Lens Construction 13 Elements in 9 Groups Angle of View 180 degrees Number of Diaphragm Blades 6 Blades Minimum Aperture F22 Minimum Focusing Distance 13.5cm/5.3 in. Maximum Magnification 1:6 Filter Insertion-type gelatin filter into rear of the lens Dimensions Diameter 76.2mm X Length 77.8mm 3.0 in. X 3.1 in. Weight 470g/16.6 oz. Corresponding AF Mounts Sigma, Nikon, Canon