JPH11352549A - Optical system for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical system which is small-sized and also where the occurrence of parallax is reduced by providing the system with a photographing lens, whose a part is cut and which is noncircular and a finder optical member arranged at the photographing lens with a part cut. SOLUTION: A photographing optical system 100 is constituted of a first group lens 10, a mirror M1, a shutter 13, a second group lens 11 and a third group lens 12. The third group lens 12 is constituted of a front lens 12-1 and a rear lens 12-2, and they are noncircular lenses the upper and lower parts of which are cut by leaving a photographing lens part executing an image formation action. A finder optical system is constituted of the mirrors M1 and M2, a finder optical system 1 (16), a finder lens 18, mirrors M3 and M4 and a finder optical system 2 (17). The finder lens 18 is integrally formed by integral formation at the part of the rear lens 12-2, where the upper part is cut and moves with the rear lens 12-2 as a unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical system of a camera.

[0002]

2. Description of the Related Art As an optical system of a camera, a photographing optical system and a finder optical system are known. Since these two optical systems are provided as independent optical systems, there is a problem that parallax occurs between the two optical systems.

[0003] Japanese Patent Application Laid-Open No. Hei 9-138464 discloses that a part of a photographing optical system is also used as a finder optical system.
It discloses a configuration in which parallax is eliminated by splitting a light beam in the middle of an optical path and guiding the light beam to a finder optical system.

[0004]

However, in the above-mentioned Japanese Patent Application Laid-Open No. 9-138464, a finder optical system is arranged adjacent to a circular lens used as a photographing optical system, so that the finder optical system after the divergence is obtained. Since the light beam is guided, there is a problem that the optical system becomes large.

The present invention has been made in view of such a problem, and an object of the present invention is to reduce the size and size of a finder optical system by arranging a part of the finder optical system in a cut portion of the photographing optical system. An object of the present invention is to provide an optical system of a camera in which parallax is reduced.

[0006]

In order to achieve the above object, an optical system of a camera according to a first aspect of the present invention includes: a photographing optical system having a non-circular photographing lens with a part cut;
A finder optical system having a finder optical member disposed at a cut portion of the non-circular taking lens.

The optical system of the camera according to the second invention is the optical system of the camera according to the first invention, wherein the finder optical member is provided integrally with the non-circular taking lens. .

The optical system of a camera according to a third aspect of the present invention is the optical system of the camera according to the first aspect, wherein the photographing optical system comprises a plurality of optical members, and the non-circular photographing lens comprises: The optical member closest to the imaging surface of the imaging medium among the plurality of optical members.

The optical system of a camera according to a fourth aspect of the present invention is the optical system of the camera according to the first aspect, wherein the photographing optical system comprises a plurality of optical members, and the non-circular photographing lens comprises: The optical member farthest from the imaging surface of the imaging medium among the plurality of optical members.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration of an optical system of a camera according to a first embodiment of the present invention. As shown in FIG. 1, the photographing optical system 100 includes a first lens unit 10, a mirror M, which are arranged in the order in which an optical image from a subject passes.
1, shutter 13, second group lens 11, third group lens 1
2 Reference numeral 15 denotes a film as an imaging medium. The third lens group 12 includes a front lens 12-1 and a rear lens 12-2, each of which is a non-circular lens in which the upper and lower portions are cut off except for a photographic lens portion that performs an image forming operation. Immediately before the front lens 12-1, a light-shielding mask 14 for preventing stray light generated around the cut portion from reaching the film 15 because the upper and lower portions thereof are cut is provided. A shutter 13 is provided immediately before the second group lens 11.

The finder optical system is arranged in the order in which the optical image from the subject passes through the mirrors M1, M2, the finder optical system 1 (16), the finder lens 18,
It is composed of mirrors M3 and M4 and a finder optical system 2 (17).

Here, the finder lens 18 is integrally formed by integral molding at a portion where the upper part of the rear lens 12-2 is cut, and moves integrally with the rear lens 12-2. Is corrected by the finder optical system 1 (16). The finder lens 18 and the rear lens 12-2 may be formed separately.

FIGS. 2A and 2B are a front view and a side view, respectively, of the front lens 12-1 of the third lens group 12 shown in FIG. 1, and FIGS. 3A and 3B respectively. FIG. 3 is a front view and a side view of a rear lens 12-2 and a finder lens 18 of the third group lens 12 shown in FIG. These figures well show that the front lens 12-1 and the rear lens 12-2 of the third group lens 12 have their upper and lower portions cut off.

