| 摘要 |
PURPOSE:To prevent the generation of an exposure error caused by a variation of the running characteristic of a shutter blade by providing an aperture detecting means for detecting a variation of the aperture of a photographic lens, and correcting the charging characteristic of an integration circuit in accordance with its detecting means. CONSTITUTION:The output of an operational amplifier 33 for constituting a photometric circuit 30 is connected to the ground through a transistor 35, and only when the transistor 35 is cut off, a charging operation of a capacitor 37 is executed. Accordingly, when a ratio of a cut-off time of the transistor 35 is raised by following the opening of a shutter blade 1, the charging characteristic of the capacitor 37 can be followed to the variation of the integral characteristic of an exposure quantity which follows an opening of the shutter blade. Therefore, by a pulse generated by a duty converting circuit 80, the transistor 35 is made to execute a switching operation, and also off-time of a pulse generated by the duty converting circuit 80 by following the rise of a counting value in a counter 20 is raised. Variation of the charging characteristic of the photometric circuit can be followed to the variation of an opening characteristic of the shutter blade, therefore, exposure control can be executed exactly.
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