| 摘要 |
<p>PURPOSE:To allow an interchangeable lens for a single-lens reflex camera to be used by using liquid-crystal for a filter which varies in light transmissivity with an electric signal, and adjusting the light transmissivity through a liquid-crystal driving circuit. CONSTITUTION:An image pickup signal from an image pickup element 1 is preamplified 4 and its brightness is detected 5 to make a level adjustment 6. A liquid-crystal driving circuit 18 is driven with the output of an adjusting circuit 6, the light transmissivity of the liquid-crystal filter 15 in a mount adapter 16 is adjusted through a switch 20, and the quantity of incident light from an interchangeable lens system 14 is adjusted to input the light to the image pickup element 1. The attachment of the mount adapter 16 is detected 21 to close the switch 20, and a switch 19 is opened. When the mount adapter 16 is detached, the switch 19 is closed and the switch 20 is opened to put a standard lens system 10 in operation, so that the camera enters a normal photographic mode. Consequently, interchangeable lenses for the single-lens reflex camera are used to attain telephoto and wide-angle photography.</p> |
