JP2020118807A - Converter device, interchangeable lens, and image capturing device - Google Patents

Abstract

To provide a converter device which allows for adjusting a field curvature component independently from other aberration components.SOLUTION: An optical system of a converter device 300 of the present invention is a re-imaging optical system CL configured to re-form a primary image formed by a lens device 200 onto an image surface as a secondary image. The re-imaging optical system CL includes a movable group VL capable of moving along an optical axis. The position of the movable group VL in the re-imaging optical system CL is predetermined.SELECTED DRAWING: Figure 7

Description

The present invention relates to a converter device, an interchangeable lens, and an image pickup device.

In an imaging system including an imaging device such as a single-lens reflex camera or a mirrorless camera, and an interchangeable lens detachable from the imaging device, a converter device mounted between the imaging device and the interchangeable lens is known. In such an imaging system, a converter device is used to expand a shooting function or a shooting magnification.

Patent Document 1 discloses a converter device having an optical system for re-imaging a primary image formed by an interchangeable lens as a secondary image on an image plane.

JP, 2017-102227, A

In recent years, in order to expand the photographic expression, an optical system in which a user can independently adjust a predetermined aberration component while suppressing a focus shift at the center of the screen is desired. For example, by adjusting the field curvature aberration independently of other aberration components, it is possible to obtain an image in which the periphery of the screen is blurred with respect to the center of the screen.

However, in the converter device described in Patent Document 1, since the position of each lens group is fixed, it is difficult to add such a shooting expression function to the primary image formed by the interchangeable lens. ..

In view of the above problems, it is an object of the present invention to provide a converter device, an interchangeable lens, and an imaging device that can adjust the field curvature aberration component independently of other aberration components.

A converter device according to an embodiment of the present invention is a converter device that is mounted between a lens device that is attachable to and detachable from an imaging device and the imaging device, and an optical system included in the converter device is the lens device. Is a re-imaging optical system for re-imaging the primary image formed as a secondary image on an image plane, the re-imaging optical system having a movable group movable along an optical axis, The moving group is the distance from the image plane of the primary image to the most object-side surface of the moving group during normal shooting, and the distance from the most image-side surface of the moving group to the image surface during normal shooting. When the smaller one is Dm and the total lens length of the re-imaging optical system CL is TTD,
|Dm|/TTD<0.40
It is characterized by satisfying the following conditional expression.

According to the converter device of one embodiment of the present invention, the field curvature aberration component can be adjusted independently of other aberration components.

6 is a sectional view of the main optical system of Example A at the wide-angle end. FIG. 9 is an aberration diagram of the main optical system of Example A at an object distance of infinity. FIG. FIG. 16 is a sectional view of the main optical system of Example B at the wide-angle end. 16 is an aberration diagram of the main optical system of Example B at an object distance of infinity. FIG. Sectional drawing of the main optical system of Example C. 16 is an aberration diagram of the main optical system of Example C at an object distance of infinity. FIG. 3 is a cross-sectional view of the re-imaging optical system of Example 1. FIG. 6 is an aberration diagram of the re-imaging optical system of Example 1. FIG. FIG. 6 is a sectional view when the main optical system of Example A and the re-imaging optical system of Example 1 are used. FIG. 9 is an aberration diagram during normal shooting when the main optical system of Example A and the re-imaging optical system of Example 1 are used. FIG. 9 is an aberration diagram when the main optical system of Example A and the re-imaging optical system of Example 1 are used and the field curvature aberration excessive side is set. FIG. 7 is an aberration diagram when the main optical system of Example A and the re-imaging optical system of Example 1 are used and the field curvature aberration underside is set. 6 is a cross-sectional view of the re-imaging optical system of Example 2. FIG. FIG. 9 is an aberration diagram of the re-imaging optical system of Example 2. FIG. 13 is a cross-sectional view when the main optical system of Example B and the re-imaging optical system of Example 2 are used. FIG. 16 is an aberration diagram during normal shooting when the main optical system of Example B and the re-imaging optical system of Example 2 are used. FIG. 9 is an aberration diagram when the main optical system of Example B and the re-imaging optical system of Example 2 are used and the overside curvature of field is set. FIG. 16 is an aberration diagram when the field curvature aberration underside is set when the main optical system of Example B and the re-imaging optical system of Example 2 are used. FIG. 9 is a cross-sectional view of the re-imaging optical system according to the third embodiment. 16 is an aberration diagram of the re-imaging optical system of Example 3. FIG. Sectional drawing when the main optical system of Example B and the re-imaging optical system of Example 3 are used. FIG. 16 is an aberration diagram during normal shooting when the main optical system of Example B and the re-imaging optical system of Example 3 are used. FIG. 16 is an aberration diagram when the main optical system of Example B and the re-imaging optical system of Example 3 are used and the overside curvature of field is set. FIG. 16 is an aberration diagram when the field curvature aberration is set to the under side when the main optical system of Example B and the re-imaging optical system of Example 3 are used. 11 is a sectional view of the re-imaging optical system of Example 4. FIG. 16 is an aberration diagram of the re-imaging optical system of Example 4. FIG. Sectional drawing when the main optical system of Example B and the re-imaging optical system of Example 4 are used. FIG. 16 is an aberration diagram during normal shooting when the main optical system of Example B and the re-imaging optical system of Example 4 are used. FIG. 16 is an aberration diagram when the main optical system of Example B and the re-imaging optical system of Example 4 are used and the overside curvature of field is set. FIG. 16 is an aberration diagram when the field curvature aberration is set to the under side when the main optical system of Example B and the re-imaging optical system of Example 4 are used. 16 is a sectional view of the re-imaging optical system of Example 5. FIG. 16 is an aberration diagram of the re-imaging optical system of Example 5. FIG. FIG. 16 is a sectional view when the main optical system of Example C and the re-imaging optical system of Example 5 are used. FIG. 16 is an aberration diagram when the main optical system of Example C and the re-imaging optical system of Example 5 are used. It is a figure which shows the structure of the imaging system concerning an Example.

FIG. 35A and FIG. 35B are diagrams showing the configuration of an imaging system including the converter device according to the embodiment. The imaging system includes an imaging device 100, an interchangeable lens 200 detachable from the imaging device 100, and a converter device 300 attachable between the imaging device 100 and the interchangeable lens 200. The interchangeable lens 200 has a main optical system ML, and the converter device 300 is a re-imaging optical system as an optical system for re-imaging the primary image formed by the main optical system ML on the image plane in the imaging device 100. With CL.

FIG. 35A shows a configuration in which the interchangeable lens 200 is attached to the imaging device 100 without the converter device 300. Further, FIG. 35B shows a case where the interchangeable lens 200 is attached to the imaging device 100 via the converter device 300.

In this image pickup system, the image pickup apparatus 100 can take an image regardless of whether or not the converter apparatus 300 is attached. By configuring the re-imaging optical system CL to re-image the primary image formed by the main optical system ML of the interchangeable lens 200, the converter device 300 can be downsized.

Further, the converter device 300 has an operation member 301 such as a switch, a dial, and a button. The operation member 301 is used by the user to instruct the adjustment direction and the adjustment amount of the field curvature aberration amount.

Further, converter device 300 has movable field curvature adjustment group VL (moving group) and control unit 302 including a CPU. The field curvature adjustment group VL is a lens group capable of largely changing the field curvature aberration by movement, as compared with other aberration components.

When the user operates the operation member 301, the operation direction and operation amount are output to the control unit 302. Then, the control unit 302 determines the moving direction and the moving amount of the field curvature adjustment group VL according to the operation amount of the operation member 301, and controls an actuator (not shown) for moving the field curvature adjustment group VL. To do. As described above, the control unit 302 moves the image surface curvature adjustment group VL in accordance with the operation of the operation member 301, whereby it is possible to arbitrarily adjust the focus around the screen of the image captured by the imaging device. ..

Hereinafter, the re-imaging optical system CL according to the embodiment, which is preferable for realizing such a shooting expression, will be described in detail with reference to the accompanying drawings.

1, 3 and 5 are sectional views of the main optical system ML, and FIGS. 7, 13, 19, 25 and 31 are sectional views of the re-imaging optical system CL. FIG. 9 is a sectional view when the re-imaging optical system CL of Example 1 is arranged on the image side of the main optical system ML of Example A, and FIG. 15 is on the image side of the main optical system ML of Example B. FIG. 21 is a cross-sectional view when the re-imaging optical system CL of Example 2 is arranged, and FIG. 21 shows the re-imaging optical system CL of Example 3 arranged on the image side of the main optical system ML of Example B. FIG. 27 is a sectional view when the re-imaging optical system CL of Example 4 is arranged on the image side of the main optical system ML of Example B, and FIG. 33 is an image side of the main optical system ML of Example C. 16 is a cross-sectional view when a re-imaging optical system CL of Example 5 is arranged. In each sectional view, the left side is the object side (front side), and the right side is the image side (rear side). Further, in each sectional view, when i is the order of the lens groups from the object side to the image side, Li represents the i-th lens group. The CG is an optical member whose object side and image side are flat.

