JP3074965U - Camera close-up attachment - Google Patents

Abstract

(57) [Problem] To provide a close-up attachment that is easy to assemble and that makes the light amount in the central part and the peripheral part of the master lens uniform. SOLUTION: A screw peripheral surface that meshes with each other is formed on a front end side fitting surface of a cylindrical support frame and a transparent frame, and a concave peripheral surface is formed behind the screw peripheral surface, and the mutual screw peripheral surface and the concave peripheral surface are rotated. The frame is loosely fitted, and the transparent frame is non-rotatably pressed by a screw. A filter is provided at the center opening of the cylindrical support frame to uniformly adjust the light amount at the center and the periphery of the master lens. The filter may be a two-sided parallel filter in which a convex spherical body with a limited light transmittance and a transparent concave spherical body are joined, or a convex lens with a limited light transmittance.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a close-up attachment that is coupled to the front of a master lens of a camera and presses a mask (photographing range frame) at a tip against a subject surface to photograph.

[0002]

[Background of the Invention]

 As shown in FIG. 5, the close-up attachment 3 used by being attached to the front of the master lens 2 of the camera 1 has a mask 5 for regulating the photographing range frame formed at the tip of a transparent frame 4 having a predetermined length. . The camera 1 and the mask 5 need to be oriented in order to shoot with the camera 1 in the correct direction. However, the close-up attachment 3 is generally rotated around the tip of the barrel of the master lens 2 of the camera 1 and screwed. Therefore, the directions of the camera 1 and the mask 5 do not always coincide with each other at the position where the combination is completed, that is, the position where the subject is in focus.

For this purpose, a close-up attachment 3 of this type has conventionally been divided into a cylindrical support frame 6 screwed to the distal end of the barrel of the master lens 2 and a transparent frame 4 rotatably connected to the distal end thereof. After the support frame 6 has been connected to the master lens 2 side, the transparent frame 4 is rotated and aligned, and the position is fixed with screws 7 or the like.

In this case, the rotation engagement between the cylindrical support frame 6 and the transparent frame 4 must be a mechanism that does not shift the focus of the subject due to rotation, and the entire close-up attachment 3 composed of the cylindrical support frame 6 and the transparent frame 4 The transparent frame 4 must be non-rotatably and integrally connected to the cylindrical support frame 6 in order to be able to be attached and detached by one operation. For this reason, as shown in FIG. 5, the conventional close-up attachment 3 divides the transparent frame 4 into a connecting ring 4a connected to the cylindrical support frame 6 and a transparent frame main body 4b connected to the distal end side of the connecting ring 4a. At the same time, a locking ring 8 screwed to the tip of the cylindrical support frame 6 is separately prepared, and the connecting ring 4a is rotatably fitted to the outer periphery of the cylindrical support frame 6; The connecting ring 4a is rotatably connected to the cylindrical support frame 6 by screwing the locking ring 8 to the outer periphery of the distal end, and then the transparent frame body 4b is screwed to the distal end of the connecting ring 4a.

[0005] Such a conventional close-up attachment has a large number of parts and is not only complicated in processing, but also requires time and labor for assembling and increases costs.

Therefore, a first object of the present invention is to provide a close-up attachment for a camera which has a simple structure and is easy to assemble.

When a close-up of a subject is performed using this type of close-up attachment, the master lens has a difference in light amount (brightness) between a central portion and a peripheral portion. There was a problem that the part became dark.

Accordingly, a second object of the present invention is to provide a close-up attachment having the above-described structure, which can take a picture with uniform brightness at the center and the periphery of a video screen.

In order to achieve the first object, the close-up attachment of the present invention includes a cylindrical support frame attached to a distal end of a barrel of a master lens of a camera body, and a rotatable distal end of the cylindrical support frame. A cylinder having a transparent frame of a predetermined length fitted with a mask of a photographing range frame at the end thereof, and locking means for fixing the transparent frame to the cylindrical support frame so as to be non-rotatable; The fitting surface of the support frame and the transparent frame has a screw peripheral surface that meshes with each other on the front end side facing each other, and has a concave peripheral surface behind it. The screw peripheral surface and the concave peripheral surface are formed so as to be loosely fitted and rotatably coupled to each other, and the locking means penetrates from the outside of the support frame to the concave peripheral surface and engages with the fitting surface of the transparent frame. Cannot rotate It is characterized by being a screw that is in pressure contact with.

In order to achieve the second object, the close-up attachment of the present invention includes a filter for equalizing the amount of light at the center and the periphery of the master lens at the center opening of the cylindrical support frame facing the master lens. Is provided.

