Rollei-werke Franke & Heidecke

Karl-Peter Strauss

Dietmar Elke

Electronic circuitry for setting or controlling either one of two exposure value factors of a photographic camera, namely, the exposure time (shutter speed) and the diaphragm aperture. The circuitry includes a comparator which receives an input responsive to the film sensitivity, the brightness of the subject, and the preset selected value of the one of the two exposure factors which is to be set manually rather than automatically. The comparator is connected to a flip-flop, a counter, and a decoder in such a way as to provide a signal which can control or operate either a photographic shutter mechanism or a diaphragm aperture mechanism, and the signal also controls the lighting of luminous diodes to give a visual indication of the exposure factor value which has been determined by the circuit as the proper value for an optimum exposure. There is also provision for storing the determined exposure value for later use.

Photographic camera with automatic exposure control

A camera having means for manually preselecting the value of one of the two main exposure factors (shutter speed and diaphragm aperture) and means for automatically setting the other of these two exposure factors, in response to prevailing light conditions. If the available range of the automatically set factor is not sufficient to provide an acceptable exposure value in view of prevailing light conditions, then the automatic mechanism moves the previously selected or preset exposure factor to a value which will give an acceptable exposure value. Relatively simple and inexpensive circuitry is provided to accomplish this, and to enable the exposure values to be set entirely manually rather than automatically, if desired.

Camera with automatic exposure control system

Electronic means for controlling the aperture of an electromagnetically operated diaphragm of a photographic camera, especially a single lens mirror reflex camera. The diaphragm aperture is set by a pot-shaped electromagnet. The coil of the electromagnet is supplied with current by an electronic circuit which responds to light falling on a photoelectric converter placed behind the diaphragm, which compares the value of this response to a nominal value resulting from a shutter speed setting and a film speed or sensivity setting, and transmits current in a rapid series of pulses to the coil of the magnet which operates the diaphragm. The pulsing nature of the current applied to the electromagnet tends to cause a slight vibration in the mechanical parts of the diaphragm mechanism, and this vibration helps to overcome the static friction of the moving parts of the diaphragm mechanism, facilitating the setting of the diaphragm to the exact value desired.

Control means for a diaphragm of a single lens reflex camera

A photographic camera in which at least one of the two main exposure factors (shutter speed and diaphragm aperture) may be set either manually or automatically. Indicating means is provided, visible in the viewfinder of the camera, to indicate to the user both the exposure factor value which he has set manually (if any) and the exposure factor value which the automatic mechanism would select according to prevailing light conditions, regardless of whether the user plans to utilize the automatic setting feature or whether he prefers to set the factor manually.

Camera with automatic exposure factor mechanism

Mechanism for synchronizing the illumination produced by flash units of two different types, with the operation of a camera shutter, especially a shutter of the type having one blade mechanism for opening the shutter to start the exposure, and a separate blade mechanism for closing the shutter to terminate the exposure. The synchronizing mechanism has electronic circuitry which produces, at a single bi-polar contact, a first voltage variation at the beginning of the shutter opening movement and a second voltage variation at a later time, not later than the beginning of the shutter closing movement. A first form of adapter, used with a combustible flash bulb of the current-operated type, is plugged into the synchronous contact of the camera, and this adapter fires the flash bulb in response to the first voltage variation, far enough in advance of the termination of the exposure to allow time for the combustible flash bulb to achieve sufficient illumination intensity while the exposure is still in progress. A second form of adapter is plugged into the synchronous contact of the camera when an electronic flash unit is used, and responds to the second voltage variation, to cause firing of the electronic flash unit at a time when the shutter is open.

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Volkmarode, Germany

Karl-Peter Strauss