The CE, and CM 3s are M 42 the CE and CM 4s are K mount, for the most part the same camera with differnt mounts. I use my CE and CM 3 more often than the
4s as I have wider range of M 42 lens. I also have a CP7 which is much differnt from the CE 4, built in motor wider, LED controls, needs the K mount lens with A mode for all functions. I would also take a look at the Ricoh K mounts if you want a better winder.