The Nikon Nikkor T ED 270mm f/6.3 is a telephoto-design large format lens with a 160mm image circle, covering 4x5in with minimal movements. At 590g with a 67mm filter thread, the T designation indicates a telephoto optical design that provides a significantly shorter back focus than a conventional lens of the same focal length. The ED (Extra-low Dispersion) glass reduces chromatic aberration. It is designed for cameras with limited bellows extension.