All right everyone, thank you so much for your input.
After much more research, I discovered that there is a newer version of the Tokina. It’s a 11-20mm f/2.8, and it handles ghosting much better than the 11-16mm. I also discovered that Tokina also makes a 14-20mm f/2 (and I think it’s a step up from the 11-20mm).
However, I did not get either of these. I eventually decided to go with the Canon EF-S 10-18mm f/4.5-5.6 for a couple of reasons. First, it didn’t have much of an issue with chromatic aberration or ghosting—which are the two biggest complaints with the Tokina 11-16mm and 11-20mm. Secondly, I could not, could not beat the price. I was able to get it in Canon’s “Power to Create” kit, which came with the EF 50mm 1.8 (my first prime lens) for $350 (I saved about $50 by buying them in the kit instead of seperately), as opposed to the Tokina lenses each costing around $400-600. I then used part of the rest of my budget to purchase some quality B&W UV filters (I even replaced the $10 Zomei filter on my 18-200mm… I haven’t seen a difference much yet) and some third-party lens hoods.
So far, I am impressed with my new lens’s 10mm focal length and the fact that I can’t hear the autofocus motor work unless I put my ear to the lens! I might have also noticed a little boost in sharpness from my 18-200mm, but I haven’t used it much to really tell.
Thanks for your input again!
—Logan