A4×h 4 +A6×h6 +A8×h 8 +A10×h 10 +A12×h 12 In addition, "e±XX" in each aspheric coefficient is "×10± XX " It means.

[0069] [Numerical Example 1] Unit: mm Surface Data Surface number rd 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 ∞ Aspheric Data Front page 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 2nd side 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 Page 20 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 Page 26 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 Page 27 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 Mid-Telephoto Focal length 10.33 15.00 19.39 F-number 4.08 4.08 4.12 Half angle of view (°) 61.36 55.26 48.13 Image height 18.92 21.64 21.64 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 Zoom lens group data Group starting plane 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 rd 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 ∞ Aspheric Data Front page 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 2nd side 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 Page 20 K = 0.00000e+00 A 4= 1.88217e-05 A 6=-1.07644e-07 A 8=-8.81979e-10 A10= 3.51547e-12 A12= 2.13797e-14 Page 26 K = 0.00000e+00 A 4= 1.99287e-04 A 6=-1.86752e-06 A 8= 9.76715e-09 A10=-7.11283e-11 A12= 4.03250e-13 Page 27 K = 0.00000e+00 A 4= 2.02967e-04 A 6=-1.31168e-06 A 8= 1.15301e-09 A10=2.03422e-11 A12=-3.00629e-14 Various data Zoom ratio 1.94 Wide Angle Mid-Telephoto Focal length 9.20 16.04 17.90 F-number 4.08 4.08 4.12 Half angle of view (°) 64.04 53.45 50.40 Image height 18.90 21.64 21.64 Lens length 125.26 118.57 119.35 BF 10.50 10.50 10.50 d 9 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 Zoom lens group data Group starting plane 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 rd 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 ∞ Aspheric Data Front page 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 2nd side 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 Page 21 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 Page 27 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 Page 28 K = 0.00000e+00 A 4= 5.07750e-05 A 6=-4.00620e-07 A 8= 1.66532e-10 A10= 4.59683e-12 A12= 8.96637e-15 Various data Zoom ratio 2.12 Wide Angle Mid-Telephoto Focal length 11.30 16.61 23.90 F-number 4.08 4.08 4.12 Half angle of view (°) 59.29 52.49 42.15 Image height 19.02 21.64 21.64 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 Zoom lens group data Group starting plane 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 rd 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 ∞ Aspheric Data Front page 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 2nd 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 Page 13 K = 0.00000e+00 A 4=-3.08173e-06 A 6=-9.07213e-09 A 8= 3.76703e-11 A10=-9.38527e-14 Page 20 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 Page 26 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 Page 27 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 Mid-Telephoto Focal length 11.30 14.97 22.00 F-number 2.89 2.89 2.89 Half angle of view (°) 59.44 55.32 44.52 Image height 19.14 21.64 21.64 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 Zoom lens group data Group starting plane 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 rd 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 (Aperture) ∞ (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 ∞ Aspheric Data Front page 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 2nd side 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 Page 22 K = 0.00000e+00 A 4= 3.62847e-05 A 6=-2.63477e-07 A 8= 1.92638e-09 A10=-6.70834e-11 A12= 4.52971e-13 Page 28 K = 0.00000e+00 A 4= 1.17855e-04 A 6=-1.63605e-06 A 8= 9.00680e-09 A10=-6.51152e-11 A12= 3.38027e-13 Page 29 K = 0.00000e+00 A 4= 1.30738e-04 A 6=-1.32589e-06 A 8= 4.36587e-09 A10=-2.34452e-12 A12= 1.29797e-14 Various data Zoom ratio 1.90 Wide Angle Mid-Telephoto Focal length 10.30 16.00 19.60 F-number 4.08 4.08 4.12 Half angle of view (°) 61.86 53.52 47.83 Image height 19.26 21.64 21.64 Lens length 114.35 105.41 104.44 BF 14.75 21.84 26.22 d 9 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 Zoom lens group data Group starting plane 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 rd 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 ∞ Aspheric Data Front page 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 2nd side 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 Page 22 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 Page 28 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 Page 29 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 Mid-Telephoto Focal length 10.30 15.22 19.80 F-number 2.89 3.50 4.12 Half angle of view (°) 61.76 54.87 47.54 Image height 19.18 21.64 21.64 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 Zoom lens group data Group starting plane 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 The various values ​​in each numerical example are summarized in Table 1 below.

