A camera which automatically controls an exposure by identifying a change in composition in image field and the kind of main object. The camera comprisesan exposure device for exposing an image-taking plane to an image of the object field formed by an image-taking lens;a focus detection device for generating a focus detection signal corresponding to the amount of defocus of the image, formed by the image-taking lens, of the object field with respect to a predetermined plane;an in-focus state detection device for detecting that the image of the object field is focused to the predetermined plane, based on the focus detection signal;a device for releasing a detection start signal for causing the in-focus state detection device to start an in-focus state detecting operation prior to the operation of the exposure device;a device for releasing an exposure start signal for starting the operation of the exposure device;a discrimination device for discriminating, after the in-focus state detection device detects that the image of the object field was once focused to the predetermined plane, whether the object of the object field is still focused to the predetermined plane in response to the exposure start signal, the discrimination device being adapted to execute the discrimination based on the focus detection signal prior to the start of operation of the exposure device; anda control device for controlling the exposure device based on the result of discrimination by the discrimination device.