The Sigma 18-35mm f/1.8 is the first wide angle zoom lens to achieve a 1.8 aperture. It incorporates a molded glass aspherical lens with Special Low Dispersion (SLD) glass to compensate for lens flare and aberrations. A nice feature on this lens is that the zoom and focusing are internal, and the Hyper Sonic Motor ensures fast and quiet focusing.
The Sigma 18-35mm is a DC lens, which means it should be used on DX cameras.

Number of diaphragm blades: 9 <br/>
Minimum f/stop: 16 <br/>
Maximum f/stop: 1.8 <br/>
Closest focusing distance: 11 in. <br/>
Weight (approx.): 28 oz. <br/>
Dimensions (approx.): 3.1 in. x 4.8 in. <br/>
External front filter: 72mm (does not rotate)