Covering a useful wide-angle focal length range, the EF 16-35mm f/4L IS USM is a Canon L-series lens distinguished by its constant f/4 maximum aperture, sophisticated optical design, and use of image stabilization to realize sharp imagery. Two ultra-low dispersion elements are used to greatly reduce color fringing and chromatic aberrations throughout the zoom range for high clarity and color accuracy, and a Super Spectra coating has also been applied to suppress flare and ghosting for improved contrast. Three aspherical elements are also featured and help to control distortion and minimize spherical aberrations for improved sharpness. Complementing the imaging capabilities, this wide-angle zoom also features a four-stop-effective Image Stabilizer system that minimizes the appearance of camera shake for sharper handheld shooting. A ring-type USM and internal focusing mechanism also afford 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. Wide-angle zoom is designed for full-frame Canon EF-mount DSLRs, however can also be used with APS-C models where it provides a 25.6-56mm equivalent focal length range.Constant f/4 maximum aperture maintains consistent illumination throughout the zoom range.Two ultra-low dispersion glass elements noticeably reduce color fringing and chromatic aberrations for high clarity and color fidelity.Three aspherical elements minimize spherical aberrations and distortions for improved sharpness and accurate rendering.Super Spectra coating has been applied to individual elements to minimize ghosting and flare for greater contrast and color neutrality when working in strong lighting conditions.An Optical Image Stabilizer helps to minimize the appearance of camera shake by up to four shutter speed stops to better enable working in low-light conditions and with slower shutter speeds.A ring-type Ultrasonic Motor (USM), along with an internal focusing system, is employed to deliver fast, precise, and quiet autofocus performance as well as full-time manual focus override.Rounded nine-blade diaphragm contributes to a pleasing out of focus quality that benefits the use of shallow depth of field and selective focus techniques.Protective fluorine coating has been applied to the front and rear element to resist fingerprints and smudges and to make cleaning these elements significantly easier.As a member of the esteemed L-series, this lens is sealed against dust and moisture for working in inclement environmental
