JPH0157771B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a single-lens reflex camera, in which the light beam from a photographing lens is reflected by a flip-up mirror disposed behind the lens and projected onto a focus plate for focusing. This relates to a shutter that uses a raised mirror.

This type of shutter has traditionally been known as a mirror shutter. With this mirror shutter, the time it takes for the flip-up mirror to jump up from the reflection position where it reflects the light flux from the photographing lens and return to this reflection position (more precisely, the time it takes for the flip-up mirror to reflect the light flux from the photographic lens) The exposure time of the film with the light from the photographing lens, that is, the shutter speed, is controlled by controlling the time during which the light from the photographing lens jumps out of the optical path.

In conventional cameras using this mirror shutter, the diaphragm is placed inside the photographic lens, so the operation of the diaphragm and shutter must be linked to each other during shooting, but the structure of this interlocking mechanism is The process is very complicated, it is not possible to achieve a high shutter speed, and there are disadvantages in that exposure unevenness occurs.

SUMMARY OF THE INVENTION An object of the present invention is to provide a program-controlled mirror shutter that has a simple structure and can control the aperture size of the aperture and the shutter speed at the same time.

The program-controlled mirror shutter according to the present invention is characterized in that by controlling the amount of movement of the flip-up mirror, that is, the amount of flip-up, the shutter speed is controlled and the size of the aperture of the diaphragm is also controlled. It is something. That is, the program-controlled mirror shutter according to the present invention is a single-lens reflex camera equipped with a photographing lens for rear aperture and a flip-up mirror disposed at approximately 45 degrees with respect to the optical axis of the photographing lens. an auxiliary diaphragm member disposed such that its raised position can be set to block a lower portion of the light beam from the front edge of the mirror; has an aperture whose top part is approximately triangular, and moves integrally with the mirror to form a diaphragm aperture together with the auxiliary diaphragm member so as to block the upper part of the light flux from the photographing lens. A main diaphragm whose aperture size is changed according to the size of the movement.
a shutter blade; a holding member that integrally holds the blade and the mirror; a closing direction spring member that urges the blade in a direction to close the diaphragm opening; a raised position of the auxiliary diaphragm member; an aperture control member that controls the size of the aperture by simultaneously setting the raised position of the aperture control member; an exposure setting member that sets the exposure by controlling the position or orientation of the aperture control member; It is characterized by comprising a mirror jumping means for flipping up the blade together with the mirror against the force of the closing direction spring member, and wherein programmed exposure control is performed by the aperture control member controlled by the exposure setting member. be.

The program controlled mirror shutter of the present invention includes:
As described above, the aperture aperture size and shutter speed can be controlled simultaneously, and a complicated interlocking mechanism between the aperture and shutter is not required, resulting in a simple structure and low camera manufacturing costs. It has the advantage of becoming

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a program-controlled mirror shutter according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic perspective view for explaining the principle of a camera incorporating a program-controlled mirror shutter 1 of the present invention.

The camera is equipped with a taking lens 2 designed for a rear aperture for purposes to be explained later. A support plate 4, which constitutes an example of a holding member according to the present invention, is disposed at the rear of the photographic lens 2 and whose rear edge is rotatably attached to a shaft 3. This support plate 4 is biased counterclockwise by a coil spring 5, which is an example of the closing direction spring member of the present invention and is wound around the shaft 3. From the front edge of the support plate 4 downward,
A main diaphragm/shutter blade 6 having a substantially cylindrical shape centered on the shaft 3 is provided. As shown unfolded in FIG. 2, this blade 6 has an opening 7 formed in its center. The opening 7 has a triangular top and a vertically elongated rectangular portion below it. A light shielding plate 8 is disposed on the substantially fan-shaped side surface formed by the support plate 4 and the blade 6. A protrusion 9 protrudes from a portion of the lower part of the light shielding plate 8 for the purpose to be explained later.

A mirror 10 is mounted on the support plate 4, and the box 11 formed by the mirror 10, the support plate 4, the blade 6, and the light shielding plate 8 rotates together around the axis 3. and is biased counterclockwise by a spring 5. A stopper 12 is disposed at the rear of the box 11, and the box 11 is prevented from rotating further in the counterclockwise direction by coming into contact with the stopper 12, as shown by the dashed line in the figure. There is.
When the box body 11 is in the position shown by this dashed line,
The mirror 10 on the support plate 4 is positioned on the optical axis of the photographic lens 2 at an angle of 45 degrees with respect to this optical axis.

