| 摘要 |
PURPOSE:To optimize particularly exposure in photography by calculating deficient exposure all the time corresponding to the time when the quantity of irradiation light varies from a value for examination to a value for photography, and extending a photographic time by a time long enough to compensate the deficiency. CONSTITUTION:An optimum photographic time (t) corresponding to the maximum quantity of light of a light source lamp 24 is calculated from a photographic constant such as film sensitivity, the quantity of examination light, and the quantity of light obtained by a photodetecting element 23 to discriminate whether the current quantity of examination light is the maximum quantity of light in photography or not; and an exposure time corresponding to the calculated value is calculated and added to a proper photographic time. Thus, the photographic time (t+to) is calculated and outputted. A light source control circuit 26 switches the quantity of irradiation light of a period to the maximum quantity of light for photography in a period of the photographic time (t+to). Therefore, even if a lamp with a slow rise in variation in the quantity of light is used, the proper photographic time is found. |
