| 摘要 |
PURPOSE:To perform durable and stable detection by detecting a light-and-dark pattern part provided to the outer peripheral part of a focus ring or zoom ring by a photosensor. CONSTITUTION:An infrared ray 23 is emitted by a light emitting element 20 at any time and reflected by white parts of the light-and-dark pattern part 16a printed on the circumference of the zoom ring 12, and reflected light 24 is incident on a photodetecting element 21a, so that the infrared ray from the light emitting element 20 is detected. A surface facing a photodetecting element 21b, on the other hand, is not a white part of the light-and-dark pattern part 16b, but a black frosted part on the surface of the zoom ring 12 and almost none of the infrared rays from the light emitting element 20 is reflected, so the photodetecting element 21b detects no reflected light. Thus, the specific light-and-black pattern is provided to the circumference of the zoom ring 12 to obtain a signal corresponding to the light-and-black pattern, thereby detecting the position of the zoom ring 12. |
