I bet you are wondering what this strange contraption is! This one is actually the world's largest telephoto lens developed especially for a customer! The ZEISS Apo Sonnar T* 4/1700 was developed by Carl Zeiss for a wild life photographer who was using a Hasselblad 203FE 6x6cm medium format camera.The lens has a focal length of 1700mm and a speed of f/4. It weighs 256 kg (564 lbs. and the lens consists of 15 optical elements in 13 groups.