About.com - Sigma EX 12-24mm Lens User Report
Sigma have recently released a new wide-angle zoom lens which will appeal to all digital SLR owners. The Sigma 12-24/F4.5-5.6 ex DG Asph may be quite slow but it will translate to a 19-38mm lens on a Canon EOS 10D/300D, for example. About.com has just posted an extensive user report.
“This is a lens that opens up the wide-angle end of the range for DSLRs. It’s a lens that needs care in use, but can give superb results. The specification and performance would have been unbelievable only a few years ago, and are still exceptional. Within the limits of aperture and focal length there is little more it could be expected to do. It is a superb lens, but perhaps something of a specialist tool.”