Camera diaphragm control device for flash photography

Abstract

A camera diaphragm control device which arrests a diaphragm when a TTL light measurement output represents a given relationship with respect to a reference signal during stop down operation of the diaphragm can automatically set the diaphragm to a specific aperture for flash photography by the aid of a preliminary flash light produced prior to the production of a primary flash light with its intensity maintained substantially constant for a duration covering the period of time from the automatic setting of the diaphragm to the setting of the specific aperture. At the initial stage of the production of the preliminary flash light prior to the stop down of the diaphragm, an operational circuit means correlates or associates the TTL light measurement output with a signal representative of a set film sensitivity and a signal representative of the diaphragm step-difference between the maximum and specific apertures to thereby generate an output representative of a proper exposure time for the specific aperture as the reference signal. Furthermore, circuits are provided for automatically setting the diaphragm to a larger or smaller aperture when the object of interest is located outside the permissible distance range for flash photography with the specific aperture and with the primary flash light.