| 摘要 |
PURPOSE:To stop focusing operation during photogrphy by coupling a means of detecting a mirror position optically with the switch means of the automatic focusing device of a single-lens reflex camera. CONSTITUTION:In an automatic focusing lens structure for a single-lens reflex camera which drive a lens continuously according to the variation of a subject, an image is blurred unless focusing operation is stopped during photography. For the purpose, a focusing device consisting of a focusing lens 7, a photo- detecting element 8, a detecting circuit 9, and a driving circuit 10 for an objective lens 1 is provided with a position detecting means for a quick-return mirror 2 which consists of a light emitting element 14 and a photodetecting element 15, and a switch means 13 is turned on and off by the output of said photodetecting element to achieve focusing operation only when the mirror 2 is lowered. |
