The Sigma 12-24mm f/4.5-5.6 EX DG HSM is a professional-level wide-angle zoom lens made by Sigma Corporation.[1] At launch it was the widest rectilinear lens available for full-frame 35mm SLR cameras, providing a field of view of 122 degrees. It has since been surpassed by the Canon EF 11-24mm f/4L zoom lens and the Irix 11mm f/4, a manual focus prime lens.[2] The Sigma 12-24 has low distortion even compared to less wide zooms like the Canon EF 16-35mm lens.[3]
This lens is available in Canon, Nikon, and Sigma, Pentax, and Sony mounts. HSM focusing is available only in the Canon, Nikon, and Sigma variants.[4] The build quality is typical of Sigma EX lenses, with a painted metal lens barrel and damped focus and zoom rings. As expected for a lens of these specifications, there is a bulbous front element.[5]