Sigma AF 12-24mm f/4.5-5.6 Asp EX DG HSM

Manufacturer's Description:

"This ultra wide angle zoom lens offers 122 degree super wide angle of view along the diagonal axis

Sigma will always be guaranteed a place in the history books as pioneers of the wide-angle zoom lens. Our advanced super wide angle technology was developed far earlier than any of our competitors.
Sigma designed and produced the first wide-angle zoom lens, the “zoom gamma 21-35mm F3.5-4.2”, in 1979. The wide-angle zoom category didn't even exist before this date. The market comprised only standard and telephoto zoom lenses with most people believing that wide angle zooms were impossible to develop.
However Sigma's advanced design and pioneering technology went on to prove them wrong and strongly influence subsequent product development."