Exchangeable lenses for single lens reflex cameras

Abstract

Disclosed are exchangeable lenses for use in single lens reflex cameras which include a diaphragm setting ring having an indicia for automatic aperture control and an aperture scale for manual aperture setting thereon, the scale extending from a mininum f-number to a maximum f-number of the respective lenses. The diaphragm setting ring is able to set to a desired f-number position within the scale or set to the indicia. The diaphragm setting ring is provided with a single information transmitting member whose position relative to the aperture scale is such that the member may transmit information as to the step-difference between a desired set f-number and the minimum f-number, by coupling with an information receiving member on a camera body, to an exposure indicating and/or control mechanisms in the camera body when the ring is set to any one of the manual aperture setting positions, and in such a position relative to the indicia that the member may also transmit information as to the minimum f-number of the lens through the same coupling to the camera body mechanism when the ring is set to an automatic aperture control position. Without any other information transmitting and receiving members, the cameras utilizing these lenses are capable of receiving information as to the minimum f-number of the lens mounted on their body upon automatic diaphragm control and thus the cameras may indicate an f-number corresponding to aperture to be automatically controlled before commencement of a stopping-down operation.