In the present specification, the “lens group” in the case where the main optical system ML is a zoom lens is a group divided by the distance between the lenses which changes during zooming. In the case of the re-imaging optical system CL, the “lens group” is a group divided by the distance between the lenses, which changes when the field curvature is adjusted. The "lens group" may be composed of a plurality of lenses or may be composed of one lens.

The aperture stop SP determines (limits) the light flux of the open F number (Fno). AP is a flare cut diaphragm that cuts unnecessary light.

The image plane of the primary image is defined as the primary image plane IP1, and the image plane of the secondary image is defined as the secondary image plane IP2. In the case where the re-imaging optical system CL is arranged between the main optical system ML and the imaging device 100 and the imaging device 100 is a digital video camera, a digital camera, or the like, the secondary imaging plane IP2 Corresponds to an image pickup surface of an image pickup element (photoelectric conversion element) such as a CCD sensor or a CMOS sensor. In the case where the re-imaging optical system CL is arranged between the main optical system ML and the imaging device 100, and the imaging device 100 is a silver salt film camera, the secondary imaging plane IP2 is the film surface. Equivalent to. When the re-imaging optical system CL is not arranged between the main optical system ML and the imaging device 100, the primary imaging surface IP1 instead of the secondary imaging surface IP2 corresponds to the corresponding imaging surface or film surface. ..

2, 4, and 6 are aberration diagrams of the main optical system ML, and FIGS. 8, 14, 20, 26, and 32 are aberration diagrams of the re-imaging optical system CL of each example described later. 10 to 12 are aberration diagrams when the re-imaging optical system CL of Example 1 is arranged on the image side of the main optical system ML of Example A, and FIGS. 16 to 18 are main optical system ML of Example B. 22 to 24 are aberration diagrams when the re-imaging optical system CL of Example 2 is arranged on the image side of FIG. 22, and FIGS. 22 to 24 are re-imaging optical systems of Example 3 on the image side of the main optical system ML of Example B. FIG. 6A is an aberration diagram when G is arranged. 28 to 30 are aberration diagrams when the re-imaging optical system CL of Example 4 is arranged on the image side of the main optical system ML of Example B, and FIG. 34 is an image of the main optical system ML of Example C. FIG. 16 is an aberration diagram when the re-imaging optical system CL of Example 5 is arranged on the side. In the spherical aberration diagram, the solid line indicates the d line and the chain double-dashed line indicates the g line. In the astigmatism diagram, the broken line ΔM is the meridional image plane, and the solid line ΔS is the sagittal image plane. The distortion aberration is shown for the d line. The chromatic aberration of magnification is shown for the g-line. ω is a half angle of view (degree), and Fno is an F number.

The re-imaging optical system CL according to the embodiment of the present invention is, for example, an optical system included in the converter device 300 and re-imaging the primary image formed by the main optical system ML as a secondary image on the image plane. is there. Further, the re-imaging optical system CL is movable in the field curvature adjustment group VL along the optical axis in order to allow the peripheral focus to be intentionally adjusted while maintaining the image forming performance at the image center. Have.

In particular, it is necessary to be able to independently adjust the field curvature aberration while suppressing an increase in the amount of spherical aberration, which is the main factor that determines the optical performance at the center of the screen. Since the field curvature aberration occurs due to the off-axis light flux, the field curvature adjustment group VL should be arranged at a position where the on-axis light flux and the off-axis light flux are relatively separated in the direction orthogonal to the optical axis. Thus, when the field curvature adjustment group VL is moved, the field curvature aberration can be largely changed as compared with the spherical aberration and the like.

Therefore, in the present embodiment, the distance from the primary imaging plane IP1 to the most object-side surface of the field curvature adjustment group VL (moving group) during normal shooting and the field curvature adjustment group VL during normal shooting. When the smaller one of the distances from the image-side surface to the image surface is Dm and the total lens length of the re-imaging optical system CL is TTD,
|Dm|/TTD<0.40 (1)
It is characterized by satisfying the following conditional expression.

Here, “during normal imaging” means when the amount of field curvature aberration is minimized.

The total lens length TTD is calculated from the air-equivalent distance on the optical axis from the primary imaging plane IP1 to the lens surface of the re-imaging optical system CL closest to the object side, and from the lens surface of the re-imaging optical system CL closest to the object side. A length obtained by adding the distance on the optical axis to the lens surface closest to the image and the air-equivalent distance on the optical axis from the lens surface closest to the image of the re-imaging optical system CL to the secondary image formation surface IP2. Is.

Conditional expression (1) indicates that the field curvature adjustment group VL is arranged at a position relatively close to the primary imaging plane IP1 or the secondary imaging plane IP2.

When the upper limit of conditional expression (1) is exceeded and the position of the field curvature adjustment group VL moves away from the primary image formation plane IP1 or the secondary image formation plane IP2, the on-axis light flux and the off-axis light flux are orthogonal to the optical axis. The field curvature adjustment group VL is arranged at a position that is not sufficiently separated. Therefore, the amount of fluctuation of spherical aberration becomes large when adjusting the field curvature due to the movement of the field curvature adjustment group VL, and it becomes difficult to independently adjust the field curvature aberration as compared with other aberration components, which is preferable. Absent. Alternatively, when the total lens length of the re-imaging optical system CL is shortened and the refracting power of the re-imaging optical system CL is increased to exceed the upper limit value of the conditional expression (1), spherical aberration and the like are deteriorated, and from the center of the screen. It is not preferable because it is difficult to provide high optical performance around the periphery.

Thus, by satisfying the conditional expression (1), it becomes possible to adjust the field curvature aberration according to the preference of the user. In particular, when the re-imaging optical system CL is provided in the converter device 300, while maintaining the original function of the converter device 300 such as changing the focal length of the entire system, an expression expansion function of adjusting the field curvature aberration is provided. Can be equipped. Further, particularly when the re-imaging optical system CL is provided in the converter device 300, only one converter device 300 is required to provide a field curvature aberration adjusting function for various types of interchangeable lenses 200. It is possible to give.

The numerical range of conditional expression (1) is preferably set as follows.
|Dm|/TTD<0.30 (1a)

Furthermore, it is preferable that the numerical range of the conditional expression (1) is as follows.
|Dm|/TTD<0.20 (1b)

Note that the field curvature adjustment group VL is arranged adjacent to the image side of the most object-side lens and the most object-side lens among the lenses having refractive power included in the re-imaging optical system CL. In the case where any one of the lens closest to the image side and the lens disposed adjacent to the object side of the lens closest to the image side is included, it is possible to obtain substantially the same effect as in the case where the conditional expression (1) is satisfied. ..

Furthermore, it is preferable that the re-imaging optical system CL satisfy at least one of the following conditional expressions (2) to (9).
0.50<|Hbi/Hgi|<2.00 (2)
0.01<|(1-βm ² )βr ² |<1.50 (3)
0.10<|fm/f|<50 (4)
-10.0<βc<-0.45 (5)
-10.0<PI/f<-1.00 (6)
-10.0<PO/f<-0.10 (7)
-0.30<Di/TTD<0.30 (8)
0.01<skd/f<1.00 (9)

However, the height of the chief ray of the most off-axis light flux incident on the most object-side surface of the field curvature adjustment group VL during normal shooting is Hbi, and the maximum image height of the primary image during normal shooting is Hgi. The lateral magnification of the field curvature adjustment group VL at the time of normal shooting is βm. Let βr be the combined lateral magnification of all the lenses arranged on the image side of the field curvature adjustment group VL during normal shooting. The focal length of the field curvature adjustment group VL during normal shooting is fm, and the focal length of the re-imaging optical system CL during normal shooting is f. Let βc be the lateral magnification of the re-imaging optical system CL during normal shooting.

Let PI be the distance on the optical axis from the primary imaging plane IP1 to the entrance pupil position of the re-imaging optical system CL during normal imaging. Here, the entrance pupil position means a position on the optical axis of the entrance pupil. The sign of PI is positive when the entrance pupil position is on the image side of the primary imaging plane IP1, and is negative when the entrance position is on the object side of the primary imaging plane IP1. Let PO be the distance on the optical axis from the secondary imaging plane IP2 to the exit pupil position of the re-imaging optical system CL during normal imaging. Here, the exit pupil position means a position on the optical axis of the exit pupil. The sign of PO is positive when the exit pupil position is on the image side of the secondary imaging plane IP2 and is negative when the exit pupil position is on the object side of the secondary imaging plane IP2.

