| 摘要 |
PURPOSE:To prevent the wasteful power consumption of a flash means by varying a flash current and flash duration according to the depth of field, which is determined by means of a focal distance and a diaphragm value at the time of photographing. CONSTITUTION:When a diaphragm value determined by metering is set for open and a focal distance found based on a shutter speed is tele-end (long focal distance), a current which flows in an AF infrared ray emitting element (IRED)9 is made maximum, and the length of time which corresponds to double integral is also made maximum. When the diaphragm value is set for narrowing down and the focal length becomes a wide-end (short focal distance), the maximum current of the IRED 9 or the maximum length of time corresponding to the double integral is reduced. That is, the maximum current of the IRED 9 and the maximum length of time corresponding to the integral are reduced according to the depth of field determined by the amount of diaphragm and the focal distance. |
