| 摘要 |
PURPOSE:To perform various kinds of exposure control with high precision and to eliminate the need to transmit an open aperture value by correcting an error in illuminance due to vignetting, etc., by the amount of the preliminary run of a stop, and providing an auto position at specific distance from a minimum aperture value. CONSTITUTION:A resistance value of a camera-side variable resistance R is selected from a preset value of the aperture settling ring (a) of a reference lens A (with an open aperture value F1.4 and a minimum aperture value F22), but settling rings (b) and (c) of lenses B and C of different kind are made different in relative position relation with the resistance R and the error in illuminance due to the optical characteristics of the lenses and the arrangement of a light metering element is corrected by substituting deviation -DELTARVB', etc., with the amount of the preliminary run of the stop. Further, the deviation DELTAAVB at the auto position corresponds to the sum of said deviation and the difference in the number of stop-down stages from open aperture to minimum aperture and the aperture value in shutter priority exposure is calculated on the basis of the difference in the minimum aperture value between the lens A and other lenses.
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