JPH01200239A - Photographing system for single-lens reflex camera - Google Patents

Abstract

PURPOSE:To shorten the height of a camera by appropriately arranging a reflecting mirror and a reflection type prism so that a finder optical system can be constituted. CONSTITUTION:At the time of photographing, a photographic lens 2 and a 1st reflecting mirror 4 are arranged on positions shown by a continuous line so as to guide luminous flux passing through a lens 2 to a focal plate 6 through the reflecting mirror 4 and a 1st reflecting prism 5 to form a finder image. Next, the finder image is observed at an eye level with an eyepiece lens 10 through a 2nd reflecting prism 8 and a 2nd reflecting mirror 9 as the erect image of an object. At the time of not photographing, the reflecting mirror 4 is turned and stopped on a position shown by a dotted line and the lens 2 is housed in a camera main body on the position of a dotted line. Since the finder optical system can be constituted without using a conventional pentagonal prism with such a constitution, the height of the camera main body can be shortened. And since a part of or all of the photographing lens can be housed in the main body at the time of not photographing the total length of the camera can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a photographing system for a single-lens reflex camera suitable for a photo camera, a video camera, etc., and particularly to a photographing system for a single-lens reflex camera suitable for photo cameras, video cameras, etc. The present invention relates to a photographing system for a single-lens reflex camera that allows the photographic lens to be housed within the camera body, thereby reducing the overall size of the camera.

(Prior Art) In recent years, there has been a demand for eye reflex cameras to be as compact as lens shutter cameras.

- In an eye reflex camera, especially a photographic camera, the light beam from the subject that passes through the photographic lens is reflected in the height direction toward the camera by a rotating reflecting mirror, and then a finder image is formed on the focusing plate. A finder optical system in which a finder image is observed through an eyepiece through a pentaprism is often used.

For this reason, there has been a tendency for the entire camera to increase in size in the height direction by an amount corresponding to the size of the pentaprism.

Furthermore, since the photographic lens is attached to the curved surface of the camera body, the overall size of the camera increases by an amount corresponding to the length of the photographic lens. In particular, when a photographic lens with a long overall length, such as a zoom lens or a telephoto lens, is attached, the overall size of the camera tends to become larger.

(Problems to be Solved by the Invention) The present invention constructs a finder optical system by appropriately arranging a plurality of reflecting mirrors and a plurality of reflecting prisms without using a conventional pentaprism, thereby reducing the size of the entire camera. The object of the present invention is to provide a photographing system for a single-lens reflex camera that is particularly compact in the height direction.

A further object of the present invention is to provide a photographing system for a single-lens reflex camera in which a part of the photographic lens attached to the front of the camera body can be stored inside the camera body, making it easy to downsize the entire camera when not photographing. be.

(Means for solving the problem) The light flux from the subject that has passed through the photographing lens is reflected by a first reflecting mirror in the direction of the first optical axis, which is lateral to the photographing optical axis.
Next, a finder image is formed after being reflected in the direction of a second optical axis lateral to the first optical axis through a first reflective prism placed outside the effective shooting light beam, and the light beam based on the finder image is is reflected in the direction of a third optical axis lateral to the second optical axis through a second reflective prism, and then reflected in the direction of a fourth optical axis substantially parallel to the photographing optical axis by a second reflecting mirror. After letting
The structure is such that the finder image is observed.

(Embodiment) FIGS. 1 and 2 are a top view and a side view of essential parts of a first embodiment of the present invention.

In the figure, 1 is a camera body, and 1a is a grip.

Reference numeral 2 denotes a photographing lens, which is attached to a thin section of the camera body 1. It is configured so that it is edged out at the position shown by the solid line when photographing, and part or all of it can be stored in the camera body 1 as shown by the dotted line when not photographing. 3 is an imaging plane, such as a film plane or an imaging plane. 4 is a first reflecting mirror, which is rotatably attached as shown by an arrow 4a. The first reflecting mirror 4 reflects the light beam from the subject that has passed through the photographing lens 2 laterally with respect to the photographing optical axis 2a, in the direction of the first optical axis 21, which is perpendicular to the photographing optical axis 2a in this embodiment.

Reference numeral 5 denotes a first reflective prism, which is disposed outside the effective photographing light beam and directs the light beam from the first reflecting mirror 4 in the direction of a second optical axis 22 perpendicular to the first optical axis 21 and in the height direction of the camera body 1. ) is reflected. 6 is a focusing plate, on which a finder image is formed by the JrA shadow lens 2. A condenser lens 7 condenses the light beam diverging from the finder image on the focusing plate 6. A second reflective prism 8 reflects the light beam from the condenser lens 7 in the direction of a third optical axis 23 orthogonal to the second optical axis 22 .

