Imaging optical system, imaging device including the same and camera system

Abstract

To provide: a zoom lens capable of obtaining excellent optical performance throughout the zoom range; an imaging device using the zoom lens; and an interchangeable lens device.SOLUTION: An imaging optical system includes, in order from the object side to the image side, the first lens group having positive power, the second lens group having negative power, the third lens group having positive power, the fourth lens group having positive power, the fifth lens group having negative power, the sixth lens group having power. When zooming, the movements of at least the first, second, third, fourth, fifth and sixth lens groups in the optical axis direction change the intervals of respective lens groups.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present disclosure relates to an imaging optical system in which various aberrations are well corrected across the entire zoom range, and an imaging device and an interchangeable lens device that include the same. [Background technology]

[0002] Patent Document 1 discloses a zoom lens having, arranged in order from the object side to the image side, a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power, a third lens group L3 with positive refractive power, a fourth lens group L4 with positive refractive power, and an Nth lens group LN with negative refractive power that is arranged closest to the image side, in which the spacing between adjacent lens groups changes during zooming. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-104137 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide an imaging optical system in which various aberrations are well corrected across the entire zoom range, and an imaging device and an interchangeable lens device that include the imaging optical system. [Means for solving the problem]

[0005] The imaging optical system in the present disclosure includes, in order from the object side to the image side, a first lens group having positive power, a second lens group having negative power, a third lens group having positive power, a fourth lens group having positive power, a fifth lens group having negative power, and a sixth lens group having power.

[0006] During zooming, at least the first, second, third, fourth, fifth, and sixth lens groups move in the optical axis direction, changing the spacing between the lens groups. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide an imaging optical system in which various aberrations are well corrected across the entire zoom range, and an imaging device and an interchangeable lens device that include the imaging optical system. [Brief explanation of the drawings]

[0008] [Figure 1A] FIG. 1 is a lens arrangement diagram showing an infinity focused state of an imaging optical system according to a first embodiment (numerical example 1); [Figure 1B] 1 is a longitudinal aberration diagram of the imaging optical system according to Numerical Example 1 in a state of focusing at infinity. [Figure 1C] 10A and 10B are lateral aberration diagrams in a basic state where image blur correction is not performed and in a state where image blur correction is performed at the telephoto end of the imaging optical system according to Numerical Example 1. [Figure 2A] FIG. 10 is a lens arrangement diagram showing an infinity focused state of an imaging optical system according to a second embodiment (Numerical Example 2). [Figure 2B] 10A and 10B are longitudinal aberration diagrams of the imaging optical system according to Numerical Example 2 in a state of focusing at infinity. [Figure 2C] 10A and 10B are lateral aberration diagrams in a basic state where image blur correction is not performed and in a state where image blur correction is performed at the telephoto end of an imaging optical system according to Numerical Example 2. [Figure 3A] FIG. 10 is a lens arrangement diagram showing an infinity focused state of an imaging optical system according to a third embodiment (Numerical Example 3). [Figure 3B] 10A and 10B are longitudinal aberration diagrams of the imaging optical system according to Numerical Example 3 in a state of focusing at infinity. [Figure 3C] 10A and 10B are lateral aberration diagrams at the telephoto end of an imaging optical system according to Numerical Example 3 in a basic state where image blur correction is not performed and in a state where image blur correction is performed. [Figure 4A] FIG. 10 is a lens arrangement diagram showing an infinity focused state of an imaging optical system according to a fourth embodiment (numerical example 4); [Figure 4B]FIG. 10 is a longitudinal aberration diagram of the imaging optical system according to Numerical Example 4 in a state where the imaging optical system is focused at infinity. [Figure 4C] 10A and 10B are lateral aberration diagrams in a basic state where image blur correction is not performed and in a state where image blur correction is performed at the telephoto end of an imaging optical system according to Numerical Example 4. [Figure 5A] FIG. 10 is a lens arrangement diagram showing an infinity focused state of an imaging optical system according to a fifth embodiment (numerical example 5). [Figure 5B] FIG. 10 is a longitudinal aberration diagram of the imaging optical system according to Numerical Example 5 in a state of focusing at infinity. [Figure 5C] 10A and 10B are lateral aberration diagrams at the telephoto end of the imaging optical system according to Numerical Example 5 in a basic state where image blur correction is not performed and in a state where image blur correction is performed. [Figure 6] 1 is a schematic diagram of an imaging device according to a first embodiment; [Figure 7] 1 is a schematic diagram of a camera system according to a first embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of well-known matters or redundant explanation of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following explanation and to facilitate understanding by those skilled in the art.

[0010] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0011] (Embodiments 1 to 5) The imaging optical systems according to the first to fifth embodiments will be individually described below with reference to the drawings.

[0012] 1A, 2A, 3A, 4A, and 5A are lens layout diagrams of imaging optical systems according to first to fifth embodiments, respectively, and all show imaging optical systems in an infinity focused state.

[0013] (a) of Figures 1A, 2A, 3A, 4A, and 5A shows the lens arrangement at the wide-angle end (shortest focal length state: focal length fW). (d) of each figure shows the lens arrangement at the intermediate position (intermediate focal length state: focal length fM = √(fW * fT)). (e) of each figure shows the lens arrangement at the telephoto end (longest focal length state: focal length fT). Note that the aspect ratio is the same in (a), (d), and (e) of each figure.

[0014] An asterisk * attached to the surface of a particular lens element shown in (a) of each figure indicates that the surface is aspherical.

[0015] The broken arrows in (c) of each figure show, from top to bottom, the positions of the lens groups in each state: wide-angle end (WIDE), middle position (MID), and telephoto end (TELE). Note that the arrows simply connect the wide-angle end and middle position, and the middle position and telephoto end, and do not show the actual movement of each lens group.

[0016] In (b) of each figure, the lens groups are labeled G1 to G7 in accordance with the positions of the lens groups shown in (a).

[0017] The symbols (+) and (-) attached to the reference numerals of each lens group (G1 to G7) shown in (b) of each figure correspond to the power of each lens group. That is, the symbol (+) indicates positive power, and the symbol (-) indicates negative power.

[0018] The arrows attached to the lens groups shown in (b) of each figure represent focusing from an infinity-focused state to a close-focused state. In Figures 1A, 2A, 3A, 4A, and 5A, the reference numerals of each lens group are written below the positions of the lens groups in (a), and therefore, for convenience, arrows representing focusing are attached below the reference numerals of each lens group. However, the direction in which each lens group moves during focusing in each zoom state will be specifically explained later for each embodiment.

[0019] In each of (a), (d), and (e) of the figures, the line drawn on the far right indicates the position of the image plane S (the object-side surface of the image sensor). Therefore, the left side of the figure corresponds to the object side. Furthermore, a parallel plate P, such as a low-pass filter or cover glass, is disposed between the image plane S and the final lens group facing the image plane S.

[0020] (Embodiment 1) FIG. 1A shows an imaging optical system according to the first embodiment.

[0021] The imaging optical system is composed of, in order from the object side to the image side, a first lens group G1 having positive power, a second lens group G2 having negative power, a third lens group G3 having positive power, a fourth lens group G4 having positive power, a fifth lens group G5 having negative power, and a sixth lens group G6 having negative power.

[0022] The imaging optical system forms an image at the position of an image plane S.

[0023] The first lens group G1 is composed of, in order from the object side to the image side, a first lens element L1 having negative power, a second lens element L2 having positive power, and a third lens element L3 having positive power. The first lens element L1 and the second lens element L2 are a cemented lens bonded together with an adhesive or the like.

[0024] The second lens group G2 is composed of, in order from the object side to the image side, a fourth lens element L4 having negative power, a fifth lens element L5 having negative power, a sixth lens element L6 having positive power, and a seventh lens element L7 having negative power. The fifth lens element L5 and the sixth lens element L6 are a cemented lens bonded together with an adhesive or the like.

[0025] The third lens group G3 is composed of, in order from the object side to the image side, an aperture stop A, an eighth lens element L8 having positive power, a ninth lens element L9 having negative power, a tenth lens element L10 having positive power, and an eleventh lens element L11 having negative power. The ninth lens element L9 and the tenth lens element L10 are a cemented lens bonded together with an adhesive or the like.

[0026] The fourth lens group G4 is composed of, in order from the object side to the image side, a twelfth lens element L12 having positive power and a thirteenth lens element L13 having positive power.

[0027] The fifth lens group G5 is composed of, in order from the object side to the image side, a fourteenth lens element L14 having positive power and a fifteenth lens element L15 having negative power. The fourteenth lens element L14 and the fifteenth lens element L15 are a cemented lens bonded together with an adhesive or the like.

[0028] The sixth lens group G6 is composed of, in order from the object side to the image side, a sixteenth lens element L16 having negative power and a seventeenth lens element L17 having positive power.

[0029] Each lens element will now be described.

[0030] The lens elements in the first lens group G1 will be described. The first lens element L1 is a meniscus lens with a convex surface facing the object side. The second lens element L2 is a biconvex lens. The third lens element L3 is a meniscus lens with a convex surface facing the object side.

[0031] The lens elements in the second lens group G2 will be described. The fourth lens element L4 is a meniscus lens having a convex surface facing the object side. The fifth lens element L5 is a biconcave lens. The sixth lens element L6 is a biconvex lens. The seventh lens element L7 is a biconcave lens.

[0032] The lens elements in the third lens group G3 will be described. The eighth lens element L8 is a biconvex lens. The ninth lens element L9 is a meniscus lens having a convex surface on the object side. The tenth lens element L10 is a biconvex lens. The eleventh lens element L11 is a meniscus lens having a convex surface on the image side. Here, the eighth lens element L8 is an example of the lens element LG3F1. The eighth lens element L8 is an example of the fixed group G3Obj that does not move in a direction perpendicular to the optical axis during image stabilization. The ninth lens element L9 is an example of the lens element LG3F2. The ninth lens element L9 and the tenth lens element L10 are examples of image stabilization groups that move in a direction perpendicular to the optical axis during image stabilization. The eleventh lens element L11 is an example of the lens element LG3R1. The eleventh lens element L11 is an example of the fixed group G3Img that does not move in a direction perpendicular to the optical axis during image stabilization.

[0033] The lens elements in the fourth lens group G4 will be described. The twelfth lens element L12 is a meniscus lens having a convex surface on the object side. The thirteenth lens element L13 is a biconvex lens. The object-side and image-side surfaces of the thirteenth lens element L13 are aspheric. Here, the twelfth lens element L12 is an example of lens element LG4F1. The twelfth lens element L12 is an example of lens element LG4Fp1. The thirteenth lens element L13 is an example of lens element LG4F2.

[0034] The lens elements in the fifth lens group G5 will be described. The fourteenth lens element L14 is a biconvex lens. The fifteenth lens element L15 is a biconcave lens.

[0035] The lens elements in the sixth lens group G6 will be described. The sixteenth lens element L16 is a meniscus lens having a convex surface facing the image side. The seventeenth lens element L17 is a biconvex lens.

[0036] In the imaging optical system according to Embodiment 1, during zooming from the wide-angle end to the telephoto end during imaging, the first lens group G1, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 move toward the object side with respect to the image plane S. During zooming, each lens group moves along the optical axis so that the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 decreases, the distance between the fourth lens group G4 and the fifth lens group G5 increases, and the distance between the fifth lens group G5 and the sixth lens group G6 increases.

[0037] In the imaging optical system according to the first embodiment, the fifth lens group G5 moves toward the image side along the optical axis during focusing from an infinite object point focused state to a close object focused state.

[0038] The ninth lens element L9 and the tenth lens element L10 (image stabilization group) in the third lens group G3 move in a direction perpendicular to the optical axis to optically correct image blur. These image blur correction lens elements enable the imaging optical system to correct image point movement caused by vibration of the entire system. In other words, the imaging optical system can optically correct image blur caused by hand shake, vibration, etc.

[0039] (Embodiment 2) FIG. 2A shows an imaging optical system according to the second embodiment.

[0040] The imaging optical system is composed of, in order from the object side to the image side, a first lens group G1 having positive power, a second lens group G2 having negative power, a third lens group G3 having positive power, a fourth lens group G4 having positive power, a fifth lens group G5 having negative power, and a sixth lens group G6 having negative power.

[0041] The imaging optical system forms an image at the position of an image plane S.

[0042] The first lens group G1 is composed of, in order from the object side to the image side, a first lens element L1 having negative power, a second lens element L2 having positive power, and a third lens element L3 having positive power. The first lens element L1 and the second lens element L2 are a cemented lens bonded together with an adhesive or the like.