A close-up attachment of this type is capable of enlarging a subject and taking a close-up. Generally, as a means for enlarging and taking a close-up of a subject, a means for adjusting a focal length between a camera body and a master lens is used. When setting the length of the transparent frame of the close-up attachment so that it fits the focal length with the intermediate tube interposed, and when enlarging close-ups, or when the master lens is directly connected to the camera body, lenses of various magnifications are attached to the close-up attachment. In some cases, close-up photography is performed by setting the length of the transparent frame so as to match the mounting and focal length. In the former case, the filter is made of a material with limited light transmittance, and one side has a convex spherical body. A filter parallel to both sides is used in which a filter body with the other side formed as a flat surface and a transparent concave spherical body are used, and in the latter case, the filter is optically transparent. A convex lens of a predetermined magnification with a limited rate is used.

[0012]

[Embodiment of the invention]

 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. 1 and 2 show an embodiment of a close-up attachment according to the present invention. First, the structure of the close-up attachment frame structure common to both embodiments will be described. As shown in FIGS. 1 and 2, the close-up attachment 3 according to the present invention has a cylindrical support frame 6 attached to the distal end of the lens barrel 9 of the master lens 2 of the camera 1, and is rotatable around the distal end of the cylindrical support frame 6. It has a transparent frame 4 of a predetermined length integrally connected, and a locking means 10 for fixing the position of the transparent frame 4 to the cylindrical support frame 6 so as not to rotate.

The cylindrical support frame 6 integrally has a relatively short cylindrical portion 6b in front of a base block 6a having an opening formed in the center, and the outer periphery of the base block 6a has a distal end of a lens barrel 9 of the master lens 2. The screw thread for screwing to the mounting screw portion 11 is formed.

The transparent frame 4 has a connecting portion of a size fitted on the inner peripheral surface of the cylindrical portion 6b of the cylindrical support frame 6 on the rear end side, and a predetermined portion for restricting the photographing range frame of the subject on the front end side. It is made of a transparent material (plastic, glass, etc.) that is made of a cylindrical body with a length and through which light from the outside can enter.

As shown in FIG. 3, the inner peripheral surface of the cylindrical portion 6b of the cylindrical support frame 6 is formed with a thread 6c having a predetermined width at the front, and has a predetermined width at the rear end at the rear thereof. A flat concave peripheral surface 6d is formed. On the other hand, the outer peripheral surface of the rear end mounting portion of the transparent frame 4 fitted to the cylindrical portion 6b of the cylindrical support frame 6 is screwed to the thread 6c of the cylindrical portion 6b of the cylindrical support frame 6, and further advanced. After the engagement is released, a thread 4c having a predetermined width is formed to fit into the concave peripheral surface 6d of the cylindrical portion 6b, and the thread 6c of the cylindrical support frame 6 fits in front of the thread 4c. A concave peripheral surface 4d having a flat width is formed. Preferably, the concave peripheral surface 6d of the cylindrical portion 6b of the cylindrical support frame 6 is equal to or slightly wider than the width of the thread 4c of the transparent frame 4, and the concave peripheral surface 4d of the transparent frame 4 is cylindrical. The width of the thread 6c of the cylindrical portion 6b of the support frame 6 is equal to or slightly larger than the width.

Thus, when the thread 4c at the tip of the transparent frame 4 is screwed into the thread 6c of the cylindrical portion 6b of the cylindrical support frame 6 and fed toward the rear end of the cylindrical portion 6b, the transparent frame 4 and the cylindrical support frame When the screw threads 4c, 6c of the No. 6 are released, the threads 4c, 6c of the mating surfaces are fitted with the concave peripheral faces 6d, 4d, and the transparent frame 4 is pulled out from the cylindrical support frame 6. It is integrated so as to be rotatable in an impossible state.

An interlocking means 10 for fixing the transparent frame 4 to the cylindrical support frame 6 so as to be non-rotatable is provided between the cylindrical support frame 6 and the transparent frame 4. The locking means 10 in the illustrated embodiment comprises a screw hole 12 formed in the cylindrical portion 6b of the cylindrical support frame 6 and a screw 7 screwed into the screw hole 12. 4, the transparent frame 4 is non-rotatably fixed to the cylindrical support frame 6. In the illustrated embodiment, the screw hole 12 of the locking means 10 is formed toward the thread 4c of the transparent frame 4, but may be formed toward the concave peripheral surface 4d of the transparent frame 4. The latter structure is suitable for the case where the deformation of the thread 4c of the transparent frame 4 is eliminated and the transparent frame 4 can be replaced.

