Abstract A photographic apparatus having a structure for automatically determining the exposure aperture according to the lighting conditions. An electrical circuit is provided with a switch for opening and closing the circuit. A photosensitive resistor is connected with the circuit for influencing the current flowing therethrough according to the intensity of the light which is received by the photosensitive resistor. An adjustable diaphragm is provided to determine the size of the exposure aperture, and this diaphragm has a fully closed position where no aperture is provided. A moving coil instrument is operatively connected with the circuit and with the diaphragm for automatically adjusting the latter according to the intensity of the light which is received by the photosensitive resistor. When the switch opens the circuit, the moving coil instrument automatically places the diaphragm in its fully closed position, so that when the structure is not used, with the circuit open, no light will pass through an objective with which the diaphragm coacts.
In a photographic apparatus, electrical circuit means having a switch for opening and closing said electrical circuit means, photosensitive means operatively connected with said electrical circuit means for influencing the flow of current therethrough according to the intensity of light received by said photosensitive means, adjustable diaphragm means for providing an exposure aperture the magnitude of which is determined by the adjustment of said diaphragm means, the latter having a fully closed position where no exposure aperture is provided, and meter means operatively connected to said circuit means and to said diaphragm means for automatically adjusting the latter to provide an exposure aperture according to the intensity of light received by said photosensitive means, said meter means automatically placing said diaphragm means in said fully closed position thereof when said circuit means is opened by said switch, so that no exposure aperture is provided when current does not flow through said circuit means.
Claim 2
Dependent Claim
153 words
In a photographic apparatus, electrical circuit means having a switch for opening and closing said electrical circuit means, photosensitive means operatively connected with said electrical circuit means for influencing the flow of current therethrough according to the intensity of light received by said photosensitive means, adjustable diaphragm means for providing an exposure aperture the magnitude of which is determined by the adjustment of said diaphragm means, the latter having a fully closed position where no exposure aperture is provided, and meter means operatively connected to said circuit means and to said diaphragm means for automatically adjusting the latter to provide an exposure aperture according to the intensity of light received by said photosensitive means, said meter means automatically placing said diaphragm means in said fully closed position thereof when said circuit means is opened by said switch, so that no exposure aperture is provided when current does not flow through said circuit means.
Claim 3
Dependent Claim
98 words
The combination of claim 1 and wherein said circuit means is a bridge circuit one arm of which is formed by said photosensitive means, other arms of said bridge circuit including variable resistors and said meter means being a moving coil instrument, said diaphragm means including a pair of diaphragm blades one of which is operatively connected with said instrument to be turned thereby and the other of which is oriented oppositely to said one blade and linked therewith for carrying out movements equal and opposite to said one blade upon movement of the latter by said instrument.