Lens Construction 12 Elements in 7 Groups Angle of View 154 degrees (180° for Nikon, 167° for Canon) Number of Diaphragm Blades 7 Blades Minimum Aperture F22 Minimum Focusing Distance 13.5cm/5.3 in. Maximum Magnification 1:3.3 Filter Insertion-type gelatin filter into rear of the lens Dimensions Diameter 75.8mm X Length 83.1mm 3.0 in. X 3.3 in. Weight 16.8 oz/475g Corresponding AF Mounts Sigma, Nikon, Canon