[0043] The second lens group G2 is composed of, in order from the object side to the image side, a fourth lens element L4 having negative power, a fifth lens element L5 having negative power, a sixth lens element L6 having positive power, and a seventh lens element L7 having negative power. The fifth lens element L5 and the sixth lens element L6 are a cemented lens bonded together with an adhesive or the like.

[0044] The third lens group G3 is composed of, in order from the object side to the image side, an aperture stop A, an eighth lens element L8 having positive power, a ninth lens element L9 having negative power, a tenth lens element L10 having positive power, and an eleventh lens element L11 having negative power. The ninth lens element L9 and the tenth lens element L10 are a cemented lens bonded together with an adhesive or the like.

[0045] The fourth lens group G4 is composed of, in order from the object side to the image side, a twelfth lens element L12 having positive power and a thirteenth lens element L13 having positive power.

[0046] The fifth lens group G5 is composed of, in order from the object side to the image side, a fourteenth lens element L14 having positive power and a fifteenth lens element L15 having negative power. The fourteenth lens element L14 and the fifteenth lens element L15 are a cemented lens bonded together with an adhesive or the like.

[0047] The sixth lens group G6 is composed of, in order from the object side to the image side, a sixteenth lens element L16 having negative power and a seventeenth lens element L17 having positive power.

[0048] Each lens element will now be described.

[0049] The lens elements in the first lens group G1 will be described. The first lens element L1 is a meniscus lens with a convex surface facing the object side. The second lens element L2 is a biconvex lens. The third lens element L3 is a meniscus lens with a convex surface facing the object side.

[0050] The lens elements in the second lens group G2 will be described. The fourth lens element L4 is a meniscus lens having a convex surface facing the object side. The fifth lens element L5 is a biconcave lens. The sixth lens element L6 is a biconvex lens. The seventh lens element L7 is a biconcave lens.

[0051] The lens elements in the third lens group G3 will be described. The eighth lens element L8 is a biconvex lens. The ninth lens element L9 is a meniscus lens having a convex surface facing the object side. The tenth lens element L10 is a biconvex lens. The eleventh lens element L11 is a biconcave lens. Here, the eighth lens element L8 is an example of the lens element LG3F1. The eighth lens element L8 is an example of the fixed group G3Obj that does not move in a direction perpendicular to the optical axis during image stabilization compensation. The ninth lens element L9 is an example of the lens element LG3F2. The ninth lens element L9 and the tenth lens element L10 are examples of image stabilization groups that move in a direction perpendicular to the optical axis during image stabilization compensation. The eleventh lens element L11 is an example of the lens element LG3R1. The eleventh lens element L11 is an example of the fixed group G3Img that does not move in a direction perpendicular to the optical axis during image stabilization compensation.

[0052] The lens elements in the fourth lens group G4 will be described. The twelfth lens element L12 is a biconvex lens. The thirteenth lens element L13 is a biconvex lens. The object-side and image-side surfaces of the thirteenth lens element L13 are aspheric. Here, the twelfth lens element L12 is an example of lens element LG4F1. The twelfth lens element L12 is an example of lens element LG4Fp1. The thirteenth lens element L13 is an example of lens element LG4F2.

[0053] The lens elements in the fifth lens group G5 will be described. The fourteenth lens element L14 is a meniscus lens having a convex surface facing the image side. The fifteenth lens element L15 is a biconcave lens.

[0054] The lens elements in the sixth lens group G6 will be described. The sixteenth lens element L16 is a meniscus lens having a convex surface facing the image side. The seventeenth lens element L17 is a biconvex lens.

[0055] In the imaging optical system according to Embodiment 2, during zooming from the wide-angle end to the telephoto end during imaging, the first lens group G1, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 move toward the object side with respect to the image plane S. During zooming, each lens group moves along the optical axis so that the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 decreases, the distance between the fourth lens group G4 and the fifth lens group G5 increases from the wide-angle end to a middle position and decreases from the middle position to the telephoto end, and the distance between the fifth lens group G5 and the sixth lens group G6 decreases from the wide-angle end to a middle position and increases from the middle position to the telephoto end.

[0056] In the imaging optical system according to the second embodiment, the fifth lens group G5 moves toward the image side along the optical axis during focusing from an infinite object point focused state to a close object focused state.

[0057] The ninth lens element L9 and the tenth lens element L10 (image stabilization group) in the third lens group G3 move in a direction perpendicular to the optical axis to optically correct image blur. These image blur correction lens elements enable the imaging optical system to correct image point movement caused by vibration of the entire system. In other words, the imaging optical system can optically correct image blur caused by hand shake, vibration, etc.

[0058] (Embodiment 3) FIG. 3A shows an imaging optical system according to the third embodiment.

[0059] The imaging optical system is composed of, in order from the object side to the image side, a first lens group G1 having positive power, a second lens group G2 having negative power, a third lens group G3 having positive power, a fourth lens group G4 having positive power, a fifth lens group G5 having negative power, and a sixth lens group G6 having negative power.

[0060] The imaging optical system forms an image at the position of an image plane S.

[0061] The first lens group G1 is composed of, in order from the object side to the image side, a first lens element L1 having negative power, a second lens element L2 having positive power, and a third lens element L3 having positive power. The first lens element L1 and the second lens element L2 are a cemented lens bonded together with an adhesive or the like.

[0062] The second lens group G2 is composed of, in order from the object side to the image side, a fourth lens element L4 having negative power, a fifth lens element L5 having negative power, a sixth lens element L6 having positive power, and a seventh lens element L7 having negative power. The fifth lens element L5 and the sixth lens element L6 are a cemented lens bonded together with an adhesive or the like.

[0063] The third lens group G3 is composed of, in order from the object side to the image side, an aperture stop A, an eighth lens element L8 having positive power, a ninth lens element L9 having negative power, a tenth lens element L10 having positive power, and an eleventh lens element L11 having negative power. The ninth lens element L9 and the tenth lens element L10 are a cemented lens bonded together with an adhesive or the like.

[0064] The fourth lens group G4 is composed of, in order from the object side to the image side, a twelfth lens element L12 having positive power and a thirteenth lens element L13 having positive power.

[0065] The fifth lens group G5 is composed of, in order from the object side to the image side, a fourteenth lens element L14 having positive power and a fifteenth lens element L15 having negative power. The fourteenth lens element L14 and the fifteenth lens element L15 are a cemented lens bonded together with an adhesive or the like.

[0066] The sixth lens group G6 is composed of, in order from the object side to the image side, a sixteenth lens element L16 having negative power and a seventeenth lens element L17 having positive power.

[0067] Each lens element will now be described.

[0068] The lens elements in the first lens group G1 will be described. The first lens element L1 is a meniscus lens with a convex surface facing the object side. The second lens element L2 is a biconvex lens. The third lens element L3 is a meniscus lens with a convex surface facing the object side.

[0069] The lens elements in the second lens group G2 will be described. The fourth lens element L4 is a meniscus lens having a convex surface facing the object side. The fifth lens element L5 is a biconcave lens. The sixth lens element L6 is a biconvex lens. The seventh lens element L7 is a biconcave lens.

[0070] The lens elements in the third lens group G3 will be described. The eighth lens element L8 is a biconvex lens. The ninth lens element L9 is a meniscus lens having a convex surface on the object side. The tenth lens element L10 is a biconvex lens. The eleventh lens element L11 is a meniscus lens having a convex surface on the image side. Here, the eighth lens element L8 is an example of the lens element LG3F1. The eighth lens element L8 is an example of the fixed group G3Obj that does not move in a direction perpendicular to the optical axis during image stabilization. The ninth lens element L9 is an example of the lens element LG3F2. The ninth lens element L9 and the tenth lens element L10 are examples of image stabilization groups that move in a direction perpendicular to the optical axis during image stabilization. The eleventh lens element L11 is an example of the lens element LG3R1. The eleventh lens element L11 is an example of the fixed group G3Img that does not move in a direction perpendicular to the optical axis during image stabilization.

[0071] The lens elements in the fourth lens group G4 will be described. The twelfth lens element L12 is a meniscus lens having a convex surface on the object side. The thirteenth lens element L13 is a biconvex lens. The object-side and image-side surfaces of the thirteenth lens element L13 are aspheric. Here, the twelfth lens element L12 is an example of lens element LG4F1. The twelfth lens element L12 is an example of lens element LG4Fp1. The thirteenth lens element L13 is an example of lens element LG4F2.

[0072] The lens elements in the fifth lens group G5 will be described. The fourteenth lens element L14 is a biconvex lens. The fifteenth lens element L15 is a biconcave lens.

[0073] The lens elements in the sixth lens group G6 will be described. The sixteenth lens element L16 is a meniscus lens having a convex surface facing the image side. The seventeenth lens element L17 is a biconvex lens.

[0074] In the imaging optical system according to Embodiment 3, during zooming from the wide-angle end to the telephoto end during imaging, the first lens group G1, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 move toward the object side with respect to the image plane S. During zooming, each lens group moves along the optical axis so that the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 decreases, the distance between the fourth lens group G4 and the fifth lens group G5 increases from the wide-angle end to a middle position and decreases from the middle position to the telephoto end, and the distance between the fifth lens group G5 and the sixth lens group G6 increases.

[0075] In the imaging optical system according to the third embodiment, the fifth lens group G5 moves toward the image side along the optical axis during focusing from an infinite object point focused state to a close object focused state.

[0076] The ninth lens element L9 and the tenth lens element L10 (image stabilization group) in the third lens group G3 move in a direction perpendicular to the optical axis to optically correct image blur. These image blur correction lens elements enable the imaging optical system to correct image point movement caused by vibration of the entire system. In other words, the imaging optical system can optically correct image blur caused by hand shake, vibration, etc.

[0077] (Fourth embodiment) FIG. 4A shows an imaging optical system according to the fourth embodiment.

[0078] The imaging optical system is composed of, in order from the object side to the image side, a first lens group G1 having positive power, a second lens group G2 having negative power, a third lens group G3 having positive power, a fourth lens group G4 having positive power, a fifth lens group G5 having negative power, a sixth lens group G6 having negative power, and a seventh lens group G7 having negative power.

[0079] The imaging optical system forms an image at the position of an image plane S.

[0080] The first lens group G1 is composed of, in order from the object side to the image side, a first lens element L1 having negative power, a second lens element L2 having positive power, and a third lens element L3 having positive power. The first lens element L1 and the second lens element L2 are a cemented lens bonded together with an adhesive or the like.

[0081] The second lens group G2 is composed of, in order from the object side to the image side, a fourth lens element L4 having negative power, a fifth lens element L5 having negative power, a sixth lens element L6 having positive power, and a seventh lens element L7 having negative power. The fifth lens element L5 and the sixth lens element L6 are a cemented lens bonded together with an adhesive or the like.

[0082] The third lens group G3 is composed of, in order from the object side to the image side, an aperture stop A, an eighth lens element L8 having positive power, a ninth lens element L9 having negative power, a tenth lens element L10 having positive power, and an eleventh lens element L11 having negative power. The ninth lens element L9 and the tenth lens element L10 are a cemented lens bonded together with an adhesive or the like.

[0083] The fourth lens group G4 is composed of, in order from the object side to the image side, a twelfth lens element L12 having positive power and a thirteenth lens element L13 having positive power.

[0084] The fifth lens group G5 is composed of, in order from the object side to the image side, a fourteenth lens element L14 having positive power and a fifteenth lens element L15 having negative power. The fourteenth lens element L14 and the fifteenth lens element L15 are a cemented lens bonded together with an adhesive or the like.

[0085] The sixth lens group G6 is composed of, in order from the object side to the image side, a sixteenth lens element L16 having negative power and a seventeenth lens element L17 having positive power.

[0086] The seventh lens group G7 is composed of an eighteenth lens element L18 having negative power.

[0087] Each lens element will now be described.

[0088] The lens elements in the first lens group G1 will be described. The first lens element L1 is a meniscus lens with a convex surface facing the object side. The second lens element L2 is a biconvex lens. The third lens element L3 is a meniscus lens with a convex surface facing the object side.

[0089] The lens elements in the second lens group G2 will be described. The fourth lens element L4 is a meniscus lens having a convex surface facing the object side. The fifth lens element L5 is a biconcave lens. The sixth lens element L6 is a biconvex lens. The seventh lens element L7 is a biconcave lens.

