1. Field of the Invention
The present invention relates to an automatic light adjustment camera capable of dividing a field into a plurality of areas for photometry at the time of flash emission and conducting light adjustment in accordance with the result of the photometry, and the exchangeable lenses which can be mounted on this camera.
2. Related Background Art
As a camera of the king, there is a camera disclosed in U.S. Ser. No. 789,967 filed by the applicant hereof on Nov. 21, 1991, for example. The camera disclosed therein has an electronic flash apparatus capable of emitting preliminary flash and main flash, and conducts photometry by dividing the reflected light from the field at the time of preliminary flash emission into a plurality of photometric areas. Thus, on the basis of the photometric outputs and photographing distance, the photometric areas (effective areas) which are allowed to contribute to light adjustment at the time of main flash emission and the photometric areas (cut areas) which are not allowed to contribute thereto are determined. In this way, the light adjustment is performed in accordance with the photometric signals from the above-mentioned effective areas when the main flash is emitted.
In the above-mentioned camera, however, there is a possibility that if the detection accuracy of a photographing distance is not excellent, even an area where a main subject which should not be cut essentially is cut. In such a case, a problem is encountered that any correct exposure cannot be obtained. Particularly, when the photographing distance is long or the focus length of a photo-graphic lens is short, the detection accuracy of the film-to-object distance is lowered. Hence, a problem such as this tends to occur.