| 摘要 |
PURPOSE:To effectively perform the aperture control with a very simple constitution in an electronic camera or the like by controlling an aperture value setting step motor in the still mode and controlling a servomotor in the movie mode. CONSTITUTION:When a mode changeover switch SWC is switched to the still side S, a photometric circuit is operated to calculate a proper value. Then, the rotation angle of a pinion 2 of a step motor 1 is determined, and the position of an aperture value setting cam face 4b is set. Thus, a servomotor 5 is started to turn a pinion 6, and aperture blades 9 are driven and are set to a prescribed aperture value. Next, the switch SEC is switched to the movie side M, and the step motor 1 is started to set an aperture value transmission ring 4 to a minimum aperture value, and aperture blades 9 are narrowed to a minimum aperture position. Meanwhile, the servomotor 5 is controlled directly by a control circuit 21 to control the turning direction of a driving ring 7, and the ring 7 is drive to attain the prescribed aperture value.
|
