Offering a versatile wide-angle range, the EF 17-40mm f/4L USM lens is a Canon L-series zoom lens featuring a constant f/4 maximum aperture, sophisticated optical design, and durable construction. It features one Super UD element, along with three aspherical elements, which help reduce chromatic and spherical aberrations for high sharpness, clarity, and color accuracy. A Super Spectra coating has also been applied to suppress flare and ghosting for improved contrast in difficult lighting conditions. Complementing the imaging capabilities, this wide-angle zoom also features a ring-type USM and an internal focusing mechanism to deliver fast, quiet, and accurate autofocus performance, as well as full-time manual focus override. Additionally, this lens is weather-sealed for use in challenging environmental conditions.
