| 摘要 |
PURPOSE:To prevent an aperture value depending upon a body value from being set beyond the aperture range of a mounted lens by inputting digital values corresponding to the open aperture value minimum aperture value of the lens mounted on an interchangeable lens camera. CONSTITUTION:The minimum aperture value of the lens is inputted to an input terminal IN of a comparing circuit 2 digitally, and the open aperture value of the lens is also inputted to an input terminal IN2 of a comparing circuit 3. The comparing circuit 2 generates an active output when the contents of a counter 1 are larger than or equal to the minimum aperture value of the lens, and the comparing circuit 3 generates an active output when the contents of the counter 1 are smaller than or equal to the open aperture value of the lens. For example, when the open aperture value of an interchanged lens is larger than an aperture value set previously, the output OUT of the comparing circuit 3 becomes active and the open aperture value of the new lens is inputted as an active signal to a logical circuit 6 to update Q1-Q5 of the counter 1.
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