Officially known as the Tokina 12-24mm f/4 AT-X 124 AF Pro DX II Lens, this is the lens I use for my landscape photos. This is the only non-Nikon lens I own but I couldn't rationalize spending an extra couple hundred bucks for the Nikon version. I don't regret my decision to by this off brand lens at all. I use it for all my landscape photos and am really happy with the results. The auto focus isn't that good but I just don't use it and do manual focus all the time. I would guess more than half the photos I have posted on this blog have been taken with this lens, the results speak for themselves. Maybe the Nikon version is better but I have never tried it so I don't know any better and I love the photos I am able to take with this lens so thats all that matters.
At the time of writting, most of the photos I post to his site are taken with this lens, check out all the photos I have posted that were taken with this lens.