| 摘要 |
PURPOSE:To avoid a malfunction for detection of a focusing state, by putting a space filter having the transmission factor reducing gradually toward the circumference part from the center area between an image forming lens and a photodetecting element train. CONSTITUTION:A grey filter 11 which has the transmission factor T reducing gradually toward the circumference part from the center area is put between an image forming lens and a photodetector 5 comprising a photodetecting element train. As a result, a malfunction can be prevented for detection of a focusing state. |
