The Nikon Nikkor T ED 1200mm f/18 is the longest focal length in Nikon's large format range, a massive telephoto-design lens with a 310mm image circle. At 1480g with a 95mm filter thread, the telephoto construction is the only way to achieve 1200mm on a practical camera. The f/18 maximum aperture demands bright light for focusing. The ED glass controls chromatic aberration at this extreme focal length. A highly specialised optic for extreme long-distance large format photography.