I'm a hobbiest and have two kids that play year-round competitive-level sports (indoor and outdoor). I've been shooting with a 5DM3 and a 70-200 2.8 is II. It's a huge upgrade from my previous gear, and was looking for full frame when I purchased it a few years ago. I am now hunting for something more geared for sports - better FPS. Budget isn't much - under $1K. Am I going to be sacrificing major ISO going down to something in that price range?