The distance on the optical axis from the primary imaging plane IP1 at the time of normal photographing to the most object-side surface of the re-imaging optical system CL is Di. Here, the sign of Di is positive when the most object-side surface of the re-imaging optical system CL is on the image side of the primary imaging surface IP1, and the most object-side surface of the re-imaging optical system CL is 1. The value is negative when it is on the object side of the next image plane IP1. The distance Di is an air conversion distance. Let skd be the air-converted distance on the optical axis from the most object-side surface of the re-imaging optical system CL to the image plane during normal shooting.

Conditional expression (2) is set to the most object-side surface of the field curvature adjustment group VL in order to intentionally operate the imaging performance around the screen while suppressing the deterioration of the imaging performance at the optical axis center. It defines the ratio between the height Hbi of the principal ray of the off-axis light beam and the maximum image height Hgi on the primary image plane IP1. If the upper limit of conditional expression (2) is exceeded, the height Hbi of the chief ray of the most off-axis light beam incident on the field curvature adjustment group VL becomes large, or the maximum image height Hgi at the primary image plane IP1 becomes small. Then, the outer diameter of the re-imaging optical system CL becomes larger than the outer diameter of the main optical system ML, and the re-imaging optical system CL becomes large, which is not preferable. Below the lower limit of conditional expression (2), the height Hbi of the chief ray of the most off-axis light flux entering the field curvature adjustment group VL becomes small, or the maximum image height Hgi at the primary image plane IP1 becomes large. In this case, the amount of fluctuation of spherical aberration becomes large when adjusting the field curvature, and it becomes difficult to independently adjust the field curvature aberration as compared with other aberration components, which is not preferable.

Conditional expression (3) defines the relationship between the lateral curvature adjustment group VL and the lateral magnification of the lens arranged on the image side of the negative field curvature adjustment group VL. That is, the conditional expression (3) is the sensitivity indicating the variation amount of the field curvature per unit movement amount of the field curvature adjustment group VL. When the value exceeds the upper limit of the conditional expression (3), the variation amount of the field curvature aberration per unit movement amount becomes large, and it becomes difficult to finely adjust the field curvature aberration. Therefore, it is not preferable from the viewpoint of operability. Further, in order to correct the generated focus deviation, it is necessary to move the sub-group that is included in the main optical system ML and moves during focusing, which is not preferable. When the value goes below the lower limit of the conditional expression (3), the amount of movement of the field curvature adjustment group VL required to sufficiently adjust the amount of field curvature aberration becomes long, and the re-imaging optical system CL becomes large. Therefore, it is not preferable. If the amount of movement is limited, it is difficult to obtain the effect of adjusting the curvature of field that is the object of the present case, which is not preferable.

Conditional expression (4) defines the focal length fm of the field curvature adjustment group VL and the focal length f of the re-imaging optical system CL. If the upper limit of conditional expression (4) is exceeded and the focal length of the field curvature adjustment group VL becomes longer and the refractive power of the field curvature adjustment group VL becomes weaker, the amount of field curvature aberration will be adjusted sufficiently. The amount of movement of the field curvature adjustment group VL required for the above becomes long and the re-imaging optical system CL becomes large, which is not preferable. When the upper limit of conditional expression (4) is exceeded and the focal length of the re-imaging optical system CL becomes short and the refracting power of the re-imaging optical system CL becomes strong, various aberrations other than field curvature increase. In order to correct this, it is necessary to add a lens for correction, and the re-imaging optical system CL becomes large, which is not preferable. When the value is below the lower limit of the conditional expression (4) and the focal length of the field curvature adjustment group VL becomes short and the refractive power becomes strong, the variation amount of the field curvature aberration per unit movement amount becomes large. This makes it difficult to finely adjust the field curvature aberration, which is not preferable from the viewpoint of operability. Further, when the refractive power of the field curvature aberration adjustment group VL becomes strong, not only field curvature aberration but also coma aberration and chromatic aberration become large, so that the optical performance of the re-imaging optical system CL deteriorates, which is not preferable. When the lower limit of conditional expression (4) is exceeded and the focal length of the re-imaging optical system CL becomes long and the refracting power of the re-imaging optical system CL becomes weak, the total lens length of the re-imaging optical system CL becomes long. Is not preferable.

Conditional expression (5) defines the lateral magnification βc of the re-imaging optical system CL. The primary image is inverted by the re-imaging optical system CL and re-imaged as a secondary image on the imaging surface, so that the lateral magnification has a negative value. When the absolute value of the lateral magnification βc of the re-imaging optical system CL becomes smaller than the upper limit value of the conditional expression (5), the converter device having the re-imaging optical system CL is provided between the interchangeable lens 200 and the imaging device 100. Vignetting of the off-axis light flux occurs when it is attached, or the outer diameter of the main optical system ML becomes large in order to avoid the vignetting, which is not preferable. If the absolute value of the lateral magnification βc of the re-imaging optical system CL is increased below the lower limit of conditional expression (5), it becomes difficult to correct the axial chromatic aberration occurring in the re-imaging optical system CL, which is not preferable.

When the re-imaging optical system CL is configured such that the absolute value of the lateral magnification (shooting magnification) is larger than 1, as in Examples 1 to 3 and Example 5 described later, when the converter device 300 is not attached. It is possible to prevent vignetting of the off-axis light flux when the converter device 300 is attached without increasing the size of the interchangeable lens 200. In addition to expanding the photographing function (variable field curvature function), the size of the image can be expanded.

Conditional expression (6) is on the optical axis from the primary imaging plane IP1 to the entrance pupil position of the re-imaging optical system CL in order that the re-imaging optical system CL properly takes in the light rays from the main optical system ML. It defines the relationship between the distance PI and the focal length f of the re-imaging optical system. When the distance PI exceeds the upper limit value of the conditional expression (6) and the distance PI becomes short, the maximum incident angle of the off-axis light beam entering the re-imaging optical system CL becomes large, and the outer diameter of the lens near the primary imaging plane IP1. Is large, which is not preferable. In addition, the position sensitivity to the field curvature aberration during the movement of the field curvature adjustment group VL also becomes high, which makes it difficult to finely adjust the field curvature aberration, which is not preferable. Further, when the field curvature adjustment group VL moves, the off-axis light flux emitted from the main optical system ML is likely to be vignetted, which is not preferable. Further, since the focal length of the re-imaging optical system CL becomes longer than the upper limit value of the conditional expression (6), the total lens length of the re-imaging optical system CL becomes long and the converter device 300 becomes large, which is preferable. Absent. If the distance PI becomes lower than the lower limit of conditional expression (6), the main optical system ML of the interchangeable lens 200 is limited to an optical system having a long exit pupil. Therefore, it becomes difficult to obtain the converter device 300 applicable to various interchangeable lenses, which is not preferable from the viewpoint of versatility. If the focal length of the re-imaging optical system CL is shortened and the refracting power of the re-imaging optical system CL is increased below the lower limit of the conditional expression (6), aberrations other than the field curvature aberration are increased. Therefore, it is not preferable because it becomes difficult to correct the aberration or the number of lenses increases for the correction.

Conditional expression (7) defines the relationship between the exit pupil position PO of the re-imaging optical system CL and the focal length of the re-imaging optical system. If the upper limit of conditional expression (7) is exceeded and the length of the distance PO is shortened, the refractive power of the lens arranged near the secondary imaging plane IP2 becomes strong. Therefore, it becomes difficult to reduce the field curvature aberration during normal shooting, which is not preferable. Further, when the focal length of the re-imaging optical system CL becomes longer than the upper limit value of the conditional expression (7) and the refracting power of the re-imaging optical system CL becomes weak, the total lens length of the re-imaging optical system CL becomes large. This is not preferable because it becomes long and the converter device 300 becomes large. If the length of the distance PO becomes longer than the lower limit value of the conditional expression (7), the maximum incident angle on the secondary image formation plane IP2 becomes too large and shading easily occurs, which is not preferable. If the lower limit value of the conditional expression (7) is exceeded and the focal length of the re-imaging optical system CL becomes short and the refracting power of the re-imaging optical system CL becomes strong, various aberrations such as spherical aberration become large, and correction is performed. Is difficult to do, which is not preferable. Conditional expression (8) is used for properly propagating the off-axis light beam emitted from the main optical system ML to the re-imaging optical system CL from the primary imaging plane IP1 to the first lens of the re-imaging optical system CL. This is a conditional expression that defines the distance Di to the object-side image side surface and the total lens length TTD of the re-imaging optical system CL. When the distance Di exceeds the upper limit of conditional expression (8) and the surface of the re-imaging optical system CL closest to the object side is separated from the image side of the primary imaging plane IP1, the distance of the re-imaging optical system CL is increased. This is not preferable because the total lens length becomes long and the re-imaging optical system CL becomes large. Even if the most object-side surface of the re-imaging optical system CL is separated from the image side of the primary imaging plane IP1, if the extension of the total lens length of the re-imaging optical system CL is suppressed, refraction of the re-imaging optical system CL Since it is necessary to increase the force and various aberrations such as spherical aberration increase, it is not preferable. When the distance Di becomes smaller than the lower limit of the conditional expression (8), the re-imaging optical system CL enters the back focus range of the main optical system ML. For this reason, it is not preferable because the mechanical layout of the connecting portion between the interchangeable lens 200 and the converter device 300 becomes difficult. Alternatively, if the distance Di becomes smaller than the lower limit value of the conditional expression (8), the total lens length of the re-imaging optical system CL becomes long and the converter device 300 becomes large, which is not preferable.