[0070] [Table 1]

[0071] [Imaging device] Next, an embodiment of a digital camera (imaging device) using the zoom lens L0 of the present invention as an imaging optical system will be described with reference to Fig. 13. Fig. 13 is a schematic diagram of an imaging device (digital still camera) 10 of this embodiment. The imaging device 10 includes a camera body 13, a zoom lens 11 similar to any one of the above-mentioned embodiments 1 to 6, and a light receiving element (imaging element) 12 that photoelectrically converts an optical image formed by the zoom lens 11.

[0072] The imaging device 10 of this embodiment has a zoom lens 11 that is small and has good optical characteristics, and therefore can obtain high-quality images.

[0073] An imaging element such as a CCD or CMOS sensor can be used as the light receiving element 12. In this case, the image quality of the output image can be improved by electrically correcting various aberrations such as distortion aberration and chromatic aberration of the image acquired by the light receiving element 12. The camera body 13 may be a so-called single-lens reflex camera having a quick-turn mirror, or a so-called mirrorless camera having no quick-turn mirror.

[0074] The zoom lens L0 of each of the above-mentioned embodiments can be applied not only to the digital still camera shown in FIG. 13, but also to various optical instruments such as silver halide film cameras, video cameras, and telescopes. [Imaging system] An imaging system (surveillance camera system) may be configured including the zoom lens L0 of each embodiment and a control unit that controls the zoom lens L0. 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. In this case, the control unit does not need 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 far away from a drive unit that drives each lens of the zoom lens L0 includes a transmission unit that sends a control signal (command) for controlling the zoom lens L0. With such a control unit, the zoom lens L0 can be remotely controlled.

[0075] Also, the control unit may be provided with an operation unit such as a controller or buttons for remotely controlling the zoom lens L0, so that the zoom lens L0 is controlled in response to a user's input to the operation unit. For example, a zoom-in button and a zoom-out button may be provided as the operation unit. Then, the control unit may be configured to send a signal to a drive unit for the zoom lens L0 so that the magnification of the zoom lens L0 increases when the user presses the zoom-in button, and decreases when the user presses the zoom-out button.

[0076] The imaging system may also have a display unit such as a liquid crystal panel that displays information (movement state) related to the zoom of the zoom lens L0. The information related to the zoom of the zoom lens L0 is, for example, the zoom magnification (zoom state) and the movement amount (movement state) of each lens group. In this case, the user can remotely operate the zoom lens L0 via the operation unit while viewing the information related to the zoom of the zoom lens L0 displayed on the display unit. In this case, the display unit and the operation unit may be integrated by adopting, for example, a touch panel.

[0077] The disclosure of each of the above embodiments includes the following configurations.