According to the first embodiment, since a part of the finder optical system is arranged at the cut portion of the rear lens of the photographing optical system, the size of the optical system can be reduced. Further, since the optical path is branched from the middle of the photographing optical system and the light flux is guided to the finder through the empty area of the cut portion, parallax can be eliminated.

FIG. 4 is a diagram showing a configuration of an optical system of a camera according to a second embodiment of the present invention. As shown in FIG. 4, the photographing optical system 100 includes a first group lens 10, a second group lens 11, and a third group lens 12 arranged in the order in which an optical image from a subject passes. Reference numeral 15 denotes a film as an imaging medium. The third lens group 12 is a front lens 12
-1 and a rear lens 12-2, both of which are cut off at the upper and lower portions except for a photographic lens portion for performing an image forming operation. Immediately before the front lens 12-1, a light-shielding mask 14 for preventing stray light generated around the cut portion from reaching the film 15 because the upper and lower portions thereof are cut is provided. A shutter 13 is provided immediately before the second group lens 11.

The finder optical system is arranged in the order in which an optical image from a subject passes.
(16), finder lens 18, mirror M3, M
4. It is composed of a finder optical system 2 (17).

According to the second embodiment, since a part of the finder optical system is arranged at the cut portion of the rear lens of the photographing optical system, the size of the optical system can be reduced. In addition, the parallax can be reduced, and the optical system can be further miniaturized because there is no mirror for branching the light beam and guiding it to the finder optical system.

In the above-described first and second embodiments, the rear lens 12-2 as a non-circular photographing lens is arranged at a position closest to the imaging medium, that is, the film 15, but is farthest from the film 15. It may be arranged at a position.

Further, the above-described specific embodiment includes an invention having the following configuration. 1) In a photographing optical device for guiding an optical image to a film,
It is characterized by having a lens that separates and passes the photographing light beam and the finder light beam in a part of the photographing optical path. 2) In a photographing optical device for guiding an optical image to a film,
The imaging optical path has a portion that passes the imaging optical system and the finder optical system in common, and the imaging optical path has a portion that passes the imaging optical system and the finder optical system independently, and passes independently. In some aspects, the taking lens has a non-circular shape. 3) In a photographing optical device for guiding an optical image to a film,
A portion that passes the imaging optical system and the finder optical system in the imaging optical path in common, and a portion that independently passes the imaging optical system and the finder optical system in the imaging optical path, and passes independently. Is characterized in that a portion through which a photographing light beam passes and a portion through which a finder light beam passes are integrally formed. 4) In the above supplementary note 1, 2 or 3, the integrally formed lens is formed by integral molding.

[0020]

According to the present invention, the generation of parallax can be reduced and the optical system of the camera can be miniaturized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an optical system of a camera according to a first embodiment of the present invention.

FIGS. 2A and 2B are a front view and a side view, respectively, of a front lens 12-1 of a third lens group 12 shown in FIG.

FIGS. 3A and 3B are a front view and a side view of a rear lens 12-2 and a finder lens 18 of the third group lens 12 shown in FIG. 1, respectively.

FIG. 4 is a diagram illustrating a configuration of an optical system of a camera according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... 1st group lens, 11 ... 2nd group lens, 12 ... 3rd group lens, 13 ... Shutter, 14 ... Light shielding mask, 15 ... Film, 16 ... Finder optical system 1, 17 ... Finder optical system 2, 100 ... Shooting optical system.

Claims (4)

[Claims] 1. A photographic optical system having a non-circular photographic lens with a part cut off, a finder optical system having a finder optical member disposed at a cut part of the non-circular photographic lens,
An optical system for a camera, comprising: 2. The optical system according to claim 1, wherein the finder optical member is provided integrally with the non-circular taking lens. 3. The imaging optical system includes a plurality of optical members, and the non-circular imaging lens is an optical member closest to an imaging surface of an imaging medium among the plurality of optical members. The optical system of the camera according to claim 1. 4. The imaging optical system includes a plurality of optical members, and the non-circular imaging lens is an optical member farthest from an imaging surface of an imaging medium among the plurality of optical members. The optical system of the camera according to claim 1.