I'm sorry if this is not the proper forum for this question but would ask your help in indentifying a lens. It is in a black barrel 5" in length 4" in diameter with a mounting flange and makers mark engraved of of Ernest leitz Wetzlar. The word EPIS f=32.5cm 1:36 is engraved on the barrel. No serial number, no shutter, just one big lens. What could this possibly been used for and where might I find more information? Thanks for any help.