Like a normal single-lens reflex camera, a focusing plate P is arranged above the mirror 10, and a film surface F is located behind the mirror 10 and at a position optically conjugate with the focusing plate P with respect to the mirror. It is provided. When the box body 11 is in the position indicated by the dashed line in the figure, the mirror 10 is on the optical axis of the photographic lens 2 and forms an angle of 45 degrees with it, as described above, so that it cannot be seen from the photographic lens. The beam of light is projected onto the reticle. Focusing is performed using this projected image. This position of the mirror at which the light beam from the photographing lens is reflected is hereinafter referred to as the reflection position.

In front of the mirror 10 and the box body 11, an auxiliary diaphragm member 13 for blocking the lower part of the light beam from the photographing lens 2 is arranged so as to be movable in the vertical direction. This diaphragm member 13 has a T-shape on its side, and is biased upward by a spring 14. A protrusion 15 is formed in the vertical portion of the diaphragm member 13 and protrudes horizontally therefrom.
This protrusion 15 is operated by one arm 18 of a lever 17 whose center is pivotally supported by a rotating shaft 16 . This lever 17 is biased clockwise by a spring 19 attached to an arm 18. Since this spring 19 is stronger than the spring 14, when the arm 18 rotates clockwise and comes into contact with the protrusion 15, the rotational force of the arm is greater than the upward force of the auxiliary aperture member 13. force, so that arm 18 rotates further clockwise and presses down on the auxiliary diaphragm member. It is necessary to provide a stopper so that the auxiliary throttle member stops being pushed down to an appropriate position. Lever 17
The arm 18 is rotated counterclockwise in response to force upon shutter release, and this rotation causes the arm 18 to disengage from the protrusion 15. Then, the auxiliary throttle member 13 is raised by the action of the spring 14.

At the rear of the protruding part 9 of the box body 11, this protruding part 9
A jumping member 20 is provided which constitutes a mirror jumping means that flips up the box body 11 and the mirror 10 so as to integrally rotate clockwise. A spring 21 is attached to the jumping member 20, which becomes charged when the film is wound up. The jumping member 20 is normally locked at the position shown by the dashed line by a locking means. This locking means is designed to be unlocked in conjunction with the shutter release. When this lock is released, the jumping member 20 moves in the direction shown by the arrow and hits the protrusion 9, causing the box 11 and the mirror 10 to jump up. When the box body is lifted up, the aperture 7 provided in the blade 6 is located on the optical axis of the photographic lens 2, so that the light beam from the photographic lens 2 passes through the aperture 7 and is projected onto the film surface F. The aperture 7 of the blade 6 and the auxiliary aperture member 13 combine to create an aperture 2
form 2. Therefore, it is desirable that the auxiliary throttle member be placed as close as possible to the raised blade 6. In FIG. 3, the light beam from the photographing lens 2 is shown by a dashed line. It is desirable that the diaphragm aperture 22 is formed so that its center substantially coincides with the central axis of the light flux, that is, the optical axis of the photographic lens 2. When the opening 22 is enlarged, the arrangement of the blade 6 and the auxiliary diaphragm member 13 is as shown in FIG.

The size of the diaphragm opening 22 increases in proportion to the amount of lift of the blade 6, and decreases in proportion to the amount of rise of the auxiliary diaphragm member 13. The amount of jump of the blade 6 and the amount of rise of the auxiliary aperture member 13 are controlled by the aperture control means 23. This opening control means 23 has a lever 25 pivotally mounted on a rotating shaft 24. This lever 25 consists of arms 26 and 27 extending in opposite directions from the rotation axis. One of these arms 26
The arm 27 is in contact with the support plate 4 to control the amount of rise of the blade 6, and the other arm 27 is in contact with the vertical portion of the auxiliary diaphragm member 13 to control the amount of rise of the auxiliary diaphragm member. It is for. The blade 6 is raised so that the top end of the aperture 7 is above the central axis of the light beam from the lens, and the auxiliary diaphragm member 13 is raised so that the top edge of the auxiliary diaphragm member is above the central axis of the light beam from the lens. Therefore, the amount of jump of the blade 6 and the amount of rise of the auxiliary diaphragm member 13 are determined to be below the central axis of the light beam (the light of the photographing lens 2). control is almost symmetrical about the axis).