[0090] The lens elements in the third lens group G3 will be described. The eighth lens element L8 is a biconvex lens. The ninth lens element L9 is a meniscus lens having a convex surface facing the object side. The tenth lens element L10 is a biconvex lens. The eleventh lens element L11 is a biconcave lens. Here, the eighth lens element L8 is an example of the lens element LG3F1. The eighth lens element L8 is an example of the fixed group G3Obj that does not move in a direction perpendicular to the optical axis during image stabilization compensation. The ninth lens element L9 is an example of the lens element LG3F2. The ninth lens element L9 and the tenth lens element L10 are examples of image stabilization groups that move in a direction perpendicular to the optical axis during image stabilization compensation. The eleventh lens element L11 is an example of the lens element LG3R1. The eleventh lens element L11 is an example of the fixed group G3Img that does not move in a direction perpendicular to the optical axis during image stabilization compensation.

[0091] The lens elements in the fourth lens group G4 will be described. The twelfth lens element L12 is a biconvex lens. The thirteenth lens element L13 is a biconvex lens. The object-side and image-side surfaces of the thirteenth lens element L13 are aspheric. Here, the twelfth lens element L12 is an example of lens element LG4F1. The twelfth lens element L12 is an example of lens element LG4Fp1. The thirteenth lens element L13 is an example of lens element LG4F2.

[0092] The lens elements in the fifth lens group G5 will be described. The fourteenth lens element L14 is a biconvex lens. The fifteenth lens element L15 is a biconcave lens.

[0093] The lens elements in the sixth lens group G6 will be described. The sixteenth lens element L16 is a meniscus lens having a convex surface facing the image side. The seventeenth lens element L17 is a biconvex lens.

[0094] The lens elements in the seventh lens group G7 will be described below. The eighteenth lens element L18 is a meniscus lens having a convex surface on the image side.

[0095] In the imaging optical system of embodiment 4, when zooming from the wide-angle end to the telephoto end during imaging, the first lens group G1, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, the sixth lens group G6, and the seventh lens group G7 move toward the object side relative to the image plane S. During zooming, each lens group moves along the optical axis so that the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 decreases, the distance between the fourth lens group G4 and the fifth lens group G5 increases from the wide-angle end to the intermediate position and decreases from the intermediate position to the telephoto end, the distance between the fifth lens group G5 and the sixth lens group G6 decreases from the wide-angle end to the intermediate position and increases from the intermediate position to the telephoto end, and the distance between the sixth lens group G6 and the seventh lens group G7 increases from the wide-angle end to the intermediate position and decreases from the intermediate position to the telephoto end.

[0096] In the imaging optical system according to the fourth embodiment, the fifth lens group G5 moves toward the image side along the optical axis during focusing from an infinite object point focused state to a close object focused state.

[0097] The ninth lens element L9 and the tenth lens element L10 (image stabilization group) in the third lens group G3 move in a direction perpendicular to the optical axis to optically correct image blur. These image blur correction lens elements enable the imaging optical system to correct image point movement caused by vibration of the entire system. In other words, the imaging optical system can optically correct image blur caused by hand shake, vibration, etc.

[0098] (Embodiment 5) FIG. 5A shows an imaging optical system according to the fifth embodiment.

[0099] The imaging optical system is composed of, in order from the object side to the image side, a first lens group G1 having positive power, a second lens group G2 having negative power, a third lens group G3 having positive power, a fourth lens group G4 having positive power, a fifth lens group G5 having negative power, and a sixth lens group G6 having negative power.

[0100] The imaging optical system forms an image at the position of an image plane S.

[0101] The first lens group G1 is composed of, in order from the object side to the image side, a first lens element L1 having negative power, a second lens element L2 having positive power, and a third lens element L3 having positive power. The first lens element L1 and the second lens element L2 are a cemented lens bonded together with an adhesive or the like.

[0102] The second lens group G2 is composed of, in order from the object side to the image side, a fourth lens element L4 having negative power, a fifth lens element L5 having negative power, a sixth lens element L6 having positive power, and a seventh lens element L7 having negative power. The fifth lens element L5 and the sixth lens element L6 are a cemented lens bonded together with an adhesive or the like.

[0103] The third lens group G3 is composed of, in order from the object side to the image side, an aperture stop A, an eighth lens element L8 having positive power, a ninth lens element L9 having negative power, a tenth lens element L10 having positive power, and an eleventh lens element L11 having negative power. The ninth lens element L9 and the tenth lens element L10 are a cemented lens bonded together with an adhesive or the like.

[0104] The fourth lens group G4 is composed of, in order from the object side to the image side, a twelfth lens element L12 having positive power, a thirteenth lens element L13 having positive power, and a fourteenth lens element L14 having positive power.

[0105] The fifth lens group G5 is composed of, in order from the object side to the image side, a fifteenth lens element L15 having positive power and a sixteenth lens element L16 having negative power. The fifteenth lens element L15 and the sixteenth lens element L16 are a cemented lens bonded together with an adhesive or the like.

[0106] The sixth lens group G6 is composed of, in order from the object side to the image side, a seventeenth lens element L17 having negative power and an eighteenth lens element L18 having positive power.

[0107] Each lens element will now be described.

[0108] The lens elements in the first lens group G1 will be described. The first lens element L1 is a meniscus lens with a convex surface facing the object side. The second lens element L2 is a biconvex lens. The third lens element L3 is a meniscus lens with a convex surface facing the object side.

[0109] The lens elements in the second lens group G2 will be described. The fourth lens element L4 is a meniscus lens having a convex surface facing the object side. The fifth lens element L5 is a biconcave lens. The sixth lens element L6 is a biconvex lens. The seventh lens element L7 is a biconcave lens.

[0110] The lens elements in the third lens group G3 will be described. The eighth lens element L8 is a biconvex lens. The ninth lens element L9 is a meniscus lens having a convex surface facing the object side. The tenth lens element L10 is a biconvex lens. The eleventh lens element L11 is a biconcave lens. Here, the eighth lens element L8 is an example of the lens element LG3F1. The eighth lens element L8 is an example of the fixed group G3Obj that does not move in a direction perpendicular to the optical axis during image stabilization compensation. The ninth lens element L9 is an example of the lens element LG3F2. The ninth lens element L9 and the tenth lens element L10 are examples of image stabilization groups that move in a direction perpendicular to the optical axis during image stabilization compensation. The eleventh lens element L11 is an example of the lens element LG3R1. The eleventh lens element L11 is an example of the fixed group G3Img that does not move in a direction perpendicular to the optical axis during image stabilization compensation.

[0111] The lens elements in the fourth lens group G4 will be described. The twelfth lens element L12 is a meniscus lens having a convex surface on the object side. The thirteenth lens element L13 is a meniscus lens having a convex surface on the image side. The fourteenth lens element L14 is a biconvex lens. The object-side and image-side surfaces of the fourteenth lens element L14 are aspherical. Here, the twelfth lens element L12 is an example of lens element LG4F1. The twelfth lens element L12 is an example of lens element LG4Fp1. The thirteenth lens element L13 is an example of lens element LG4F2.

[0112] The lens elements in the fifth lens group G5 will be described. The fifteenth lens element L15 is a biconvex lens. The sixteenth lens element L16 is a biconcave lens.

[0113] The lens elements in the sixth lens group G6 will be described. The seventeenth lens element L17 is a meniscus lens having a convex surface facing the image side. The eighteenth lens element L18 is a biconvex lens.

[0114] In the imaging optical system according to Embodiment 5, when zooming from the wide-angle end to the telephoto end during imaging, the first lens group G1, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 move toward the object side with respect to the image plane S. During zooming, each lens group moves along the optical axis so that the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, the distance between the third lens group G3 and the fourth lens group G4 decreases, the distance between the fourth lens group G4 and the fifth lens group G5 increases, and the distance between the fifth lens group G5 and the sixth lens group G6 increases.

[0115] In the imaging optical system according to the fifth embodiment, the fifth lens group G5 moves toward the image side along the optical axis during focusing from an infinite object point focused state to a close object focused state.

[0116] The ninth lens element L9 and the tenth lens element L10 (image stabilization group) in the third lens group G3 move in a direction perpendicular to the optical axis to optically correct image blur. These image blur correction lens elements enable the imaging optical system to correct image point movement caused by vibration of the entire system. In other words, the imaging optical system can optically correct image blur caused by hand shake, vibration, etc.

[0117] (Other embodiments) As described above, the first to fifth embodiments have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to these, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate.

[0118] Although the imaging optical systems according to the first to fifth embodiments have been described above as examples in which the entire zoom range from the wide-angle end to the telephoto end is used, it is not necessary to use the entire zoom range. For example, a range in which optical performance is ensured may be selected according to a desired zoom range and used as an imaging optical system. In other words, it may be used as an imaging optical system with a lower magnification than the imaging optical systems described below in Numerical Examples 1 to 5 corresponding to the first to fifth embodiments. Furthermore, a focal length in which optical performance is ensured according to a desired zoom position may be selected and used as a single focal length lens system.

[0119] Furthermore, the number of lens groups and the number of lens elements in each lens group are substantial, and lenses with substantially no power may be added.

[0120] In addition, image blur correction is performed by moving the image blur correction lens element in a direction perpendicular to the optical axis, but it is possible to correct image blur by moving the lens element in a way that includes a vertical component. For example, if a more complex lens barrel structure is allowed, image blur correction may be performed by rotating the image blur correction lens element so that the center of rotation is on the optical axis.

[0121] (Conditions and effects, etc.) Below, we will explain conditions that can be satisfied by the imaging optical systems according to, for example, Embodiments 1 to 5. Note that, although multiple possible conditions are defined for the imaging optical systems according to Embodiments 1 to 5, the most effective imaging optical system configuration is one that satisfies all of these multiple conditions. However, it is also possible to obtain imaging optical systems that achieve the respective corresponding effects by satisfying individual conditions.

[0122] The imaging optical systems according to the first to fifth embodiments each include, in order from the object side to the image side, a first lens group having positive power, a second lens group having negative power, a third lens group having positive power, a fourth lens group having positive power, a fifth lens group having negative power, and a sixth lens group having power. During zooming, at least the first lens group, the second lens group, the third lens group, the fourth lens group, the fifth lens group, and the sixth lens group move in the optical axis direction, thereby changing the spacing between the lens groups. This is the basic configuration.

[0123] The basic configuration of the imaging optical system is ideal for miniaturizing the zoom lens. This allows the various aberrations that occur in each lens group to be canceled out during zooming, providing an imaging optical system in which various aberrations are well corrected throughout the entire zoom range.

[0124] Furthermore, for example, in an imaging optical system, it is desirable that the third lens group G3 includes an image stabilization group consisting of a plurality of lens elements that moves in a direction perpendicular to the optical axis during image stabilization correction, and a fixed group G3Obj that is located on the object side of the image stabilization group and consists of one or more lens elements and does not move in a direction perpendicular to the optical axis, and that the following condition (1) is satisfied:

[0125] 0.06 < Th_IS_Obj / Th_G3 < 0.50 ···(1) where: Th_IS_Obj: the air gap on the optical axis between the vibration isolation group and the fixed group G3Obj, Th_G3: thickness of the third lens group G3 on the optical axis, is.

[0126] Condition (1) is a condition for specifying the ratio of the air gap on the optical axis between the vibration isolation group and the fixed group G3Obj to the thickness on the optical axis of the third lens group G3 (the thickness on the optical axis from the object-side surface of the lens element closest to the object among the lens elements constituting the third lens group G3 to the image-side surface of the lens element closest to the image among the lens elements constituting the third lens group G3).

[0127] If the lower limit of condition (1) is not met, spherical aberration will be excessive (positive in the spherical aberration diagram described later) throughout the entire zoom range, and the image plane will be excessively undercorrected (negative in the spherical aberration diagram described later) throughout the entire zoom range, which is undesirable.

[0128] Conversely, if the upper limit of condition (1) is exceeded, spherical aberration will be under-corrected throughout the entire zoom range, and the image plane will be over-corrected throughout the entire zoom range, which is undesirable.

[0129] Preferably, the above-mentioned effects can be further enhanced by satisfying either one or both of the following conditions (1a) and (1b):

[0130] 0.08 < Th_IS_Obj / Th_G3 ···(1a) Th_IS_Obj / Th_G3 < 0.30 ···(1b) More preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (1c) and (1d):

[0131] 0.10 < Th_IS_Obj / Th_G3 ···(1c) Th_IS_Obj / Th_G3 < 0.25 ···(1d) More preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (1e) and (1f):

[0132] 0.12 < Th_IS_Obj / Th_G3 ···(1e) Th_IS_Obj / Th_G3 < 0.20 ···(1f) Furthermore, for example, in the imaging optical system, it is desirable that the fourth lens group G4 has at least two lens elements and satisfies the following condition (2).

[0133] 0.05 < Th_G4_Air / Th_G4 < 0.80 ···(2) where: Th_G4_Air: the maximum air spacing between adjacent lens elements constituting the fourth lens group G4, Th_G4: the thickness of the fourth lens group G4 on the optical axis, is.

