Need Ultra-Wide Zoom - Sigma 12-24

I have a 17-40 f4 on my fill frame and would like to replace it with the Sigma 12-24, any thoughts on this. I need something a little wider but not a fish eye like the Canon 8-15.

I recently bought a Rokinon 14mm f/2.8 UMC. It is reviewed to be sharper than the Sigma 12-24. I checked photozone.de, where the two are about equivalent in everything else, vignetting, CA, field curvature and the like. The Rok 14 is manual aperture and manual focus, which is a much better way of handling this focal length. The Sigma 12-24 has AF, which completely wastes the lenses potential if you focus on anything more than 5 feet from the camera. Sigma is about $875 new. The Rokinon is about $300 new.

Oh, and I don't plan on selling my 17-40. The Rok 14 is a specialty lens for me.

I own both the 12-24 and the 17-40 and i shoot the 17-40 far more often and would not part with it or suggest anyone replace it with the 12-24.

The 12-24 is amazingly wide.. but it needs to be stopped down quite a bit to even get in the same ballpark as the 17-40 for sharpness.

Wait a little longer for Tamron to release the 15-30mm f/2.8 IS?

Wow! a 17-40 isn't wide enough for you on a full frame camera. a 10-22 on my crop that would equal up to being 16mm on a full frame camera is wide enough for me.

Silverwolfpup wrote in post #17280126
Wow! a 17-40 isn't wide enough for you on a full frame camera. a 10-22 on my crop that would equal up to being 16mm on a full frame camera is wide enough for me.

I said the same thing last year. Now my Rokinon 14 isn't quite wide enough. But it sure is fun!