Conditional expression (9) is the distance on the optical axis from the most object-side surface of the re-imaging optical system CL to the image plane that is also the secondary imaging plane IP2 (hereinafter referred to as back focus) and the re-imaging optical system CL. It defines the focal length of.

If the back focus skd of the re-imaging optical system CL becomes longer than the upper limit of the conditional expression (9), the total lens length of the re-imaging optical system CL becomes long and the converter device 300 becomes large, which is not preferable. Further, when the upper limit of conditional expression (9) is exceeded and the focal length of the re-imaging optical system CL becomes short and the refracting power of the re-imaging optical system CL becomes strong, various aberrations such as spherical aberration become large. However, it becomes difficult to correct the various aberrations with the number of lenses that can be arranged within the range of the back focus, which is not preferable. If the lower limit of the conditional expression (9) is exceeded and the back focus of the re-imaging optical system CL becomes short, the mechanical layout related to the connecting portion between the converter device 300 and the imaging device 100 becomes difficult, which is not preferable. If the focal length of the re-imaging optical system CL becomes longer and the refracting power of the re-imaging optical system CL becomes weaker than the lower limit value of the conditional expression (9), the total lens length of the re-imaging optical system CL becomes smaller. It is not preferable because it becomes long.

Furthermore, it is preferable that the numerical ranges of the conditional expressions (2) to (9) are set as follows.
0.55<|Hbi/Hgi|<1.50 (2a)
0.02<|(1-βm ² )βr ² |<1.00 (3a)
0.20<|fm/f|<40 (4a)
-5.0<βc<-0.50 (5a)
−8.00<PI/f<−1.25 (6a)
-5.00<PO/f<-0.25... (7a)
-0.20<Di/TTD<0.20 (8a)
0.05<skd/f<0.80 (9a)

Furthermore, it is preferable that the numerical ranges of the conditional expressions (2) to (9) are set as follows.
0.60<|Hbi/Hgi|<1.35 (2b)
0.03<|(1-βm ² )βr ² |<2,10 (3b)
0.40<|fm/f|<30 (4b)
−3.0<βc<−0.60 (5b)
-5.00<PI/f<-1.50 (6b)
−3.50<PO/f<−0.35 (7b)
-0.15<Di/TTD<0.16 (8b)
0.10<skd/f<0.60 (9b)

By satisfying at least one of the above conditional expressions, it is possible to secure at least one of miniaturization of the maximum optical system CL and ease of correction of aberrations other than field curvature aberration.

In the re-imaging optical system CL according to the present embodiment, it is preferable that the field curvature adjustment group VL includes a lens that is arranged closest to the object side among the lenses having the refractive power included in the re-imaging optical system CL. .. The lens disposed closest to the object side of the re-imaging optical system CL is often disposed at a position where the on-axis light flux and the off-axis light flux are separated in the direction orthogonal to the optical axis, and thus the field curvature aberration is larger than that of other aberrations. It becomes easy to greatly change.

Further, it is preferable that the field curvature adjustment group VL has a positive refractive power. This makes it easy to increase the positive refracting power of the re-imaging optical system CL on the primary imaging surface IP1 side or the secondary imaging surface IP2 side, and the diameter of the re-imaging optical system CL can be reduced. The lens barrel system of the converter device 300 can be downsized.

Next, the main optical system ML of the example and the re-imaging optical system CL of the example will be described.

[Example of main optical system]
First, Examples A to C of the main optical system ML arranged on the object side of the re-imaging optical system CL will be described.

(Example A)
FIG. 1 is a sectional view of a main optical system ML of Example A at a wide-angle end. 2A and 2B are aberration diagrams of the object distance infinity at the wide-angle end and the telephoto end of the main optical system ML of Example B. The main optical system ML of Example A includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power, which are sequentially arranged from the object side to the image side. , A zoom lens having a fourth lens group having a positive refractive power and a zoom ratio of 2.35 and an F number of 2.06.

(Example B)
FIG. 3 is a sectional view of the main optical system ML of Example B at the wide-angle end. FIG. 4A and FIG. 4B are aberration diagrams of the object distance infinity at the wide-angle end and the telephoto end of the main optical system ML of Example B. The main optical system ML of Example B includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power, which are sequentially arranged from the object side to the image side. , A zoom lens having a fourth lens group having a positive refractive power and a zoom ratio of 2.75 and an F number of 2.91.

(Example C)
FIG. 5 is a sectional view of the main optical system ML of Example C at the wide-angle end. FIG. 6 is an aberration diagram of the main optical system ML of Example C. The main optical system ML of Example C is a single focus lens having a focal length of 39 mm and an F number of 2.86.

[Example of re-imaging optical system]
Next, the re-imaging optical system CL of Examples 1 to 5 will be described. A cross-sectional view and an aberration diagram in the case of using any of the main optical systems ML described above are also shown for each example.

[Example 1]
FIG. 7 is a sectional view of the re-imaging optical system CL of the first embodiment.

8(A), 8(B), and 8(C) are aberration diagrams of the reimaging optical system CL of Example 1 at the time of normal shooting and the field curvature aberration are set to the over side, respectively. FIG. 6A is an aberration diagram when, and FIG. 8B is an aberration diagram when the field curvature aberration is set to the under side. FIG. 9 is a cross-sectional view at the wide-angle end when the re-imaging optical system CL of Example 1 is arranged on the image side of the main optical system ML of Example A.

FIGS. 10A and 10B show the wide-angle end at the time of normal shooting when the re-imaging optical system CL of Example 1 is arranged on the image side of the main optical system ML of Example A, respectively. FIG. 3 is an aberration diagram at a telephoto end. 11(A) and 11(B), respectively, when the re-imaging optical system CL of Example 1 is arranged on the image side of the main optical system ML of Example A, the field curvature aberration over-side setting is shown. FIG. 7 is an aberration diagram at a wide-angle end and a telephoto end at the time. 12(A) and 12(B) are respectively set to the underside of the field curvature aberration when the re-imaging optical system CL of Example 1 is arranged on the image side of the main optical system ML of Example A. FIG. 7 is an aberration diagram at a wide-angle end and a telephoto end at the time.

In the re-imaging optical system CL of the first embodiment, the field curvature adjustment group VL is composed of a positive lens closest to the object side of the re-imaging optical system CL and a negative lens arranged adjacent to the image side of the positive lens. Become. The field curvature adjustment group VL moves from the position at the time of normal shooting toward the secondary imaging plane IP2 along the optical axis direction, so that the field curvature aberration becomes excessive, and the optical axis moves from the position at the time of normal shooting to the optical axis. By moving along the direction toward the primary imaging plane IP1, the field curvature aberration becomes under.

In the re-imaging optical system CL of the first embodiment, the position of the most object-side surface of the re-imaging optical system CL during normal shooting is 3 mm away from the primary imaging plane IP1 to the secondary imaging plane IP2 side. The position. The re-imaging optical system CL of Example 1 has a lateral magnification (shooting magnification) of −2.0 times and an F number of 4.12.

[Example 2]
FIG. 13 is a sectional view of the re-imaging optical system CL of the second embodiment.

14(A), 14(B), and 14(C) are aberration diagrams of the re-imaging optical system CL of Example 2 at the time of normal shooting and the field curvature aberration are set to the over side, respectively. FIG. 6A is an aberration diagram when, and FIG. 8B is an aberration diagram when the field curvature aberration is set to the under side.

