JP3217273B2 - Camera system and interchangeable lens - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera system, a camera body, and an interchangeable lens in which the mounting of an interchangeable lens having a fixed back focus or less is restricted by the camera body. .

[0002]

2. Description of the Related Art Conventionally, in a camera system of this type, when the mount shape of a camera body and an interchangeable lens is common to each other, the interchangeable lens and the camera body can be mounted even if the back focus is different. is there. In rare cases, in the case of wide-type interchangeable lenses, the back focus is short and the rear end of the interchangeable lens may hit the mirror of the camera body. It is customary.

[0003] In such a camera system, the mount itself may be renewed and changed in order to make use of the characteristics of the interchangeable lens.

On the other hand, Japanese Utility Model Laid-Open No. 25435/1993 discloses that even though the basic mount shape is almost the same, the mutual bayonet mount claw of the intermediate adapter and the interchangeable lens that can be mounted is attached to
A camera system having a projection and a notch is disclosed.

[0005]

However, in the above-mentioned prior art, even if the back focus of the camera body is short (for example, about 38 mm from the film surface), the interchangeable lens can be mounted, and the camera cannot be used. When the photographer uses the mirror up when hitting the mirror, there is a risk that the mirror of the camera is damaged due to the carelessness of the photographer, and the photographing itself is restricted.

On the other hand, depending on the manufacturer's convenience, the back focus is short (for example, a back focus of 30 mm or less).
Changing the conventional mount itself, including the position of the metal back, in order to prepare a large number of interchangeable lenses wastes the conventional camera system. The disadvantage is great for the manufacturer.

The invention of Japanese Utility Model Laid-Open No. 25435/1993 discloses a case in which a projection and a notch are provided on a mutual bayonet mount claw of an interchangeable lens which can be mounted on an intermediate adapter, that is, the relationship between whether or not the intermediate adapter and a specific lens can be mounted. Because there is
This can be handled by partially changing the shape of both mounts at the same time. However, in the case of a camera body and an interchangeable lens, if the basic mount shape is the same, the new camera body can be fitted with all interchangeable lenses, and the old camera body can not be fitted with only a specific lens It is difficult.

[0008]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, a metal back from a mount reference surface to a film surface has the same size and a body-side mount has the same shape. And a second camera body, and a camera system having a common lens-side mount engaged with the body-side mount, and a plurality of interchangeable lens groups having different back focuses .
It said first camera body, as is possible the attachment of any of the interchangeable lens unit, in the interior of the body side mount,
The second camera body has a relief portion over the mounting range of the interchangeable lens group, and the second camera body has a flange inside the body-side mount so that only the interchangeable lens group having a back focus of a certain size or more can be mounted. Part ,
Interchangeable lens group with back focus less than a certain size
When trying to attach it to the second camera body
Interfering with the flange portion inside the body side mount,
Fix the mounting projections that hinder the mount
The fixing projection is provided on the inner side of the body.
Lens side electrical contacts connected to the body side electrical contacts
It is a protection member for protecting the air contact .

According to a second aspect of the present invention, in the camera system according to the first aspect, when the protection member is attached to the first or second camera body, the first or second camera body is attached to the first or second camera body. It is characterized in that a buffer portion for buffering the contact with the constituent member on the camera body side is provided.

According to a third aspect of the present invention, a plurality of camera bodies having the same size of metal back from the mount reference surface to the film surface and having the same shape of the body-side mount, and a common camera body engaged with the body-side mount. An interchangeable lens used in a camera system having a plurality of interchangeable lens groups having a lens-side mount, having a back focus of a certain size or less, and having a flange provided inside the body-side mount. When an attempt is made to mount the camera body to which only the interchangeable lens group having the above-mentioned back focus can be mounted, the fixing protrusion interferes with the flange portion inside the body side mount and hinders the mount coupling.
A protrusion is provided on an inner diameter portion of the lens-side mount between the lens-side mount and the optical system, and the fixing protrusion is provided on the body.
For connecting to the body-side electrical contacts provided on the side mount
A protection member for protecting the lens-side electrical contact .

[0011] A fourth aspect of the present invention, in the interchangeable lens according to claim 3, wherein the protective member, when an attempt is attached to the plurality of camera body, the contact between the camera body side of the component It is characterized in that a buffer portion for buffering is provided.

