Specialized and versatile, the EF 8-15mm f/4L Fisheye USM 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, this lens is weather-sealed and has a protective fluorine coating on the exposed elements for use in trying environmental conditions. Unique fisheye zoom is designed for full-frame Canon EF-mount DSLRs, however can also be used with APS-C models where it provides a 12.8-24mm equivalent focal length range. Constant f/4 maximum aperture maintains consistent illumination throughout the zoom range. Zoom allows you to change from a circular 180° fisheye look to a rectangular image. Both ends produce dramatic, creatively distorted imagery. Two ultra-low dispersion glass elements noticeably reduce color fringing and chromatic aberrations for high clarity and color fidelity. A Sub Wavelength Coating has been applied to individual elements to control lens flare and ghosting for greater contrast and color fidelity when working in strong lighting conditions. A ring-type Ultrasonic Motor (USM), along with optimized focusing algorithms and a high-speed CPU, is employed to deliver fast, precise, and quiet autofocus performance as well as full-time manual focus override. As a member of the esteemed L-series, this lens is sealed against dust and moisture for working in inclement environmental conditions. Protective fluorine coating has been applied to the front bulbous element to resist fingerprints and smudges and to make cleaning significantly easier. Built-in filter holder is located at the rear of the lens and accepts cut gel filters.