Abstract:
In a flash synchronization circuit, an array of flashbulbs are fired sequentially in synchronism with sequential actuations of the shutter mechanism. The shutter mechanism is opened and closed by electromagnets driven by Schmitt triggers. The sequential firing of the flashbulbs is controlled in response to signals derived from the Schmitt triggers and generated by the electromagnets.
Abstract:
An exposure control system for photographic apparatus which functions automatically to regulate both exposure apertures and exposure interval. The system is operable under an exposure program wherein over a select range of light levels, aperture area is varied with respect to scene light values in a relationship less than 1:1. The system provides for sequential regulation first of aperture, then of exposure interval. Voltagesensitive triggering circuits are used for controlling the apertures and shutter mechanisms. These circuits are coupled to receive the output of a light-sensitive circuit and are arranged in series with a power source to develop a voltage reference level for use with differential amplification stages within the system. The system is calibrated or accommodating varying sensitometric characteristics of films through the use of a gain control in connection with an amplification stage. The system is capable of operating under a predetermined exposure program through the use, inter alia, of an aperture control arrangement which functionally relates aperture blade dynamics, the output of a photosensing circuit and the signal of a function generator.
Abstract:
An exposure control system incorporating an improved flash synchronization arrangement. The timing of the initiation of flash illumination relative to an exposure interval is controlled to substantially equate the quantity of scene light entering the aperture of a photographic apparatus during an exposure interval initiating period with the quantity of light entering the aperture during the corresponding period required for terminating an exposure interval. In a preferred embodiment the dynamic characteristics of a flash lamp are adjusted by follow-focus means to normalize the amount of light reaching the film plane of a camera.
Abstract:
A photographic camera configured to receive a film cassette which supports either thermistors or resistors having resistance values corresponding to film speed. This film speed is automatically inserted into an exposure control system with the insertion of the cassette into a camera. A backup arrangement is provided which inserts a standby resistor element into the system in the instance of an open circuit condition at the cameracassette resistor unit interface.
Abstract:
AN AUTOMATIC EXPOSURE CONTROL SYSTEM FOR REGULATING ONE OR MORE VARIABLE PHOTOGRAPHIC EXPOSURE PARAMETERS. THE LIGHT LEVELS OF A SCENE ARE EVALUATED USING ONE OR MORE PHOTOYOLTAIC CELLS. THE CELLS ARE OPERATED IN A CURRENT MODE THROUGH USE OF AN OPERATIONAL AMPLIFIER HAVING AN INPUT CIRCUIT WHICH INCORPORATES A CAPACITIVE FEEDBACK PATH. WITH THE SYSTEM, A HIGHLY RESPONSIVE LINEAR OUTPUT REPRESENTATIVE OF SCENE LIGHT LEVELS IS DERIVED FOR USE IN CONTROLLING AN EXPOSURE.