Jeff, absolutely agree that these kinds of results are possible. That level of clarity and sharpness is what I'm wanting from this 80D, and as Joe's/my photos have demonstrated, there's peculiar happenings at play, be they atmospherics, particular combinations of TC/body or TC/lens, or perhaps I'm just missing something boneheaded. Definitely wouldn't be the first time, so I'm just trying to eliminate variables and possibilities is all.
What's weird is that I went through this a year or two back, and after help from you friendly forum folk, started seeing fantastic results. I have no doubt about what is possible, seen it with my own eyes. But, I stupidly parted with that particular 100-400 II when I switched to the DO II, thinking I wouldn't need the zoom anymore... definitely one of those boneheaded moves I previously mentioned, because I ended up repurchasing another one a few short months later. Lesson learned: don't sell your 100-400 II's.
I'm at odds with that. If Canon had of offered both the 100-400 II and a 400 5.6 II IS I have said I would have gotten the prime. I shot for 8 years with 300L F4 IS and I still can't get used to zooming while I shoot. I know Jake who had the older version preferred the pull/push over rotation.
Now I'm not so sure. I don't think I'll give up the 100-400 even though 90% of my shots are at 400mm if I ever get the 400 DO II.