5200mm Canon Lens World's MOST powerful Super telephoto EF FD (updated upload)

Canon 5200mm F14 Prime Lens. The world's largest dedicated SLR Super Telephoto lens. Extremely rare. Made in Japan. Most probably a government ordered cold war spy tool - it certainly wasn't designed to look at the stairs with the use of it's ND filters... It uses a mirror & lens combination. The front lens is massive.