[0078] (Configuration 1) the first lens group having a negative refractive power, the second lens group having a positive refractive power, and a rear group including one or more lens groups, arranged in this order from the object side to the image side; A zoom lens in which the spacing between adjacent lens groups changes during zooming, the first lens group includes three or more negative lenses arranged in order from the object side to the image side, the second lens group is made up of one positive lens that moves from the object side to the image side during focusing from infinity to a close distance, Let TLw be the total optical length of the zoom lens at the wide-angle end, D2w be the distance on the optical axis from the lens surface of the zoom lens closest to the object side at the wide-angle end to the lens surface of the second lens group closest to the object side, and νdGP be the Abbe number of the positive lens with respect to the d-line. 0.25 <D2w / TLw<0.53 25<νdGP<45 A zoom lens characterized by satisfying the following conditional expressions: (Configuration 2) 2. The zoom lens according to configuration 1, further comprising an aperture stop arranged on the object side of the second lens group. (Configuration 3) Let DSPw be the distance on the optical axis from the aperture stop to the image plane at the wide-angle end, and DISw be the distance on the optical axis from the aperture stop to the lens surface of the image stabilization group closest to the object, 0.35 <DISw / DSPw<0.80 3. The zoom lens according to configuration 1 or 2, wherein the following condition is satisfied: (Configuration 4) When the back focus of the zoom lens at the wide-angle end is Skw and the total optical length of the zoom lens at the wide-angle end is TLw, 0.04 <Skw / TLw<0.25 4. The zoom lens according to any one of configurations 1 to 3, wherein the following condition is satisfied: (Configuration 5) When the focal length of the first lens group is fL1 and the focal length of the second lens group is fL2, -0.45 <fL1 / fL2<-0.15 5. The zoom lens according to any one of configurations 1 to 4, wherein the following condition is satisfied: (Configuration 6) Let fL1 be the focal length of the first lens group, and fLN be the focal length of the lens group located closest to the image side in the zoom lens, 0.00<|fL1 / fLN|<0.40 6. The zoom lens according to any one of configurations 1 to 5, wherein the following condition is satisfied: (Configuration 7) In the zoom lens, the focal length of the lens group arranged closest to the image side is taken as fLN, and the focal length of the image stabilization group is taken as fLIS. 0.50<|fLN / fLIS|<1.60 7. The zoom lens according to any one of configurations 1 to 6, wherein the following condition is satisfied: (Configuration 8) When the refractive index of the positive lens in the focus lens group with respect to the d-line is ndGP, 1.60 <ndGP<1.91 8. The zoom lens according to any one of configurations 1 to 7, wherein the following condition is satisfied: (Configuration 9) Let νdGIS be the Abbe number for the d-line of the negative lens that constitutes the image stabilization group. 35<νdGIS<60 9. The zoom lens according to any one of configurations 1 to 8, wherein the following condition is satisfied: (Configuration 10) Let νdG1P be the Abbe number for the d-line of the positive lens having the strongest refractive power among the positive lenses included in the first lens group. 22<νdG1P<50 10. The zoom lens according to any one of configurations 1 to 9, wherein the following condition is satisfied: (Configuration 11) The negative lens in the image stabilization group has a meniscus shape with its convex surface facing the object side. When the radius of curvature of the lens surface on the object side of the negative lens is R1 and the radius of curvature of the lens surface on the image side of the negative lens is R2, 3.5<(R1+R2) / (R1-R2)<13.0 11. The zoom lens according to any one of configurations 1 to 10, wherein the following condition is satisfied: (Configuration 12) When the maximum image height at the wide-angle end when focusing on infinity is Ymax_w and the focal length of the first lens group is fL1, -1.60 <Ymax_w / fL1<-0.40 