Colyn, it depends on the camera and lens some have the threads worn. The Leica specs are 39mm X 26tpi (turns per inch) (.977mm) and the Russian lenses are 39mm X 1mm. Read the last paragraph here on the Survival Guide: http://jay.fedka.com/index_files/Page433.htm
I have a IIIa that doesn't take Russian lenses and a IIIc that does. Yes, they are good lenses, if you find a good one.
Last edited by lacavol; 07-24-2012 at 02:56 AM. Click to view previous post history.
Reason: addt'l info & correct pitch