FIG. 15 is a cross-sectional view at the wide-angle end when the re-imaging optical system CL of Example 2 is arranged on the image side of the main optical system ML of Example B.

16A and 16B show the wide-angle end at the time of normal shooting when the re-imaging optical system CL of Example 2 is arranged on the image side of the main optical system ML of Example B, respectively. FIG. 3 is an aberration diagram at a telephoto end.

17(A) and 17(B), respectively, when the re-imaging optical system CL of Example 2 is arranged on the image side of the main optical system ML of Example B, the field curvature aberration over-side setting is shown. FIG. 7 is an aberration diagram at a wide-angle end and a telephoto end at the time.

18(A) and 18(B) respectively show the setting of the field curvature aberration under side when the re-imaging optical system CL of Example 2 is arranged on the image side of the main optical system ML of Example B. FIG. 7 is an aberration diagram at a wide-angle end and a telephoto end at the time.

In the re-imaging optical system CL of the second embodiment, the field curvature adjustment group VL is composed of one positive lens arranged on the most object side of the re-imaging optical system CL. The positive lens is arranged at a position closest to the primary image plane IP1. The field curvature adjustment group VL moves from the position at the time of normal shooting toward the secondary imaging plane IP2 along the optical axis direction, so that the field curvature aberration becomes excessive, and the optical axis moves from the position at the time of normal shooting to the optical axis. By moving along the direction toward the primary imaging plane IP1, the field curvature aberration becomes under.

In the re-imaging optical system CL of the second embodiment, the position of the most object-side surface of the re-imaging optical system CL during normal shooting is 16.72 mm from the primary imaging plane IP1 to the secondary imaging plane IP2 side. It is a distant position. The re-imaging optical system CL of Example 2 has a lateral magnification (shooting magnification) of −2.0 and an F number of 5.65.

[Example 3]
FIG. 19 is a sectional view of the re-imaging optical system CL of the third embodiment.

20(A), 20(B), and 20(C) are aberration diagrams of the reimaging optical system CL of Example 3 at the time of normal photographing and the field curvature aberration are set to the over side, respectively. FIG. 6A is an aberration diagram when, and FIG. 8B is an aberration diagram when the field curvature aberration is set to the under side.

FIG. 21 is a sectional view at the wide-angle end when the re-imaging optical system CL of Example 3 is arranged on the image side of the main optical system ML of Example B.

22(A) and 16(B) respectively show the wide-angle end at the time of normal shooting when the re-imaging optical system CL of Example 3 is arranged on the image side of the main optical system ML of Example B. FIG. 3 is an aberration diagram at a telephoto end. 23A and 23B respectively show the setting of the over-field curvature aberration side when the re-imaging optical system CL of Example 3 is arranged on the image side of the main optical system ML of Example B. FIG. 7 is an aberration diagram at a wide-angle end and a telephoto end at the time. 24A and 24B respectively show the setting of the field curvature aberration under side when the re-imaging optical system CL of Example 3 is arranged on the image side of the main optical system ML of Example B. FIG. 7 is an aberration diagram at a wide-angle end and a telephoto end at the time.

In the re-imaging optical system CL of the third embodiment, the field curvature adjustment group VL is composed of one positive lens arranged closest to the image side of the re-imaging optical system CL. The positive lens is arranged at a position closest to the secondary image plane IP2. The field curvature adjustment group VL moves from the position at the time of normal shooting toward the primary imaging plane IP1 along the optical axis direction, so that the field curvature aberration becomes excessive, and the optical axis moves from the position at the time of normal shooting to the optical axis. By moving along the direction toward the secondary image plane IP2, the field curvature aberration becomes under.

In the re-imaging optical system CL of the third embodiment, the position of the most object-side surface of the re-imaging optical system CL during normal shooting is 4.03 mm from the primary imaging plane IP1 to the secondary imaging plane IP2 side. It is a distant position. The re-imaging optical system CL of Example 3 has a lateral magnification (shooting magnification) of 1.0 times and an F number of 5.65. Since the lateral magnification (shooting magnification) is -1.0 times, the size of the image can be aligned with the image formed by the main optical system ML, and the user uses only the interchangeable lens 200 having the main optical system ML. The field curvature aberration amount can be changed while maintaining the angle of view of.

[Example 4]
FIG. 25 is a sectional view of the re-imaging optical system CL of the fourth embodiment.

26(A), 26(B), and 26(C) are aberration diagrams of the reimaging optical system CL of Example 4 at the time of normal photographing and the field curvature aberration are set to the over side, respectively. FIG. 6A is an aberration diagram when the field curvature aberration is set to the under side and FIG.

27 is a cross-sectional view at the wide-angle end when the re-imaging optical system CL of Example 4 is arranged on the image side of the main optical system ML of Example B.

28A and 28B respectively show the wide-angle end at the time of normal shooting when the re-imaging optical system CL of Example 4 is arranged on the image side of the main optical system ML of Example B. FIG. 3 is an aberration diagram at a telephoto end. 29(A) and 29(B) are respectively set to the over-field curvature aberration side when the re-imaging optical system CL of Example 4 is arranged on the image side of the main optical system ML of Example B. FIG. 7 is an aberration diagram at a wide-angle end and a telephoto end at the time. 30(A) and 30(B) respectively show the setting of the field curvature aberration under side when the re-imaging optical system CL of Example 4 is arranged on the image side of the main optical system ML of Example B. FIG. 7 is an aberration diagram at a wide-angle end and a telephoto end at the time.

In the re-imaging optical system CL of Example 4, the field curvature adjustment group VL is composed of one positive lens arranged closest to the object side of the re-imaging optical system CL. The positive lens is arranged at a position closest to the primary image plane IP1. The field curvature adjustment group VL moves from the position at the time of normal shooting toward the primary imaging plane IP1 along the optical axis direction, so that the field curvature aberration becomes under, and the optical axis from the position at the time of normal shooting becomes the optical axis. By moving along the direction toward the secondary image plane IP1, the field curvature aberration becomes excessive.

In the re-imaging optical system CL of Example 4, the position of the most object-side surface of the re-imaging optical system CL during normal shooting is 3.00 mm from the primary imaging plane IP1 to the secondary imaging plane IP2 side. It is a distant position. The re-imaging optical system CL of Example 4 has a lateral magnification (shooting magnification) of −0.63 and an F number of 5.65.

[Example 5]
FIG. 31 is a sectional view of the re-imaging optical system CL of the fourth embodiment.

32A, 32B, and 32C are aberration diagrams of the reimaging optical system CL of the fifth embodiment at the time of normal shooting and the field curvature aberration are set to the over side, respectively. FIG. 6A is an aberration diagram when, and FIG. 8B is an aberration diagram when the field curvature aberration is set to the under side.

FIG. 33 is a sectional view when the re-imaging optical system CL of Example 5 is arranged on the image side of the main optical system ML of Example C.

34(A) and 34(B) respectively show the setting of the over-field curvature aberration side when the re-imaging optical system CL of Example 5 is arranged on the image side of the main optical system ML of Example C. FIG. 7 is an aberration diagram at a wide-angle end and a telephoto end at the time.

In the re-imaging optical system CL of the fifth embodiment, the field curvature adjustment group VL is composed of one positive lens arranged second from the object side of the re-imaging optical system CL. The field curvature adjustment group VL moves from the position at the time of normal shooting toward the primary imaging plane IP1 along the optical axis direction, so that the field curvature aberration becomes under, and the optical axis from the position at the time of normal shooting becomes the optical axis. By moving along the direction toward the secondary image plane IP1, the field curvature aberration becomes excessive.

In the re-imaging optical system CL of the fifth embodiment, the position of the most object-side surface of the re-imaging optical system CL during normal shooting is 3.14 mm from the primary imaging plane IP1 to the secondary imaging plane IP2 side. It is a distant position. The re-imaging optical system CL of Example 5 has a lateral magnification (shooting magnification) of 1.0 and an F number of 5.65.

[Numerical example]
Numerical Examples of the main optical system ML and Numerical Examples 1 to 5 corresponding to the re-imaging optical systems CL of Examples 1 to 5 will be shown.

Further, in each numerical example, the surface number indicates the order of the optical surface from the object side. r is the radius of curvature of the optical surface (mm), d at the surface number i is the distance (mm) between the i-th optical surface and the (i+1)th optical surface, and nd is the refractive index of the material of the optical member at the d-line, νd is the Abbe number of the material of the optical member based on the d line. The Abbe number νd of a certain material is the refractive index of d-line (587.56 nm), F-line (486.13 nm), C-line (656.27 nm) and g-line (wavelength 435.84 nm) of Fraunhofer line. , NC,
νd=(Nd-1)/(NF-NC)
It is represented by.

