I've converted 8 of these, 6 with uncoated optics. This is the best of all of them, has been my pick of the litter for almost 10 years. The only one modified for closer focus. For sale is a 1934 Carl Zeiss Jena 5cm F2 uncoated Sonnar mounted in a 1955 Jupiter-8 Leica Thread Mount focus module, EX condition. Glass is near perfect- rare for an F2 Sonnar of this vintage. The focus module is modified to focus to ~.8m or so, closer than the normal 1m. This lens is optimized for wide-open and close-up use on the Leica. The example shots are with my M9. It focuses properly to infinity even at F2. Price: $350 shipped within the United States Priority Mail, $370 anywhere else via International Priority Mail. Paypal, Personal Check, Money Order. I reserve the right to hold shipment until check/MO clears. Return policy: returns must be made within 10 days, refund for the price of the item will be given after receipt. Postage cost is not refundable. Coated Walz filter and homemade rear cap included (It's a Milk Cap that I cut the liner out of. Makes a perfect push-on rear Cap for thread mount lenses). At F2: F4: Shows Sonnar focus shift, that you hear so much about. about the same as my new C-Sonnar. F2, standard 1m close-focus: F2, AFTER the modification for closer focus. Modification to threads, allows RF follower to maintain contact with the Cam of the lens. This lens on a film camera, Kodak C41 Black and White, at F2. On the Leica M8, wide-open: At F2, the colors are muted. Very different from coated optics.