A second reflecting mirror 9 reflects the light beam from the second reflective prism 8 in the direction of a fourth optical axis 24, which is perpendicular to the third optical axis 23 and substantially parallel to the photographing optical axis 2a. Reference numeral 10 denotes an eyepiece lens which receives the light beam from the second reflecting mirror 5 and observes the finder image on the focusing plate 6.

A reflective prism 11 is provided on a part of the reflective surface 5a of the first reflective prism 5, and guides the light beam that has passed through a part of the reflective surface 5a to the light receiving element 12, for example, a rigid type prism. Performs photometry or distance measurement.

Reference numeral 13 denotes a shutter means, which controls the drive of a shutter curtain 13a arranged in front of the imaging plane 3. 14 is a film cartridge, 15 is a film spool, 16 is a lithium battery, 17 is a strobe capacitor, and 18 is a strobe light emitting unit.

In this embodiment, the photographing lens 2 and the first reflecting mirror 4 are used when photographing.
are placed at the positions indicated by solid lines.

Then, the light flux from the subject that has passed through the photographing lens 2 is
A finder image is formed on the focusing plate 6 via the reflection m4 and the first reflective prism 5.

Next, the finder image on the focusing plate 6 is passed through the second reflecting prism 8 and the second reflecting mirror 9, and an erect image of the subject is observed with the eyepiece lens 10.

Also, when not photographing, the first reflecting mirror 4 is rotated and stopped at the position shown by the dotted line, and the photographing lens 2 is moved to the camera body as shown by the dotted line! It is configured to be stored inside.

In this example, the finder optical system uses two reflecting mirrors and two reflective prisms instead of the conventional pentaprism.
By using and configuring as described in 11, it is possible to shorten the height of the camera body.

In addition, part or all of the photographic lens can be housed within the camera body when not photographing, thereby shortening the overall length of the camera when not photographing.

In this way, this embodiment allows for the incorporation of a strobe light, and also makes it possible to achieve a single-lens reflex camera that is as compact as a lens-shutter camera.

In this embodiment, a simple reflecting mirror may be used instead of the reflecting prism, or conversely, a reflecting prism may be used instead of the reflecting mirror. Also, 1st ° 2nd. Third. The fourth optical axes do not necessarily have to be orthogonal to each other, and may be set at an angle that simply reflects the optical axes laterally.

FIG. 3 is a top view of essential parts of a second embodiment of the present invention.

In the embodiment shown in FIG. 1, each element is configured such that the focus plate 6 on which the finder image is formed is located on the grip la side of the camera body 1, but in this embodiment, the strobe light is emitted on the opposite side. Each element is configured so as to be located on the camera body 18 side, and the embodiment shown in FIG.
The only difference is the external shape, and the wood quality is similar to the embodiment shown in FIG.

(Effects of the Invention) According to the present invention, by configuring the finder optical system by arranging two reflective mirrors and two reflective prisms as described above, the height of the camera can be shortened, and the camera can be shortened in the length direction. It is possible to achieve a photographing system for a single-lens reflex camera that can easily reduce the size of the entire camera and shorten the time.

[Brief explanation of the drawing]

1 and 2 are a top view and a side view of essential parts of a first embodiment of the present invention. FIG. 3 is a top view of essential parts of a second embodiment of the present invention. In the figure, 1 is the camera body, 1a is the grip, 2 is the photographing lens, 3 is the imaging plane, 4 is the first reflecting mirror, 5 is the first reflective prism, 6 is the focusing plate, 7 is the condenser lens, and 8 is the condenser lens. a second reflecting prism; 9 a second reflecting mirror; 10 an eyepiece; 13 a shutter means; 14 a film cartridge;
Reference numeral 15 designates a filmstable, 16 a lithium battery, 17 a strobe capacitor, and 18 a strobe light emitting unit. Patent applicant: Canon Co., Ltd.

Claims (1)

[Claims] (1) The light beam from the subject that has passed through the photographing lens is reflected by the first reflecting mirror in the direction of the first optical axis, which is lateral to the photographing optical axis, and then the first reflective prism is placed outside the effective photographing light beam. A finder image is formed after being reflected in the direction of a second optical axis lateral to the first optical axis, and a luminous flux based on the finder image is directed to the second optical axis via a second reflective prism. The light is reflected laterally in the direction of the third optical axis, and then the second optical axis is reflected.
A photographing system for a single-lens reflex camera, characterized in that the finder image is observed after being reflected by a reflecting mirror in a fourth optical axis direction substantially parallel to the photographing optical axis.