Lens mount, camera mount, optical apparatus, imaging apparatus, and imaging system

Abstract

To provide a lens mount that improves the workability of attaching an optical apparatus to an imaging apparatus.SOLUTION: A lens mount 110 attachable to and detachable from a camera mount 210 comprises a lens mount outer diameter portion 112 fitted to a camera mount inner diameter portion 212 of the camera mount 210. The lens mount outer diameter portion 112 includes a first region and a second region located closer to an object side than the first region. A length in a circumferential direction of a first fitting portion fitted to the camera mount inner diameter portion 212 in the second region is longer than a fitting circumferential length Y in the circumferential direction of a second fitting portion fitted to the camera mount inner diameter portion 212 in the first region.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a lens mount, a camera mount, an optical device, an imaging device, and a photographing system.

Background Art

[0002] A lens mount for attaching an optical device such as a lens device, an adapter, or an extender to an interchangeable-lens camera is provided at the image side end of the optical device. Since the center of gravity of the optical device is located on the object side with respect to the lens mount, a moment is generated around the lens mount. The longer the distance from the lens mount to the center of gravity of the optical device and the greater the mass of the lens device, the greater this moment becomes.

[0003] Patent Document 1 discloses a lens device having a configuration in which a camera unit and a lens mount are connected and fixed by a bayonet structure.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When the length of the fitting portion in the optical axis direction in the lens mount is long, jamming may occur in the fitting portion due to tipping by the moment, and the lens mount cannot be smoothly inserted into the camera unit, which may reduce the ease of attaching the optical device to the camera.

[0006] An object of the present invention is to provide a lens mount that is easily attachable to a camera mount.

Means for Solving the Problems

[0007] The present invention relates to a lens mount that is detachable from a camera mount, has an outer diameter portion that fits into the inner diameter portion of the camera mount, the outer diameter portion includes a first region and a second region located closer to the object side than the first region, and the circumferential length of a first fitting portion that fits into the inner diameter portion in the second region is longer than the circumferential length of a second fitting portion that fits into the inner diameter portion in the first region.

Effect of the Invention

[0008] According to the present invention, it is possible to provide a lens mount that is easily attachable to a camera mount.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

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Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Best Mode for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the present invention will be described in detail based on the examples shown in the drawings.

[0011] (Embodiment 1) The typical configuration of the lens device 100 (optical device) in Embodiment 1 is shown in FIGS. 1 to 11. FIGS. 1 and 2 show a typical configuration of a photographing system using the lens device 100 of the present invention and a camera 200 (imaging device). The lens device 100 is provided with a lens mount 110 for detachably attaching the lens device 100 to the camera mount 210 and a lens (not shown), and the camera 200 is provided with a camera mount 210 and an imaging element 200a. Further, the photographing system of the present invention is composed of a lens device 100 and a camera 200 provided with an imaging element 200a for photographing an image formed by the lens device 100. FIG. 1 shows a state before the lens mount 110 is fixed to the camera mount 210. FIG. 2 shows a state where the lens mount 110 in the correct position is fixed to the camera mount 210 by a bayonet structure, and light rays are incident on the imaging element 200a along the optical axis O - O' from the object side toward the image side.

[0012] Figs. 3(A) to 3(D) are diagrams showing the lens mount structure of the lens mount 110 in Embodiment 1 of the present invention. Fig. 3(A) is a front view, Fig. 3(B) is a side view, Fig. 3(C) is a plan view, and Fig. 3(D) is a perspective view. As shown in Fig. 3(B), the lens mount 110 is provided with a flange surface 111 extending in a radial direction perpendicular to the optical axis O-O', and a lens mount outer diameter portion 112 that fits into the camera mount inner diameter portion 212 (described later) of the camera mount 210 and is parallel to the optical axis O-O'. Then, as shown in Fig. 3(A), a lens-side positioning groove 113 (recess) and a lens contact 114 (electrical contact) for positioning are provided on the flange surface 111 of the lens mount 110. In this embodiment, the lens contact 114 is arranged with the vertically upper side as the center with respect to the optical axis O-O'.

