| 摘要 |
PURPOSE:To inform a photographer of a photographable period by providing a reference level varying means which varies the relative value of a reference level to the charging level of a main capacitor according to variation of irradiation characteristics and displaying the completion of charging to a level suitable for the irradiation characteristics. CONSTITUTION:When a power switch 2 is closed, a DC-DC converter 3 operates to charge the main capacitor 6. Then, a voltage V1 divided by resistances 7 and 8 is inputted to the uninverted input terminal of a comparator 18. A constant voltage VREF, on the other hand, is developed by a reference voltage generating circuit 12. Then, one of contacts (a), (b), and (c) of a switch 17 is selected associatively with a change in zoom state by the photographer to set a turn-on voltage Vi, which is inputted to the inverted input terminal of the comparator 18. When the voltage V1 rises above a level higher than the turn-on voltage Vi, a switching transistor 22 turns on and a pilot lamp 23 illuminates to inform the photographer of a photographable period. |
