Device for indicating an object distance for flash photography

摘要

In a device for indicating a camera-to-object distance for flash photography, an electronic flash device receives data from a camera, the data being indicative of a set value of film speed, a set value of exposure to be compensated from a proper exposure and a value of diaphragm aperture to be controlled. The flash device calculates a camera-to-object distance in accordance with the above three data and the limit value of the flash light to be emitted from a light emitter, the camera-to-object distance indicating such an effective object distance that an object at the distance is illuminated with sufficient amount of flash light to effect a desired film exposure corresponding to the exposure compensation value, or an automatic flash available range of the object distance that an object within the range is illuminated by automatically controlled flash light to effect the desired film exposure corresponding to the exposure compensation value.