BF indicates back focus. The back focus in the numerical example of the main optical system ML is the distance on the optical axis from the most image-side surface of the main optical system ML to the image forming surface of the image formed by the main optical system ML, which is the air-equivalent length. Shall be indicated by. The back focus in the numerical example of the re-imaging optical system CL is expressed as the distance on the optical axis from the most image-side surface of the re-imaging optical system CL to the secondary imaging plane IP2 in terms of air-converted length. To do.

The total lens length in the main optical system ML is back to the distance on the optical axis from the most object side surface (first lens surface) of the main optical system ML to the most image side surface (final lens surface) of the main optical system ML. It is the length with focus added. The total lens length (TTD) of the re-imaging optical system CL is as described above.

The image height is the maximum image height that defines the half angle of view. The lateral magnification is the ratio of the image heights of the primary image and the secondary image.

When the optical surface is an aspherical surface, the symbol * is added to the right of the surface number. As for the aspherical shape, X is the amount of displacement from the surface vertex in the optical axis direction, H is the height from the optical axis in the direction perpendicular to the optical axis, R is the paraxial radius of curvature, K is the conic constant, A4, A6, When A8, A10, and A12 are aspherical coefficients of each order,

It is represented by. In each aspherical surface coefficient, “e±x” means “10 ^±x ”.

In the numerical examples of the main optical system ML, the part where the distance d between the optical surfaces is described as (variable) indicates that the distance changes during zooming.

In the numerical example of the re-imaging optical system CL, the part where the distance d between the optical surfaces is (variable) indicates that the distance changes when the field curvature is adjusted. In each of the numerical examples, the surface distances are set for normal shooting, when the field curvature aberration is set to the over side and when the field curvature aberration is set to the under side.

In addition, unless otherwise specified, values such as zoom ratio, focal length, F number, half angle of view, image height, total lens length, and BF indicate values at the time of normal shooting.

[Table 1] shows the physical quantities used in the conditional expressions described above and the values corresponding to the conditional expressions described above in each of Numerical Examples 1 to 5.

[Numerical Examples of Main Optical System]
(Main optical system of Example A)
Unit mm

Surface data Surface number rd nd vd
1 187.418 2.20 1.80810 22.8
2 76.661 8.55 1.72916 54.7
3 335.605 0.15
4 58.970 8.05 1.77250 49.6
5 158.730 (variable)
6* 167.209 1.55 1.76902 49.3
7 20.639 9.56
8 -49.152 1.00 1.76385 48.5
9 26.487 8.15 1.85478 24.8
10 -51.463 1.45
11 -42.283 5.85 1.48749 70.2
12 -19.110 1.20 1.88300 40.8
13* -64.186 (variable)
14 (aperture) ∞ 0.30
15 55.781 5.05 1.72916 54.7
16 ∞ 0.15
17 42.901 9.50 1.80400 46.6
18* -87.269 3.80
19 -50.369 1.50 1.73800 32.3
20 24.706 7.70 1.49700 81.5
21 166.989 (variable)
22 ∞ -2.59
23 30.373 7.30 1.43875 94.7
24 -664.868 0.15
25 48.839 5.50 1.59522 67.7
26 -100.131 0.57
27 66.531 4.55 1.49700 81.5
28 -115.190 1.20 1.80610 33.3
29 51.069 3.84
30* -1000.000 3.00 1.85400 40.4
31* 119.129 3.42
32 -39.992 1.30 1.48749 70.2
33 50.003 6.30 2.00 100 29.1
34 -131.617 (variable)
35 ∞ 1.96 1.51633 64.1
36 ∞ (variable)
Image plane ∞

Aspheric surface data 6th surface
K = 0.00000e+000 A 4= 4.38428e-006 A 6=-2.70954e-009 A 8= 4.53124e-012
A10=-5.11345e-016 A12= 2.85627e-018

Surface 13
K = 0.00000e+000 A 4=-2.04866e-006 A 6=-6.82741e-010 A 8=-2.06847e-011
A10= 9.28973e-014 A12=-1.47499e-016

Surface 18
K = 0.00000e+000 A 4= 2.64029e-006 A 6=-2.43625e-009 A 8=-1.84031e-012
A10=-2.30946e-017 A12= 4.15861e-018

30th side
K = 0.00000e+000 A 4=-4.43289e-005 A 6=-1.56326e-008 A 8= 3.31996e-010
A10=-1.13489e-012 A12= 2.02156e-015

Surface 31
K = 0.00000e+000 A 4=-2.52968e-005 A 6= 2.32789e-008 A 8= 3.09529e-010
A10=-9.01793e-013 A12= 1.19241e-015

Various data zoom ratio 2.35
Wide-angle mid-telephoto focal length 28.90 50.00 67.90
F number 2.06 2.06 2.06
Half angle of view 36.82 23.40 17.67
Image height 21.64 21.64 21.64
Total lens length 157.51 170.61 179.07
BF 2.75 2.75 2.75

d 5 3.93 20.98 29.21
d13 15.61 6.51 2.27
d21 8.67 4.59 3.61
d34 15.00 24.22 29.66
d36 2.75 2.75 2.75

Zoom lens group Data group Start surface Focal length
1 1 104.99
2 6 -19.17
3 14 47.05
4 22 44.67
CG 35 ∞

(Main optical system of Example B)
Unit mm

Surface data Surface number rd nd vd
1 204.560 2.10 1.84666 23.9
2 72.156 7.40 1.77250 49.6
3 333.009 0.15
4 56.551 6.70 1.77250 49.6
5 147.768 (variable)
6* 107.703 1.60 1.88300 40.8
7 16.578 7.87
8 -46.474 1.15 1.59522 67.7
9 21.417 4.45 1.88300 40.8
10 67.901 1.27
11 129.834 3.48 1.59270 35.3
12 -49.739 1.61
13 -23.347 1.15 1.72916 54.7
14 404.189 2.69 1.84666 23.9
15 -57.801 (variable)
16 ∞ 1.90
17 (Aperture) ∞ 0.00
18 27.563 1.45 1.88300 40.8
19 21.253 11.00 1.49700 81.5
20 -64.876 0.20
21 43.054 2.70 1.58313 59.4
22* 63.670 4.61
23 -44.565 1.40 1.72047 34.7
24 -153.891 (variable)
25 31.112 7.13 1.43875 94.9
26 -203.991 0.20
27 47.466 5.85 1.49700 81.5
28 -71.666 1.96
29* -205.992 2.10 1.85006 40.2
30* 88.343 2.63
31 -442.074 1.40 1.83400 37.2
32 61.478 5.17 1.51633 64.1
33 -61.478 (variable)
34 ∞ 1.96 1.51633 64.1
35 ∞ (variable)
Image plane ∞

Aspheric surface data 6th surface
K = 0.00000e+000 A 4= 7.12736e-006 A 6=-9.11631e-009 A 8= 2.35269e-011
A10=-5.05824e-014 A12= 7.73415e-017

22nd surface
K = 0.00000e+000 A 4= 5.39187e-006 A 6= 5.52428e-009 A 8=-8.87533e-012
A10= 1.15050e-013 A12=-9.43064e-017

Surface 29
K = 0.00000e+000 A 4= 2.73309e-005 A 6=-1.56548e-007 A 8= 3.98764e-010
A10=-7.46700e-013 A12= 6.95925e-016

30th side
K = 0.00000e+000 A 4= 4.43162e-005 A 6=-1.34466e-007 A 8= 3.25418e-010
A10=-4.48417e-013 A12= 2.53228e-016

Various data zoom ratio 2.75
Wide-angle mid-telephoto focal length 24.70 34.91 67.88
F number 2.91 2.91 2.91
Half angle of view (degrees) 41.22 31.79 17.68
Image height 21.64 21.64 21.64
Total lens length 154.68 162.21 186.04
BF 1.79 1.79 1.79

d 5 2.75 11.74 30.36
d15 13.71 7.72 0.23
d24 8.82 4.84 0.74
d33 35.00 43.51 60.31
d35 1.79 1.79 1.79

Zoom lens group Data group Start surface Focal length
1 1 106.37
2 6 -16.39
3 16 57.88
4 25 46.04
CG 34 ∞

(Main optical system of Example C)
Unit mm

Surface data Surface number rd nd vd
1 38.100 3.13 1.80400 46.6
2 -86.125 1.00 1.51742 52.4
3 11.970 1.40
4 14.745 2.40 1.72916 54.7
5 28.138 2.87
6 (Aperture) ∞ 5.48
7 -12.440 1.00 1.69895 30.1
8 77.467 3.39 1.83481 42.7
9 -19.410 0.15
10* -41.813 3.19 1.58313 59.4
11 -15.394 35.00
12 ∞ 1.96 1.51633 64.1
13 ∞ (variable)
Image plane ∞

