A reader sent me a link to this rare Leica 90mm f/1.0 lens currently listed on eBay that was developed for x-ray use. The original 90mm f/1 Elcan lens was developed by Leica Canada (Elcan from Ernst Leitz CANada) for the American Army/Navy and comes with a focusing mechanism and interchangeable fix-focus rings, as can be seen on this picture. This is how the lens looks mounted on a Leica M camera:
Also seen on eBay – a Noctilux coffee mug:
