| 摘要 |
The digital shutter control circuit comprises a reference clock pulse generating circuit, a binary counter circuit having a plurality of output stages each issuing, upon counting the pulses from the reference pulse generating circuit, output signals corresponding to the exposure time to be set in the shutter in terms of 2n where n is an integer and a selector circuit connected to the shutter closing means and selectively connectable to any of the output stages. The binary counter circuit is actuated simultaneously with the actuation of the shutter opening means for opening the shutter so that the shutter closing means is actuated when the output signal is issued from the output stage to which the selector circuit is connected thereby closing the shutter to provide the selected shutter speed. The shutter control circuit incorporates an AND circuit the inputs of which are connected to at least two output stages selected from the plurality of output stages and the output is selectively connectable to the selector circuit so that, when connected, an exposure time is obtained which is intermediate the values obtained from the above selected two output stages. The exposure times may comprise the series of 1/1000 sec., 1/500 sec.-1/2 sec. and 1 sec. and the selected two output stages may be made 1/1000 sec. and 1/125 sec. so that substantially 1/114 sec. of the exposure time is obtained which exposure time is effective to insure the synchronization of an electric flash device with the shutter in which shutter opening and closing blades are actuated in parallel to the minor sides of the frames of 35 mm film.
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