Presenting an impressively unique 180° angle of view, the Sigma 8mm f/3.5 EX DG Circular Fisheye Lens is a creative tool for producing dramatically distorted, circular imagery. Designed for full-frame-format Sigma SA-mount DSLRs, this lens intentionally does not cover the full image frame and rather produces a fully circular image in the center of a black frame. One Special Low Dispersion (SLD) glass element is incorporated in the lens design and helps to reduce some chromatic aberration and color fringing for increased clarity. The lens also features a close minimum focusing distance of 5.3", along with a 1:4.6 maximum magnification ratio, to enable creative close-up shooting from unique perspectives. An internal focusing design maintains the overall length of the lens during use, and a selector switch allows you to quickly change between autofocus and manual focus settings.Circular fisheye design provides a 180° angle of view and produces circular images that do not fill the entire full-frame-format frame.One SLD element helps to reduce chromatic aberrations and color fringing for greater color accuracy and clarity.Minimum focusing distance of 5.3" pairs with a 1:4.6 maximum magnification ratio for creating unique close-up imagery.Focus mode selection switch lets you quickly change from auto or manual focusing control.The lens itself lacks front filter threads but does incorporate a gelatin filter holder at the rear of the lens