Thus, when the close-up attachment 3 is connected to the master lens barrel 9 of the camera, the base block 6a of the cylindrical support frame 6, which integrally connects the transparent frame 4 so as to be rotatable, is attached to the tip mounting screw of the barrel 9. After screwing to the part 11, the transparent frame 4 is rotated to align the mask 5 with the camera 1, and the screw 7 of the locking means 10 is tightened to fix the transparent frame 4 so that it cannot rotate.

The close-up attachment 3 of the present invention adjusts the central opening of the cylindrical support frame 6 facing the master lens 2 of the camera 1 so that the light amount at the center and the peripheral portion of the master lens 2 becomes uniform. A filter 13 is mounted for the operation. This filter 13 controls the amount of light entering the peripheral portion of the master lens 2 to be brighter than the amount of light entering the central portion so that the photographing screen becomes uniform. However, as shown in FIG. A camera in which an intermediate cylinder 14 is interposed between the body 1a and the master lens 2 to adjust the magnification, and a center of the close-up attachment 3 with the master lens 2 directly connected to the camera body 1a as shown in FIG. The structure of the camera of the type in which the magnification is adjusted by the convex lens 15 attached to the opening is different as follows.

That is, as shown in FIG. 1, the filter 13 of the close-up attachment 3 when the magnification of the subject is adjusted by interposing an intermediate cylinder 14 for adjusting the magnification between the camera body 1 a and the master lens 2. Is made of a material such as glass or plastic whose light transmittance is restricted, and a convex spherical body 16a having one side formed as a convex spherical surface having a predetermined curvature and the other side formed as a flat surface, and a glass, plastic or the like. The filter is made of a transparent material, and is formed of a two-sided parallel filter in which one side is formed as a concave spherical body corresponding to the convex surface of the convex spherical body 16a and the other side is joined to a concave spherical body 16b formed as a plane. I have.

On the other hand, as shown in FIG. 2, the filter 13 of the close-up attachment 3 when a camera in which the master lens 2 is coupled to the camera body 1a and the magnification is adjusted by the convex lens 15 attached to the close-up attachment 3 is used. It is composed of a convex lens 15 made of a material whose rate is limited.

The light transmittance limiting material used for the filter 13 is a gray glass or plastic lens having a light transmittance of 50% or less.

Usually, the amount of light at the periphery of the photographic lens of the camera is about 60% of the amount of light at the center. Therefore, in this case, in order to make the amount of light in the peripheral portion and the central portion uniform, the filter 13 of the embodiment of FIG. 1 requires the convex spherical body 16a constituting the filter 13 to have a curvature R1 of a convex spherical body. 16a is designed so that the thickness T1 of the central portion and the thickness T2 of the peripheral portion are about 2: 1. Similarly, the filter 13 of the embodiment of FIG. 2 has the thickness T1 of the central portion and the thickness of the peripheral portion. The curvatures R1 and R2 on both surfaces of the convex lens 15 are designed so that T2 is about 2: 1.

Thus, the filter 13 of each of the embodiments shown in FIGS. 1 and 2 has a convex spherical body 16a or a convex lens 15 whose light transmittance is restricted, so that the light amount in the peripheral portion is about twice as large as that in the central portion. Therefore, the light amounts at the central portion and the peripheral portion of the master lens 2 are made uniform.

In this case, since the filter 13 of the embodiment shown in FIG. 1 is constituted by a two-sided parallel filter in which the convex spherical body 16a and the transparent concave spherical body 16b are joined, the filter itself has no influence on the magnification. The magnification is adjusted exclusively by the intermediate cylinder 14 interposed between the camera body 1a and the master lens 2. As described above, the close-up attachment 3 of the embodiment of FIG. 1 is used for a camera that determines the magnification by adjusting the focal length by the intermediate tube 14 on the camera side. In this case, the lens barrel length of the close-up attachment 3 The distance L1 from the rear principal point H2 of the master lens 2 to the camera film surface 17 is

(Equation 1) In contrast, the distance L2 from the front principal point H1 of the master lens 2 to the tip of the mask 5 of the close-up attachment 3 is

(Equation 2) Is determined so that In Equations (1) and (2), F1 is the focal length of the master lens, M is the magnification of the master lens, F2 is F1 × M, T3 is the overall thickness of the filter 13 having both parallel surfaces, and n is the refractive index of the filter ( BK7 ≒ 1.5163), and FIG. 1 shows a case where the magnification is the same.

