| 摘要 |
PURPOSE:To execute dimming with high reliability, by integrating a current corresponding to only the light emission quantity of a flash light emission tube, detecting whether its integral value exceeds an integral value of a current by the light emission quantity to a marginal time, and providing an exposure suitability detecting circuit on only the flash device side. CONSTITUTION:When an X contact SWX is turned on by operating correspondingly with release of a camera and a flash discharge tube FL emits light, a current flows to a resistance R1, diode D1 and an integration capacitor C2, and the charge stored in the integral capacitor C2 is compared with voltage Vref applied to a + terminal of a comparator CP. The voltage Vref is set to voltage charged by a marginal time which is a little longer than the shortest light emitting time, therefore, when a stop pulse is outputted from a photometric circuit at some time point which has exceeded the marginal time due to proper exposure, an error light emission alarm lamp L2, an under-alarm lamp L3 and an over-alarm lamp L4 are all turned off. In case of overexposure or underexposure, the respective alarm lamps L4, L3 flicker and each alarm is issued. |