12. The zoom lens according to any one of configurations 1 to 11, wherein the following condition is satisfied: (Configuration 13) When the amount of distortion at the maximum image height Ymax_w when focusing on infinity at the wide-angle end is Dist_w, -20 <Dist_w<-8.0 13. The zoom lens according to any one of configurations 1 to 12, wherein the following condition is satisfied: (Configuration 14) 14. The zoom lens according to any one of configurations 1 to 13, further comprising a storage unit that stores distortion correction data for correcting distortion aberration. (Configuration 15) 15. The zoom lens according to any one of configurations 1 to 14, wherein the first lens group includes four or more negative lenses and at least one positive lens. (Configuration 16) 16. A zoom lens according to any one of configurations 1 to 15, wherein the first lens group is movable during zooming. (Configuration 17) 17. The zoom lens according to any one of configurations 1 to 16, wherein the lens group arranged closest to the image side in the zoom lens is composed of three lenses or less. (Configuration 18) 18. The zoom lens according to any one of configurations 1 to 17, wherein, among the intervals between adjacent lens groups in the zoom lens, the interval between the first lens group and the second lens group is maximum at the wide-angle end. (Configuration 19) 19. The zoom lens according to any one of configurations 1 to 18, wherein the rear group includes two or more lens groups. (Configuration 20) 20. The zoom lens according to any one of configurations 1 to 19, wherein the lens group arranged closest to the image side in the zoom lens is fixed during zooming. (Configuration 21) 20. The zoom lens according to any one of configurations 1 to 19, wherein the rear group consists of a third lens group having positive refractive power and a fourth lens group having positive refractive power, arranged in that order from the object side to the image side. (Configuration 22) The zoom lens according to any one of configurations 1 to 19, wherein the rear group consists of, arranged in order from the object side to the image side, a third lens group having positive refractive power, a fourth lens group having negative refractive power, and a fifth lens group having positive refractive power. (Configuration 23) The zoom lens according to any one of configurations 1 to 19, wherein the rear group consists of, arranged in order from the object side to the image side, a third lens group having negative refractive power, a fourth lens group having positive refractive power, and a fifth lens group having negative refractive power. (Configuration 24) The zoom lens according to any one of configurations 1 to 19, wherein the rear group consists of, arranged in order from the object side to the image side, a third lens group having negative refractive power, a fourth lens group having positive refractive power, a fifth lens group having negative refractive power, and a sixth lens group having positive refractive power. (Configuration 25) 25. An imaging device comprising: the zoom lens according to any one of configurations 1 to 24; and an imaging element that receives an image formed by the zoom lens. (Configuration 26) 26. The imaging apparatus according to configuration 25, wherein the effective image circle diameter at the wide-angle end is smaller than the effective image circle diameter at the telephoto end. (Configuration 27) 25. An imaging system comprising: a zoom lens according to any one of configurations 1 to 24; and a control unit that controls the zoom lens during zooming. (Configuration 28) 28. The imaging system according to configuration 27, wherein the control unit is configured separately from the zoom lens and has a transmission unit that transmits a control signal for controlling the zoom lens. (Configuration 29) 29. The imaging system according to configuration 27 or 28, wherein the control unit is configured as a separate entity from the zoom lens and has an operation unit for operating the zoom lens. (Configuration 30) 30. The imaging system according to any one of configurations 27 to 29, further comprising a display unit that displays information related to the zoom of the zoom lens.

