JPH01200240A - Photographing system for single-lens reflex camera provided with finder visual field switching means - Google Patents

Abstract

PURPOSE:To shorten the height direction of a camera provided with a finder visual field switching means by appropriately arranging plural reflecting mirrors, plural reflecting prism and a roof prism without using a pentagonal prism. CONSTITUTION:At the time of photographing, a finder image is formed on a focal plate 6 after reflecting luminous flux which passes through a lens 2 to the lateral by the reflecting mirror and then reflecting it to the lateral through the reflection type prism 5 arranged out of effective luminous flux. The luminous flux based on the finder image is reflected to the lateral through the reflection type prism 8 and then reflected in a direction nearly parallel with a photographic optical axis by the movable reflecting mirror 9, so that the finder image can be observed from the eye level. And also the reflecting mirror 9 is made to retreat out of the optical path of a finder and the luminous flux from the reflection type prism 8 is reflected to the lateral by the roof prism 31, then reflected to the lateral by the reflecting mirror 32, so that the finder image can be observed from a waits level. At the time of not photographing, the reflecting mirror 4 is turned to be stopped on a position shown by a dotted line and the lens 2 is housed in a camera main body 1 on a position shown by a dotted line. With such a constitution the entire camera can be miniaturized.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a photographing system for a single-lens reflex camera having a finder field switching means suitable for photo cameras, video cameras, etc. The present invention relates to a photographing system for a single-lens reflex camera that has a viewfinder field switching means that can shorten the direction and downsize the entire camera, and can easily switch between the eye-level and waist-level viewfinder fields.

(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 flux from the subject that has passed 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, in conventional single-lens reflex cameras, there has been a tendency to increase the size of the entire camera in the height direction by an amount corresponding to the size of the pentaprism.

On the other hand, it has both an eye-level finder system that observes the viewfinder field of view from a direction along the photographing optical axis and a waist-level finder system that observes the viewfinder field of view from a direction perpendicular to the photographic optical axis. Various single-lens reflex cameras have been proposed that have a finder field switching means that allows one viewfinder system to be selected for observation using a switching means.

However, finder systems that have eye-level and waist-level switching means tend to have complicated optical systems and tend to increase the size of the camera as a whole.Furthermore, the switching operation requires, for example, an eyepiece integrated with a prism, to be performed simultaneously as a whole. It was very troublesome as it had to be rotated.

(Problems to be Solved by the Invention) The present invention does not use a conventional pentagonal prism, but by appropriately arranging a plurality of reflecting mirrors, a plurality of reflecting prisms, and a roof prism, the eye level and waist level can be adjusted. To provide a photographing system for a single-lens reflex camera having a finder visual field switching means that can easily switch between the viewfinder system and the overall size of the camera, particularly in the height direction.

(Means for solving the problem) The light beam from the object that has passed through the photographing lens is reflected by a first reflecting mirror in the direction of the first optical axis on the full side with respect to the photographing optical axis, and then placed outside the effective photographing light beam. After reflecting in the direction of a second optical axis lateral to the first optical axis through a first reflective prism, a finder image is formed, and a light beam based on the finder image is transmitted through a second reflective prism. te J Pig 2nd
The finder image is reflected in the direction of the third optical axis, which is lateral to the optical axis, and then reflected by the movable second reflecting mirror in the direction of the fourth optical axis, which is approximately parallel to the photographing optical axis. At the same time, the second reflecting mirror is retracted out of the finder optical path, and the light beam from the second reflecting prism is directed by a roof prism to the side of the third optical axis direction and to the photographing optical axis. Then, the finder image is reflected from the waist level to the fifth optical axis direction by the third reflecting mirror, which is lateral to the fifth optical axis. It was configured to be 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. FIG. 3 is a schematic diagram of the main parts of the optical system showing switching between the eye level and waist level finder systems according to the present invention.

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

Reference numeral 2 denotes a photographic lens, which is attached to the front of the camera body 1. When photographing, it is extended to the position shown by the solid line, and when not photographing, a part or all of it can be stored in the camera body 1, as shown by the dotted line. 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 converts the light flux from the subject that has passed through the photographing lens 2 into photographing light 1ITlh2a.
In this embodiment, the first optical axis 21 is perpendicular to the
It is reflected in the direction.

Reference numeral 5 denotes a first reflective prism, which is disposed outside the effective photographing light beam and transforms the light beam from the first reflecting mirror 4 into a second light beam I? which is perpendicular to the first optical axis 21. The light is reflected in the 4I22 direction (the height direction of the camera body 1). 6 is a focusing plate, on which a finder image formed by the photographing lens 2 is formed. 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 the third light ll1lh23 perpendicular to the second optical axis 22.

