I'm having some trouble deciding... Canon EF 20mm f/2.8 USM or Sigma 20mm f/1.8 EX DG DF RF I'm leaning towards the Canon, but I thought I'd ask you guys before I spend any money... Anybody have experience with either of these lenses? I'll mostly be using it outside with lots of light and inside with typical "living room" light levels. I don't think I really need the f/1.8, but it couldn't hurt - not a deciding factor. If there's another lens that I've overlooked I'd like to hear about that too. I'd like to keep this under $600, including a hood (which the Canon lenses don't come with...). No EF-S lenses though, I need to be able to use it on a full frame/film body. Thanks.