The Canon EF 8-15mm f/4L Fisheye is a super sharp and ultrawide L series lens designed for both full frame and crop frame sensor cameras. On a full frame camera you will get a fully circular image at 8mm but a more traditional full frame image at 15mm. If you are shooting with a crop body, the lens barrel has markings for APS-C/APS-H sensors showing which focal length to use in order to avoid vignetting. This lens is built like a tank and is dust and moisture resistant. It also features ultra low dispersion elements, a Sub-Wavelength coating to reduce ghosting, and a fluorine coating (also found in Canon's super-teles) to prevent fingerprints and smudging on the exposed elements. This lens is ideal for fine art photography, street photography, urban settings, wide expanses, and parties.