[0013] At least one notch 115 is provided along the circumferential direction of the outer diameter portion 112 of the lens mount. The outer diameter portion 112 of the lens mount includes a first region and a second region located closer to the object side than the first region. The notch 115 is provided in the first region along the circumferential direction, but not in the second region. The notch 115 is formed in the outer diameter portion 112 of the lens mount so as to have a non-fitting circumferential length X that does not engage with the inner diameter portion 212 of the camera mount within a predetermined length A in the optical axis direction and within a range of a predetermined angle along the circumferential direction. The first region is an annular region on the image side of the outer diameter portion 112 of the lens mount having a width of length A in the optical axis direction. The second region is an annular region on the object side of the outer diameter portion 112 of the lens mount having a predetermined length B in the optical axis direction. The circumferential length that fits into the inner diameter portion 212 of the camera mount in the second region is the length obtained by subtracting the circumferential length of a plurality of screw grooves 112a provided for screwing from the total circumferential length of the outer diameter portion 112 of the lens mount. On the other hand, the circumferential length that fits into the inner diameter portion 212 of the camera mount in the first region is the fitting circumferential length Y as shown in Fig. 3(A). The total circumferential length of the fitting portion (first fitting portion) that fits into the inner diameter portion 212 of the camera mount in the second region is longer than the circumferential length (fitting circumferential length Y) of the fitting portion (second fitting portion) that fits into the inner diameter portion 212 of the camera mount in the first region. The distance from the center of the lens mount 110 to the fitting portion (first fitting portion) is longer than the distance from the center to the notch 115. Also, in a state where the lens mount 110 is attached to the camera mount 210, the flange surface 111 is located closer to the object side than the second region.

[0014] The notch 115 of this embodiment is provided on the vertical line passing through the center in the first region in a state where the lens mount 110 is attached to the camera mount 210 at the correct position. That is, it is provided on one side, either the upper side or the lower side, or both the upper side and the lower side, centered on the vertical direction. When the notch 115 is provided on both the upper side and the lower side, the circumferential length that fits into the inner diameter portion 212 of the camera mount in the first region is twice the fitting circumferential length Y (2Y). And the notch 115 has a non-fitting circumferential length X in a range of a predetermined angle along the circumferential direction, and is provided in a range of a predetermined length A in the optical axis direction, that is, in a range of length A from the image-side tip of the fitting portion of the outer diameter portion 112 of the lens mount. At this time, the distance (length A + length B) in the optical axis direction from the flange surface 111 of the lens mount 110 to the image-side end of the fitting portion (first fitting portion) of the outer diameter portion 112 of the lens mount is configured to be 12 mm or less.

[0015] Also, in this embodiment, the notch 115 has a shape that spreads with respect to the vertical direction. Furthermore, the notch 115 is provided in the direction in which the moment due to the center of gravity of the lens device 100 is generated. With this configuration, the regulation of inclination due to fitting in an easily inclined direction when inserting the outer diameter portion 112 of the lens mount into the inner diameter portion 212 of the camera mount is relaxed, and the workability of attaching the lens device 100 to the camera 200 can be improved. Furthermore, in this embodiment, in the range of the angle Z of the phase of ±90° in the circumferential direction with respect to the lens contact 114 provided on the lens mount 110, no notch 115 is provided in the first region of the outer diameter portion 112 of the lens mount. With this configuration, the fall around the vertical axis is regulated, and it becomes possible to accurately contact the lens contact 114 and the camera contact 214 described later when attaching the lens device 100 to the camera 200.

[0016] FIG. 4 is a perspective view showing a camera mount 210 that is detachable from the lens mount 110 in Embodiment 1 of the present invention. The camera mount 210 is provided with a mount surface 211 perpendicular to the optical axis O - O' and a camera mount inner diameter portion 212 parallel to the optical axis O - O'. On the mount surface 211 of the camera mount 210, a camera - side positioning pin 213 (protrusion) corresponding to the lens - side positioning groove 113 and a camera contact 214 are provided. Note that the length of the camera - side positioning pin 213 along the optical axis direction is shorter than the length B of the second region in the optical axis direction. In this embodiment, the camera contact 214 is arranged centered on the vertically upper side with respect to the optical axis O - O'. The mount ring 215 is screwed onto the camera mount 210 and can be switched between a fixed position and an open position by rotation.

[0017] FIGS. 5 to 9 show the mechanism of the mount structure when the lens device 100 is attached to the camera 200. FIG. 5 is a perspective view showing the state before the lens mount 110 is inserted into the camera mount 210, and the lens device 100 is not shown. In the bayonet structure for attaching the lens device 100 to the camera 200, the outer diameter portion 112 of the lens mount is inserted toward the inner diameter portion 212 of the camera mount, and the circumferential phases of the camera - side positioning pin 213 and the lens - side positioning groove 113 are visually aligned.

