Tokina 12-28mm Review
Why??? Better optics than the Tokina 12-24...for $100 more...a lens that covers FULL-frame from 18mm to 28mm....the extra 10 degrees angle of view difference between 24mm on the 12-24 and the 28mm on the 12-28mm means the newer lens has a "whole 'nother lens" in there...24mm is 24mm, and distorts people and objects placed at or near the edges of the frame on FF...28mm not nearly so much...
I think the 12-28mm is the better deal, and the better "lens" optically. Tokina, for its cooler, more-neutral color rfendition, and NOT Sigma, with its warm, yellowish color rendition. Color rendition can never be completely eliminated with white balance adjustments; it is an inherent property of the lens glass and how it's made. Sigmas are made for Canons. Tokina was started by a group of Nikon engineers who left Nikon and started their own lens-making company, and they strive for the cooler, more-neutral color rendition of Nikkors.
By getting the 12-28mm f/4 Tokina ATX, you get 1) better optics 2)wider range and a more-versatile lens 3) a DX-optimized lens that also shoots very well on high-rez Nikon FF.
The 11-16 mm is ONE thing: a wide zoom. NOT very versatile. A very,very narrow range. 12 to 28mm is a lens that can be used in a LOT of situations.