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION

(Camera System) FIGS. 1 to 4 are sectional views showing a main part of an embodiment of a camera system according to the present invention. FIGS. 5 and 6 are cross-sectional views showing the first and second interchangeable lenses of the present embodiment. 7 and 8 are sectional views showing the first and second camera bodies of the present embodiment. FIG. 9 is a sectional view and a side view showing another embodiment of the first interchangeable lens. The camera system according to this embodiment includes first and second interchangeable lenses 10 and 20, and first and second camera bodies 30 and 40. First interchangeable lens 1
0 is short back focus (back focus 30
mm to about 38 mm) (see FIGS. 1, 3, 5, and 9). The second interchangeable lens 20 is a lens having a long back focus (a back focus of about 38 mm or more) (see FIGS. 2, 4, and 6). The first camera body 30 is a body to which the first and second interchangeable lenses 10, 20 can be attached (see FIGS. 1, 2, and 7). The second camera body 40 is a body that can only be mounted with the second interchangeable lens 20 having a certain back focus or more (see FIGS. 3, 4, and 8). Hereinafter, the detailed structures of the first and second interchangeable lenses 10 and 20 and the first and second camera bodies 30 and 40 will be described.

(First Interchangeable Lens) FIG. 5A is a sectional view schematically showing an interchangeable lens 10 having a short back focus C (back focus of about 30 mm to 38 mm). The interchangeable lens 10 has the optical systems 1 and 2 in a lens barrel. The metal back A is the distance from the film surface 100 to the mount reference surface 101. G is the distance between the rear end portion 10a of the lens and the mount reference plane 101.

FIG. 5B is a view of the interchangeable lens 10 as viewed from behind the lens-side mount 3. The lens-side mount 3 includes a bayonet mount claw 3a, a mount opening 3
b are alternately arranged. The lens-side mount 3 is provided with a fixing protrusion 10a between the inner diameter side and the optical system 2 so as to interfere with the flange portion 141a of the second camera body 40 (see FIG. 8) when the mount is mounted. Further, the lens-side mount 3 is located between the inner diameter side and the optical system 2 and at a position one step lower than the fixing protrusion 10a,
A plane portion 10b is provided.

(Second Interchangeable Lens) FIG. 6A is a cross-sectional view schematically showing an interchangeable lens 20 having a long back focus B (a back focus of about 38 mm or more). The interchangeable lens 20 has optical systems 21 and 22 in a lens barrel. The metal back A has the same length as the interchangeable lens 10. F is the distance between the rear end portion 20a of the lens and the mount reference plane 101.

FIG. 6B is a view of the interchangeable lens 20 as viewed from behind the lens-side mount 3. The lens-side mount 3 includes a bayonet mount claw 3a, a mount opening 3
b are alternately arranged and have the same shape as the mount of the interchangeable lens 10.

(First Camera Body) FIG. 7 is a sectional view showing the first body 30. First camera body 30
Includes a body-side mount 130. The body-side mount 130 has bayonet mount claws 130a and mount openings 130b alternately arranged, and the shape is the same as that of the body-side mount 14 of the second camera body 40.
Same as 0. Since the first camera body 30 also supports an interchangeable lens having a shorter back focus than a second camera body 40 described later, the shape of the mirror 31 is slightly smaller than that of the first body 40, It is approaching the film surface 100.

The body side mount 130 has a rear portion,
The camera body 30 has a fixed part that also serves as a mirror box 131, and as shown in FIG.
, A flat recess 131a is formed. In order to avoid interference with the part behind the lens-side mount 3 of the interchangeable lens 10 having a short back focus, the flat concave portion 131a is used when the lens is mounted.
This is a portion that avoids the protrusion of the inner diameter portion.
E is a flat concave portion 1 from the body side mount reference surface 102.
The dimensions are up to 31a. The trajectory of the mirror 31 passes through the film surface side from the flat concave portion 131a.

(Second Camera Body) FIG. 8 is a sectional view showing the second body 40. Second camera body 40
Includes a body-side mount 140. The body-side mount 140 has bayonet mount claws 140a and mount openings 140b alternately arranged. The body-side mount 140 has a fixing portion that also serves as a mirror box 141 of the body at a rear portion thereof. As shown in FIG. 8A, a flat flange portion 141a is formed on the right side and an upper portion of the mirror 41. ing. D is a dimension from the body-side mount reference surface 102 to the flat flange portion 141a. The trajectory of the mirror 41 is the flat flange portion 1
The film passes through the film surface side from 41a.

