An evening shot using D7100, central focus points, Sigma 10-24mm set to: 14mm, F/11, 1/80sec (handheld), ISO 200, Lens adjustment in RAW. Sharpening 145, 0.8, 1 in Photoshop 6. Attached image is 904KB on my computer.
This lens seems sharp enough for a neurotic pixel-peeper like me. What do you get when you pay more for a wide angle lens? What would a Nikon 12-24 f/2.8 do that this lens can't (besides the obvious speed advantage)?