PURPOSE: To provide a single lens reflex camera capable of very easily changing over the size of a photographic picture frame in a state where a film is still loaded, without greatly modifying.

CONSTITUTION: This single lens reflex camera is equipped with a mirror lever 103 rocking a mirror 90 from a nonphotographing position to a position capable of photographing, at the time of photographing, a focusing plate 94 reducing a transmission part in full size photographing, to a panoramic size, in panoramic photographing, a panoramic mask 11 provided with a panoramic size transmission hole, disposed between a panoramic photographing position and a full size photographing position, and energized toward the full size photographing position, and a panoramic lever 13 permitting the panoramic mask 11 to rock and return to the panoramic photographing position, based on the rocking of the mirror lever 103 when the full size photographing is completed.