| 摘要 |
PURPOSE:To facilitate easy handling of a video camera with no increment of the size and weight by performing the exposure in a still picture mode after opening an automatic diaphragm with a still signal and then closing the diaphragm again with an exposure time control signal. CONSTITUTION:A program type exposure time control circuit 60 detects a sight out of a subject field to calculate the optimum exposure value and delivers the result of calculation as an exposure time control signal. While a gate circuit 70 supplies both the exposure time control signal and still signal and delivers an automatic diaphragm shutter control signal which controls the open/close of the automatic diaphragm in a still picture shooting mode. This control signal opens and closes an automatic diaphragm 10 through an automatic diaphragm driving circuit 21. The diaphragm 10 is closed for a fixed period of time after the still signal is delivered. Then the diaphrgam 10 is gradually opened for a period during which the exposure is given based on a program after the fixed period elapses. Then the diaphragm 10 is closed again for said exposure time. |
