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 significantly 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. A ring-type USM and internal focusing mechanism also afford quick, quiet, and accurate autofocus performance, as well as a 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. Constant f/4 maximum aperture maintains consistent illumination throughout the zoom range. Three aspherical elements minimize spherical aberrations and distortions for improved sharpness and accurate rendering.

An Optical Image Stabilizer helps to reduce the appearance of camera shake by up to four shutter speed stops to enable better working in low-light conditions and with slower shutter speeds. The 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.