| 摘要 |
<p>PURPOSE:To enable program photography, by changing the program to a proper position when the calculated aperture value Av and exposure time value Tv reach out of the coupling range of the exposure control function or the camera-shake limit. CONSTITUTION:A program shutter functions by controlling the exposure according to the Av value and Tv value stored in recording circuits 17, 18. A gate 11 compares the result of operation, Av'=Av-beta, with the open aperture value Avo in a comparator circuit 12, and is opened while Avo<Av', thereby sending the noncoincidence signal of the comparator circuit 16 into an agrument beta setting circuit 6. A gate 15 compares the inverted signal of the output of the comparator circuit 12 or Tv'=Tv-alpha with the output Tvh of a camera-shake limit value setting circuit 10, and is opend while Tvh<Tv', thereby sending the noncoincidence signal of the comparator circuit 16 into an argument alpha setting circuit 8. Thus, as the program starts from the minimum aperture diameter maximum shutter speed and moves to the lower exposure value side until the shutter s peed reaches the camera-shake limit, the shutter speed is fixed and only the aperture is being opened until fixed at the open aperture. Then, the gate 15 is opened again, and the shutter speed is changed again toward the lower side.</p> |