Reference numeral 9 denotes a rotatable second reflecting mirror, which is set so as to be rotatable as indicated by an arrow 9a by a switching means (not shown). When observing the finder system at eye level, for example, the second reflecting mirror 9 is rotated and stopped at the position indicated by the dotted line by the switching means.

Then, the light beam from the second reflective prism 8 is directed to the third optical axis 23.
The fourth light I is perpendicular to the photographing optical axis 2a and substantially parallel to the photographing optical axis 2a.
II! It is reflected in 1I24 directions. The eyepiece 10 receives the light beam from the second reflecting mirror 9 and observes the finder image on the focusing plate 6 at eye level.

On the other hand, when observing the finder system at waist level, the second reflecting mirror 9 is rotated and retracted out of the finder optical path at the position indicated by the solid line by the switching means. Then, the light beam from the second reflective prism 8 is reflected by the roof prism 31 in the direction of the fifth optical axis 25, which is perpendicular to the third optical axis 23 and substantially parallel to the photographing light l1iIII2a. The sixth light is reflected in the direction of the sixth light @26 above the camera body 1 which is perpendicular to the fifth optical axis 25. Then, the finder image on the focusing plate 6 is observed at waist level using the eyepiece lens 33.

Incidentally, reference numeral 11 denotes a reflective prism, which 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. Photometry or distance measurement is carried out.

Further, 13 is a shutter means, which controls the drive of a shutter curtain 13a arranged in front of the image forming plane 3. 1
4 is Film Patrone, 15 is Filmsbourg, 1
6 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 a focusing plate 6 via a reflecting mirror 4 and a first reflective prism 5.

Next, the finder image on the focusing plate 6 is transmitted to the eyepiece 1 via a second reflective prism 8 and a rotatable second reflective mirror 9.
0, an erect image of the subject is observed at eye level.

In addition, the second reflecting mirror 9 is retracted out of the finder optical path, and the eyepiece 3 is reflected via the roof prism 31 and the third reflecting mirror 32.
3 allows the subject to be observed at waist level.

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 housed within the camera body 1 as shown by the dotted line.

In this example, the finder optical system is constructed using multiple reflecting mirrors, multiple reflective prisms, and a roof prism as described above, instead of using a conventional pentaprism, thereby reducing the height of the camera body. At the same time, we have achieved a photographing system for a single-lens reflex camera that can switch between the eye-level and waist-level viewfinder systems by simply rotating the reflector.

In addition, part or all of the photographic lens can be stored inside the camera body when not photographing, thereby shortening the overall length of the camera when not in use.

As described above, in this embodiment, it is possible to incorporate a strobe light, and moreover, it is possible to achieve a single-lens reflex camera with a simple structure that is as compact as a lens-shutter camera.

In this example, rII is used instead of the reflective prism.
- may be used, or conversely, a reflective prism may be used instead of the reflecting mirror. Also, 1st ° 2nd. Third. 4th. Fifth. The sixth optical axes do not necessarily need to be orthogonal to each other, and may be set at an angle that simply reflects the optical axes laterally.

(Effects of the Invention) According to the present invention, a plurality of reflecting mirrors and a plurality of reflecting prisms,
By configuring the finder optical system by arranging the roof prism as described above, the height of the camera can be shortened, the overall size of the camera can be made smaller, and the eye-level and waist-level finder systems can be easily switched. It is possible to achieve a photographing system for a single-lens reflex camera that has a finder field of view switching means that can perform the following.

[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 schematic diagram of the main parts of the optical system showing switching between the eye level and waist level finder systems according to the present invention. In the figure, 1 is the camera body, 1a is the clip, 2 is the photographic 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. 2nd reflective prism, 9 is a second reflective mirror, 10.33 is an eyepiece, 13 is a shutter means, 14 is a film cartridge, 15 is a film souvenir, 16 is a lithium battery,
17 is a strobe capacitor, 18 is a strobe light emitting unit, 31 is a roof prism, and 32 is a third reflecting mirror. Patent Applicant: Canon Co., Ltd. 1. Condolence 1. Diagram 2.

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 object is reflected in the direction of a third optical axis on the side, and then reflected in the direction of a fourth optical axis substantially parallel to the photographing optical axis by a movable second reflecting mirror, and then the viewfinder image is observed from eye level. At the same time, the second reflecting mirror is retracted out of the finder optical path, and the light beam from the second reflecting prism is directed by the roof prism to the side of the third optical axis direction and approximately parallel to the photographing optical axis. The viewfinder image is then observed from waist level after being reflected by a third reflecting mirror in the direction of a sixth optical axis on the side of the fifth optical axis. A photographing system for a single-lens reflex camera having a finder field of view switching means.