[0134] Condition (2) is a condition for defining the ratio of the maximum value of the air gap between adjacent lens elements that make up the fourth lens group G4 to the thickness of the fourth lens group G4 on the optical axis.

[0135] If the lower limit of condition (2) is not met, spherical aberration will be excessively excessive (positive in the spherical aberration diagram described later) on the telephoto side, and the image plane will be excessively excessively excessively excessively excessively excessively excessive (negative in the spherical aberration diagram described later) on the telephoto side, which is undesirable.

[0136] Conversely, if the upper limit of condition (2) is exceeded, spherical aberration will be under-corrected at the telephoto end, and the image plane will be over-corrected at the telephoto end, which is undesirable.

[0137] Preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (2a) and (2b).

[0138] 0.075 < Th_G4_Air / Th_G4 ···(2a) Th_G4_Air / Th_G4 < 0.700 ···(2b) More preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (2c) and (2d):

[0139] 0.100 < Th_G4_Air / Th_G4 ···(2c) Th_G4_Air / Th_G4 < 0.600 ···(2d) More preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (2e) and (2f):

[0140] 0.150 < Th_G4_Air / Th_G4 ···(2e) Th_G4_Air / Th_G4 < 0.500 ···(2f) Preferably, the above-mentioned effects can be further enhanced by satisfying either one or both of the following conditions (2g) and (2h):

[0141] 0.190 < Th_G4_Air / Th_G4 ···(2g) Th_G4_Air / Th_G4 < 0.400 ···(2h) Furthermore, for example, it is desirable for the imaging optical system to include an image stabilization group consisting of a plurality of lens elements that move in a direction perpendicular to the optical axis during image stabilization correction, a fixed group G3Obj that is located on the object side of the image stabilization group and consists of one or more lens elements and does not move in a direction perpendicular to the optical axis, and a fixed group G3Img that is located on the image side of the image stabilization group and consists of one or more lens elements and does not move in a direction perpendicular to the optical axis.

[0142] This makes it possible to suppress movement of the vibration reduction group during vibration reduction compensation, allowing for good aberration correction even if the vibration reduction group moves in a direction perpendicular to the optical axis.

[0143] Furthermore, in an imaging optical system, for example, it is desirable that the object side surface of the lens element LG3R1, which is the negative lens element constituting the third lens group G3 and is closest to the image side, has a convex shape facing the image side.

[0144] This allows for excellent correction of spherical aberration occurring in the third lens group, which has positive power, over the entire zoom range.

[0145] Furthermore, for example, in an imaging optical system, it is desirable that the third lens group G3 include an image stabilization group consisting of a plurality of lens elements that moves in a direction perpendicular to the optical axis, and a fixed group G3Img that is located on the image side of the image stabilization group and consists of one or more lens elements and does not move in a direction perpendicular to the optical axis, and that the following condition (3) is satisfied:

[0146] 0.05 < Th_IS_Img / Th_G3 < 0.80 ···(3) where: Th_IS_Img: Air gap on the optical axis between the vibration isolation group and the fixed group G3Img, Th_G3: thickness of the third lens group G3 on the optical axis, is.

[0147] Condition (3) is a condition for specifying the ratio of the air gap on the optical axis between the vibration reduction group and the fixed group G3Img to the thickness on the optical axis of the third lens group G3 (the thickness on the optical axis from the object-side surface of the lens element closest to the object among the lens elements constituting the third lens group G3 to the image-side surface of the lens element closest to the image among the lens elements constituting the third lens group G3).

[0148] If the lower limit of condition (3) is not reached, spherical aberration will be too great (plus in the spherical aberration diagrams described later) throughout the entire zoom range, which is not desirable.

[0149] Conversely, exceeding the upper limit of condition (3) is undesirable because spherical aberration will be significantly undercorrected (negative in the spherical aberration diagram described later) across the entire zoom range.

[0150] Preferably, the above-mentioned effects can be further enhanced by satisfying either one or both of the following conditions (3a) and (3b):

[0151] 0.075 < Th_IS_Img / Th_G3 ···(3a) Th_IS_Img / Th_G3 < 0.400 ···(3b) More preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (3c) and (3d):

[0152] 0.120 < Th_IS_Img / Th_G3 ···(3c) Th_IS_Img / Th_G3 < 0.200 ···(3d) Furthermore, for example, it is desirable that the imaging optical system satisfy the following condition (4):

[0153] 0.0 < (R2_LG3F1+R1_LG3F2) / (R2_LG3F1-R1_LG3F2) < 1.0 ···(4) where: R2_LG3F1: radius of curvature of the image-side surface of the lens element LG3F1 located closest to the object in the third lens group G3, R1_LG3F2: radius of curvature of the object-side surface of the lens element LG3F2 adjacent to the image side of the lens element LG3F1, is.

[0154] Condition (4) is a condition for setting forth the ratio between the radius of curvature of the image side surface of the lens element LG3F1, which is closest to the object in the third lens group G3, and the radius of curvature of the object side surface of the lens element LG3F2, which is adjacent to and on the image side of the lens element LG3F1.

[0155] If the lower limit of condition (4) is not met, spherical aberration will be excessive (positive in the spherical aberration diagrams described later) on the telephoto side, and the image plane will be excessively excessive (positive in the astigmatism diagrams described later) across the entire zoom range, which is undesirable.

[0156] Conversely, exceeding the upper limit of condition (4) causes spherical aberration to be under-corrected at the telephoto end (negative in the spherical aberration diagrams described later), and also causes the image plane to be excessively under-corrected (negative in the astigmatism diagrams described later) throughout the entire zoom range, which is undesirable.

[0157] Preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (4a) and (4b):

[0158] (R2_LG3F1+R1_LG3F2) / (R2_LG3F1-R1_LG3F2)< 0.97 ···(4a) 0.65 < (R2_LG3F1+R1_LG3F2) / (R2_LG3F1-R1_LG3F2) ···(4b) More preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (4c) and (4d):

[0159] (R2_LG3F1+R1_LG3F2) / (R2_LG3F1-R1_LG3F2)< 0.95 ···(4c) 0.80 < (R2_LG3F1+R1_LG3F2) / (R2_LG3F1-R1_LG3F2) ···(4d) Furthermore, in an imaging optical system, for example, it is desirable that the image side surface of the positive lens element LG4Fp1, which is located closest to the object side in the fourth lens group G4, has a convex shape facing the object side.

[0160] This allows the flatness of the image surface S to be corrected well over the entire zoom range.

[0161] Furthermore, for example, it is desirable that the imaging optical system satisfy the following condition (5):

[0162] -10.0 < (R2_LG4F1+R1_LG4F2) / (R2_LG4F1-R1_LG4F2) < 1.0 ···(5) where: R2_LG4F1: radius of curvature of the image-side surface of the lens element LG4F1 located closest to the object in the fourth lens group G4, R1_LG4F2: radius of curvature of the object-side surface of the lens element LG4F2 adjacent to the image side of the lens element LG4F1, is.

[0163] Condition (5) is a condition for setting forth the ratio between the radius of curvature of the image side surface of the lens element LG4F1, which is closest to the object in the fourth lens group G4, and the radius of curvature of the object side surface of the lens element LG4F2, which is adjacent to the lens element LG4F1 on the image side.

[0164] If the lower limit of condition (5) is not reached, the image plane will be too under-biased (negative in the astigmatism diagram to be described later) throughout the entire zoom range, which is not desirable.

[0165] Conversely, exceeding the upper limit of condition (5) is undesirable because the image plane will be excessively inclined toward the over side (plus side in the astigmatism diagrams described later) throughout the entire zoom range.

[0166] Preferably, the above-mentioned effects can be further enhanced by satisfying either one or both of the following conditions (5a) and (5b):

[0167] (R2_LG4F1+R1_LG4F2) / (R2_LG4F1-R1_LG4F2) < 0.75 ···(5a) ―8.0 < (R2_LG4F1+R1_LG4F2) / (R2_LG4F1-R1_LG4F2) ···(5b) More preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (5c) and (5d):

[0168] (R2_LG4F1+R1_LG4F2) / (R2_LG4F1-R1_LG4F2) < 0.50 ···(5c) ―6.0 < (R2_LG4F1+R1_LG4F2) / (R2_LG4F1-R1_LG4F2) ···(5d) Furthermore, for example, it is desirable that the imaging optical system satisfy the following condition (6):

[0169] nd_LG4Fp1 < 1.6 (6) where: nd_LG4Fp1: the refractive index of the positive lens element LG4Fp1 located closest to the object in the fourth lens group G4, is.

[0170] Condition (6) sets forth the refractive index of the positive lens element LG4Fp1 located closest to the object in the fourth lens group G4.

[0171] If the upper limit of the condition (6) is exceeded, the spherical aberration will be excessively excessive (positive in the astigmatism diagrams described later) throughout the entire zoom range, which is undesirable.

[0172] Preferably, the above effect can be further enhanced by satisfying the following condition (6a):

[0173] nd_LG4Fp1 < 1.55 (6a) It is more preferable to satisfy the following condition (6b):

[0174] 1.40 < nd_LG4Fp1 ···(6b) If the lower limit of condition (6b) is exceeded, there is a risk that the spherical aberration will become too under (negative in the astigmatism diagram to be described later).

[0175] Also, for example, in an imaging optical system, it is desirable to configure the fifth lens group G5 to move toward the image side when focusing from an object focused at infinity to a close object.

[0176] This ensures good focusing performance during focusing.

[0177] Furthermore, for example, in an imaging optical system, it is desirable to satisfy the following condition (7):

[0178] 0.1 < ThwG5_G6 / fw < 0.8 (7) where: ThwG5_G6: the distance on the optical axis between the fifth lens group G5 and the sixth lens group G6 at the wide-angle end, fw: focal length at the wide-angle end, is.

[0179] Condition (7) sets forth the ratio between the axial distance between the fifth lens group G5 and the sixth lens group G6 at the wide-angle end and the focal length at the wide-angle end.

[0180] If the lower limit of condition (7) is not met, the amount of movement toward the image side becomes small when focusing from an object focused at infinity to a nearby object, which is undesirable because it reduces the focusing accuracy.

[0181] Conversely, exceeding the upper limit of condition (7) is undesirable because the amount of movement toward the image side becomes too large when focusing from an object focused at infinity to a close object, resulting in a long overall optical length.

[0182] Preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (7a) and (7b):

[0183] 0.20 < ThwG5_G6 / fw ···(7a) ThwG5_G6 / fw < 0.70 ···(7b) More preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (7c) and (7d):

[0184] 0.32 < ThwG5_G6 / fw ···(7c) ThwG5_G6 / fw < 0.60 ···(7d) Furthermore, for example, in an imaging optical system, it is desirable to satisfy the following condition (8):

[0185] 0.2 < fG1 / fT < 1.0 (8) where: fG1: focal length of the first lens group G1, fT: focal length at the telephoto end, is.

[0186] Condition (8) sets forth the ratio between the focal length of first lens group G1 and the focal length at the telephoto end.

[0187] If the lower limit of condition (8) is not reached, the focal length of the first lens group G1 becomes too short, which is undesirable because it becomes difficult to increase the focal length of the optical system at the telephoto end.

[0188] Conversely, if the upper limit of condition (8) is exceeded, the focal length of the first lens group G1 becomes too long, which is undesirable because the amount of movement of the first lens group G1 during zooming becomes too large.

[0189] Preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (8a) and (8b):

[0190] 0.25 < fG1 / fT (8a) fG1 / fT < 0.80 (8b) More preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (8c) and (8d):

[0191] 0.30 < fG1 / fT (8c) fG1 / fT < 0.50 (8d) Furthermore, for example, in an imaging optical system, it is desirable to satisfy the following condition (9):

[0192] -2.5 < fG5 / fW < -1.0 (9) where: fG5: focal length of the fifth lens group G5, fW: focal length at the wide-angle end, is.

[0193] Condition (9) sets forth the ratio of the focal length of the fifth lens group G5 to the focal length at the wide-angle end.

[0194] If the lower limit of condition (9) is not reached, the focal length of the fifth lens group G5 becomes too short, which is undesirable because it becomes difficult to suppress fluctuations in aberrations from the wide-angle end to the telephoto end during zooming.

[0195] Conversely, if the upper limit of condition (9) is exceeded, the focal length of the fifth lens group G5 becomes too long, which is undesirable because the amount of movement required during focusing becomes too large.

