The third generation EF 16-35mm f/2.8L III USM from Canon is a full-frame wide-angle lens featuring an updated optical design that uses modern coating technologies for improved outer and corner sharpness along with minimal distortion and enhanced peripheral illumination. It is also compatible with APS-C format cameras where it will provide a 25.6-56mm equivalent focal length range. It features a fast constant maximum aperture of f/2.8 for low-light performance and consistent results throughout the zoom range.
The optical design uses two large diameter GMO dual surface aspherical elements and one ground aspherical element to minimise distortions throughout the zoom range, and two Ultra-low Dispersion glass elements to control chromatic aberrations. It also features both a Subwavelength Coating and an Air Sphere Coating to minimise flare and ghosting. This is complimented by a rounded nine-blade aperture to capture smooth out-of-focus 'bokeh' areas.
A ring-type USM focusing motor combined with a high-speed CPU and optimised AF algorithms ensures fast and accurate autofocus. The lens has an internal focus design and offers full-time manual focus override for fine-tuning of your focus position when working in the AF mode. It is finished with a dust- and water-resistant construction and a fluorine coating on the exposed front and rear elements to help prevent fingerprints and dust from adhering to the lens surface.
