Canon's EF 16-35mm f/2.8L III USM Lens embraces a revamped optical design with modern coating technologies that promise improved outer and corner sharpness along with minimal distortion and enhanced peripheral illumination. A member of Canon's legendary L series, this full-frame 16-35mm delivers outstanding image quality and a professional-grade durability. It also offers a fast and constant f/2.8 maximum aperture for consistent performance and light transmission throughout the zoom range. With the incorporation of two large diameter GMO dual surface aspherical elements and one ground aspherical element, the lens will minimize distortions throughout the zoom range as well as maintain edge-to-edge sharpness and illumination. Along with those elements, the lens utilizes two Ultra-low Dispersion glass elements which minimize chromatic aberrations. Also, it uses both a Subwavelength Coating and an Air Sphere Coating to minimize flare and ghosting.