| 摘要 |
PURPOSE:To obtain always correct exposure irrespectively of the light intensities of a light source by correcting the value corresponding to the exposure to be exposed only during the closing operation period of a shutter from the target value corresponding to the correct exposure. CONSTITUTION:A position detector 6 opens a switch 20 when a rotary disc 3 comes to such a position where it transmits the light from a light source fully. The switch 20 opens at the full opening of the shutter, after which it is held open until the end of exposure operation. Hence, a capacitor 21 connected in series to the switch 20 holds the voltage corresponding to the integrated value of the quantity of light. Further, a differential amplifier 22 is inputted with reference voltage Es which is a target value and the voltage Vc of the capacitor 21 and outputs the differential value VR thereof. A comparator 15 compares the integrated voltage Vs of the quantity of light and the voltage VR and when these coincide nearly, its output inverts to reset an FF circuit 16. Since in this way the start of the shutter closing operation is changed according to the integrated value of the quantity of light, always the correct exposure is obtained irrespectively of the light intensities of the light source. |
