Seikosha Co., Ltd.

Yoichi Nakano

Nobuo Shinozaki

Ichiro Nemoto

Hiroaki Ishida

Koji Sato

Seiichi Imano

Atsushi Takami

Hiroto Tsuyuki

Yoshiyuki Iwamatsu

Isamu Ishii

A shutter for a single lens reflex camera, comprises a drive gear rotatable in opposite directions by a motor and having a non-tooth portion, a control gear directly or indirectly engageable with the drive gear, shutter blades driven by the control gear to open and close a shutter opening, and a spring for constantly biasing the control gear in a direction to close the shutter opening. Upon rotation of the drive gear, the control gear is rotated to face the non-tooth portion of the drive gear whereby the shutter blades are moved under the action of the spring to close the shutter opening. When the control gear is brought into meshing engagement with the drive gear, the shutter blades are rendered operative to open and close the shutter opening.

Shutter for a single lens reflex camera

A camera system of the type having a lens shutter, a focal-plane shutter, an aperture defined by the lens shutter, and a camera lens, includes a selector circuit which sets an operation mode to either a lens shutter mode in which the lens shutter is operated as a programmed shutter or a focal-plane shutter mode in which the shutter speed is controlled by the focal-plane shutter and the aperture of the camera system is controlled by the lens shutter; a first driving system which controls the lens shutter; a second driving system which controls the time during which the focal-plane shutter is operated; a sequential control circuit which controls the timing of the first and second driving systems; a setting circuit which sets the focal length of the camera lens; an arithmetic circuit which produces an output signal in response to the brightness of the subject, the distance to the subject, the focal length of the lens and the sensitivity of the film; and a switching circuit which switches the operation mode to the focal-plane shutter mode irrespective of the setting of the selector circuit when the exposure value to be controlled exceeds the programmed exposure value of the lens shutter and for switching either the operation mode or the shutter speed in accordance with the set focal length to prevent photographic blurring during camera shake, in response to the output from the arithmetic circuit.

Camera system

Growing community of inventors

Chiba, Japan

Yoichi Nakano