| 摘要 |
PURPOSE:To obtain a variable focus camera which cuts off a shutter at the time of the stroboscope photographing after the constant second from the beginning of the opening of a sector to prevent the lack of the exposure due to the shutter speed excess at the short focus distance and prevent camera shake at the time of the full opening of the sector at the long focus distance. CONSTITUTION:By pressing down a releasing button, a sequencer 137 is started. A circuit 116 measures the distance, adjusts the focus, and outputs the distance information of four bits. By the working of counters 113 and FF 132, a driver 134 opens the shutter. In accordance with the rise and fall of the voltage waveform of a resistance 102 due to rays of light, for each pulse, gating 109 is executed, counting 113 is executed and the four-bit information concerning the starting of exposure and the diaphragm position is outputted. A circuit 114 compares a film sensitivity 115, distance information 116 and exposure start and diaphragm information 113 and determines a flash period. In short focus photographing, a switch 20 is closed, and the shading period is determined by the earlier output of an exposure completing signal 129 or a counter 125 (camera shake limit). In long focus photographing, the switch 20 is opened and shading is started by the full opening signal of a gate 124 or an exposure completing signal 129. The counting time of the counter 125, naturaly is longer than the shutter full-opening detecting time. |
