The Sigma 15mm f/2.8 EX DG Diagonal Fisheye is a full-frame fisheye auto focus lens that fills the entire 35mm negative with a full 180 degree diagonal field of view. This unique lens enables you to create a variety of unusual compositions even when shooting ordinary subjects. The improved DG lens coating reduces flare and ghosting, which is a common problem of digital cameras, and also creates an optimum color balance.