Sorry folks... no pics to post yet, but they'll come next weekend. I got back last night at about 11pm and had to be up at 4am for a flight this morning.
I have had a 5D3 for about 2 years and just bought a 7D2 and 100-400 II last week and had 3 days of shooting flag football with them together. I am very impressed with the 7D2 and the 100-400, however there were a few quirks and wondering if it was me or not.
First off, I shot in poor lighting at night, as well as during the day in clouds and bright sun (Florida). I kept the 7D2 mounted to the 100-400 II all weekend, and the 5D3 mounted to the 70-200 II. The night shooting was no match for the 7D2. Even under the lights, I was needing ISO 12800-25600 to get a decent shutter speed at f/2.8. During the day, I used them together... about 50/50 to start, swithing when the range got short. By the end of the 3rd day I put the 5D3 away and stuck with the 7D2.
So the good... having been 2 years since I retired my 1D3, boy did I miss 10 fps. I'm not a burst shooter usually, but its nice to have it at times. And the extra range from the crop body. I found that on the first day I was shooting way too tight. I ended up shooting nearly half the field from the end zone with the 100-400 during the day. The lens is amazing... extremely fast. The pair could lock on most of the time, even when I was late getting to the target. I tried IS (mode 2), and also non-IS, and didn't see a big difference. I setup the 7D2 exactly as I've been shooting the 5D3 for other sports. I used Case 2 AF.
So now the things that gave me a little trouble.
* For the first day, I kept having times when the camera was unresponsive. I'd be tracking and hit the shutter release and ... nothing happened. I had noticed this when shooting birds last week af few times. I finally diagnosed that it only happened when shooting portrait orientation with the grip shutter release. I took the grip off and put it back on a few times and it still did it. Then about half way through the day it stopped doing it and never did it again. Not sure what to make of that. I may return the grip just to be safe.
* The bigger annoyance was that about 1/3 of the time the image review mode just seemed to not work. I am a chimper... big time. I take a lot of pics and try to delete non keepers immediately. So after each play I quickly hit the arrow and review, then delete. A lot of time I'd hit the arrow and either start to zoom or scroll back and after 1-2 seconds the screen would go blank. I'd hit it again, and it would do it again. It seemed to do the same thing whether I hit the Set key to immediately zoom, or I hit the arrow. It was just fighting with me a bit, almost like a computer that gets bogged down and is behind your clicks. I have never had a problem on any other Canon body with this. I thought it might be buffereing, because it did it a few times after a burst... but that didn't seem to be consistent. Although I couldn't confirm it was always, it seemed that if I hit buttons to quickly... review, then zoom... that did it, but not always. I need more time to see if its me. I have muscle memory from the 5D3 and work quickly, so It may just be me.
* Although I've not reviewed the images in Lightroom yet, zooming in on the camera, the tracking and sharpness seemed to be extremely good. It locked on to the target (Case 2, 12 point zone), and stayed on it through obstacles. There were a few sitations where it inexplicably locked on to something that wasn't the target, and stayed on it so the subject remained slightly OOF throughout a burst. In one case it was a ref in the background that shouldn't have been picked up because he wasn't under the lit focus points to start and was much smaller in the background. Out of about several thousand images, I only saw about 3-4 instances of this.... and many more cases where I just missed... proven by the focus point lit not being on the target. Also amazingly, there were cases... many more of them... where I missed and it seemed to still pick up what I wanted it to follow. Never had a Canon body do that before. In all prior bodies, if the lit focus point was off to start, it definitely did not get the shots. The 7D2 did a great job making up for my errors here.... very forgiving.
* Using the 5D3 and 7D2 side by side, the 5D3 seemed slow because of the lower fps... but it almost seemed more responsive to me. I'm guessing that's just because its a "finely worn glove" since its been my only body for 2 years. They are so similar though, its the easiest pair of different bodies to use I've ever worked with. The other thing I noticed was that the 5D3 viewfinder seemed to feel so much bigger and brighter... but I'm not sure if that was the f/2.8 lens, FF, or what? I need more time with different lenses to get a feel for that. And the viewfinder difference wasn't that different... just an observation.
So first serious outing with the 7D2 and 100-400, I loved it. As I said, I liked it to the point of laying down the 5D3 for the last couple of games. The one thing I didn't try was the 100-400 on the 5D3. I liked being able to shoot from the end zone and didn't want to give up the range.
I'll post some pics next weekend. If anyone has had similar issues with either the grip, or the image review issue, please let me know.