To summarize the above dimensional relationships, the camera system is configured so that E> G> D> F, B + F> A, and C + G> A.

Next, whether the first or second camera body and the first or second interchangeable lens of the camera system according to the present embodiment can be mounted will be described. The first interchangeable lens 10 has a short back focus B,
Since the first camera body 30 can be attached to all the interchangeable lenses, as shown in FIG.
0 can be attached to the first camera body 30.

When the first interchangeable lens 10 and the first camera body 30 are mounted, the luminous flux is
And a part of the light is reflected by a quick return mirror 31 having a semi-transmissive portion, enters the finder optical system, passes through a reticle 32, a condenser lens 33, a pentaprism 34, and an eyepiece 35, and Reach the eyes. On the other hand, the remaining light flux passes through the semi-transmissive portion of the mirror 31 and passes from the reflecting mirror 36 through the lens 37 to the light receiving element 38.
The focus detection circuit 39 determines the focus based on the output of the light receiving element 38. These are known techniques and will not be described further.

Since the second interchangeable lens 20 has a long back focus and the second body 30 can be mounted on all the interchangeable lenses, as shown in FIG. It can be mounted on one camera body 30.

Here, the first interchangeable lens 10 has a short back focus, and the second body 40 can only be attached with an interchangeable lens having a certain back focus or more. Therefore, as shown in FIG. The fixed protrusion 10a at the rear end of the first interchangeable lens 10 and the flange 141a behind the body-side mount 140 of the second body 40 interfere with each other. Therefore, the combination of the first interchangeable lens 10 and the second camera body 40 cannot be mounted even if their mount shapes are the same.

The second interchangeable lens 20 has a long back focus, and the second body 40 can only be attached with an interchangeable lens having a certain back focus or more. Therefore, as shown in FIG. The interchangeable lens 20 of the second
Can be mounted on the body 40.

(Another Embodiment of First Interchangeable Lens) FIG. 9
FIG. 5A is a view of another embodiment of the interchangeable lens 10 as viewed from the rear of the lens mount 3. FIG. 9B is a side view showing a part of another embodiment of the interchangeable lens 10.
In the following description, the same members as those in the first embodiment will be denoted by the same reference numerals, and detailed description of those portions will be omitted.

The interchangeable lens 10 is provided with an electric contact 50 connected to an electric contact on the camera body 30 side for supplying power and communicating information. As shown in FIG. 9, the fixing protrusion 10a is provided so as to surround the electric contact 50 around the optical axis O of the interchangeable lens 10. Specifically, the fixed protrusion 10a extends from the upper part of the aperture lever 60 to the upper part of the attachment / detachment groove 3d in a counterclockwise direction (in FIG. 9A, a position directly above the optical system 2 about the optical axis O is sandwiched). About ± 40 °
Is provided so as not to interfere with the aperture lever 60 and the detachable groove 3d. Thus, when the first interchangeable lens 10 is mounted on the first camera body 30, the electrical contacts 50 can be protected by the fixing protrusions 10a. Also, when the first interchangeable lens 10 is carried or stored, it is possible to prevent another member from contacting the electrical contact 50 and being damaged.

The fixing projection 10a can be provided with inclined surfaces 10c and 10d at both ends around the optical axis O. Thus, when the first interchangeable lens 10 is mounted on the first camera body 30, the slopes 10c and 10d
The contact between the zero and the components inside the first camera body 30 is reduced, and these members are prevented from being damaged. Also, the first
When trying to mount the interchangeable lens 10 of the first embodiment eccentrically on the body-side mounts 130 and 140, the first interchangeable lens 1
0 lens-side mount 3 is turned in the opposite direction to that in normal mounting, or the first interchangeable lens 10 is
Even when mounted on the zero or second camera body 40 at a position different from the normal position, it is possible to prevent the aperture lever 60 and the components inside the first camera body 30 from being damaged.

Various modifications and changes are possible without being limited to the above-described embodiment, and these are also within the equivalent scope of the present invention. For example, the camera system of the present embodiment may include another interchangeable lens group having a different back focus.

[0036]

As described above, according to the present invention, the first camera body escapes the inside of the mount on the body side over the mounting range of the interchangeable lens so that all the interchangeable lenses can be mounted. When trying to mount an interchangeable lens shorter than a certain back focus, the camera body of No. 1 interfered with the flange part and the fixing member, and prevented the mount coupling, so for the first camera body,
It is possible to use a wide variety of interchangeable lenses, which is advantageous for the user.

