Lens Construction 7 Elements in 6 Groups Angle of View 180 degrees Number of Diaphragm Blades 7 Blades Minimum Aperture F22 Minimum Focusing Distance 15cm/5.9 in. Maximum Magnification 1:3.8 Filter Size Rear (Gelatin filter) Dimensions Diameter 73.5mm X Length 65mm 2.9 in. X 2.6 in. Weight 370g/13.0 oz. Corresponding AF Mounts SIGMA,