| 摘要 |
PURPOSE:To perform suitable automatic exposure control by correcting integral output of photometry, by using the signal obtained by differential the integral output of the optical current photometry of a photoelectric conversion element for photometry. CONSTITUTION:Photoelectric conversion element PD1 for photometry of the reflecting light sent from the film surface and curtain surface of a shutter, photoelectric current integral circuit OP1 and differential circuit OP2 which obtains the output corresponds to the photoelectric current by differentiating are provided. Correction voltage is output from the differential circuit output based on the reflecting light from the top curtain immediately before the extreme portion of the top curtain of the shutter passes through the center portion of the photographing screen and the differential circuit output based on the reflecting light sent from the film surface immediately after the extreme of the top curtain passes through the center portion of the photographing screen. Variation of photometry integral output based on the variation of reflectivity of the film and top curtain surface of the shutter by using the correction voltage in the variable gain amplifier circuit OP4. |