[0196] Preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (9a) and (9b):

[0197] -1.90 < fG5 / fW (9a) fG5 / fW < -1.50 (9b) More preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (9c) and (9d):

[0198] -2.25 < fG5 / fW (9c) fG5 / fW < -1.80 (9d) Furthermore, for example, in an imaging optical system, it is desirable to satisfy the following condition (10):

[0199] 0.5 < Th_G2_G3 / Yw < 3.0 (10) where: Th_G2_G3: Air gap on the optical axis between the second lens group G2 and the third lens group G3 at the wide-angle end, Yw: Maximum image height at the wide-angle end, is.

[0200] Condition (10) is a condition for specifying the ratio of the air gap on the optical axis between the second lens group G2 and the third lens group G3 at the wide-angle end (the thickness on the optical axis from the image-side surface of the lens element closest to the image among the lens elements constituting the second lens group G2 to the object-side surface of the lens element closest to the object among the lens elements constituting the third lens group G3) to the maximum image height at the wide-angle end. Note that in a camera system or an imaging device, the maximum image height at the wide-angle end can be regarded as the length of the diagonal on the image sensor of the image formation position corresponding to the angle of view at the wide-angle end.

[0201] If the lower limit of condition (10) is not met, the change in the spacing during zooming becomes too small, which is undesirable because it makes it difficult to correct aberrations during zooming.

[0202] Conversely, if the upper limit of condition (10) is exceeded, the change in the spacing during zooming becomes too large, which makes it difficult to arrange the mechanism for moving the second lens group G2 or the third lens group G3, which is undesirable.

[0203] Preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (10a) and (10b):

[0204] 0.75 < Th_G2_G3 / Yw (10a) Th_G2_G3 / Yw < 2.00 ···(10b) More preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (10c) and (10d):

[0205] 0.85 < Th_G2_G3 / Yw (10c) Th_G2_G3 / Yw < 1.00 ···(10d) Furthermore, for example, it is desirable that the imaging optical system satisfy the following condition (11):

[0206] 0.3 < BFw / Yw < 3.0 (11) where: BFw: Back focus at the wide-angle end Yw: Maximum image height at the wide-angle end, is.

[0207] Condition (11) is a condition for specifying the ratio of the back focus at the wide-angle end (the distance on the optical axis from the lens element closest to the image side at the wide-angle end to the image plane S) to the maximum image height at the wide-angle end. Note that in a camera system or an imaging device, the maximum image height at the wide-angle end can be regarded as the length of the diagonal on the image sensor of the image formation position corresponding to the angle of view at the wide-angle end.

[0208] If the lower limit of the condition (11) is not reached, the back focal length becomes narrow, which makes it difficult to arrange the members that fasten the imaging optical system and the imaging element disposed on the image plane S, which is undesirable.

[0209] Conversely, if the upper limit of the condition (11) is exceeded, the back focal length becomes too wide, which is undesirable because the imaging optical system becomes too large.

[0210] Preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (11a) and (11b).

[0211] 0.40 < BFw / Yw (11a) BFw / Yw < 2.40 (11b) More preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (11c) and (11d):

[0212] 0.50 < BFw / Yw (11c) BFw / Yw < 1.20 (11d) More preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (11e) and (11f):

[0213] 0.75 < BFw / Yw (11e) BFw / Yw < 0.90 (11f) Furthermore, for example, in an imaging optical system, it is desirable to satisfy the following condition (12):

[0214] 2.0 < TTLw / Yw < 10.0 (12) where: TTLw: Optical length at the wide-angle end, Yw: Maximum image height at the wide-angle end, is.

[0215] Condition (12) specifies the ratio of the total optical length at the wide-angle end (the distance from the object-side surface of the lens element closest to the object to the image plane S) to the maximum image height at the wide-angle end. In a camera system or an imaging device, the maximum image height at the wide-angle end can be regarded as the diagonal length on the image sensor of the image formation position corresponding to the angle of view at the wide-angle end.

[0216] If the lower limit of condition (12) is not reached, the total optical length at the wide-angle end becomes too short, which is undesirable because it becomes difficult to effectively correct aberrations.

[0217] Conversely, if the upper limit of the condition (12) is exceeded, the total optical length at the wide-angle end becomes too long, which is not preferable.

[0218] Preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (12a) and (12b):

[0219] 3.0 < TTLw / Yw (12a) TTLw / Yw < 8.0 (12b) More preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (12c) and (12d):

[0220] 4.0 < TTLw / Yw (12c) TTLw / Yw < 5.5 (12d) Furthermore, for example, in an imaging optical system, it is desirable to satisfy the following condition (13):

[0221] 0.1 < (TTLt−TTLw) / TTLt < 0.5 ···(13) where: TTLt: Total optical length at the telephoto end, TTLw: Optical length at the wide-angle end, is.

[0222] Condition (13) sets forth the ratio of the difference between the total optical length at the telephoto end and the total optical length at the wide-angle end to the maximum image height at the telephoto end. The total optical length is the distance from the object-side surface of the lens element closest to the object to the image plane S.

[0223] If the lower limit of condition (13) is not met, the change in the total optical length during zooming becomes too small, making it difficult to ensure a sufficient zoom ratio, which is undesirable.

[0224] Conversely, if the upper limit of condition (13) is exceeded, the change in the total optical length during zooming becomes too large, which is undesirable because it makes it difficult to arrange the mechanism for moving the lens groups.

[0225] Preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (13a) and (13b):

[0226] 0.20 < (TTLt−TTLw) / TTLt ···(13a) (TTLt−TTLw) / TTLt < 0.40 ···(13b) More preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (13c) and (13d):

[0227] 0.25 < (TTLt−TTLw) / TTLt ···(13c) (TTLt−TTLw) / TTLt < 0.30 ···(13d) Furthermore, for example, in an imaging optical system, it is desirable that the third lens group G3 includes an image stabilization group consisting of a plurality of lens elements that move in a direction perpendicular to the optical axis during image stabilization compensation, and a negative lens element LG3n that does not move in a direction perpendicular to the optical axis during image stabilization compensation.

[0228] This makes it possible to suppress movement of the vibration reduction group during vibration reduction compensation, allowing for good aberration correction even if the vibration reduction group moves in a direction perpendicular to the optical axis.

[0229] Also, in an imaging optical system, for example, it is desirable that the third lens group G3 be made up of at least four lens elements, and at most six lens elements.

[0230] This allows for good correction of aberrations caused by the vibration reduction group, even when the vibration reduction group moves in a direction perpendicular to the optical axis.

[0231] Furthermore, for example, it is desirable that the imaging optical system includes a vibration reduction group consisting of a plurality of lens elements that move in a direction perpendicular to the optical axis during vibration reduction compensation, and a fixed group G3Obj that is located on the object side of the vibration reduction group and consists of one or more lens elements and does not move in a direction perpendicular to the optical axis, and that it satisfies the following condition (14):

[0232] 0.01 < Th_IS_Obj / Yw < 1.00 ···(14) where: Th_IS_Obj: the air gap on the optical axis between the vibration isolation group and the fixed group G3Obj, Yw: Maximum image height at the wide-angle end, is.

[0233] Condition (14) is a condition for specifying the ratio of the air gap on the optical axis between the image stabilization group and the fixed group G3Obj to the maximum image height at the wide-angle end. Note that in a camera system or an imaging device, the maximum image height at the wide-angle end can be regarded as the length of the diagonal on the image sensor of the image formation position corresponding to the angle of view at the wide-angle end.

[0234] If the lower limit of condition (14) is not reached, spherical aberration will be excessively large (plus in the astigmatism diagrams described later) throughout the entire zoom range, which is not desirable.

[0235] Conversely, exceeding the upper limit of condition (14) is undesirable because spherical aberration will be too significantly under-corrected (negative in the astigmatism diagrams described later) throughout the entire zoom range.

[0236] Preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (14a) and (14b):

[0237] 0.05 < Th_IS_Obj / Yw ···(14a) Th_IS_Obj / Yw < 0.75 ···(14b) More preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (14c) and (14d):

[0238] 0.08 < Th_IS_Obj / Yw ···(14c) Th_IS_Obj / Yw < 0.25 ···(14d) Furthermore, for example, it is desirable that the imaging optical system includes an image stabilization group consisting of a plurality of lens elements that moves in a direction perpendicular to the optical axis during image stabilization correction, and a fixed group G3Obj that is located on the object side of the image stabilization group, consists of one or more lens elements, and does not move in a direction perpendicular to the optical axis, and that it satisfies the following condition (15):

[0239] 0.02 < Th_IS_Img / Yw < 1.00 ···(15) where: Th_IS_Img: Air gap on the optical axis between the vibration isolation group and the fixed group G3Img, Yw: Maximum image height at the wide-angle end, is.

[0240] Condition (15) specifies the ratio of the air gap on the optical axis between the image stabilization group and the fixed group G3Img to the maximum image height at the wide-angle end. Note that in a camera system or an imaging apparatus, the maximum image height at the wide-angle end can be regarded as the length of the diagonal on the image sensor of the image formation position corresponding to the angle of view at the wide-angle end.

[0241] If the lower limit of condition (15) is not reached, spherical aberration will be too great (plus in the astigmatism diagrams described later) over the entire zoom range, which is not desirable.

[0242] Conversely, exceeding the upper limit of condition (15) is undesirable because spherical aberration will be too significantly under-corrected (negative in the astigmatism diagrams described later) throughout the entire zoom range.

[0243] Preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (15a) and (15b):

[0244] 0.05 < Th_IS_Img / Yw ···(15a) Th_IS_Img / Yw < 0.50 ···(15b) More preferably, the above-mentioned effect can be further enhanced by satisfying either one or both of the following conditions (15c) and (15d):

[0245] 0.08 < Th_IS_Img / Yw ···(15c) Th_IS_Img / Yw < 0.15 ···(15d) Furthermore, in an imaging optical system, for example, it is desirable that the image side surface of the positive lens element LG4F1, which is located closest to the object side in the fourth lens group G4, has a convex shape facing the object side.

[0246] This makes it possible to cancel out spherical aberration that occurs in the under-focus range, thereby enabling good correction of spherical aberration throughout the entire zoom range.

[0247] In addition, in the example in which the aperture diaphragm A is provided in the third lens group G3, the aperture diaphragm A is located closest to the object in the third lens group G3 and moves integrally with the third lens group G3 during zooming. However, the aperture diaphragm A may be located closest to the image in the third lens group G3 and move integrally with the third lens group G3 during zooming. Alternatively, the aperture diaphragm A may be located closest to the image in the second lens group G2 and move integrally with the second lens group G2 during zooming. Alternatively, the aperture diaphragm A may be provided between the second lens group G2 and the third lens group G3 and move independently of the second lens group G2 and the third lens group G3 during zooming.

[0248] However, by providing aperture stop A closest to the object side of third lens group G3 and moving together with third lens group G3 during zooming, it is possible to prevent the effective diameter of the front lens (first lens element L1) from becoming too large.

[0249] Furthermore, an actuator or the like that controls the aperture diameter of aperture diaphragm A must be placed on the object side of the imaging optical system, which shifts the center of gravity balance toward the object side; however, by positioning aperture diaphragm A closest to the image side of second lens group G2, and moving it together with second lens group G2 during zooming, it is possible to prevent the effective diameter of the front lens (first lens element L1) from becoming too large.

[0250] Alternatively, if the complexity of the cam mechanism for zooming is tolerated, the aperture stop A can be moved independently of the second lens group G2 and the third lens group G3, preventing the effective diameter of the front lens (first lens element L1) from becoming too large.

[0251] (Schematic configuration of an imaging device to which the first embodiment is applied) 6 shows a schematic configuration of an imaging device to which the imaging optical system according to Embodiment 1 is applied. Note that the imaging optical systems according to Embodiments 2 to 5 can also be applied to imaging devices.

[0252] The imaging device 100 is made up of a housing 104, an imaging element 102, and an imaging optical system 101 according to Embodiment 1. A specific example of the imaging device 100 is a digital camera.

[0253] The lens barrel 302 holds the lens groups of the imaging optical system 101 and the aperture stop A.

[0254] The image pickup element 102 is disposed at the position of the image plane S in the image pickup optical system according to the first embodiment.

[0255] The imaging optical system 101 is configured so that the lens frames included in the lens barrel 302 are attached or engaged with each other so that the first lens group G1, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 move during zooming.

[0256] The imaging optical system 101 is configured so that the lens frames included in the lens barrel 302 are attached or engaged with each other so that the lens frames holding the first lens group G1, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 can be moved during zooming.

[0257] This makes it possible to realize an imaging device that can effectively correct various aberrations.

[0258] Although the imaging optical system according to the first embodiment described above is applied to a digital camera, it can also be applied to a surveillance camera, a smartphone, and the like.

