The EF 16-35mm f/4L IS USM ultra wide-angle zoom lens features newly developed, high quality Canon optics that incorporate three GMo (Glass-Molded) aspheric lens elements, including a large-diameter aspheric lens, which help improve image quality by correcting aberrations. Two additional UD lens elements help reduce chromatic aberration from edge to edge throughout the entire zoom range for excellent image quality with high resolution and contrast. The lens also features enhanced fluorine lens coatings on the front and rear lens surfaces to repel dust particles and help ensure superb color balance while minimizing ghosting. The inner focusing and ring USM offer silent, fast and accurate autofocusing. Full-time manual focus adjustment is available in autofocus (AF) mode. A nine-blade circular aperture creates beautiful, soft backgrounds. A new compact four-group zoom system provides a minimum focusing distance of 0.28m/11 inches throughout the zoom range and a maximum magnification of 0.23x at the telephoto end for outstanding performance.