Employing a newly designed optical system that corrects aberrations common to wide-angle lenses, this ultra wide-angle delivers sharp, high-resolution images over the entire image area along with outstanding contrast. Thanks to the precise, large-diameter GMo aspherical characteristics of the 3rd and 14th elements, distortion is effectively eliminated despite the 114° angle of view. In additions, two UD elements reduce chromatic aberration of magnification for clean images and vastly reduced color bleeding. Ultrasonic rear focus allows manual focus at any time and combines wit a high-speed CPU for fast autofocus. The circular aperture produces beautiful background blur effects and the dust- and drip-proof design is a nice touch when working in harsh environments. Flare and ghost, problems often associated with digital SLR photography, are also noticeably reduced. This lens is excellent for situations requiring crisp, precise full-frame imaging.