[0018] FIG. 6 is a side view showing the state at the start of insertion of the lens mount 110 into the camera mount 210, and the mount ring 215 is not shown. The outer diameter portion 112 of the lens mount is fitted into the inner diameter portion 212 of the camera mount (not shown), but there is a gap between the outer diameter portion 112 of the lens mount and the inner diameter portion 212 of the camera mount within the range of the upper and lower notches 115.

[0019] FIG. 7 is a side view showing a state during further insertion of the lens mount 110, where the lens mount 110, the camera mount 210, and the mount ring 215 are not shown. The lens mount 110 fits into the camera mount 210 in a range where there is no notch 115 in the outer diameter portion 112 of the lens mount. At this time, the camera-side positioning pin 213 has not yet contacted the lens-side positioning groove 113.

[0020] FIG. 8 is a perspective view showing a state where the flange surface 111 and the mount surface 211 are in contact, and the lens device 100 is not shown. The camera-side positioning pin 213 is inserted into the lens-side positioning groove 113, and the lens contact 114 is in contact with the camera contact 214. FIG. 9 is a perspective view showing a state where the attachment of the lens device 100 to the camera 200 is completed. In a state where the flange surface 111 of the lens mount 110 is abutted against the mount surface 211, the lens device 100 is fixed to the camera 200 by rotating the mount ring 215 to the fixed position.

[0021] As described above, in the lens mount 110 in this embodiment, by providing the notch 115 that extends in a part of the circumferential direction on the image side of the outer diameter portion 112 of the lens mount of the lens mount 110, the fitting circumferential length Y until the lens mount 110 is inserted halfway is short. With such a configuration, it becomes possible to allow the inclination of the lens device 100 with respect to the camera 200, and it becomes possible to reduce the rubbing between the fitting surfaces. Also, before the camera-side positioning pin 213 is inserted into the lens-side positioning groove 113, the circumferential length of the outer diameter portion 112 of the lens mount that fits into the inner diameter portion 212 of the camera mount is long. With such a configuration, it becomes possible to regulate the tilting of the lens device 100 with respect to the camera 200 and make it easier to find the position of the camera-side positioning pin 213. According to the present invention, it is possible to provide a lens mount 110 that improves the workability of attaching the lens device 100 to the camera 200.

[0022] (Modification 1) Figs. 10(A) to (D) are diagrams showing the lens mount structure of the lens mount 110 in Modification 1 of Embodiment 1 of the present invention. Fig. 10(A) is a front view, Fig. 10(B) is a side view, Fig. 10(C) is a plan view, and Fig. 10(D) is a perspective view. As shown in Fig. 10(B), the shape of the notch portion 116 of Modification 1 is formed by being divided into a shape having a plurality of fitting circumferences. The notch portion 116 is composed of a large notch portion 116a (first notch portion) that forms a short fitting circumference Y1 and a small notch portion 116b (second notch portion) that forms a long fitting circumference Y2. At least one notch portion 116 is provided along the circumferential direction of the lens mount outer diameter portion 112. The lens mount outer diameter portion 112 includes a first region and a second region located closer to the object side than the first region. The notch portion 116 is provided along the circumferential direction in the first region, but the notch portion 116 is not provided in the second region. The large notch portion 116a is formed to have a non-fitting circumference X1 that does not engage with the camera mount inner diameter portion 212 within a predetermined length A1 in the optical axis direction and within a range of a predetermined angle along the circumferential direction in the lens mount outer diameter portion 112. The small notch portion 116b is formed to have a non-fitting circumference X2 that does not engage with the camera mount inner diameter portion 212 within a predetermined length A2 in the optical axis direction and within a range of a predetermined angle along the circumferential direction in the lens mount outer diameter portion 112. The first region is an annular region on the image side of the lens mount outer diameter portion 112 having a width of length A1 + length A2 in the optical axis direction. The second region is an annular region on the object side of the lens mount outer diameter portion 112 having a predetermined length B in the optical axis direction. That is, a plurality of, for example, the large notch portion 116a and the small notch portion 116b having different lengths in the circumferential direction are formed in the first region. At the start of insertion of the lens device 100, the large notch portion 116a results in a short fitting circumference Y1. As the insertion progresses, the small notch portion 116b results in a long fitting circumference Y2. As the insertion further progresses, it becomes a range without the notch portion 116, and it becomes possible to gradually increase the fitting circumference. With this configuration, since the change in the fitting circumference due to the insertion depth can be reduced, the insertion of the lens mount 110 can be made smooth.

