ISO 10157:1991 PDF

This International Standard applies to photoelectric flash exposure meters which measure the time integral of the luminance or of the illuminance of a photographic object (to be called thereafter “object”) illuminated by a source of light for a brief illumination period l) and indicate the time integral or a number corresponding to the time integral or thefinumber required for the correct exposure of a photographic film with a given speed. Continuous light, which is available in addition to the light emitted by the flash light source, is also evaluated. NOTE 1 If the object is illuminated by electronic flash equipment with automatic exposure control, the measuring results of the flash exposure meter can deviate from the calibration values of the flash equipment.