A flexible zoom distinguished by its relatively lightweight and compact design, the EF 70-200mm f/4L USM is a Canon L-series optic spanning a useful portrait-length to medium telephoto range. The constant f/4 maximum aperture allows you to maintain a consistent exposure throughout the zoom range and also contributes to the sleeker form factor when compared to other 70-200mm lenses. In regard to its optical performance, this lens employs one fluorite element and two ultra-low dispersion elements, which work in concert to suppress chromatic aberrations and color fringing for notable clarity and color accuracy. A Super Spectra coating has also been applied to control flare and ghosting for improved contrast when working in harsh lighting. Complementing the optical attributes, this lens also features a ring-type USM and internal focusing mechanism for quick, quiet, and accurate autofocus performance, as well as full-time manual focus override.