A pin 28 is attached to the front of the arm 26 of the lever 25.
The position of this pin is adjusted by an exposure control cam surface 30 provided on the inner peripheral edge of an exposure control ring 29, which constitutes an example of the exposure setting member of the present invention. This pin 28 is connected to the cam surface 3
0, the lever 25 is biased counterclockwise by a spring means. When the pin 28 is pushed down by the cam surface 30, the lever 25 is rotated clockwise, so that the arm 26 is lowered and the arm 27 is raised. Therefore,
Since the amount of jump of the blade 6 becomes smaller and the amount of rise of the auxiliary aperture member 13 becomes larger, the size of the aperture opening 22 formed becomes smaller. Conversely, when lever 25 rotates counterclockwise, arm 26 rises and arm 27 falls. Therefore blade 6
The amount of jump-up increases, and the amount of rise of the auxiliary diaphragm member 13 decreases, so that the diaphragm aperture 22 formed
becomes larger.

Also, depending on the position of the arm 26, the blade 6
It is also possible to control the time during which the aperture 22 jumps up and forms the diaphragm aperture 22.

Next, the shutter release operation in the program controlled shutter of the present invention will be described with reference to FIGS. 5, 6 and 7 (blade 6 is shown in an expanded state in FIGS. 5, 6 and 7).

Before the shutter release, as shown in FIG.
is the lower position (first
The robot is waiting at the position indicated by the broken line in the figure. When the blade 6 is in this position, the mirror 10 is placed in the reflection position and reflects the light beam L upward to the focusing plate P.
The image of the subject is projected onto it.

Next, press the shutter release button (not shown)
When the auxiliary throttle member 13 is pushed down, the auxiliary diaphragm member 13 first rises to a position where it comes into contact with the arm 27, as shown in FIG. 6, and is set at this position.

Further, when the shutter release button is pressed down, the jump member 20 is released and the spring 2 is released.
1 in the direction of the arrow (FIG. 1) and hit the protrusion 9. Then, the blade 6 is raised to a position where the support plate 4 comes into contact with the arm 26, as shown in FIG. 7, thereby forming the diaphragm opening 22. At this time, the film is exposed to light passing through the aperture 22. As the blade 6 returns to its original position by the action of the spring 5, the blade 6 closes in the opening 22.
Close.

In this way, both aperture and shutter speed can be controlled simultaneously.

As described above, according to the program-controlled mirror shutter of the present invention, it is possible to simultaneously control the shutter and the aperture aperture with a simple structure by utilizing the action of flipping up the mirror.

Furthermore, since a mechanism for linking the lifting of the mirror with the opening and closing of the diaphragm is not required, the structure of the camera becomes simple and the manufacturing cost becomes low.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view for explaining the principle of the program-controlled mirror shutter of the present invention, and FIG.
The figure is a developed view of the main diaphragm/shutter blade used in the program-controlled mirror shutter of the present invention, and Figures 3 and 4 show the aperture aperture formed by the main diaphragm/shutter blade and the auxiliary diaphragm member. FIGS. 5, 6 and 7 are explanatory diagrams showing aspects of the shutter release in the program-controlled mirror shutter of the present invention. DESCRIPTION OF SYMBOLS 1... Program control mirror shutter, 2... Taking lens, 6... Main diaphragm/shutter blade, 13... Auxiliary diaphragm member, 20... Jumping member, 2
3...Control member, F...Film surface, P...Focal plate.

Claims (1)

[Scope of Claims] 1. In a single-lens reflex camera equipped with a rear aperture photographing lens and a flip-up mirror disposed at approximately 45 degrees with respect to the optical axis of the photographing lens, the light beam from the photographing lens is directed downwardly. an auxiliary diaphragm member disposed such that its raised position can be set to block light from the mirror; It has a triangular aperture, moves integrally with the mirror to form a diaphragm aperture together with the auxiliary diaphragm member, and blocks the upper part of the light beam from the photographic lens, and the size of the diaphragm aperture is The main aperture is designed to change according to the magnitude of the movement.
a shutter blade; a holding member that integrally holds the blade and the mirror; a closing direction spring member that urges the blade in a direction to close the diaphragm opening; a raised position of the auxiliary diaphragm member; an aperture control member that controls the size of the aperture by simultaneously setting the raised position of the aperture control member; an exposure setting member that sets the exposure by controlling the position or orientation of the aperture control member; The program control comprises a mirror jumping means for flipping up the blade together with the mirror against the force of the closing direction spring member, and the program exposure control is performed by the aperture control member controlled by the exposure setting member. Mirror shutter.