mamiya's c-series, introduced in the 1960s, the c-3, c-2, c-33, c-22 and the mamiya c330 and mamiya c220 along with their predecessor the mamiyaflex, are the main conventional tlr cameras to feature truly interchangeable lenses. "bayonet-mount" tlrs, notably rolleis & yashicas, had both wide-angle and tele supplementary front add-ons, with rollei's zeiss mutars being expensive but fairly sharp. rollei also made separate tlrs having fixed wide-angle or tele lenses: the tele rollei and the rollei wide, in relatively limited quantities; higher sharpness, more convenient (faster than changing lenses) if one could carry multiple cameras around one's neck, but much more costly than using 1 camera with supplements. the mamiya tlrs also employ bellows focusing, making extreme closeups possible.