JPH08286273A - Single lens reflex camera - Google Patents

Abstract

PURPOSE: To realize high speed consecutive photographing by visually confirming a subject image by a finder means for visually confirming the subject image not through a photographing lens but through a pentagonal prism by keeping a mirror in an up-state from the point of time when photographing is started. CONSTITUTION: When an external mirror 10 is moved to a position B, the subject image is observed through the objective lens 8 of a finder, a prism 9, the pentagonal prism 6 and an ocular (finder optical path Y). At the time of consecutive photographing, the mirror 10 is retreated to the position B as soon as mirror-up operation is started. Photographing is executed while confirming the switched finder at the time of high speed consecutive photographing. Since the image obtained by the finder optical path Y is confirmed on the finder at the time of consecutive photographing, image loss does not occur and the state of the subject is stably confirmed even at the time of quick photographing. As soon as the final shutter operation is executed and the mirror-down operation is performed at the time of consecutive photographing, the mirror 10 is restored to a home position A. At the time other than consecutive photographing, the mirror 10 is disposed at the position A and the mirror 3 repeats rising and lowering every one shot.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-lens reflex camera that switches between two types of finder means, and by switching between two types of finder means, high-speed continuous shooting is possible that is faster than that of an ordinary single-lens reflex camera. Concerning continuous shooting single-lens reflex camera.

[0002]

2. Description of the Related Art FIG. 6 shows a basic structure of a conventional single-lens reflex camera. The subject image light beam that has passed through the taking lens 4 is reflected by the mirror 3, is focused on the focus glass 5, and is visually recognized from the eyepiece 7 through the pentaprism 6. The photographer performs focusing by checking the image formation state on the focus glass. As the mirror, a total reflection mirror is generally used. At the time of exposure, the mirror is flipped up and the object image light beam that has passed through the taking lens reaches the shutter 1 and the film 2 for exposure. When the exposure is completed, the mirror descends again and returns to the original state. During continuous shooting, the mirror repeatedly moves up and down in conjunction with exposure and film winding.

Also, in some single-lens reflex cameras, a system is adopted in which the light flux from the photographing lens is divided into an eyepiece lens and a film by making the mirror semi-transparent, and the mirror is not flipped up even during photographing. There is.

[0004]

In the conventional single-lens reflex camera in which the mirror repeatedly moves up and down, the movement speed of the mirror is limited and the continuous shooting speed is limited. In the case of a general 35 mm single-lens reflex camera, the speed is limited to about 5 frames per second. Also, as the continuous shooting speed becomes faster, the subject image confirmed with the viewfinder will blink at a faster speed,
The mirror stop position is also unstable, making it difficult to see. Also, the generation of sound accompanying the raising and lowering of the mirror increases as the continuous shooting speed increases.

In a single-lens reflex camera in which a semitransparent mirror is fixed, the movement of the mirror is unnecessary, so that
A model that achieves a speed of about 10 frames per second with a single-lens reflex camera is commercially available. Further, since there is no image disappearance in the viewfinder during exposure, it is possible to shoot while confirming a stable viewfinder image. However, this type of single-lens reflex camera has some disadvantages and is not widely used. First of all, since the light flux passing through the taking lens is divided into two, the amount of light reaching each of the film and the finder is reduced in principle. Originally, high-speed continuous shooting is required when shooting a subject with a lot of movement such as sports shooting, so it is necessary to increase the shutter speed as much as possible. It is against this requirement that the amount of light reaching the film surface is reduced. Secondly, since something other than the photographing optical system enters the optical path reaching the film surface, the image quality is deteriorated. In order to suppress the deterioration of image quality, the mirror is made of an extremely thin film, but there are problems such as ghost. Also, if dust adheres to the mirror itself,
The image quality is affected unlike the general single-lens reflex camera. With single-lens reflex cameras, the mirror is exposed when the lens is replaced, so it is difficult to take measures against dust. Third,
Since the amount of light reaching the eyepiece is reduced in principle, the finder image becomes dark. Due to these problems, a single-lens reflex camera with a semitransparent mirror fixed is not generally used except for users who need high-speed continuous shooting.

Some single-lens reflex cameras take pictures with the mirror raised during high-speed continuous shooting. With this method, there are no disadvantages during normal shooting, but during high-speed continuous shooting the viewfinder is completely invisible, making it impossible to check the framing and subject condition. Therefore, the application is limited, for example, when the camera is fixed to a tripod or the like in advance and the composition is fixed to perform continuous shooting.