[0079] Although the preferred embodiments and examples of the present invention have been described above, the present invention is not limited to these embodiments and examples, and various combinations, modifications, and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0080] L0 Zoom Lens L1 First lens group L2 Second lens group LR rear group

Claims

1. the first lens group having a negative refractive power, the second lens group having a positive refractive power, and a rear group including two or more lens groups and having a positive refractive power as a whole, the first lens group being arranged in this order from the object side to the image side; A zoom lens in which the spacing between adjacent lens groups changes during zooming, the first lens group includes three or more negative lenses arranged in order from the object side to the image side, the second lens group is made up of one positive lens that moves from the object side to the image side during focusing from infinity to a close distance, Let TLw be the total optical length of the zoom lens at the wide-angle end, D2w be the distance on the optical axis from the lens surface of the zoom lens closest to the object side at the wide-angle end to the lens surface of the second lens group closest to the object side, and νdGP be the Abbe number of the positive lens with respect to the d-line. 0.48<D2w / TLw<0.65 25<νdGP≦38.26 A zoom lens characterized by satisfying the following conditional expressions:

2. 2. The zoom lens according to claim 1, further comprising an aperture stop disposed on the object side of the second lens group.

3. A lens system comprising: a first lens group having negative refractive power, an aperture stop, a second lens group having positive refractive power, and a rear group including two or more lens groups and having positive refractive power as a whole, said first lens group having negative refractive power, and an aperture stop, said second lens group having positive refractive power, A zoom lens in which the spacing between adjacent lens groups changes during zooming, the first lens group includes three or more negative lenses arranged in order from the object side to the image side, the second lens group is made up of one positive lens that moves from the object side to the image side during focusing from infinity to a close distance, Let TLw be the total optical length of the zoom lens at the wide-angle end, D2w be the distance on the optical axis from the lens surface of the zoom lens closest to the object side at the wide-angle end to the lens surface of the second lens group closest to the object side, and νdGP be the Abbe number of the positive lens with respect to the d-line. 0.48<D2w / TLw<0.65 25<νdGP<45 A zoom lens characterized by satisfying the following conditional expressions:

4. Let DSPw be the distance on the optical axis from the aperture stop to the image plane at the wide-angle end, and DISw be the distance on the optical axis from the aperture stop to the lens surface of the image stabilization group closest to the object side at the wide-angle end. 0.35<DISw / DSPw<0.80 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

5. When the back focus of the zoom lens at the wide-angle end is Skw and the total optical length of the zoom lens at the wide-angle end is TLw, 0.04<Skw / TLw<0.25 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 second lens group is fL2, -0.45<fL1 / fL2<-0.15 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

7. When the focal length of the first lens group is fL1 and the focal length of the lens group disposed 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:

8. A zoom lens comprising: a first lens group having a negative refractive power; a second lens group having a positive refractive power; and a rear group including two or more lens groups and having a positive refractive power as a whole, said first lens group having a negative refractive power; and A zoom lens in which the spacing between adjacent lens groups changes during zooming, the first lens group includes three or more negative lenses arranged in order from the object side to the image side, the second lens group is made up of one positive lens that moves from the object side to the image side during focusing from infinity to a close distance, Let TLw be the total optical length of the zoom lens at the wide-angle end, D2w be the distance on the optical axis from the lens surface of the zoom lens closest to the object side at the wide-angle end to the lens surface of the second lens group closest to the object side, νdGP be the Abbe number of the positive lens with respect to the d-line, fL1 be the focal length of the first lens group, and fLN be the focal length of the lens group disposed closest to the image side in the zoom lens. 0.48<D2w / TLw<0.65 25<νdGP<45 0.00<|fL1 / fLN|<0.40 A zoom lens characterized by satisfying the following conditional expressions:

9. In the zoom lens, the focal length of the lens group arranged closest to the image side is taken as fLN, and the focal length of the image stabilization group is taken as fLIS. 0.50<|fLN / fLIS|<1.60 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

10. When the refractive index of the positive lens in the focus lens group with respect to the d line is ndGP, 1.60<ndGP<1.91 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

11. When the Abbe number for the d-line of the negative lens constituting the image stabilization group is νdGIS, 35<νdGIS<60 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

12. Let νdG1P be the Abbe number for the d-line of the positive lens having the strongest refractive power among the positive lenses included in the first lens group. 22<νdG1P<50 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

13. The negative lens in the image stabilization group has a meniscus shape with its convex surface facing the object side. When the radius of curvature of the lens surface on the object side of the negative lens is R1 and the radius of curvature of the lens surface on the image side 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:

14. When the maximum image height at the wide-angle end when focusing on infinity 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:

15. When the amount of distortion at the maximum image height Ymax_w when focusing on infinity at the wide-angle end is Dist_w, -20<Dist_w<-8.0 2. The zoom lens according to claim 1, wherein the following condition is satisfied:

16. 2. The zoom lens according to claim 1, further comprising a storage unit for storing distortion correction data for correcting distortion aberration.

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

18. 2. The zoom lens according to claim 1, wherein the first lens group is movable during zooming.

19. 2. The zoom lens according to claim 1, wherein the lens group disposed closest to the image side in the zoom lens is composed of three or less lenses.

20. 2. The zoom lens according to claim 1, wherein, among the intervals between adjacent lens groups in the zoom lens, the interval between the first lens group and the second lens group is maximum at a wide-angle end.

21. 2. The zoom lens according to claim 1, wherein the lens unit arranged closest to the image side in the zoom lens is fixed during zooming.

22. 2. The zoom lens according to claim 1, wherein the rear group comprises, in order from the object side to the image side, a third lens group having a positive refractive power and a fourth lens group having a positive refractive power.

