The worldu2019s first fisheye zoom lens that offers both Circular and Diagonal fisheye effects*. With just one lens, it allows EOS full-frame DSLR cameras to achieve both 180-degree Circular and Diagonal images perfectly. It also supports DSLR cameras with APS-H or APS-C sensors, u2018Hu2019 and u2018Cu2019 markings are provided on the lens to indicate the zoom position when the 180-degree Diagonal fisheye view can be achieved respectively. Also, a zoom-limiter is specially designed for APS-C format users on the lens body, allowing the zoom range to be limited from u201cCu201d to the 15mm focal length. This lens consists of 14 lens elements in 11 groups, including one Ultra-low Dispersion (UD) element and one high-precision glass-molded (GMo) aspherical lens to correct various kinds of aberrations. The inner surface of its front lens element is treated with SWC (Sub Wavelength Structure Coating) to minimize flare and ghosting common to wide angle lenses as a result. The lens features rear focusing design and a ring-type ultrasonic motor (USM), and together with a high-speed CPU and an improved AF algorithm, making AF quick and accurate. The minimum focusing distance of the lens is 0.15m which is particularly useful for close-up photography with an exceptional perspective. A circular aperture can create a beautiful bokeh effect that helps bringing out the subject. The front and rear lens elements are applied with Fluorine coating which can repel water and oil effectively, making it easier to be cleaned to ensure image clarity and color retention.