[0023] (Modification Example 2) Figs. 11(A) to (D) are diagrams showing the lens mount structure of the lens mount 110 in Modification Example 2 of Embodiment 1 of the present invention. Fig. 11(A) is a front view, Fig. 11(B) is a side view, Fig. 11(C) is a plan view, and Fig. 11(D) is a perspective view. The shape of the notch portion 117 in Modification Example 2 is a tapered shape inclined with respect to the optical axis O - O'. More specifically, it is a tapered shape in which the radial length of the lens mount 110 gradually increases as it approaches the object side at an angle α with respect to the optical axis O - O'. That is, the plane extending along the circumferential direction of the notch portion 117 is inclined at an angle α with respect to the optical axis O - O'. With this configuration, the fitting circumferential length Y can be continuously changed along the optical axis direction, enabling smoother insertion of the lens mount 110.

[0024] (Embodiment 2) The representative structure of the lens device 100 in Embodiment 2 will be described. Since the mechanism of the mount structure when the lens device 100 is attached to the camera 200 is the same as that in Embodiment 1, the drawings thereof are omitted.

[0025] Figs. 12(A) to (D) are diagrams showing the lens mount structure of the lens mount 120 in Embodiment 2 of the present invention. Fig. 12(A) is a front view, Fig. 12(B) is a side view, Fig. 12(C) is a plan view, and Fig. 12(D) is a perspective view. As shown in Fig. 12(B), the lens mount 120 is provided with a flange surface 121 perpendicular to the optical axis O - O' and a lens mount outer diameter portion 122 parallel to the optical axis O - O'. And as shown in Fig. 12(A), on the flange surface 121 of the lens mount 120, a lens - side positioning pin 123 (protrusion) for positioning and a lens contact 124 (electrical contact) are provided. In this embodiment, the lens contact 124 is arranged centered on the right side in the horizontal direction with respect to the optical axis O - O'.

[0026] At least one notch portion 125 is provided along the circumferential direction of the lens mount outer diameter portion 122. The lens mount outer diameter portion 122 includes a first region and a second region located closer to the object side than the first region. The notch portion 125 is provided along the circumferential direction in the first region, but not in the second region. The notch portion 125 is formed so as to have a non-fitting circumferential length X that does not engage with the camera mount inner diameter portion 222 (see FIG. 13) within a predetermined length A in the optical axis direction and within a range of a predetermined angle along the circumferential direction in the lens mount outer diameter portion 122. The first region is an annular region on the image side of the lens mount outer diameter portion 122 having a width of length A in the optical axis direction. The second region is an annular region on the object side of the lens mount outer diameter portion 122 having a predetermined length B in the optical axis direction. The circumferential length that fits into the camera mount inner diameter portion 222 in the second region is the length obtained by subtracting the circumferential length of a plurality of screw grooves 122a provided for screwing from the total circumferential length of the lens mount outer diameter portion 122. On the other hand, the circumferential length that fits into the camera mount inner diameter portion 222 in the first region is the fitting circumferential length Y as shown in FIG. 12(A). The total circumferential length in the circumferential direction of the fitting portion (first fitting portion) that fits into the camera mount inner diameter portion 222 in the second region is longer than the circumferential length (fitting circumferential length Y) of the fitting portion (second fitting portion) that fits into the camera mount inner diameter portion 222 in the first region.

[0027] In the present embodiment, the notch portion 125 is provided on a horizontal line passing through the center in the first region in a state where the lens mount 120 is attached to the camera mount 210 in the correct position. That is, it is provided on both the right side and the left side centered on the horizontal direction. Since the notch portion 125 is provided on both the left side and the right side, the circumferential length that fits into the inner diameter portion 222 of the camera mount in the first region is twice the fitting circumferential length Y (2Y). And the notch portion 125 has a non-fitting circumferential length X in a range of a predetermined angle along the circumferential direction, and is provided in a range of a predetermined length A in the optical axis direction, that is, in a range of length A from the image side tip of the fitting portion of the outer diameter portion 122 of the lens mount. At this time, the distance (length A + length B) in the optical axis direction from the flange surface 121 of the lens mount 120 to the image side end of the fitting portion (first fitting portion) of the outer diameter portion 122 of the lens mount is configured to be 12 mm or less.

[0028] Also, in the present embodiment, the notch portion 125 has a shape that spreads with respect to the horizontal. Further, in the range of the angle Z of ±90° in the circumferential direction with respect to the lens contact point 124 provided on the lens mount 120, the notch portion 125 is not provided in the first region of the outer diameter portion 122 of the lens mount. With this configuration, tilting around the horizontal axis is restricted, and when the lens device 100 is attached to the camera 200, the lens contact point 124 and the camera contact point 224 can be accurately brought into contact.