On the other hand, in the close-up attachment 3 of the embodiment shown in FIG. 2, since the filter 13 itself is composed of the convex lens 15, the magnification can be adjusted by using the camera in which the master lens 2 is directly connected to the camera body 1a. In this case, the lens barrel length F3 of the close-up attachment 3 in this case is determined based on the combined focal length of the master lens 2 and the filter convex lens 15. 1 and 2, the position of the tip mask 5 of the close-up attachment 3 is set to be the focal position.

[0027]

[Effect of the invention]

 In the close-up attachment of the present invention, the fitting surface of the cylindrical support frame and the transparent frame is formed on the screw peripheral surface and the concave peripheral surface, and the screw peripheral surface and the concave peripheral surface are rotatably fitted at the correct fitting position. As a result, a close-up attachment that is simple to manufacture, has a small number of parts, and is ready for assembly can be obtained.

By providing the close-up attachment with a filter for controlling the amount of light transmitted between the center and the periphery, the amount of light at the center and the periphery of the master lens becomes uniform, and the decrease in the periphery of the captured image becomes darker is improved. You.

The use of a filter in which a convex spherical body having a limited light transmittance and a transparent concave spherical body are joined in parallel to each other makes it possible to cope with a camera whose magnification is adjusted by an intermediate cylinder.

By configuring the filter with a convex lens whose light transmittance is limited, magnification adjustment and uniform light quantity can be handled by one lens.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a close-up attachment according to an embodiment of the present invention;

FIG. 2 is a longitudinal sectional view of a close-up attachment according to another embodiment of the present invention;

FIG. 3 is a front side view of a close-up attachment.

FIG. 4 is a sectional view of a main part of the close-up attachment.

FIG. 5 is a sectional view of a main part of a conventional close-up attachment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Camera 1a ... Camera body 2 ... Master lens 3 ... Close-up attachment 4 ... Transparent frame 4a ... Connection ring 4b ... Transparent frame main body 4c ... Thread 4d ... Concave peripheral surface 5 ... Mask 6 ... Cylindrical support frame 6a ... Base end block 6b: Cylindrical portion 6c: Thread 6d: Concave peripheral surface 7: Screw 8: Locking ring 9: Master lens barrel 10: Locking means 11: Mounting screw portion 12: Screw hole 13: Filter 14: Intermediate tube 15 ... Convex lens 16a: convex spherical body 16b: concave spherical body 17: camera film surface

[Reference number] UMS00-004

Claims (4)

[Utility model registration claims] A cylindrical support frame attached to the distal end of a barrel of a master lens of a camera body; a cylindrical support frame rotatably fitted to the distal end side of the cylindrical support frame; A transparent frame, and locking means for fixing the transparent frame to the cylindrical support frame so that the transparent frame cannot rotate. The fitting surfaces of the cylindrical support frame and the transparent frame are meshed with each other at the front ends facing each other. It has a screw peripheral surface, and has a concave peripheral surface behind it, so that the mutual screw peripheral surface and concave peripheral surface are loosely fitted and rotatably coupled at the correct fitting position. The close-up attachment for a camera, wherein the locking means is a screw that penetrates from the outside of the support frame into the concave peripheral surface and presses the fitting surface of the transparent frame in a non-rotatable manner. 2. A cylindrical support frame attached to the end of a barrel of a master lens of a camera body, and a cylindrical support frame rotatably fitted to the end of the cylindrical support frame and having a mask of a shooting range frame at the end. A transparent frame, and locking means for fixing the transparent frame to the cylindrical support frame so that the transparent frame cannot rotate. The fitting surfaces of the cylindrical support frame and the transparent frame are meshed with each other at the front ends facing each other. It has a screw peripheral surface, and has a concave peripheral surface behind it, so that the mutual screw peripheral surface and concave peripheral surface are loosely fitted and rotatably coupled at the correct fitting position. The locking means comprises a screw which is threaded from the outside of the support frame to the concave peripheral surface to press the fitting surface of the transparent frame non-rotatably, and further comprises the cylindrical support opposed to the master lens. 2. A close-up attachment for a camera according to claim 1, wherein a filter is provided at a central opening of the frame to uniformly adjust the amount of light at the central portion and at the peripheral portion of the master lens. 3. A close-up attachment for a camera according to claim 2, wherein the filter is a filter having both surfaces parallel to each other in which a convex spherical body having a limited light transmittance and a transparent concave spherical body are joined. 4. The close-up attachment for a camera according to claim 2, wherein the filter is a convex lens having a limited light transmittance.