Abstract: According to the present invention, light from a taking lens is reflected by a quick return mirror in a lateral direction of a body unit. Then, after passing through a screen, the light is reflected toward an upper side of the body unit by a second mirror except part of the light. The light reflected by the second mirror is reflected by a third mirror in a direction opposite to a direction in which the light is reflected by the quick return mirror, and is further reflected by a fourth mirror toward an eyepiece located on a back side of the body unit. Part of the light which passing though the screen is taken by an AF sensor unit provided in rear of the second mirror, and an image formation position of an optical image is detected.

Abstract: A multifocal lens system to be used for digital cameras for setting any one of a plurality of lenses in a picture taking (image capturing) position comprising a wide-angle lens (shorter focal length lens) mounted in front of an image sensor in a picture taking (image capturing) position, a telephoto lens (longer focal length lens) mounted alongside the wide-angle lens, a parallelogram prism (rhombic prism) or a pair of triangular prisms removably arranged between the two lenses at the rear of them. When the wide-angle lens is to be used, the parallelogram prism or one of the two triangular prisms is to be removed from the rear of wide-angle lens so that the wide-angle lens can be focused on the sensor enabling light to pass therethrough.

Abstract: In a digital camera having a half mirror retractable out of the optical path and an optical viewfinder receiving light reflected from the half mirror, the sensitivity of an image-sensing device is set as specified by the user. When a relatively high sensitivity is specified, an image to be recorded is shot with the half mirror operated as a quick-return mirror, and, when a relatively low sensitivity is specified, an image to be recorded is shot with the half mirror kept in the optical path. A sensitivity that cannot be coped with simply by changing the position of the half mirror is set by adjusting, in conjunction therewith, the output gain of the image-sensing device.

Abstract: A single-lens-reflex camera includes means for virtually eliminating vibration, noise, and motion caused by mirror movement, resulting in a higher resolution image being recorded on a light-sensitive surface at the rear of the camera. A pair of bi-parting mirrors are smoothly and noiselessly slid from a position adjacent each other, reflecting an image upward to a viewing screen for focusing and viewing, to a separated position. When mirrors are separated they are clear of the image, so the image can then fall upon the shutter and light-sensitive surface at the rear of the camera. After the image is recorded on the light-sensitive surface, the mirrors return to their original adjacent position. The mirrors are symmetrically arranged, so their inertial masses oppose and cancel each other during mirror movement, thereby eliminating camera movement from this source. This allows larger and heavier mirrors to be used in large format cameras.

Abstract: A mirror recoil preventing device suitable for a camera has a mirror and a mirror support frame. The mirror support frame movably supports the mirror in movement from a first position to a second position. In a camera having a photographic lens and a range finding element, the mirror guides light from the photographic lens to the range finding element when positioned at the second position. As a first alternative, the mirror support frame has a U-shaped groove at one end thereof. A regulating member is located in the vicinity of the second position to engage with the U-shaped groove when the mirror support frame is at the second position. As a second alternative, the mirror support frame has a leading edge and a trailing edge such that in movement from the first position to the second position, the trailing edge trails the leading edge. A first regulating member is located to be immediately adjacent to the leading edge of the mirror support frame when the mirror support frame is at the second position.