| 摘要 |
PURPOSE:To stably and accurately measure a shutter running state by providing a reflecting means for reflecting light projected from a projecting means and receiving the light reflected from the reflecting means with a light receiving means. CONSTITUTION:An optical sensor 17 provided with the projecting means 17a and the light receiving means 17b is installed on one side of a shutter substrate 13 in accordance with the traveling position of blade edges of a front curtain 15 and a rear curtain 16. On the surface of a cover plate 14, a reflecting member 20 is stick on a position irradiated with the light emitted from the projecting means 17a. When a release button is depressed and the leading edge of the front curtain 15 passes in front of the optical sensor 17 so as to open the shutter, the output level of the sensor 17 becomes high with the light reflected on the reflecting member 20 obtained. When the leading edge of the rear curtain 16 passes in front of the optical sensor 17 so as to close the shutter after an exposure time is over, the output level of the sensor 17 becomes low. Thus, an interval of the time when the front curtain and the rear curtain pass in front of the sensor 17, is measured, so that the running speed of the front curtain and the rear curtain is accurately grasped. |
