Abstract: In a distance measuring device of a camera, a distance measuring optical system unit has light-emitting and light-receiving elements for distance measurement. The distance measuring optical system unit is rotated from one end of a photographing screen to the other end thereof to perform a distance measuring operation. The distance measuring optical system unit is rotated and stopped in a set distance measuring range by a cam rotated by a DC motor and a driven arm portion of the distance measuring optical system unit. Distance measuring object ranges of the distance measuring optical system unit are switched by a switch. For example, the distance measuring object ranges are set with respect to many-point distance measurement or one-point distance measurement.

Abstract: Pulse light is emitted by controlling the operation of a driving circuit by a microcomputer and is irradiated to a photographed object. Light reflected on the photographed object is received by a semiconductor optical position detector. First and second current outputs having a current ratio are inputted to first and second detecting circuits within an AF signal processing circuit in accordance with a light receiving position corresponding to a distance of the object. The first and second detecting circuits logarithmically transform changing amounts of the first and second current outputs. A differential detecting circuit calculates a difference between changing amounts of outputs of the first and second detecting circuits, and outputs a distance measuring signal to the microcomputer. A light receiving element measures the intensity of external light and an error in the distance measuring signal caused by the external light is corrected by the microcomputer on the basis of the above results.

Abstract: A distance measuring device for an automatic focusing camera which is automatically focused on an object in accordance with information data of distance to the object from the camera. The information data is obtained by irradiating a light emitted from a light emitting element to the object and receiving the light reflected from the object by an optical sensor. The optical sensor detects an incident point of the reflection light. The device comprises: a first light emitting element; an optical sensor; a second light emitting element; a light emission control circuit for controlling sequence of light emission from the first and second light emitting elements; a distance calculation circuit for calculating the information data of distance on the basis of an output from the optical sensor; a discrimination circuit for discriminating the information data; and a finder having an area mark for defining a field range.

Abstract: A control device for driving a zoom lens of a camera, comprising; a moving mirror cylinder movable on an optical axis of the camera between a first position corresponding to the shortest focal length of the zoom lens and a second position corresponding to the longest focal length of the zoom lens, a motor for moving the moving mirror cylinder in a predetermined direction, a detector for detecting a position of the moving mirror cylinder on the optical axis, a presetter for presetting a predetermined position between the first position and the second position, the predetermined position at which the moving mirror cylinder to stop, a controller for controlling the motor such that the moving mirror cylinder at a high speed, a starter for starting an actuation of the controller, a stopper for stopping an actuation of the controller in a case where the moving mirror cylinder arrives at the first position, the second position or the predetermined position.