Disclosed is a back-focal distance control system autofocus single-lens reflex camera wherein a single-lens reflex camera body is sectioned into two blocks, one block is a fixed block while the other block is a movable block, the movable block is moved in the optical-axis direction of a lens on the basis of the fixed block, and autofocus control is conducted by adjusting a flange-focal distance of the camera. Autofocusing is attainable even by installing a manual interchangeable lens and other AF interchangeable lenses. Further, a switching operability between MF/AF operations is enhanced, and super close-range photography can be also effected. Extended further is a possible-of-AF range (from super close-range to super infinity) in combination with AF of a lens drive system. At the same time, the AF operation is conducted at a high speed with a high accuracy. Further, even when installing a lens larger in size than a standard lens, a reliability on the operation of a diaphragm mechanism is enhanced.

The invention concerns a back-driven-type autofocus camera of a photographic lens-interchangeable type, which is capable of operating an autofocus function in any lens mounted on a lens mount directly or by means of an adapter ring. The back-driven-type autofocus camera includes a movable section having a film feeding and holding device, a range-finding element, and an optical system, and a fixed section having an outer case provided with a release button and a lens mount. The fixed section incorporates therein the movable section through a slider device so as to permit focusing-adjustment driving of the movable section in the direction of the optical axis of a photographic lens. The outer case with certain rigidity is arranged so as to separate the movable section from an external force.

A method and apparatus for passive autoranging. Two cameras having different image parameters (e.g., focal gradients) generate two images of the same scene. A relaxation procedure is performed using the two images as inputs to generate a blur spread. The blur spread may then be used to calculate the range of at least one object in the scene. In one preferred embodiment, a temporal relaxation procedure is employed to focus a third camera. In another preferred embodiment, a spatial relaxation procedure is employed to determine the range of a plurality of objects.

A method for automatic focus for an image capture device comprising a lens, the method comprising, for a first lens position, processing image data generated at a plurality of local focus positions of the lens in order to generate first metric data representing a focus measure for the first lens position, adjusting the lens position on the basis of the first metric data, and generating corresponding second metric data for at least one local focus position at the new lens position, and determining an estimated point of true focus for the lens on the basis of the first and second metric data.

An image output by a camera can contain a fault such that the signal output by the camera is not constant for a uniform background. To correct this fault, the method involves memorizing, as a correction image, a destructured image of the scene to be observed; this destructured image is generated by calculating the means of the signals obtained when the selected scene is observed while the camera settings are simultaneously modified inconsistently; the correction image is then subtracted from the image formed by the signals output by the detector during real observation of the scene selected with correct camera settings. Application to all scanning cameras.