[0029] FIG. 13 is a perspective view showing the camera mount 220 in the second embodiment of the present invention. The camera mount 220 is provided with a mount surface 221 perpendicular to the optical axis O - O' and an inner diameter portion 222 of the camera mount parallel to the optical axis O - O'. On the mount surface 221 of the camera mount 220, a camera-side positioning groove 223 (recess) corresponding to the lens-side positioning pin 123 and a camera contact point 224 are provided. In the present embodiment, the camera contact point 224 is arranged centered on the left side in the horizontal direction with respect to the optical axis O - O'. The mount ring 225 is screwed to the camera mount 220 and can switch between a fixed position and an open position by rotating.

[0030] When attaching the lens device 100 to the camera 200, the outer diameter portion 122 of the lens mount is inserted toward the inner diameter portion 222 of the camera mount, and the phases of the lens-side positioning pin 123 and the camera-side positioning groove 223 are visually aligned. When the insertion starts, the outer diameter portion 122 of the lens mount fits into the inner diameter portion 222 of the camera mount, but there is a gap between the outer diameter portion 122 of the lens mount and the inner diameter portion 222 of the camera mount within the range of the left and right notches 125. When the insertion further proceeds, the outer diameter portion 122 of the lens mount fits into the inner diameter portion 222 of the camera mount in the range where there is no notch 125 in the outer diameter portion 122 of the lens mount. The lens-side positioning pin 123 fits into the camera-side positioning groove 223 after the fitting in the range where there is no notch 125 starts. When the flange surface 121 and the mount surface 221 come into contact, the lens contact 124 and the camera contact 224 come into contact. Finally, the mount ring 225 is rotated to the fixed position, and the attachment of the lens device 100 to the camera 200 is completed. Note that the length C of the lens-side positioning pin 123 along the optical axis direction is shorter than the length B of the second region in the optical axis direction. Also, although an example in which the lens-side positioning pin 123 is provided on the lens mount 120 has been described, as long as one of the camera mount 210 and the lens mount 120 is provided with a convex portion and the other is provided with a concave portion for the convex portion to fit into, it is sufficient.

[0031] As described above, in the lens mount 120 of the present embodiment, by providing a notch portion 125 extending in a part of the circumferential direction on the image side of the outer diameter portion 122 of the lens mount 120, the fitting circumferential length Y up to the middle of inserting the lens mount 120 is short. With such a configuration, it becomes possible to allow the inclination of the lens device 100 with respect to the camera 200, and it becomes possible to reduce the rubbing between the fitting surfaces. Further, before the lens-side positioning pin 123 is inserted into the camera-side positioning groove 223, the circumferential length of the outer diameter portion 122 of the lens mount that fits into the inner diameter portion 222 of the camera mount is long. With such a configuration, it becomes possible to restrict the tilting of the lens device 100 with respect to the camera 200 and to easily find the position of the lens-side positioning pin 123. According to the present invention, it is possible to provide a lens mount 120 that improves the workability of attaching the lens device 100 to the camera 200.

[0032] As described above, the preferred embodiments of the present invention have been described, but the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist thereof.

