| 摘要 |
PURPOSE:To eliminate unnecessary photographer's uneasiness and to prevent out-of-focus photography by determining whether focus detecting operation is successful or not on the basis of the open aperture value of a zoom lens and a limit aperture value for a photodetecting element. CONSTITUTION:When the open aperture value of the zoom lens which varies with focal length is read out and supplied through the circuit block LE of the zoom lens and a converter COV between this lens and a camera body, a microcomputer MC1 for controlling the camera compares this aperture value with a limit aperture value for allowing uniform luminous flux to strike a photodetecting element group which detects the aperture value and focusing. When the open aperture value is larger, the computer MC1 inhibits a microcomputer MC2 for focus detection from performing the focus detection operation. The maximum open aperture value of the zoom lens is read out through the computer MC1 and set in the camera irrelevantly; to set focal length. Therefore, even if automatic focus detection is never stopped in the middle to give a photographer unnecessary uneasiness, and out-of-focus photography is prevented by the setting of the maximum open aperture. |
