| 摘要 |
<p>An automatic exposure control system, of the type wherein a dynamic aperture blade mechanism is displaceably driven by a stepper motor, is provided with a microcomputer that is preprogrammed with data representing a plurality of different blade trajectory signal programs for different photographic conditions. In response to inputs, including scene brightness level, provided before or during an exposure cycle, the computer develops an appropriate trajectory signal program and feeds the signals to the stepper motor so as to drive the blade mechanism in a manner characterized by a corresponding trajectory curve that is correlated to the indicated photographic conditions. In one embodiment the system is configured for open loop operation, and, in an alternative embodiment, the system additionally includes a blade position feedback circuit for closed loop operation.</p> |
