| 摘要 |
PURPOSE:To eliminate malfunction such as vignetting, no light emission, etc., by triggering a flash trigger device of a shutter consisting of front and rear curtains, by a logical circuit for making it conduct only when the aperture is fully opened. CONSTITUTION:Trigger terminals J3, J4 of a flash device F are connected to terminals J1, J2 of a camera side. Only when an output of an NOR circuit 2 is in a high level, an SCR (SR) conducts, and the flash device is triggered. At the time of release, transistors Q1, Q2 conduct and a switch SX is opened, therefore, an input to the NOR circuit is in high and low levels, accordingly, its output is in a low level. When the front curtain running is completed, a switch SR is closed, the NOR output is reversed, and the flash device is triggered. When an exposure controlling circuit 1 turns off the transistors Q1, Q2, the NOR output becomes a low level. Accordingly, unless the aperture is fully opened, the SCR does not conduct, and one mechanical switch is enough, therefore, malfunction scarcely occurs. |
