PURPOSE: To perform high-precision stopping-down operation by exercising automatic aperture control by compensating by a simple mechanism a difference in open-aperture values characteristic to individual lenses mounted on a camera body interchangeably, and illuminance errors at a photodetection part influencing a photodetection part position owing to various elements of the lenses.
CONSTITUTION: Different open-aperture values characteristic to interchangeable lenses A, B and C, the illuminance error of a film surface at the open-aperture values, and an illuminance error generated relating to the position of a photodetection part are corrected by being substituted by the extent of a previous run which does not relate to light-quantity control effect by stop-down metering by a release plate 31 which relays the operation of an aperture driving member 11 at a camera body side where values equivalent to the open-aperture value of a reference lens A and deviations from those errors are controlled through the operation of an exposure control circuit to aperture blades S at a lens side. Further, an aperture blade stop error equivalent to the delay of the operation due to the mechanism of an operation system relaying the operation of the aperture driving member 11 to aperture diaphragms S is added to the extent of the previous run to be corrected.
OOKURA ZENICHI
KAWASAKI MASAHIRO
| JPS5520503U | 1980-02-08 | |||
| JPS5397422A | 1978-08-25 |
| US3486434A | 1969-12-30 |
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