23. A zoom lens comprising: a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a rear group including two or more lens groups and having a positive refractive power as a whole, said first lens group having a negative refractive power, and a second lens group having a positive refractive power, said rear group including two or more lens groups and having a positive refractive power as a whole, A zoom lens in which the spacing between adjacent lens groups changes during zooming, the first lens group includes three or more negative lenses arranged in order from the object side to the image side, the second lens group is made up of one positive lens that moves from the object side to the image side during focusing from infinity to a close distance, the rear group comprises, in order from the object side to the image side, a third lens group having a positive refractive power and a fourth lens group having a positive refractive power; Let TLw be the total optical length of the zoom lens at the wide-angle end, D2w be the distance on the optical axis from the lens surface of the zoom lens closest to the object side at the wide-angle end to the lens surface of the second lens group closest to the object side, and νdGP be the Abbe number of the positive lens with respect to the d-line. 0.48<D2w / TLw<0.65 25<νdGP<45 A zoom lens characterized by satisfying the following conditional expressions:

24. 2. The zoom lens according to claim 1, wherein the rear group comprises, arranged in order from the object side to the image side, a third lens group having positive refractive power, a fourth lens group having negative refractive power, and a fifth lens group having positive refractive power.

25. 2. The zoom lens according to claim 1, wherein the rear group comprises, arranged in order from the object side to the image side, a third lens group having negative refractive power, a fourth lens group having positive refractive power, and a fifth lens group having negative refractive power.

26. A zoom lens comprising: a first lens group having a negative refractive power; a second lens group having a positive refractive power; and a rear group including two or more lens groups and having a positive refractive power as a whole, said first lens group having a negative refractive power; and A zoom lens in which the spacing between adjacent lens groups changes during zooming, the first lens group includes three or more negative lenses arranged in order from the object side to the image side, the second lens group is made up of one positive lens that moves from the object side to the image side during focusing from infinity to a close distance, the rear group comprises, in order from the object side to the image side, a third lens group having a negative refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a negative refractive power; Let TLw be the total optical length of the zoom lens at the wide-angle end, D2w be the distance on the optical axis from the lens surface of the zoom lens closest to the object side at the wide-angle end to the lens surface of the second lens group closest to the object side, and νdGP be the Abbe number of the positive lens with respect to the d-line. 0.48<D2w / TLw<0.65 25<νdGP<45 A zoom lens characterized by satisfying the following conditional expressions:

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

28. A zoom lens comprising: a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a rear group including two or more lens groups and having a positive refractive power as a whole, said first lens group having a negative refractive power, and a second lens group having a positive refractive power, said rear group including two or more lens groups and having a positive refractive power as a whole, A zoom lens in which the spacing between adjacent lens groups changes during zooming, the first lens group includes three or more negative lenses arranged in order from the object side to the image side, the second lens group is made up of one positive lens that moves from the object side to the image side during focusing from infinity to a close distance, the rear group comprises, arranged in order from the object side to the image side, a third lens group having negative refractive power, a fourth lens group having positive refractive power, a fifth lens group having negative refractive power, and a sixth lens group having positive refractive power; Let TLw be the total optical length of the zoom lens at the wide-angle end, D2w be the distance on the optical axis from the lens surface of the zoom lens closest to the object side at the wide-angle end to the lens surface of the second lens group closest to the object side, and νdGP be the Abbe number of the positive lens with respect to the d-line. 0.48<D2w / TLw<0.65 25<νdGP<45 A zoom lens characterized by satisfying the following conditional expressions:

29. 29. An imaging apparatus comprising: the zoom lens according to claim 1; and an imaging element that receives an image formed by the zoom lens.

30. 30. The image pickup apparatus according to claim 29, wherein an effective image circle diameter at a wide-angle end is smaller than an effective image circle diameter at a telephoto end.

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

32. 32. The imaging system according to claim 31, 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.

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

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

Images