Suitable For: M42 Lens Mount (Zeiss, Pentax, Praktica, Mamiya, Zenit) PENTAX CAMERA: *ist D, *ist DL, *ist Ds, *istDL2, K100 Introduction:M42 to all Pentax PK mount adapter ring. Make M42 mount lenses (Zeiss, Pentax, Praktica, Mamiya, Zenit) can be used on Pentax PK cameras. There is no ROM connection on the ring so diaphragm control of the lens is set manually. It is possible to use Macro rings ...