| 摘要 |
1,224,262. Photographic Apparatus. POLAROID CORP. March 5, 1969 [March 6, 1968], No.11771/69. Heading G2A. The second embodiment of Specification 1, 223, 448, in which the electromagnetic holding device 97 is responsive to an electric circuit for controlling exposure duration in accordance with scene brightness, is modified in that a further switch, S 5 (switches S 4 , S 5 of the above mentioned second embodiment becoming the switches S 6 , S 4 respectively), is provided so that, when the final flash-bulb 40 of an inserted flash package 25 has been removed from its operative position, the camera will be automatically reset for photography with available light, without first having to remove the flash package. Furthermore since in flash operation the time integral of light falling on a film being exposed is not constant, and thus due to delay in movement of the shutter closing blade 48, more light than is required for proper exposure will fall on the film, a compensating resistor (226) Fig. 6 (not shown) is provided to reduce the time required to generate a signal to operate the closing blade 48. A second additional resistor (227) in parallel with photo-responsive element (224), serving to limit the duration of the exposure interval to a predetermined fixed time under low flash light conditions is also provided. Insertion of a flash package switches over the switch S 4 to bring the resistors (226, 227) into the exposure control circuit. When the last flash-bulb in the package is fixed, automatic indexing due to shutter movement causes the package to trip the switch S 5 thereby breaking the circuit through the resistors (226, 227) and setting up another circuit containing the element (224). The flash package is at that time positioned with all its faces inclined to the plane of the scene to be photographed. |
