| 摘要 |
PURPOSE:To perform diaphragm operation surely with simple constitution using electric power by detaining a moving member which is electrically driven to change aperture value by means of an electromagnetic means which is controlled according to measured values. CONSTITUTION:When a mirror is kicked up upon pressing of a shutter button, a switch 5 closes to energize a bobbin coil 13a, by which a driving ring 11 provided with a sloped plate 18 is turned counterclockwise and the aperture value is changed by way of a diaphragm pin 30 abutting on the plate 18. Upon lapse of the time corresponding to the brightness of an object, an electromagnetic coil 17 is energized by way of the time constant circuit and an inching iron piece 16 is electromagnetically driven. Thereby, the ring 11 is detained by the iron piece 16, and the diaphragm is determined according to the brightness of the object. The need for spring charging and the like is eliminated. |
