EF 16-35mm f/2.8L III USM is a premium quality ultra-wide angle zoom lens, with a constant f/2.8 maximum aperture, for the highest image quality possible even in low light conditions. Favoured by many, this new version of the classic wide zoom offers stunning sharpness throughout the zoom range the large-diameter double-surface Glass Moulded (GMo) lenses and Ultra Low Dispersion help to significantly improve image distortion and reduce chromatic aberration. While Advanced Air Sphere and SubWavelength coating work to combat ghosting and flare, so you can shoot with confidence in environments with unflattering lighting.