Thanks! I will definitely keep all those in mind. another question, even though some lenses and accessories are listing as having the same bayonet mount, they seem to be described as fitting specific rollei mf slr bodies. for example, sometimes i see bay vi lenses specified for slx bodies on sale but sl66 lenses are in another category even though they have the same bay vi mount. why is this? they will not mount interchangeably on rollei mf bodies right?