Hey everyone, I'm looking to buy either a Canon 135mm f2 or Sigma 85mm 1.4 ART. It'll mainly be used for outdoor dog photography in natural light. Been trying to decide all weekend on which to buy but I just can't figure it out!! I'm leaning more towards the Canon, mainly because it's cheaper. I've read in a few places that the Sigma ART occasionally has AF problems, which steers me away from it. Any suggestions? Cheers!