(TLR) cameras throughout the middle of the twentieth century. These were developed into the C cameras (C2, C3 through to C330s) which have interchangeable lenses as well as bellows focus.

In 1970, Mamiya introduced the RB67, a 6×7 cm (nominal) professional single lens reflex (SLR). The RB67, a large, heavy, medium-format camera with built-in closeup bellows was innovative and successful. Previous medium-format professional SLR cameras used the square 6×6 cm