Aspheric surface data surface 10
K = 0.00000e+000 A 4=-3.07394e-005 A 6= 3.02780e-008 A 8=-1.34249e-009
A10= 7.69227e-012

Various data zoom ratio 1.00
Focal length 39.00
F number 2.86
Angle of view 29.02
Image height 21.64
Total lens length 62.50
BF 2.21

d13 2.21

Lens group data
1 1 39.00
CG 34 ∞

[Numerical Examples of Reimaging Optical System]
(Numerical Example 1)
Unit mm

Surface data Surface number rd nd vd
1 ∞ (variable) * Primary image plane
2 ∞ 4.10 1.85 400 40.4
3* -33.449 0.19
4 -61.897 1.25 1.49700 81.5
5 30.560 (variable)
6 46.985 7.10 2.05090 26.9
7 -36.782 15.37
8 -20.485 0.85 1.85478 24.8
9 13.732 5.62 1.72916 54.7
10 -18.674 1.00
11 -17.043 1.00 1.56732 42.8
12 12.696 4.70 1.49700 81.5
13 -1094.747 0.15
14* 27.499 5.64 1.58313 59.4
15* -30.069 0.50
16 (aperture) ∞ 7.98
17 40.599 3.30 1.92286 20.9
18 -57.620 0.15
19 16.521 6.35 1.77250 49.6
20 -27.288 1.00 1.85478 24.8
21 11.156 12.81
22 -11.499 1.20 1.77250 49.6
23 5483.287 5.33
24 172.144 6.94 1.95375 32.3
25 -41.567 13.51
Image plane ∞

Aspherical data Third surface
K = 0.00000e+000 A 4= 2.02638e-005 A 6=-2.12398e-007 A 8= 2.64274e-009
A10=-1.41470e-011 A12= 3.07301e-014

14th surface
K = 0.00000e+000 A 4=-1.88989e-005 A 6= 2.06612e-007 A 8=-5.71987e-010
A10= 2.25515e-011 A12= 1.02091e-014

Surface 15
K = 0.00000e+000 A 4= 1.05246e-005 A 6= 1.08203e-007 A 8= 5.45766e-010
A10=-2.77310e-012 A12= 2.06681e-013


Focal length 29.32
F number 4.12
Half angle of view (degree) 36.42
Image height 21.64
Total lens length 98.49
BF 13.51
Lateral magnification -2.00

Variable interval (during normal use)
d 1 3.00
d 5 2.96

Variable spacing (when over field curvature aberration occurs)
d 1 5.00
d 5 0.96

Variable spacing (when under field curvature aberration occurs)
d 1 1.00
d 5 4.96

Lens group Data group Start surface Focal length
1 2 626.21 *Field curvature adjustment group
2 6 28.37

(Numerical example 2)
Unit mm

Surface data Surface number rd nd vd
1 ∞ (variable) * Primary image plane
2* 286.485 4.20 1.85400 40.4
3* -62.450 (variable)
4 40.336 1.25 1.84692 23.8
5 32.115 6.60 2.05090 26.9
6 -205.332 15.37
7 -27.921 0.85 1.85478 24.8
8 11.063 5.62 1.72916 54.7
9 -18.232 1.00
10 -19.511 1.00 1.56732 42.8
11 9.145 4.70 1.49700 81.5
12 40.178 0.15
13* 19.260 4.76 1.58313 59.4
14* -246.551 0.50
15 (aperture) ∞ 13.08
16 48.045 3.30 1.92286 20.9
17 -45.019 0.15
18 14.753 6.35 1.77250 49.6
19 -45.707 1.00 1.85478 24.8
20 10.480 10.35
21 -12.253 1.20 1.77250 49.6
22 -1567.932 5.93
23 155.067 6.94 1.95375 32.3
24 -42.394 16.39
Image plane ∞

Aspherical data 2nd surface
K = 0.00000e+000 A 4=-1.00971e-006 A 6=-1.79522e-008

Third side
K = 0.00000e+000 A 4= 3.28277e-006 A 6=-2.30664e-008 A 8= 9.73080e-011
A10=-4.06922e-013 A12= 6.20236e-016

Surface 13
K = 0.00000e+000 A 4= 3.65860e-006 A 6= 1.58109e-007 A 8= 2.44995e-008
A10=-4.06642e-010 A12= 2.22209e-012

14th surface
K = 0.00000e+000 A 4= 2.81052e-005 A 6= 6.05280e-008 A 8= 2.55900e-008
A10=-5.15021e-010 A12= 5.24451e-012


Focal length 39.04
F number 5.65
Half angle of view (degree) 28.99
Image height 21.64
Total lens length 52.27
BF 16.39
Lateral magnification -2.00


Variable interval (during normal use)
d 1 16.72
d 3 2.90

Variable spacing (when over field curvature aberration occurs)
d 1 17.72
d 3 1.90

Variable spacing (when under field curvature aberration occurs)
d 1 15.72
d 3 3.90

Lens group Data group Start surface Focal length
1 2 60.37 * Adjustment group
2 4 38.45

(Numerical Example 3)
Unit mm

Surface data Surface number rd nd vd
1 ∞ -8.26 * Primary image plane
2 41.678 10.18 1.85400 40.4
3* -71.663 10.06
4 -39.311 1.25 1.49700 81.5
5 165.878 3.68 2.05090 26.9
6 -76.376 16.98
7 -15.826 0.85 1.85478 24.8
8 6.511 3.82 1.77250 49.6
9 75.163 0.49
10 11.334 1.00 1.80810 22.8
11 9.681 3.66 1.49700 81.5
12 15.620 0.15
13* 9.428 2.05 1.85400 40.4
14* 16.348 1.29
15 (aperture) ∞ 0.18
16 26.842 2.78 1.89286 20.4
17 -20.234 0.15
18 20.418 7.49 1.80400 46.6
19 -6.220 1.00 1.85478 24.8
20 13.576 7.05
21 -6.032 1.20 1.84666 23.8
22 -13.292 (variable)
23 105.719 6.94 1.77250 49.6
24 -53.809 (variable)
Image plane ∞

Aspherical data Third surface
K = 0.00000e+000 A 4= 2.47081e-005 A 6=-2.83737e-007 A 8= 1.44448e-009
A10=-3.20040e-012 A12= 2.57263e-015

Surface 13
K = 0.00000e+000 A 4=-1.19840e-004 A 6= 6.86316e-008 A 8=-4.75239e-008
A10= 2.29146e-009 A12=-4.48752e-011

14th surface
K = 0.00000e+000 A 4= 1.94545e-004 A 6= 1.08293e-006 A 8=-7.04018e-008
A10= 3.70892e-009 A12=-6.90821e-011

Focal length 39.13
F number 5.65
Half angle of view (degree) 28.94
Image height 21.64
Total lens length 48.61
BF 10.00
Lateral magnification -1.00

Lens group Data group Start surface Focal length
1 1 24.51
2 23 47.05 *Field curvature adjustment group


Variable interval (during normal use)
d 22 4.03

Variable spacing (when over field curvature aberration occurs)
d 22 3.03

Variable spacing (when under field curvature aberration occurs)
d 22 5.03

(Numerical Example 4)
Unit mm

Surface data Surface number rd nd vd
1 ∞ (variable) * Primary image plane
2 46.047 13.89 1.85400 40.4
3* -54.959 (variable)
4 32.206 1.25 1.49700 81.5
5 12.990 14.60
6 858.480 0.85 1.91650 31.6
7 7.519 2.99 1.76182 26.5
8 19.256 0.50
9 10.111 1.00 1.80810 22.8
10 6.099 4.63 1.49 700 81.5
11 -31.946 0.15
12* 13.487 1.63 1.85400 40.4
13* 16.814 3.56
14 (aperture) ∞ 0.87
15 27.854 2.54 1.89286 20.4
16 -17.617 0.15
17 11.146 2.84 1.77250 49.6
18 -10.542 1.00 1.85478 24.8
19 7.323 7.48
20 -6.743 1.20 1.72342 38.0
21 -72.392 1.25
22 254.289 3.43 1.88300 40.8
23 -22.352 26.60
Image plane ∞

Aspherical data Third surface
K = 0.00000e+000 A 4= 8.03279e-006 A 6=-2.38055e-008 A 8= 7.83615e-011
A10=-1.12226e-013 A12= 5.97591e-017

