Abstract: The invention concerns a flange back mechanism for a single-lens reflex camera which has a structure permitting an image- forming surface to be moved in a distance-reducing direction further from a reference flange back position commonly defined for various interchangeable lens, to provide an ultra infinity position. By merely placing a distance ring of an interchangeable lens in the vicinity of infinity, AF response from the closest distance to infinity becomes possible.

Abstract: 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.