Further, in the conventional single-lens reflex camera, since the photometry is usually performed with the aperture open, it is necessary to perform the aperture operation each time the image is taken. However, when performing high-speed continuous shooting, shooting is performed with the aperture stopped down during continuous shooting in order to increase the continuous shooting speed, but this makes the viewfinder image darker when the aperture value is other than full aperture.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems of the prior art, and has an automatic film winding mechanism, a mirror for switching the optical path of a subject image, and a pentaprism finder. A reflex camera, a first finder means for visually recognizing a subject image that has passed through the taking lens, the mirror, and the pentaprism finder, and a second finder means for visually recognizing the subject image through the pentaprism without passing through the taking lens. In normal speed shooting, the first viewfinder means for normal shooting, and in high speed continuous shooting, the mirror is kept up from the start of shooting and the second viewfinder means is used to view the subject image. Provides a single-lens reflex camera for high-speed continuous shooting.

Further, according to the present invention, the switching between the first finder means and the second finder means is carried out by setting a subject side surface of the pentaprism as a transmitting surface and inserting and removing a mirror along the surface. Provide a camera.

Furthermore, the present invention is a single-lens reflex camera having an automatic film winding mechanism, a mirror for switching the optical path of a subject image, and a pentaprism finder, wherein the subject passes through the taking lens, the mirror, and the pentaprism finder. A first finder means for visually recognizing an image and a second finder means for visually recognizing a subject image through a pentaprism without passing through a photographing lens are provided, and normal photographing using the first finder means and a mirror from the start of photographing There is provided a single-lens reflex camera capable of maintaining a close-up state and switching between special photographing performed by visually recognizing a subject image by the second finder means.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 show an embodiment of the present invention, in which the same parts are designated by the same reference numerals. FIG. 1 shows the structure of a single-lens reflex camera according to the present invention. A subject image light beam that has passed through a taking lens 4 is reflected by a mirror 3, is focused on a focus glass 5, and is observed from an eyepiece 7 through a pentaprism 6. . The pentaprism 6 is different from the conventional single-lens reflex camera, and the final reflecting surface 6a on the optical path is not attached with a reflecting material such as silver or aluminum. Therefore, the function of the conventional single-lens reflex finder cannot be achieved only by this pentaprism. The external mirror 10 is provided outside the reflecting surface 6a.
Is attached. The external mirror 10 is movable and is usually arranged at a position facing the reflecting surface 6a. As a result, the pentaprism functions as a normal single-lens reflex finder, and the photographer can perform focusing by checking the image formation state on the focus glass (finder optical path X). When the external mirror 10 is retracted from the position of the reflection surface 6a, the state of the finder is switched, and a subject image is observed through the objective lens 8, prism 9, pentaprism 6 and eyepiece 7 of the finder.
From the eyepiece 7, the light beam that has passed through the finder optical system is guided (finder optical path Y).

FIG. 2 shows the switching state of the finder. When the external mirror 10 is in the position A, the finder functions as a normal single-lens reflex finder through the optical path X, and when the external mirror 10 moves to the position B, the objective lens 8, the prism 9, the pentaprism 6 and the eyepiece of the finder. A subject image is observed through the lens 7 (finder optical path Y). At this time, since the mirror 3 is flipped up, the optical path of the subject image from the taking lens 4 to the finder is blocked. The subject image viewed from the eyepiece 7 by the viewfinder optical path Y is adjusted to a predetermined magnification by a known means. A small motor or the like is used to drive the external mirror 10. The magnification of the finder optical path Y is set so that the same field of view as that of the taking lens 4 can be obtained, but it is configured as a zoom system to support a plurality of interchangeable lenses.

FIG. 3 shows the switching timing of the finder at the time of photographing. A is a shooting standby state, and a general single-lens reflex camera performs photometry, distance measurement, and the like. In the case of a manual-focus single-lens reflex camera, focusing can be performed on the focus glass. B shows the state during continuous shooting according to the present invention. At the same time when the mirror-up is started, the external mirror 10 retracts to the position B. High-speed continuous shooting is performed while checking the viewfinder that has been switched. Since the image obtained by the viewfinder optical path Y can be confirmed on the viewfinder during continuous shooting, the state of the subject can be stably confirmed without image disappearance during continuous shooting. At the same time as the final shutter operation is performed in continuous shooting and mirror down is performed, the external mirror 10 returns to the original A position. When other than continuous shooting or when normal continuous shooting is selected, the external mirror 10 is arranged at the position A and the mirror 3 repeats ascending and descending for each shot, as in a normal single-lens reflex camera.

