Hey, I'm planning to buy the Sigma 10-20mm for my D90 soon. I know this might sound like a stupid question, but I'm curious how the kit Nikon lens compares to the ultra-wide sigma at their common 18mm. I'd be grateful for some samples. Thanks, Paul edit: I might reconsider and buy the Tokina 11-16 f/2.8 which is said to be better than the Sigma. What do you think?