I have a FED-1d manufactured in 1940. I've read online that the lens to film register on the pre-WWII FED's aren't the standard 28.8mm of a Leica or other rangefinders which makes focusing these lenses difficult. I currently have a 50mm f3.5 Industar-10 which I really enjoy the results I've had so far and wanted to know which other lenses I can use with this body. Can I use any of the cheaper KMZ lenses or should I just keep to the older FED-1 designed lenses? The only alternatives to the 50mm for the older FED-1 is a 100mm and 28mm both of which seem to be fairly expensive for a Russian lens (+$100).