FIG. 4 shows an example in which the high-speed continuous shooting system of the present invention is applied to a single-lens reflex camera in which the pentaprism portion can be exchanged. In the single-lens reflex camera of the present invention, the pentaprism portion is larger than that of a normal single-lens reflex camera, so that a user who does not need high-speed continuous shooting becomes an unnecessarily large camera. Therefore, the pentaprism can be replaced, and the normal finder and the finder for achieving the high-speed continuous shooting system according to the present invention can be replaced. The camera body 11 and the finder 12 are electrically coupled by the connector 13.

FIG. 5 shows an example of electrical control of the configuration example of FIG. The CPU 14 on the camera side reads the attribute information written in the ROM of the finder through the connector 13. In the case of a normal finder, the shooting mode shown in the present invention does not shift regardless of the setting switches 15. The finder is switched by a finder switching signal from the CPU 14.

It should be noted that the viewfinder switching is performed by the external mirror 1.
In addition to the insertion / removal of 0, a device such as a liquid crystal or a birefringent substance can be used to statically switch between reflection and transmission by applying an electric field.

According to the present invention, in addition to performing normal photographing using the first finder means, the mirror is kept in the up state from the start of photographing and the subject image is visually recognized by the second finder means. By doing so, it is possible to realize a single-lens reflex camera that can perform shooting in a special state in which sound and vibration associated with the up / down movement of the mirror 3 are eliminated.

[0018]

According to the present invention, high-speed continuous shooting can be performed with a single-lens reflex camera. Also, unlike the conventional special high-speed continuous shooting camera, when high-speed continuous shooting is not performed, shooting can be performed in the same manner as a normal single-lens reflex camera, and there is no fear of degrading the performance of the optical system. Also, during high-speed continuous shooting, you can shoot while looking at the stable viewfinder screen with no image loss.

Further, according to the present invention, the finder image does not become dark even when the diaphragm is closed during high-speed continuous shooting.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the configuration of a single-lens reflex camera according to the present invention.

FIG. 2 is a schematic diagram showing the internal structure of an example product of the present invention.

FIG. 3 is a diagram showing a control sequence of an example product of the present invention.

FIG. 4 is a schematic view showing the appearance of an example product of the present invention.

FIG. 5 is a diagram showing control signals of the product of the embodiment of the invention.

FIG. 6 is a schematic diagram showing the internal structure of a conventional single-lens reflex camera.

[Explanation of symbols]

 1 Shutter 2 Film 3 Mirror 4 Photographic Lens 5 Focus Glass 6 Penta Prism 7 Eyepiece 8 Objective Lens 9 Prism 10 External Mirror 11 Camera Main Body 12 Finder 13 Connector 14 CPU 15 Setting Switches

Claims (3)

[Claims] 1. A single-lens reflex camera having an automatic film winding mechanism, a mirror for switching an optical path of a subject image, and a pentaprism finder for visually recognizing a subject image passing through a photographing lens, a mirror, and a pentaprism finder. Equipped with a first finder means and a second finder means for visually recognizing a subject image through a pentaprism without passing through a taking lens, and in normal speed shooting, normal shooting is performed by the first finder means and high-speed continuous shooting is performed. In this case, the single-lens reflex camera is characterized in that the mirror is kept in the up state from the start of shooting and the subject image is visually recognized by the second finder means for high-speed continuous shooting. 2. The switching between the first finder means and the second finder means is performed by using a surface of the pentaprism on the object side as a transmitting surface and inserting and removing a mirror along the surface. The single-lens reflex camera according to claim 1. 3. A single-lens reflex camera having an automatic film winding mechanism, a mirror for switching an optical path of a subject image, and a pentaprism finder, wherein a subject image passing through the taking lens, the mirror and the pentaprism finder is visually recognized. And a second viewfinder means for visually recognizing a subject image through the pentaprism without passing through the taking lens, and the normal shooting using the first viewfinder means and raising the mirror from the start of shooting. A single-lens reflex camera, characterized in that the single-lens reflex camera is maintained in this state and switched between special photographing performed by visually recognizing a subject image by the second finder means.