This standard zoom lens is designed exclusively for digital SLR cameras with the smaller size sensors, and incorporates Sigma's original OS (Optical Stabiliser) function. -This lens offers a large aperture of F2.8 at the 18mm focal length making it ideal for indoor photography and in low lighting conditions. -Two SLD (Special Low Dispersion) glass elements and three aspherical lenses provide excellent correction for all types of aberrations. High image quality is assured throughout the entire zoom range. -The incorporation of HSM (Hyper Sonic Motor) ensures a quiet and high speed AF. -The Super Multi-Layer Coating reduces flare and ghosting and provides high contrast images. -This lens has a minimum focusing distance of 30cm (11.8 inches) throughout the entire zoom range and a maximum magnification ratio of 1:4.1 making it ideal for close-up photography. Technical Specifications - Lens Construction - 16 Elements in 12 Groups Angle of View (SD Format) - 69.3 - 27.9 degrees Number of Diaphragm Blades - 7 Blades Minimum Aperture - F22 Minimum Focusing Distance - 30cm Maximum Magnification - 1:4.1 Filter Size - 67mm Dimensions - Diameter 74mm X Length 88.6mm Weight - 395g