| 摘要 |
<p>An exposure control circuit that produces a variable exposure interval depending upon scene brightness or a constant exposure interval proportional to a predetermined scene brightness, by providing a photocurrent proportional to the level of actual scene brightness and a reference current proportional to the predetermined scene brightness and, preferably automatically, selectively integrating the photocurrent or the reference current depending upon the relative magnitude of the currents. The integrated current provides a signal to produce a variable exposure interval related to actual scene brightness when the photocurrent is greater than the reference current, or provides a signal to produce a constat exposure interval when the photocurrent is less than the reference current. The selective integration may be disabled to permit only the photocurrent to be integrated over all scene brightness and thus produce only a variable exposure interval that is related to actual scene brightness.</p> |
