I shoot a 7D II and a 100-400 quite a bit for outdoor sports. And this combo is one of my go-to's when I'm humping gear around an XC course. Full disclosure: I've never shot the mark 1 version of the 7D nor any of the lenses you list, so I can't offer a direct comparison...with that said, the 100-400 will obviously get you a bit more reach than what you have, and perhaps faster and more accurate AF (can't tell from your smugmug hosting whether they're pinsharp or not. Monitor sized looks fine, pixel peeking little soft). Grabbed some recent XC shots. Let's see what Imgur does to mine;
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Last edited by ChrisF; 11/01/18.