[0259] (Schematic configuration of a camera system to which the first embodiment is applied) 7 shows a schematic configuration of a camera system to which the imaging optical system according to Embodiment 1 is applied. Note that the imaging optical systems according to Embodiments 2 to 5 can also be applied to a camera system.

[0260] The camera system 200 includes a camera body 201 and an interchangeable lens device 300 that is detachably connected to the camera body 201 .

[0261] The camera body 201 includes an image sensor 202 that receives an optical image formed by the imaging optical system of the interchangeable lens device 300 and converts it into an electrical image signal, a monitor 203 that displays the image signal converted by the image sensor 202, a memory (not shown) that stores the image signal, a camera mount unit 204, and a viewfinder 205.

[0262] The imaging optical system of the interchangeable lens device 300 is the imaging optical system according to the first embodiment.

[0263] The lens barrel 302 holds each lens group of the imaging optical system 301 and an aperture stop A, and includes a lens mount section 304 that is connected to the camera mount section 204 of the camera body 201 .

[0264] The camera mount unit 204 and the lens mount unit 304 not only provide a physical connection, but also function as an interface that electrically connects a controller (not shown) in the camera body 201 and a controller (not shown) in the interchangeable lens device 300, enabling the exchange of signals between them.

[0265] The imaging optical system 301 is configured so that the lens frames included in the lens barrel 302 are attached or engaged with each other so that the lens frames holding the first lens group G1, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 can be moved during zooming.

[0266] The imaging optical system 301 is composed of each lens group held by a lens barrel 302 and a camera body 201. The imaging optical system 301 is equipped with an actuator and a lens frame controlled by a controller within the interchangeable lens device 300 so that the fifth lens group G5 moves during focusing.

[0267] (Numerical example) Numerical examples that specifically implement the imaging optical systems according to Embodiments 1 to 5 will be described below. In each numerical example, all lengths in the tables are in "mm" and all angles of view are in "°". In each numerical example, r is the radius of curvature, d is the surface spacing, nd is the refractive index for the d-line, and νd (also written as vd) is the Abbe number for the d-line. In each numerical example, surfaces marked with an * are aspherical, and the aspherical shape is defined by the following equation:

[0268]

number

[0269] where: Z: The distance from a point on the aspheric surface at a height h from the optical axis to the tangent plane of the vertex of the aspheric surface. h: height from the optical axis, r: apex curvature radius, κ: conic constant, An: n-th order aspheric coefficient is.

[0270] 1B, 2B, 3B, 4B, and 5B are longitudinal aberration diagrams of the imaging optical systems according to the first to fifth embodiments in the infinity focused state.

[0271] In each longitudinal aberration diagram, (a) shows the aberrations at the wide-angle end, (b) shows the aberrations at the intermediate position, and (c) shows the aberrations at the telephoto end. Each longitudinal aberration diagram, from left to right, shows spherical aberration (SA (mm)), astigmatism (AST (mm)), and distortion (DIS (%)). In each spherical aberration diagram, the vertical axis represents the F-number (denoted by F in the diagram), with the solid line representing the d-line, the short-dashed line representing the F-line, and the long-dashed line representing the C-line characteristics. In each astigmatism diagram, the vertical axis represents the image height (denoted by H in the diagram), with the solid line representing the sagittal plane (denoted by s) and the dashed line representing the meridional plane (denoted by m). In each distortion diagram, the vertical axis represents the image height (denoted by H in the diagram).

[0272] 1C, 2C, 3C, 4C, and 5C are lateral aberration diagrams at the telephoto end of the imaging optical systems according to the first to fifth embodiments, respectively.

[0273] In each lateral aberration diagram, the top three aberration diagrams correspond to the basic state at the telephoto end with no image blur compensation, and the bottom three aberration diagrams correspond to the image blur compensation state at the telephoto end with the image blur compensation lens group moved a specified amount in a direction perpendicular to the optical axis. Of the lateral aberration diagrams for the basic state, the top diagram corresponds to the lateral aberration at an image point at 70% of the maximum image height, the middle diagram corresponds to the lateral aberration at an on-axis image point, and the bottom diagram corresponds to the lateral aberration at an image point at -70% of the maximum image height. Of the lateral aberration diagrams for the image blur compensation state, the top diagram corresponds to the lateral aberration at an image point at 70% of the maximum image height, the middle diagram corresponds to the lateral aberration at an on-axis image point, and the bottom diagram corresponds to the lateral aberration at an image point at -70% of the maximum image height. In each lateral aberration diagram, the horizontal axis represents the distance from the chief ray on the pupil plane, with the solid line representing the d-line, the short-dashed line representing the F-line, and the long-dashed line representing the C-line characteristics.

[0274] In the imaging optical system of each example, the amount of movement of the image blur correction lens unit in the direction perpendicular to the optical axis in the image blur correction state at the telephoto end is as follows:

[0275] Numerical example 1: 0.340 mm Numerical Example 2 0.350 mm Numerical Example 3 0.348 mm Numerical Example 4: 0.351 mm Numerical Example 5 0.349 mm The amount of image decentering when the imaging optical system is tilted by 0.3 degrees at the telephoto end with the shooting distance at infinity is equal to the amount of image decentering when the image blur correction lens group translates by the above values ​​in a direction perpendicular to the optical axis.

[0276] As is clear from each lateral aberration diagram, the symmetry of the lateral aberration at the axial image point is good. Furthermore, when comparing the lateral aberration at the +70% image point with the lateral aberration at the -70% image point in the basic state, the degree of curvature is small in both cases, and the slopes of the aberration curves are nearly equal, indicating that decentering coma and decentering astigmatism are small. This means that sufficient imaging performance is achieved even in the image blur correction state. Furthermore, for the same image blur correction angle of the imaging optical system, the amount of translation required for image blur correction decreases as the focal length of the entire imaging optical system becomes shorter. Therefore, at any zoom position, sufficient image blur correction is possible without degrading imaging characteristics for an image blur correction angle of about 0.3 degrees.

[0277] (Numerical Example 1) The imaging optical system of Numerical Example 1 corresponds to Embodiment 1 shown in Fig. 1A. Surface data of the imaging optical system of Numerical Example 1 is shown in Table 1A, aspherical surface data is shown in Table 1B, and various data in an infinity focused state are shown in Tables 1C to 1F.

[0278] (Table 1A: Surface data) Surface number rd nd vd Effective diameter object surface ∞ 1 90.10290 1.20000 1.84666 23.8 24.773 2 59.23570 6.93240 1.49700 81.6 23.749 3 -280.94820 0.20000 23.386 4 44.38180 4.64010 1.49700 81.6 20.573 5 141.93270 Variable 20.258 6 96.78490 1.00000 1.95347 32.6 13.231 7 18.86630 5.70110 10.904 8 -38.17850 0.65900 1.59462 66.8 10.436 9 23.41150 3.68120 1.86672 19.8 9.594 10 -69.86610 1.74760 9.358 11 -29.23560 0.60000 1.88300 40.8 8.624 12 542.90170 Variable 8.369 13 (Aperture) ∞ 1.40000 7.176 14 18.33090 3.15260 1.52711 57.2 8.087 15 -378.74380 2.24620 8.070 16 18.17170 0.60000 1.95698 32.3 8.050 17 12.06780 4.65620 1.52092 60.8 7.669 18 -49.83060 1.96370 7.515 19 -22.70500 0.60000 1.99236 29.7 7.160 20 -843.60570 Variable 7.254 21 17.31530 2.29190 1.49700 81.6 7.832 22 47.62670 2.13040 7.735 23* 71.12630 3.30940 1.58699 59.5 7.622 24* -28.91280 Variable 7.707 25 216.95880 2.02110 1.94372 18.0 8.379 26 -40.67040 0.60000 1.80334 32.2 8.401 27 27.07710 Variable 8.420 28 -19.87370 1.00000 1.82868 43.1 11.234 29 -58.94070 0.50000 12.663 30 109.76350 2.96010 1.76918 34.3 14.777 31 -144.98430 Variable 32 ∞ 2.10000 1.51680 64.2 33∞1.00000 34∞BF Image plane ∞ (Table 1B: Aspheric Data) Page 23 K= 2.63837E+00, A4=-3.75089E-05, A6= 7.29717E-07, A8= 8.23449E-10 A10=9.78133E-11, A12=-5.65229E-13 Page 24 K=-4.87684E-01, A4= 4.48028E-05, A6= 7.78441E-07, A8= 3.87499E-10 A10= 1.12740E-10, A12=-3.25867E-13 (Various data when focused at infinity) (Table 1C: Various data) Zoom ratio 6.65091 Wide-angle Mid-range Telephoto Focal length 28.9887 74.7234 192.8010 F-number 4.16046 5.80386 7.38074 Angle of view 37.1877 15.4912 6.1980 Image height 21.1600 21.6300 21.6300 Lens total length 112.8021 138.1617 158.9887 BF 0.00000 0.00000 0.00000 d5 0.9677 19.9101 35.5300 d12 17.9193 9.4440 1.7944 d20 4.4987 2.4455 0.8000 d24 1.7038 2.8663 3.5734 d27 15.9632 16.1916 19.4165 d31 12.8500 28.4927 38.9884 Entrance pupil position 28.2608 72.2588 143.0679 Exit pupil position -45.4074 -59.6027 -70.4186 Front principal point position 38.7453 53.1738 -192.0587 Back principal point position 83.8134 63.4383 -33.8123 (Table 1D: Single lens data) Lens starting surface focal length 1 1 -207.9336 2 2 99.1038 3 4 127.9079 4 6 -24.7328 5 8 -24.3089 6 9 20.6097 7 11 -31.4021 8 14 33.2620 9 16 -39.4375 10 17 19.1431 11 19 -23.5211 12 21 53.4015 13 23 35.4544 14 25 36.4314 15 26 -20.1547 16 28 -36.6072 17 30 81.6285 (Table 1E: Zoom lens group data) Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 77.21746 12.97250 2.91283 7.28168 2 6 -13.77232 13.38890 3.73110 7.73141 3 13 37.13341 14.61870 -7.62613 -0.25443 4 21 22.84467 7.73170 2.99875 4.56417 5 25 -46.14273 2.62110 1.71174 2.94933 6 28 -69.55417 4.46010 -2.03613 -0.40964 (Table 1F: Zoom lens group magnification) Group Starting plane Wide angle Intermediate Telephoto 1 1 0.00000 0.00000 0.00000 2 6 -0.25958 -0.40373 -0.74472 3 13 9.68185 3.59628 2.79645 4 21 -0.07097 -0.24333 -0.36531 5 25 1.63280 1.81060 1.97146 6 28 1.28914 1.51277 1.66474 (Numerical Example 2) The imaging optical system of Numerical Example 2 corresponds to Embodiment 1 shown in Fig. 2A. Surface data of the imaging optical system of Numerical Example 2 is shown in Table 2A, aspherical surface data is shown in Table 2B, and various data in an infinity focused state are shown in Tables 2C to 2F.