On the other hand, for the manufacturer side, by providing a back focus lens that cannot be mounted on a conventional camera, a camera corresponding to a lens with a short back focus is prepared, although the camera body is restricted. This enables the development of lenses that were previously considered impossible in the specifications.

[Brief description of the drawings]

FIG. 1 is a principal partial sectional view showing an embodiment of a camera system (a combination of a first interchangeable lens and a first camera body) of the present invention.

FIG. 2 is a principal partial sectional view showing an embodiment of a camera system (a combination of a second interchangeable lens and a first camera body) of the present invention.

FIG. 3 is a main partial sectional view showing an embodiment of a camera system (a combination of a first interchangeable lens and a second camera body) of the present invention.

FIG. 4 is a principal partial sectional view showing an embodiment of a camera system (a combination of a second interchangeable lens and a second camera body) of the present invention.

FIG. 5 is a cross-sectional view showing a first interchangeable lens of the present embodiment.

FIG. 6 is a cross-sectional view illustrating a second interchangeable lens of the present embodiment.

FIG. 7 is a cross-sectional view showing a first camera body of the embodiment.

FIG. 8 is a cross-sectional view illustrating a second camera body of the present embodiment.

9A is a cross-sectional view illustrating another embodiment of the first interchangeable lens, and FIG. 9B is a side view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 1st interchangeable lens 20 2nd interchangeable lens 10a Fixing protrusion 10c, 10d Slope 30 First camera body 40 Second camera body 50 Electrical contact 131a Flat concave portion 141a Flat flange portion 3 Lens side mount 130, 140 Body Side mount

Continuation of the front page (72) Inventor Hiroshi Tanioka 3-2-3 Marunouchi, Chiyoda-ku, Tokyo Nikon Corporation (56) References JP-A-9-269535 (JP, A) JP-A-8-43909 (JP) JP-A-53-66220 (JP, A) JP-A-2-163728 (JP, A) JP-A-58-140727 (JP, A) JP-A-58-72134 (JP, A) 5-25435 (JP, U) Actual opening Hei 5-55137 (JP, U)

Claims (4)

(57) [Claims] 1. A first and a second camera body in which a metal back from a mount reference surface to a film surface has the same dimensions and a body-side mount having the same shape, and a common lens engaged with the body-side mount. And a plurality of interchangeable lens groups having different back focal lengths, wherein the first camera body is provided with a side mount so that any of the interchangeable lens groups can be mounted. Inside,
The second camera body has an escape portion over a mounting range of those interchangeable lens groups, and the second camera body can be mounted only by an interchangeable lens group having a back focus of a certain size or more.
A flange portion is provided inside the body-side mount, and the interchangeable lens group having a back focus smaller than a certain size interferes with the flange portion inside the body-side mount when trying to mount the second camera body. ,
A fixing protrusion that prevents mount coupling is provided on the inner diameter portion of the lens-side mount, and the fixing protrusion is a protection member that protects a lens-side electric contact connected to a body-side electric contact provided on the body-side mount. Characterized camera system. 2. A camera system according to claim 1, wherein the protective member, when an attempt is attached to the first or second camera body, the configuration of the first or second camera body A camera system, comprising: a buffer unit that buffers contact with a member. 3. A plurality of camera bodies having the same size of metal back from the mount reference surface to the film surface and the same body-side mount, and a common lens-side mount engaged with the body-side mount. An interchangeable lens used for a camera system having a plurality of interchangeable lens groups, having a back focus of a certain dimension or less, and a back focus of a certain dimension or more provided with a flange portion inside the body side mount. When an attempt is made to mount the camera body to which only the interchangeable lens group having the mountable lens group can be mounted, the fixing protrusion between the lens side mount and the optical system interferes with the flange portion inside the body side mount and hinders the mount coupling. The fixing protrusion is provided on an inner diameter portion of the lens-side mount, and the body-side electrode provided on the body-side mount is provided. An interchangeable lens, which is a protection member for protecting a lens-side electrical contact connected to an air contact. 4. A replacement lens according to claim 3, wherein the protective member is to attached to said plurality of camera body
If was Utoshi, interchangeable lens, wherein the buffering section is provided to cushion the contact between the camera body side of the component.