Specialized and versatile, the Canon EF 8-15mm f/4L Fisheye USM with EF-mount is a Canon L-series lens offering flexibility to a conventionally niche lens type. Capable of producing both circular and rectangular fisheye effects, this lens is characterized by its notable distortion and rounded image quality along with an immense 180° angle of view at the 8mm position. The optical design incorporates two ultra-low dispersion glass elements to limit chromatic aberrations and color fringing for high clarity and color accuracy, and a Sub Wavelength coating has also been applied to control flare and ghosting for greater contrast. Balancing the refined optics, this 8-15mm f/4 also sports a ring-type USM mechanism to enable quick, quiet, and accurate autofocus performance, as well as full-time manual focus override. Additionally, Canon EF 8-15mm f/4L Fisheye USM is weather-sealed and has a protective fluorine coating on the exposed elements for use in trying environmental conditions.