| 摘要 |
PURPOSE:To control aperture with good accuracy by so arranging a titled device that photographing can be performed while driving mechanisms for an aperture control system and a mirror system are held coupled at all times without the intervention of a clutch. CONSTITUTION:When a release switch SW1 is turned on, a motor 1 starts revolving counterclockwise, a shaft 6, hence a cam 8 revolves clockwise and a cam face 8a decreases a lift gradually with respect to a pin 9, thereby giving a min. aperture diameter to a lens 17. When the output of a photodetector PD1 corresponds to the prescribed aperture value detemined by film sensitivity and a shutter speed, a control circuit C2 conducts electricity to a coil 24. Therefore, the attraction of a yoke 22 and an armature 21 is released and a pawl part 19a meshes with a rachet wheel 16, and as a result, a lever 19 is detained via a pinion 15, a gear 14, a pinion 13, and a sector gear 12. Hence, the prescribed aperture value is set to the lens 17. |