[0279] (Table 2A: Surface data) Surface number rd nd vd Effective diameter object surface ∞ 1 93.38500 1.20000 1.84666 23.8 24.106 2 60.44080 6.47880 1.49700 81.6 22.821 3 -254.35560 0.20000 22.413 4 43.18570 4.24470 1.49700 81.6 18.739 5 157.09070 Variable 18.462 6 139.63390 1.00000 1.92003 35.9 13.202 7 18.94060 5.54740 10.831 8 -39.96360 0.65900 1.59341 67.0 10.393 9 23.14480 3.69620 1.86317 20.3 9.586 10 -70.87870 2.32030 9.354 11 -26.99070 0.60000 1.88296 40.8 8.267 12 1528.98670 Variable 8.043 13 (Aperture) ∞ 1.40000 7.176 14 19.79540 3.25900 1.52986 55.8 8.146 15 -105.27840 2.23430 8.149 16 18.76860 0.60000 1.96234 31.8 8.061 17 12.45390 4.44460 1.53351 54.0 7.698 18 -58.18580 1.72980 7.545 19 -24.36650 0.60000 1.97700 30.8 7.270 20 135.37870 Variable 7.358 21 19.29630 3.21910 1.49700 81.6 8.131 22 -144.37450 3.25250 8.068 23* 450.22950 1.99400 1.58699 59.5 7.682 24* -28.52620 Variable 7.719 25 -354.64850 2.09280 1.94798 19.5 8.352 26 -30.10550 0.60000 1.80449 31.4 8.400 27 32.88070 Variable 8.487 28 -22.02600 1.00000 1.79990 44.5 11.542 29 -64.36980 0.67320 12.806 30 252.42800 2.49780 1.84568 22.3 14.371 31 -113.60360 Variable 32 ∞ 2.10000 1.51680 64.2 33∞1.00000 34∞BF Image plane ∞ (Table 2B: Aspheric Data) Page 23 K=-5.00000E+00, A4=-6.80359E-05, A6= 9.24863E-07, A8=-5.33973E-09 A10=3.23148E-10, A12=-1.78860E-12 Page 24 K= 1.81265E+00, A4= 1.89226E-05, A6= 1.01029E-06, A8=-5.28472E-09 A10=3.04395E-10, A12=-1.23164E-12 (Various data when focused at infinity) (Table 2C: Various data) Zoom ratio 6.65357 Wide-angle Mid-range Telephoto Focal length 28.9794 74.7361 192.8162 F-number 4.16053 5.95443 7.38165 Angle of view 36.7545 15.4926 6.1304 Image height 20.4600 21.6300 21.6300 Lens total length 112.7930 137.6008 158.9777 BF 0.00000 0.00000 0.00000 d5 1.1516 17.8465 34.4419 d12 16.8378 8.3951 1.7654 d20 4.2308 2.2115 0.8000 d24 2.2799 4.6044 4.3321 d27 16.7837 14.4138 20.4596 d31 12.8500 31.5471 38.5534 Entrance pupil position 27.4907 64.5952 141.2994 Exit pupil position -47.5629 -63.4954 -72.2329 Front principal point position 38.8192 51.2798 -180.7116 Back principal point position 83.8136 62.8646 -33.8385 (Table 2D: Single lens data) Lens starting surface focal length 1 1 -205.7934 2 2 98.9385 3 4 118.3732 4 6 -23.9126 5 8 -24.6030 6 9 20.5882 7 11 -30.0329 8 14 31.7333 9 16 -40.3441 10 17 19.6582 11 19 -21.0969 12 21 34.4734 13 23 45.7726 14 25 34.5949 15 26 -19.4527 16 28 -42.3033 17 30 92.9322 (Table 2E: Zoom lens group data) Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 73.83046 12.12350 3.02330 7.09929 2 6 -13.14402 13.82290 3.89670 8.10468 3 13 41.22271 14.26770 -9.88613 -1.73997 4 21 21.35212 8.46560 3.21513 4.46051 5 25 -44.61667 2.69280 1.30544 2.59593 6 28 -81.62064 4.17100 -2.45525 -1.00244 (Table 2F: Zoom lens group magnification) Group Starting plane Wide angle Intermediate Telephoto 1 1 0.00000 0.00000 0.00000 2 6 -0.25969 -0.38751 -0.75873 3 13 3.43654 2.19760 2.01004 4 21 -0.20823 -0.43179 -0.52973 5 25 1.68946 1.86214 2.06594 6 28 1.25023 1.47836 1.56472 (Numerical Example 3) The imaging optical system of Numerical Example 3 corresponds to Embodiment 1 shown in Fig. 3A. Surface data of the imaging optical system of Numerical Example 3 is shown in Table 3A, aspherical surface data is shown in Table 3B, and various data in an infinity focused state are shown in Tables 3C to 3F.

[0280] (Table 3A: Surface data) Surface number rd nd vd Effective diameter object surface ∞ 1 89.39310 1.20000 1.84666 23.8 24.744 2 59.08770 7.01900 1.49700 81.6 23.412 3 -261.65280 0.20000 22.887 4 43.01610 4.49310 1.49700 81.6 20.080 5 119.92310 Variable 19.741 6 83.79430 1.00000 1.95302 32.7 13.669 7 18.79360 6.51330 11.226 8 -36.45670 0.65900 1.59342 67.0 10.442 9 23.05660 3.70870 1.86837 20.4 9.583 10 -70.68230 1.78390 9.346 11 -28.97300 0.60000 1.88294 40.8 8.597 12 767.52780 Variable 8.347 13 (Aperture) ∞ 1.40000 7.175 14 18.98150 3.15730 1.52706 57.3 8.027 15 -164.90740 1.99820 8.025 16 18.42970 0.60000 1.95402 32.6 8.006 17 12.18010 4.55670 1.52181 60.3 7.631 18 -51.19390 1.70990 7.474 19 -23.77660 0.60000 1.99578 29.5 7.152 20 -689.93870 Variable 7.228 21 20.06570 2.48940 1.49700 81.6 7.869 22 146.51020 2.99990 7.789 23* 292.70690 2.07450 1.58699 59.5 7.540 24* -27.59030 Variable 7.600 25 290.10420 2.11100 1.95145 18.7 8.370 26 -36.00030 0.60000 1.80342 32.2 8.401 27 28.04480 Variable 8.439 28 -18.84090 1.00000 1.84252 42.4 10.951 29 -57.14670 0.58670 12.440 30 122.40400 3.20170 1.74466 38.7 14.625 31 -99.94240 Variable 32 ∞ 2.10000 1.51680 64.2 33∞1.00000 34∞BF Image plane ∞ (Table 3B: Aspheric data) Page 23 K= 5.00000E+00, A4=-5.96112E-05, A6= 8.16552E-07, A8= 8.09756E-10 A10= 1.98774E-10, A12=-8.27231E-13 Page 24 K= 1.88093E+00, A4= 2.67197E-05, A6= 8.11536E-07, A8= 2.85280E-09 A10= 1.42987E-10, A12=-8.71894E-15 (Various data when focused at infinity) (Table 3C: Various data) Zoom ratio 6.65330 Wide-angle Mid-range Telephoto Focal length 28.9799 74.7535 192.8118 F-number 4.15987 5.71599 7.38089 Angle of view 36.7522 15.4855 6.2115 Image height 20.8800 21.6300 21.6300 Lens total length 112.0885 135.2097 158.9524 BF 0.00000 0.00000 0.00000 d5 0.6000 19.4360 35.6171 d12 17.7695 8.4958 1.7816 d20 4.7515 2.2708 0.8500 d24 1.7084 3.6014 2.8630 d27 15.0738 15.4479 18.2846 d31 12.8500 26.6238 40.2372 Entrance pupil position 28.2888 71.1897 146.8197 Exit pupil position -44.9962 -57.2933 -71.0917 Front principal point position 38.5930 48.3602 -183.6243 Back principal point position 83.1086 60.4561 -33.8594 (Table 3D: Single Lens Data) Lens starting surface focal length 1 1 -209.6654 2 2 97.6971 3 4 132.3948 4 6 -25.6140 5 8 -23.7034 6 9 20.3957 7 11 -31.6093 8 14 32.4892 9 16 -39.5012 10 17 19.3326 11 19 -24.7408 12 21 46.4771 13 23 43.0576 14 25 33.7670 15 26 -19.5398 16 28 -33.7648 17 30 74.3420 (Table 3E: Zoom Lens Group Data) Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 77.61111 12.91210 2.78850 7.14845 2 6 -13.87490 14.26490 4.06986 8.26886 3 13 35.90345 14.02210 -6.13051 0.40724 4 21 23.98849 7.56380 3.14279 4.29647 5 25 -47.39546 2.71100 1.70770 2.99547 6 28 -65.78898 4.78840 -2.41412 -0.76204 (Table 3F: Zoom lens group magnification) Group Starting plane Wide angle Intermediate Telephoto 1 1 0.00000 0.00000 0.00000 2 6 -0.26030 -0.40256 -0.75879 3 13 45.92215 4.44253 3.64379 4 21 -0.01490 -0.20220 -0.27093 5 25 1.59403 1.74678 1.91530 6 28 1.31552 1.52487 1.73156 (Numerical Example 4) The imaging optical system of Numerical Example 4 corresponds to Embodiment 1 shown in Fig. 4A. Surface data of the imaging optical system of Numerical Example 4 is shown in Table 4A, aspherical surface data is shown in Table 4B, and various data in an infinity focused state are shown in Tables 4C to 4F.

[0281] (Table 4A: Surface data) Surface number rd nd vd Effective diameter object surface ∞ 1 91.07200 1.20000 1.84666 23.8 23.451 2 58.45620 6.32950 1.49700 81.6 22.172 3 -230.31680 0.20000 21.667 4 41.41310 4.23200 1.49700 81.6 18.804 5 119.66320 Variable 18.488 6 93.92320 1.00000 1.95152 32.8 13.251 7 18.22590 6.01180 10.904 8 -40.06930 0.65900 1.59353 67.0 10.357 9 21.45130 3.92760 1.86886 20.9 9.577 10 -65.44920 2.14870 9.350 11 -26.64300 0.60000 1.88300 40.8 8.365 12 2000.00000 Variable 8.142 13 (Aperture) ∞ 1.40000 7.175 14 19.66100 3.09460 1.53232 54.6 8.020 15 -150.34770 2.21410 8.027 16 18.41180 0.60000 1.99890 28.9 8.022 17 12.34910 4.45180 1.53512 53.3 7.654 18 -56.62900 1.74820 7.504 19 -24.57010 0.60000 1.97345 30.6 7.211 20 121.62620 Variable 7.294 21 19.22620 2.92120 1.49700 81.6 7.868 22 -335.45030 2.68680 7.817 23* 132.83390 2.88940 1.58699 59.5 7.578 24* -29.23300 Variable 7.659 25 1125.71610 2.21030 1.94899 18.4 8.364 26 -30.82570 0.60000 1.79893 30.9 8.400 27 30.24630 Variable 8.446 28 -19.92460 1.00000 1.80520 44.2 10.719 29 -56.08430 0.50000 11.942 30 141.20860 3.34570 1.80918 33.9 13.536 31 -65.96530 Variable 13.858 32 -77.85290 0.90000 1.99402 29.6 15.706 33 -271.88690 Variable 16.116 34 ∞ 2.10000 1.51680 64.2 35∞1.00000 36∞BF Image plane ∞ (Table 4B: Aspheric data) Page 23 K= 0.00000E+00, A4=-3.45181E-05, A6= 7.54614E-07, A8= 1.49928E-09 A10=9.30690E-11, A12=-5.69505E-13 Page 24 K= 0.00000E+00, A4= 4.14702E-05, A6= 8.08831E-07, A8= 1.34409E-09 A10= 1.01596E-10, A12=-3.07347E-13 (Various data when focused at infinity) (Table 4C: Various data) Zoom ratio 6.66602 Wide-angle Mid-range Telephoto Focal length 28.9279 74.7073 192.8342 F-number 4.16045 5.74141 7.38120 Angle of view 36.7900 15.4990 6.1612 Image height 20.6900 21.6300 21.6300 Lens total length 112.8085 136.0732 158.9817 BF 0.00000 0.00000 0.00000 d5 0.6000 18.2707 34.7853 d12 17.1989 7.7230 1.7618 d20 4.0249 1.9070 0.8500 d24 2.2953 3.9935 2.6926 d27 14.4230 13.1757 17.7055 d31 0.8329 16.5345 12.9388 d33 12.8500 13.8927 27.6909 Entrance pupil position 26.9806 65.8742 143.5504 Exit pupil position -44.7949 -51.8512 -64.6710 Front principal point position 37.2326 32.9545 -238.7267 Back principal point position 83.8806 61.3660 -33.8525 (Table 4D: Single Lens Data) Lens starting surface focal length 1 1 -196.0942 2 2 94.4969 3 4 125.1788 4 6 -23.9205 5 8 -23.4464 6 9 18.9937 7 11 -29.7725 8 14 32.8710 9 16 -39.4978 10 17 19.3818 11 19 -20.9560 12 21 36.6880 13 23 41.0898 14 25 31.6463 15 26 -19.0259 16 28 -38.8589 17 30 55.9689 18 32 -110.0009 (Table 4E: Zoom Lens Group Data) Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 74.91797 11.96150 2.67440 6.72042 2 6 -13.60299 14.34710 3.93403 8.33209 3 13 43.68476 14.10870 -10.77441 -2.46916 4 21 21.01395 8.49740 3.19484 4.70746 5 25 -48.46814 2.81030 1.60895 2.94889 6 28 -150.29826 4.84570 -7.39730 -5.95670 7 32 -110.00093 0.90000 -0.18152 0.26609 (Table 4F: Zoom lens group magnification) Group Starting plane Wide angle Intermediate Telephoto 1 1 0.00000 0.00000 0.00000 2 6 -0.26393 -0.40163 -0.78383 3 13 3.10879 2.01733 1.94873 4 21 -0.22142 -0.46586 -0.51186 5 25 1.58936 1.79134 1.95519 6 28 1.16854 1.27823 1.31643 7 32 1.14437 1.15379 1.27905 (Numerical Example 5) The imaging optical system of Numerical Example 5 corresponds to Embodiment 1 shown in Fig. 5A. Surface data of the imaging optical system of Numerical Example 5 is shown in Table 5A, aspherical surface data is shown in Table 5B, and various data in an infinity focused state are shown in Tables 5C to 5F.

