Abstract: The electromagnetic shutter in a camera having an exposure control circuit comprises shutter blades for opening and closing the aperture of the shutter, a shutter control circuit having a photoelectric element for measuring the scene brightness so as to generate the proper exposure signal, holding means for releasably holding the shutter blades in closed positions, spring means for opening the shutter blades when the shutter blades in the closed positions are released, and electromagnetic driving means actuated by the proper exposure signal for driving the shutter blades from the open positions to the closed positions against the action of spring means so as to permit the shutter blades to be held in the closed positions by the holding means.

Abstract: The electromagnetically driven programming shutter includes magnets and shutter blade driving coils provided on the respective shutter blades of the shutter and electromagnetically cooperating with the magnets and the shutter blades are actuated for opening and/or closing operation when the driving coils are energized. The present invention provides a votage compensating circuit used as the reference voltage generating circuit which is capable of varying the reference output voltage as a function of the variation in the voltage of the electric source, thereby permitting the controlled proper exposure defining output pulse to be modified so as to compensate for the variation in the actuation of the shutter blades caused by the variation in the electromagnetic force generated by the shutter blade driving coils due to the variation in the voltage of the electric source.

Abstract: A drive controlling circuit for electric shutters provided with a plurality of discriminating circuits for detecting failures and a plurality of warning circuits including buzzers or luminous diodes operated by the discriminating circuits in order that various failures of the shutter in use can be positively and quickly known. This controlling circuit makes impossible to release the shutter when something is wrong with the shutter.

Abstract: A device is provided for indicating fading operation in cinecamera. A control circuit receives the scene light indicating voltage and a manually adjusted output voltage for operating a diaphragm driving means to adjust the aperture to a proper value for the scene brightness an RC circuit is connected to the diaphragm control circuit which selectively applys either a constant charging or discharging voltage to the diaphragm control circuit, this causes the control circuit to drive the diaphragm to continuously vary the aperture for effecting the fading-out and the fading-in of the scene. A first comparator receives the output voltage of the RC circuit and the output voltage of the diaphragm control circuit and produces a signal when both voltages are coincident.

Abstract: The automatic diaphragm controlling device comprises an electric source, a servomotor having a single driving coil for driving a diaphragm of an objective lens, a scene light indicating voltage generating circuit and a reference voltage generating circuit energized by the electric source, respectively, the servomotor being controlled by the difference between the output voltages of both circuits so that a proper exposure is obtained.

Abstract: A fade-in and fade-out device of an automatic servomechanism for controlling the diaphragm exposure of cinecamera. A differential amplifier having a first input voltage corresponding to the scene light and a second reference input voltage corresponding to the requisite exposure, produces a differential control voltage which is applied to the diaphragm during fade-in or fade-out.