Don't worry about the high iso capabilities of the 7DII.I have no doubt a FF camera will be better in that respect, but the 7DII holds its own quite well in many cases. Here are some examples:How bad is the noise level? With my camera, 800 ISO is noisy. I'm using a 400L f5.6 (Non IS) so I've got to get my shutter up around 1000 for BIF. A better (f4) lens is out of the question so I thought a camera upgrade (7Dii) would be the solution.
1. Griffon Vulture iso 3200
2. Yellow Bittern, iso 4000
3. Macaque, iso 6400
4. Leoaprd, iso 6400
Of course they need a little work, but there is so much detail in the file that the end results are quite pleasing. (At least I think they are...)