 All lenses were autofocus with the exception of the Hologon 8/16mm.The flange distance between the front surface of the lens mount and the film plane is only , and Contax released the GA-1 adaptor which allowed the use of Contax/Yashica mount lenses.Unlike most bayonet-mount lenses, the Contax G mount uses a breech-lock mechanism similar to the manual-focus Canon FD and FL mount.