BESTURINGSINRICHTING VOOR EEN SLUITER.

摘要

The electronic shutter device of this invention eliminates the prior art circuit which required extremely high insulation so as to hold the charge. In this invention, the current of photosensitive element proportional to the intensity of light of an object is converted into a voltage proportional to a logarithm of said current. Said voltage is compared with a voltage induced by a correction current for setting a film speed and a current of which magnitude being varied in response to a number of pulses counted by a binary counter. When the difference between these voltages reaches a predetermined value, the counter stops its counting. When the shutter is actuated a current proportional to an exponential of a voltage representative of the number of counting is integrated as the shutter is opened until the integrated value reaches a predetermined level at which time the shutter is closed.