>>4057895I don't know if this counts, but I got an EXTREMELY rare Nikon lens in an auction. It's a 230mm f/8 (?) enlarger lens for a Noritsu photo machine. It's MASSIVE, weighs several pounds, and is entirely glass and metal. It is useable on a DSLR with the right adapter, but I can't even figure out the threading on the rear mount.
These things are unobtanium, they're so rare they're hardly even mentioned online anywhere. They are Nikon's biggest ever enlarger lens.
