| 摘要 |
<p>PURPOSE:To make exposure control with photodetectors not attaining the photometric threshold yet by changing over shutter speed priority to prescribed aperture priority mode when the photodetector for monitoring the aperture control out of plural photodetectors attains the photometric threshold. CONSTITUTION:Multiphotometry is accomplished by plural photoconductors PD2... including a photodetector PD1 for monitoring aperture control in the central part, and an aperture controlling circuit 10 is controlled by a comparator 8 and the like. The aperture is controlled in such a way that the exposure of the shutter speed of an arithmetic circuit 11 corresponding to the information having been set in a setting circuit 4 is attained, whereby the exposure is controlled with a shutter speed priority mode. When the photoelectric power output of this element PD1 attains a lower limit value, the output of a photometric threshold circuit 14 inverts to a low level to close an AND gate 18, and the aperture is held at full aperture by the circuit 10. At the same time, the shutter second time is operated by an erasing circuit 16 and the circuit 11, and the exposure is controlled with an aperture priority mode. The same holds true when the upper limit photometric threshold is attained. The exposure control takes place as far as there are the photodetectors which do not attain the threshold yet.</p> |
