Abstract: In an exposure control device, a bi-directional bi-polar transistor is connected between a light measuring circuit and a storage capacitor for connecting and disconnecting the storage capacitor from the light measuring circuit. A biasing circuit provides the bias potential to control the bi-directional bi-polar transistor either through a mechanical switch or a semiconductor.

Abstract: A camera is provided with a multi-exposure control system for obtaining proper exposure by either preselecting the diaphragm or the shutter speed and then respectively automatically controlling the shutter speed or the diaphragm aperture in accordance with the intensity of scene light passing through the diaphragm aperture. Structure is provided for obtaining a proper exposure by causing the diaphragm to be either fully opened or at its smallest aperture where with a preselected shutter speed an intermediate diaphragm aperture is not satisfactory. The exposure indicating device obtains an output voltage from an output circuit for computing exposure control voltages in response to step members representing steps of the diaphragm for stopping-down the diaphragm from its fully opened condition to a preselected value so that the output represents the shutter speed to be controlled with the preselected diaphragm aperture.

Abstract: The device according to this invention has a flash tube of the electronic type which is triggered when a charge stored in a capacitor is applied to the tube. A circuit is provided which measures light that is emitted from the tube and is reflected from an object. The light value of the reflected light is compared against a reference value and the emission of light from the flash tube is terminated when the reflected light reaches the level of the reference value. The reference value is electrically set by a mechanism calculating an aperture value set in the camera with a sensitivity value of a film to be used in the camera.

Abstract: An automatic diaphragm aperture control device for use in a camera for controlling the setting of the diaphragm with a high degree of accuracy. The diaphragm is adapted to be stopped down in association with the releasing operation of a shutter. During this stop down operation, the output of a light measuring circuit of the camera measures the light from a photographic image, which has passed through an objective lens and a diaphragm aperture. The output of the light measuring circuit is then compared with the output of an output circuit which corresponds to a pre-selected shutter speed. When the difference between the two outputs reaches a given level, the operation of an electromagnet is reversed so as to thereby cause the locking of the diaphragm and stopping its stopping-down operation.

Abstract: An automatic exposure control system for regulating one or more variable photographic parameters. The light level of a scene is evaluated using a photosensitive voltage source. A differential amplifier with a non-linear negative feedback is provided to allow one or more inexpensive linear potentiometers to be used to enter the aperture value and film sensitivity information into the system. Based on these parameters, the system automatically controls the camera shutter speed.

Abstract: The multi-exposure control device is provided with an automatic mechanism for stopping-down the diaphragm from an open position prior to exposure. A diaphragm adjusting ring stops the stopping-down operation at the pre-selected diaphragm aperture. An automatic exposure time control signal is generated from the light passing through the objective lens and stopped-down diaphragm aperture. A shutter speed selecting member provides a first mode for manual selection of the shutter speed and a second mode for automatic shutter exposure control.The device is switchable between a manual exposure control mode wherein both the shutter speed and diaphragm aperture are manually selected prior to exposure and an automatic exposure control mode having an automatic shutter speed control or automatic diaphragm aperture control.

Abstract: Light responsive circuit of low current consumption and low cost and used for camera exposure control and/or exposure indication. The circuit includes a field effect transistor, a photodiode connected between gate and source of the field effect transistor, a transistor having a collector connected to the gate of the field effect transistor and further having a base connected to the source of the field effect transistor, and a control circuit for controlling base voltage of the transistor to regulate source potential of the field effect transistor.

Abstract: A mechanism for determining the focus by an objective lens of an image on a focal plane includes a needle shaped or other narrow scanning mask transversely oscillated in the focal plane between the lens and a transversely extending photoelectric element exposed to the mask intercepted image. The output of the photosensitive element is coupled by way of a high pass filter or differentiating circuit and a rectifier to a meter, the maximum meter reading indicating maximum AC output and hence maximum focus. The output of the photosensitive element is also connected through a low-pass filter to a meter or exposed control mechanism.

Abstract: A light measuring circuit for an exposure time control device uses a photodiode to measure the object brightness and a logarithmic compressing diode to provide negative feedback between the output terminal and one input terminal of a differential amplifying circuit. The output of the light measuring circuit is summed with signals representing film sensitivity and diaphragm aperture setting and the resulting exposure time control signal is compensated for changes in temperature. An antilogarithmic converting circuit generates a signal proportional to the logarithmic value of the compensated exposure time control signal. The antilogarithmic converting circuit operates at the same reference potential as the differential amplifying circuit and its output is integrated and then used to terminate exposure.