I may be shooting a dog agility competition next weekend, and I've been warned that the location isn't all that well lit. (It's either at the Show Barn or Agriplex at the Cloverdale Fairgrounds in BC.) I've got a 40D, 17-55, 50 f/1.8, and 70-200 f/4 IS.
I can probably rent the 85 f/1.8 or 135 f/2, but I'm wondering if it's worth it. One to two stops of additional light is the difference between 1/500 and 1/125, or between ISO 800 and 3200, which would be good. On the other hand, how many shots am I going to miss because of the narrow depth of field? I've never really shot (for an extended period) with a prime before so I'm not sure how that's going to affect my positioning and composition.
As I'm writing this, I'm thinking that $20 (85mm) plus $30 (135mm) is not all that costly, and if it means an extra few image sales, it pays for itself. (Still an amateur, trying to make a few $$ on the side.)
Any comments on my thought process? Am I missing something like "the 85 is too slow to focus for action use"? Anyone ever shot at this location?
Thanks.


