Sigma's 28-200mm F3.5-5.6 Aspherical IF-Premier is one of several new Sigma lenses. It incorporates one Aspherical Lens in the rear lens group and the one Special Low Dispersion (SLD) glass element in the front lens group. This high magnification zoom lens covers focal lengths from 28mm wide angle to 200mm telephoto, with close-up capability. It incorporates special internal focusing to enable it to focus as close as 19.7 inches (50cm) from film plane to subject, at all focal lengths, and to the use of polarizing filters. A detachable "perfect hood" is provided. The optical materials used in this new lens are lead and arsenic free ecological glass. Product Identifiers Brand Sigma Model Macro MPN 785-101 Lens System Focus Type Auto & Manual Focal Length Zoom Focal Length (mm) 28 mm - 200 mm Aperture F/3.5-5.6 Compatibility Compatible Brand Canon Mount Canon EF Dimensions Weight 18 oz