(From Sigma lens literature) The Sigma Corporation is pleased to announce the launch of the new 18-50mm ƒ/2.8 EX DC Macro lens.
This lens has a large aperture of ƒ/2.8 throughout the entire zoom range, a minimum focusing distance of 20cm (7.9") and a maximum magnification of 1:3, making it ideal for close-up photography.
Specially designed to suit the characteristics of digital SLR cameras this lens provides a high level of optical performance. Its design incorporates both glass-mold and hybrid aspherical lens technology which offers extremely high image quality as well as a compact and lightweight construction. Minimal vignetting and superior peripheral brightness is ensured.
Special Low Dispersion (SLD) and Extraordinary Low Dispersion (ELD) glass elements provide excellent correction of color aberrations. The super multi-layer lens coating reduces flare and ghosting, a common problem with digital cameras. High image quality is assured throughout the entire zoom range. An inner focusing system eliminates front lens rotation, making the lens particularly suitable for using the petal-type lens hood (supplied) plus circular polarizing filters.
Note: Sigma has announced an HSM (Hyper-Sonic Motor) version of this lens for Nikon mount (which supports autofocus with D40 and D40x, as well as other Nikon DSLRs).