[0033] The disclosure of the present embodiment includes the following configurations. (Configuration 1) A lens mount detachable from a camera mount, having an outer diameter portion that fits into the inner diameter portion of the camera mount, the outer diameter portion includes a first region and a second region located closer to the object side than the first region, A lens mount characterized in that the circumferential length of a first fitting portion that fits into the inner diameter portion in the second region is longer than the circumferential length of a second fitting portion that fits into the inner diameter portion in the first region. (Configuration 2) A notch portion is provided in the first region along the circumferential direction, and the distance from the center of the lens mount to the first fitting portion is longer than the distance from the center to the notch portion. The lens mount according to Configuration 1. (Configuration 3) The lens mount according to Configuration 2, wherein the notch is not provided in the second region. (Configuration 4) The lens mount according to Configuration 2 or 3, wherein, in a state where the lens mount is attached to the camera mount in the normal position, the notch is provided on a vertical line passing through the center in the first region. (Configuration 5) The lens mount according to any one of Configurations 2 to 4, wherein, in a state where the lens mount is attached to the camera mount in the normal position, the notch is provided on a horizontal line passing through the center in the first region. (Configuration 6) The lens mount according to any one of Configurations 2 to 5, wherein an electrical contact is provided on the lens mount, and the notch is not provided in the first region within a range of ±90° in the circumferential direction with respect to the electrical contact. (Configuration 7) Of the camera mount and the lens mount, one is provided with a convex portion, and the other is provided with a concave portion for fitting the convex portion, The lens mount according to any one of Configurations 1 to 6, wherein, in the optical axis direction, the length of the convex portion is shorter than the length of the second region. (Configuration 8) The lens mount according to any one of Configurations 2 to 7, wherein the lens mount has a flange surface extending in the radial direction, and the flange surface is located on the object side with respect to the second region. (Configuration 9) The lens mount according to any one of Configurations 1 to 8, wherein the distance in the optical axis direction from the flange surface to the image-side end of the first fitting portion is 12 mm or less. (Configuration 10) The lens mount according to any one of Configurations 2 to 9, wherein a plurality of notches having different circumferential lengths are provided in the first region. (Configuration 11) The plane extending in the circumferential direction of the notch portion is inclined with respect to the optical axis, and the lens mount according to any one of Configurations 2 to 10. (Configuration 12) An optical device comprising the lens mount according to any one of Configurations 1 to 11 and a lens. (Configuration 13) A photographing system comprising the optical device according to Configuration 12 and an imaging element. (Configuration 14) A camera mount having the inner diameter portion and being detachable from the lens mount according to any one of Configurations 1 to 11. (Configuration 15) An imaging device comprising the camera mount according to Configuration 14 and an imaging element.

Explanation of Signs

[0034] 100 Lens device (optical device) 110, 120 Lens mounts 111, 121 Flange surfaces 112, 122 Outer diameter portions of lens mounts (outer diameter portions) 113 Lens-side positioning groove (recess) 114, 124 Lens contacts (electrical contacts) 115, 125 Notch portions 116, 117 Notch portions 123 Lens-side positioning pin (projection) 200 Camera (imaging device) 200a Imaging element 210, 220 Camera mounts 212, 222 Inner diameter portions of camera mounts (inner diameter portions) 213 Camera-side positioning pin (projection) 214, 224 Camera contacts 223 Camera-side positioning groove (recess) O - O’ Optical axis A Length (first region) B Length (second region) C Length Y Fitting circumferential length (length) X non-chimeric perimeter

Claims

1. A lens mount that is detachable from a camera mount, having an outer diameter portion that fits into the inner diameter portion of the camera mount, the outer diameter portion includes a first region and a second region located closer to the object side than the first region, A lens mount, wherein a circumferential length of a first fitting portion that fits into the inner diameter portion in the second region is longer than a circumferential length of a second fitting portion that fits into the inner diameter portion in the first region.

2. The lens mount according to claim 1, wherein a notch is provided in the first region along the circumferential direction, and a distance from the center of the lens mount to the first fitting portion is longer than a distance from the center to the notch.

3. The lens mount according to claim 2, wherein the second region is not provided with the notch.

4. The lens mount according to claim 2, wherein in a state where the lens mount is attached to the camera mount in a correct position, the notch is provided on a vertical line passing through the center in the first region.

5. The lens mount according to claim 2, wherein in a state where the lens mount is attached to the camera mount in a correct position, the notch is provided on a horizontal line passing through the center in the first region.

6. The lens mount according to claim 2, wherein an electrical contact is provided on the lens mount, and the first region is not provided with the notch in a range of ±90° in the circumferential direction with respect to the electrical contact.

7. Among the camera mount and the lens mount, one is provided with a convex portion, and the other is provided with a concave portion for fitting the convex portion. The lens mount according to claim 1, wherein in the optical axis direction, the length of the convex portion is shorter than the length of the second region.

8. The lens mount according to claim 1, wherein the lens mount has a flange surface extending in the radial direction, and the flange surface is located closer to the object side than the second region.

9. The lens mount according to claim 8, wherein the distance in the optical axis direction from the flange surface to the image-side end of the first fitting portion is 12 mm or less.

10. The lens mount according to claim 1, wherein a plurality of notches having different lengths in the circumferential direction are provided in the first region.

11. The lens mount according to claim 2, wherein a plane extending in the circumferential direction of the notch is inclined with respect to the optical axis.

12. An optical device comprising the lens mount according to any one of claims 1 to 11 and a lens.

13. A photographing system comprising the optical device according to claim 12 and an imaging element.

14. A camera mount having the inner diameter portion and being detachable from the lens mount according to any one of claims 1 to 11.

15. An imaging device comprising the camera mount according to claim 14 and an imaging element.

Images