[0282] (Table 5A: Surface data) Surface number rd nd vd Effective diameter object surface ∞ 1 90.03880 1.20000 1.84666 23.8 24.419 2 59.49890 6.88130 1.49700 81.6 23.425 3 -238.02650 0.20000 23.075 4 43.24200 4.46730 1.49700 81.6 20.164 5 120.72190 Variable 19.833 6 100.31340 1.00000 1.95339 32.6 13.120 7 18.70010 5.60350 10.817 8 -38.17100 0.65900 1.59300 67.1 10.401 9 22.99430 3.76860 1.86737 20.3 9.581 10 -64.91860 1.67570 9.349 11 -28.55750 0.60000 1.88300 40.8 8.653 12 841.96650 Variable 8.403 13 (Aperture) ∞ 1.40000 7.175 14 18.86310 3.15490 1.53310 54.2 8.042 15 -186.74870 2.34810 8.037 16 18.16240 0.60000 1.96749 31.4 7.995 17 12.16800 4.48690 1.52660 57.5 7.620 18 -56.78280 2.02070 7.457 19 -23.01020 0.60000 1.99774 29.3 7.087 20 257.24460 Variable 7.179 21 17.91410 2.39390 1.49700 81.6 7.845 22 60.47700 1.50600 7.772 23 -151.02030 0.95170 1.61512 62.7 7.742 24 -67.22120 0.20200 7.740 25* 129.48610 2.68730 1.60699 56.2 7.666 26* -28.96240 Variable 7.723 27 313.39890 2.16870 1.94590 18.0 8.367 28 -34.02540 0.60000 1.81627 29.3 8.392 29 28.61340 Variable 8.418 30 -19.75750 1.00000 1.81708 43.6 11.261 31 -57.66910 0.57080 12.677 32 110.58120 2.89310 1.77513 28.6 14.789 33 -155.85260 Variable 34 ∞ 2.10000 1.51680 64.2 35∞1.00000 36∞BF Image plane ∞ (Table 5B: Aspheric Data) Page 25 K=-5.38904E+01, A4=-3.89899E-05, A6= 6.61044E-07, A8= 2.96723E-09 A10= 1.15167E-10, A12=-6.86274E-13 Page 26 K= 1.41076E+00, A4= 4.20336E-05, A6= 7.19136E-07, A8= 3.35160E-09 A10= 1.06972E-10, A12=-2.50402E-13 (Various data when focused at infinity) (Table 5C: Various data) Zoom ratio 6.65181 Wide-angle Mid-range Telephoto Focal length 28.9871 74.7438 192.8169 F-number 4.15985 5.80061 7.38267 Angle of view 36.7360 15.4905 6.1953 Image height 20.6500 21.6300 21.6300 Lens total length 112.7959 138.0649 158.9983 BF 0.00000 0.00000 0.00000 d5 0.6945 19.6632 35.3906 d12 17.9169 9.3631 1.7786 d20 4.1749 2.3141 0.8000 d26 1.9042 3.1688 3.6242 d29 16.5159 16.5350 20.0114 d33 12.8500 28.3448 38.6515 Entrance pupil position 27.5063 71.0651 142.0332 Exit pupil position -45.9294 -59.8930 -70.5711 Front principal point position 38.1990 52.4328 -191.9524 Back principal point position 83.8087 63.3211 -33.8186 (Table 5D: Single Lens Data) Lens starting surface focal length 1 1 -210.9867 2 2 96.5170 3 4 133.0191 4 6 -24.2535 5 8 -24.1021 6 9 19.9742 7 11 -31.2704 8 14 32.3098 9 16 -40.0794 10 17 19.4660 11 19 -21.1463 12 21 50.2766 13 23 196.0953 14 25 39.2449 15 27 32.5473 16 28 -18.9597 17 30 -37.2237 18 32 83.8487 (Table 5E: Zoom Lens Group Data) Group starting plane Focal length Lens length Front principal point position Rear principal point position 1 1 76.84915 12.74860 2.76980 7.07585 2 6 -13.92215 13.30680 3.58400 7.58494 3 13 40.29684 14.61060 -10.29737 -1.79000 4 21 21.33848 7.74090 3.05457 4.81994 5 27 -46.39917 2.76870 1.71360 3.02924 6 30 -70.09527 4.46390 -2.04382 -0.44404 (Table 5F: Zoom lens group magnification) Group Starting plane Wide angle Intermediate Telephoto 1 1 0.00000 0.00000 0.00000 2 6 -0.26280 -0.40939 -0.76162 3 13 4.29855 2.53639 2.17021 4 21 -0.15781 -0.34228 -0.46315 5 27 1.64350 1.81528 1.97978 6 30 1.28736 1.50750 1.65549 (Condition's corresponding value) Table 1 below shows the corresponding values ​​for conditions (1) to (15).

[0283] [Table 1] [Industrial Applicability]

[0284] The imaging optical system according to the present disclosure is applicable to digital still cameras, digital cameras with interchangeable lenses, digital video cameras, cameras in mobile phone devices such as smartphones, cameras in PDAs (Personal Digital Assistances), surveillance cameras in surveillance systems, web cameras, in-vehicle cameras, and the like, and is particularly suitable for imaging optical systems that require high image quality, such as digital still camera systems and digital video camera systems. [Explanation of symbols]

[0285] G1 First lens group G2 Second lens group G3 Third lens group G4 4th lens group G5 5th lens group G6 6th lens group G7 7th lens group L1 First lens element L2 Second lens element L3 Third lens element L4 Fourth lens element L5 Fifth lens element L6 Sixth lens element L7 Seventh lens element L8 Eighth lens element L9 9th lens element L10: Tenth lens element L11 Eleventh lens element L12 12th lens element L13 13th lens element L14 14th lens element L15 15th lens element L16 16th lens element L17 17th lens element L18 18th lens element A aperture stop P parallel plate S image plane 100 Imaging device 101 Imaging optical system 102 Image sensor 104 Case 200 Camera System 201 Camera body 202 Image sensor 203 Monitor 204 Camera mount 205 Finder 300 Interchangeable lens device 301 Imaging Optical System 302 Telescope 304 Lens mount

Claims

1. From the object side to the image side, a first lens group having positive power; a second lens group having negative power; a third lens group having positive power; a fourth lens group having positive power; a fifth lens group having negative power; a sixth lens group having a power; and Equipped with During zooming, at least the first lens group, the second lens group, the third lens group, the fourth lens group, the fifth lens group, and the sixth lens group move in the optical axis direction, thereby changing the spacing between the lens groups. Imaging optical system.

2. the third lens group comprises a vibration reduction group made up of a plurality of lens elements that move in a direction perpendicular to the optical axis during vibration reduction compensation, and a fixed group G3Obj that is located on the object side of the vibration reduction group, is made up of one or more lens elements, and does not move in a direction perpendicular to the optical axis; The following condition (1) is satisfied: 0.06 < Th_IS_Obj / Th_G3 < 0.50 ... (1) where: Th_IS_Obj: the air gap on the optical axis between the vibration isolation group and the fixed group G3Obj, Th_G3: the thickness of the third lens group on the optical axis, That is, The imaging optical system according to claim 1 .

3. the fourth lens group has at least two lens elements; The following condition (2) is satisfied: 0.05 < Th_G4_Air / Th_G4 < 0.80 ... (2) where: Th_G4_Air: the maximum value of the air spacing between adjacent lens elements constituting the fourth lens group, Th_G4: the thickness of the fourth lens group on the optical axis, That is, The imaging optical system according to claim 1 .

4. The third lens group includes: a vibration reduction group consisting of a plurality of lens elements that moves in a direction perpendicular to the optical axis during vibration reduction; a fixed group G3Obj that is located on the object side of the vibration reduction group and does not move in a direction perpendicular to the optical axis, and is made up of one or more lens elements; and a fixed group G3Img that is located on the image side of the vibration reduction group and is made up of one or more lens elements and does not move in a direction perpendicular to the optical axis. The imaging optical system according to claim 1 .

5. the object side surface of the lens element LG3R1, which is the negative lens element constituting the third lens group and is closest to the image side, has a convex shape toward the image side; The imaging optical system according to claim 1 .

6. The third lens group is an image stabilization group consisting of a plurality of lens elements that move in a direction perpendicular to the optical axis; a fixed group G3Img that is located on the image side of the image stabilization group and does not move in a direction perpendicular to the optical axis, and that is made up of one or more lens elements; Equipped with The following condition (3) is satisfied: 0.05 < Th_IS_Img / Th_G3 < 0.80 ... (3) where: Th_IS_Img: the air gap on the optical axis between the vibration isolation group and the fixed group G3Img, Th_G3: the thickness of the third lens group on the optical axis, That is, The imaging optical system according to claim 1 .

7. The following condition (4) is satisfied: 0.0 < (R2_LG3F1+R1_LG3F2) / (R2_LG3F1-R1_LG3F2) < 1.0...(4) where: R2_LG3F1: radius of curvature of the image-side surface of the lens element LG3F1 located closest to the object in the third lens group, R1_LG3F2: radius of curvature of the object-side surface of the lens element LG3F2 adjacent to the image side of the lens element LG3F1, That is, The imaging optical system according to claim 1 .

8. the image side surface of the positive lens element LG4Fp1 located closest to the object side in the fourth lens group has a convex shape toward the object side; The imaging optical system according to claim 1 .

9. The following condition (5) is satisfied: -10.0 < (R2_LG4F1+R1_LG4F2) / (R2_LG4F1-R1_LG4F2) < 1.0...(5) where: R2_LG4F1: radius of curvature of the image-side surface of the lens element LG4F1 located closest to the object in the fourth lens group, R1_LG4F2: radius of curvature of the object side surface of the lens element LG4F2 adjacent to the image side of the lens element LG4F1, That is, The imaging optical system according to claim 1 .

10. The following condition (7) is satisfied: nd_LG4Fp1 < 1.6...(6) where: nd_LG4Fp1: the refractive index of the positive lens element LG4Fp1 located closest to the object in the fourth lens group, The imaging optical system according to claim 1 .

11. the fifth lens group moves toward the image side when focusing from an object focused at infinity to a close object; The imaging optical system according to claim 1 .

12. The following condition (7) is satisfied: 0.1 < ThwG5_G6 / fw < 0.8 (7) where: ThwG5_G6: the distance on the optical axis between the fifth lens group and the sixth lens group at the wide-angle end, fw: focal length at the wide-angle end, That is, The imaging optical system according to claim 1 .

13. The following condition (8) is satisfied: 0.2 < fG1 / fT < 1.0 (8) where: fG1: focal length of the first lens group, fT: focal length at the telephoto end, That is, The imaging optical system according to claim 1 .

14. The following condition (9) is satisfied: -2.5 < fG5 / fW < -1.0 (9) where: fG5: focal length of the fifth lens group, fW: focal length at the wide-angle end, That is, The imaging optical system according to claim 1 .

15. The following condition (10) is satisfied: 0.5 < Th_G2_G3 / Yw < 3.0 (10) where: Th_G2_G3: the air gap on the optical axis between the second lens group and the third lens group at the wide-angle end, Yw: maximum image height at the wide-angle end, That is, The imaging optical system according to claim 1 .

16. The following condition (11) is satisfied: 0.3 < BFw / Yw < 3.0 (11) where: BFw: back focus at the wide-angle end, Yw: maximum image height at the wide-angle end, That is, The imaging optical system according to claim 1 .

17. The following condition (12) is satisfied: 2.0 < TTLw / Yw < 10.0 (12) where: TTLw: total optical length at the wide-angle end, Yw: maximum image height at the wide-angle end, That is, The imaging optical system according to claim 1 .

18. The following condition (13) is satisfied: 0.1 < (TTLt-TTLw) / TTLt < 0.5 (13) where: TTLt: total optical length at the telephoto end, TTLw: total optical length at the wide-angle end, That is, The imaging optical system according to claim 1 .

19. an interchangeable lens device including the imaging optical system according to claim 1; a camera body that is detachably connected to the interchangeable lens device via a camera mount and includes an image sensor that receives an optical image formed by the imaging optical system and converts the optical image into an electrical image signal; A camera system comprising: the interchangeable lens device forms the optical image of the object on the imaging element; Camera system.

20. an imaging device that converts an optical image of the object into an electrical image signal and at least one of displays and stores the converted image signal, an imaging optical system according to claim 1 that forms the optical image of the object; an imaging element that converts the optical image formed by the imaging optical system into the electrical image signal; Equipped with Imaging device.

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