Bell and Howell 8mm f/3.5 Aspherical Fisheye Lens for Nikon DSLR Cameras Magnification: 7X; Lens Diameter: 50mm Field of View: 113.7m/6.5; Exit Pupil: 7.1mm; Eye Relief: 19.5mm Brightness: 50.4; Twilight Performance: 18.7 Ocular: 2 Groups in 3 Elements; Objective: 1 group 2 elements Fully Coated Optics; BK-4 Prisms