So I searched the internet for which uwa lens is good for full frame. I had the chance to try out a Canon 20mm f2.8 USM. The Canon 20mm f2.8 isn't bad at all...you can get one online for around $400-$500 brand new. If you bid on it online, you can get one for around $300. Not bad. Though I was reading a lot of reviews about it and people have mixed reviews. I've read about the 20mm being soft in the edges...which uwa's are notorious for. But really...who looks at the sides of the frame in real life? So basically I had the 20mm f2.8 and the Canon 24mm f2.8 competing for my attention. Both of these are not really uwa's but they are wide enough for me. So I decided to try out a Canon 20mm f2.8 once again, to finalize my decision. Sharpness overall wasn't bad with this lens...the contrast can be better but it's acceptable. I still am more impressed with my Sigma 10-20mm on a 1.6 crop body than with the Canon. I was ready to go out and get a 24mm until I saw this.
I have never tried a Tokina lens in my life. I used to have one of those screw on Tokina adapters. Either a wide or a telephoto one...I can't remember. But that was about it. So I asked my stepbrother, a wedding photographer, about Tokina lenses and he said that basically if the oem lenses don't work for him he'd get a Tokina over other third party lens manufacturer, and he advised me to do the same. So I went to ebay to watch an auction that was due in 4 days and I waited.
4 days later and I finally win one! For $180! I guess the guy selling it was also selling his old film camera along with some older lenses. Good thing I was able to grab one. I was so happy I didn't have to spend double on a Canon 20mm f2.8.
I open the box and there is this lens inside that is built like a tank! This lens is heavy for its size. Mainly because of the metal construction and the built in metal lens hood. I'm impressed! I've never had a lens that has a built in lens hood and it felt awkward at first, though I am pretty much used to it now. The lens has a really simple design. You can't find that finely sculpted body on this one. It's basically a metallic cylinder with a metal hood and a switch. In the middle is a distance scale which basically won't be as useful as everything else in the frame will be pretty much in focus with an uwa. I snapped it on my 5d and I was ready to go! I went to a school near us and took shots in the park. I was amazed.
The Tokina 17mm f/3.5 AT-X is a very impressive lens. From the build quality up to the image quality...2 of the most important aspects of a lens. It is a 3.5 lens...a bit slower than the 2.8 Canon 20mm. I don't really care because I never shoot uwa lenses wide open. The focusing isn't bad at all either. Pretty fast with a faint whine. Like those early ef Canon lenses. Here are the things I love about the lens:
Build Quality - This lens is a beast. Mostly metal. From the barrel up to the hood.
Contrast - Very high contrast on the images it produces. Little or no post processing required.
Sharpness - For being an ultra wide angle, beats lenses with a similar focal length. Use manual focus and it gets even better.
Focus speed - Not too bad here either for having no USM motor.
The only gripe I have about it is the fixed lens hood and the cap. It's a pain to take the cap off especially when you are in a hurry. Also, the hood prevents you from putting in a filter adapter. You can only use the screw in ones, which doesn't bother me at all, but for the image quality it produces, it's a steal for half the price of a more modern uwa lens. Paired with a full frame body, this combination is perfect for landscape and architecture shots.