A camera includes: a ring-like body mount having an inside diameter smaller than about 48 millimeters; and a solid-state image pickup device arranged oppositely to the body mount, the solid-state image pickup device having a rectangle light receiving section with a diagonal line length of about 43 millimeters or more. An apparent shape of the solid-state image pickup device viewed from a front surface side of the body mount is a rectangle in which one or more corners are oblique.