The new Sigma wide-angle model stands out with its thoroughly corrected magnification chromatic aberration and sagittal coma flare, as well as completely minimized distortion thanks to its optical design. It features water- and oil-repellent coating on the front lens element and its overall dust- and splash-proof structure ensures excellent performance even in the most challenging shooting conditions. The high-speed AF, thanks to the HSM (Hyper Sonic Motor) with an updated algorithm, captures the perfect moment instantly,This lens is a great contender for street photography, as well as shooting landscapes and night skies. SPECIFICATIONS Lens Construction 17 elements in 12 groups Angle of View (35mm) 75.4? Number of Diaphragm Blades 9 (Rounded diaphragm) Mininum Aperture F16 Minimum Focusing Distance 28cm / 11 in. Filter Size (mm) ?77? Maximum Magnifications 1?5.4 Dimensions(Diameter x Length) ?82.8mm ? 107.7mm(3.3 in. x 4.2in.) Weight 865g / 30.5oz.