Surface 12
K = 0.00000e+000 A 4=-6.06559e-006 A 6=-1.32350e-007 A 8= 5.37547e-008
A10= 1.05411e-008 A12=-3.22508e-010

Surface 13
K = 0.00000e+000 A 4= 6.17090e-005 A 6= 1.66296e-006 A 8=-4.52122e-007
A10= 6.49853e-008 A12=-2.28762e-009

Various data zoom ratio 1.00

Focal length 58.54
F number 3.64
Half angle of view (degree) 13.13
Image height 13.66
Total lens length 58.09
BF 26.60
Lateral magnification -0.63

Lens group Data group Start surface Focal length
1 1 ∞
2 2 31.32 *Field curvature adjustment group
3 4 15.62


Variable interval (during normal use)
d 1 3.00
d 3 15.87

Variable spacing (when over field curvature aberration occurs)
d 1 4.00
d 3 14.87

Variable spacing (when under field curvature aberration occurs)
d 1 2.00
d 3 16.87

(Numerical Example 5)
Unit mm

Surface data Surface number rd nd vd
1 ∞ -0.94 * Primary image plane
2 ∞ 3.75 1.81600 46.6
3* -199.466 (variable)
4 78.117 10.74 1.80400 46.6
5-64.098 (variable)
6 -17.334 0.85 1.72825 28.5
7 9.633 6.41 1.59522 67.7
8 -25.910 0.15
9* 14.605 3.63 1.73800 32.3
10* 20.967 3.92
11 (aperture) ∞ 0.60
12 32.832 2.70 1.89286 20.4
13 -27.513 0.15
14 17.355 4.13 1.80400 46.6
15 -12.717 1.00 1.85478 24.8
16 12.016 12.84
17 -9.075 1.20 1.84666 23.8
18 -41.476 2.78
19 -25.583 1.91 1.49700 81.5
20 -23.229 2.00
21 -271.779 6.94 2.05090 26.9
22 -34.012 12.32
Image plane ∞

Aspherical data Third surface
K = 0.00000e+000 A 4= 1.41579e-005 A 6=-8.38900e-008 A 8= 2.13861e-010
A10=-1.74101e-013 A12=-4.68480e-018

Side 9
K = 0.00000e+000 A 4= 1.07997e-005 A 6= 3.67521e-007 A 8=-5.62550e-009
A10= 7.60776e-011 A12= 8.17137e-013

Surface 10
K = 0.00000e+000 A 4= 8.04343e-005 A 6= 6.81723e-007 A 8=-1.66052e-008
A10= 3.57675e-010 A12=-8.77217e-014


Focal length 80.20
F number 5.60
Half angle of view (degree) 15.10
Image height 21.64
Total lens length 39.81
BF 12.32
Lateral magnification -1.00


Lens group Data group Start surface Focal length
1 1 244.44
2 4 45.32 *Field curvature adjustment group
3 6 27.87


Variable interval (during normal use)
d 3 3.14
d 5 39.80

Variable spacing (when over field curvature aberration occurs)
d 3 4.14
d 5 38.80

Variable spacing (when under field curvature aberration occurs)
d 3 2.14
d 5 40.80

[Example of interchangeable lens]
The present invention can be applied to an interchangeable lens in which the main optical system ML and the re-imaging optical system CL are configured in the same lens barrel and can be attached to and detached from the image pickup apparatus 100. The interchangeable lens may be a single focus lens or a zoom lens. In this case, the re-imaging optical system CL is configured to be insertable into and removable from the optical axis. The re-imaging optical system CL is arranged on or off the optical axis according to an instruction from the user via the operation member or the user interface. When the re-imaging optical system CL is arranged on the optical axis, the field curvature adjustment group VL moves, so that an interchangeable lens whose field curvature aberration can be adjusted compared with other aberration components can be obtained. it can.

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

ML Main optical system CL Re-imaging optical system VL Field curvature adjustment group IP1 Primary imaging surface IP2 Secondary imaging surface 100 Imaging device 200 Interchangeable lens 300 Converter device

Claims (17)

A converter device mounted between a lens device detachable from an imaging device and the imaging device,
The optical system included in the converter device is a re-imaging optical system that re-images the primary image formed by the lens device as a secondary image on an image plane,
The re-imaging optical system has a movable group movable along the optical axis,
The moving group has a distance from the image plane of the primary image at the time of normal shooting to the most object-side surface of the moving group and a distance from the most image-side surface of the moving group at the time of normal shooting to the image plane. When the smaller one of them is Dm and the total lens length of the re-imaging optical system is TTD,
|Dm|/TTD<0.40
A converter device satisfying the following conditional expression. When the height of the chief ray of the most off-axis light flux incident on the most object-side surface of the moving group during normal shooting is Hbi, and the maximum image height of the primary image during normal shooting is Hgi,
0.50<|Hbi/Hgi|<2.00
The converter device according to claim 1, wherein the following conditional expression is satisfied. When the lateral magnification of the moving group at the time of normal shooting is βm and the combined lateral magnification of all the lenses arranged on the image side of the moving group at the time of normal shooting is βr,
0.01<|(1-βm ² )βr ² |<1.50
The converter device according to claim 1 or 2, wherein the following conditional expression is satisfied. When the focal length of the moving group during normal shooting is fm and the focal length of the re-imaging optical system during normal shooting is f,
0.10<|fm/f|<50
The converter device according to any one of claims 1 to 3, which satisfies the following conditional expression. When the lateral magnification of the re-imaging optical system during normal photography is βc,
-10.0<βc<-0.45
5. The converter device according to claim 1, wherein the following conditional expression is satisfied. Let PI be the distance on the optical axis from the image plane of the primary image to the entrance pupil position of the re-imaging optical system during normal shooting, and f be the focal length of the re-imaging optical system during normal shooting. When
-10.0<PI/f<-1.00
6. The converter device according to claim 1, wherein the following conditional expression is satisfied. Let PO be the distance on the optical axis from the image plane of the primary image to the exit pupil position of the re-imaging optical system during normal shooting, and f be the focal length of the re-imaging optical system during normal shooting. When
-10.0<PO/f<-0.10.
7. The converter device according to claim 1, wherein the following conditional expression is satisfied. When the distance on the optical axis from the image forming plane of the primary image to the most object side surface of the re-imaging optical system during normal photographing is Di,
-0.30<Di/TTD<0.30
8. The converter device according to claim 1, wherein the following conditional expression is satisfied. When the distance on the optical axis from the most object-side surface of the re-imaging optical system to the image plane during normal shooting is skd and the focal length of the re-imaging optical system during normal shooting is f,
0.01<skd/f<1.00
9. The converter device according to claim 1, wherein the following conditional expression is satisfied. 10. The converter according to claim 1, wherein the moving group includes a lens disposed closest to the object side out of lenses having a refractive power included in the re-imaging optical system. apparatus. The converter device according to any one of claims 1 to 10, wherein the movable group has a positive refractive power. A converter device mounted between a lens device detachable from an imaging device and the imaging device,
The optical system included in the converter device is a re-imaging optical system that re-images the primary image formed by the lens device as a secondary image on an image plane,
The re-imaging optical system has a movable group movable along the optical axis,
The moving group includes the most object-side lens among the lenses having a refractive power included in the re-imaging optical system, the lens disposed adjacent to the image side of the most object-side lens, and the most image-side lens. A converter device including any one of lenses disposed adjacent to the object side of the most image side lens. Having an operation member used for instructing adjustment of field curvature aberration,
The converter device according to any one of claims 1 to 12, wherein the moving group is moved according to an operation of the operation member. The lens device is detachably mounted via the converter device according to any one of claims 1 to 13, and has an image sensor for receiving the secondary image formed by the re-imaging optical system. An imaging device characterized by the above. Having an operation member used for instructing adjustment of field curvature aberration,
The image pickup apparatus according to claim 14, wherein the moving group is moved according to an operation of the operation member. 16. The image pickup apparatus according to claim 14, wherein a lens that moves during focusing among the lenses that form the main optical system moves according to the movement of the moving group. An interchangeable lens that has a main optical system and a re-imaging optical system that re-images a primary image formed by the main optical system as a secondary image on an image plane, and is detachable from an imaging device. ,
The re-imaging optical system has a movable group movable along the optical axis,
The moving group has a distance from the image plane of the primary image at the time of normal shooting to the most object-side surface of the moving group and a distance from the most image-side surface of the moving group at the time of normal shooting to the image plane. When the smaller one is Dm and the total lens length of the re-imaging optical system CL is TTD,
|Dm|/TTD<0.40
An interchangeable lens characterized by satisfying the following conditional expression.

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