| 摘要 |
PURPOSE:To enable smooth change-over operation of a focal length and focusing by controlling the change-over of the focal length of a photographing optical system and focusing by means of a motor. CONSTITUTION:When, for example, a telephoto-standard change-over switch is set to the standard side, a motor 11 runs backward and a lens barrel plate 3 moves toward the rear of a camera and when a pattern detected by a contact piece 22 is interrupted, the plate 3 is held in said position. When a release operation is made in this state, the distance up to an object is measured by an AF mechanism and the distance information is obtd. Electricity is thereafter conducted again to the motor 11 so as to run forward and the plate 3 is extended and moved toward the front. A pulse plate 15 is also rotated according to the rotation of the motor 1, but when the prescribed number of pulses corresponding to the distance information is counted, the conduction of electricity is turned off and the focusing ends. The change-over of the focal length and the focusing are thus accomplished smoothly. |
