Alan,
To address your question about the 7DMK II from a birder/photographer point of view. I have a 40D and was going to upgrade to the 5DMKII primarily for two reasons:
1). The files out of that model are awesome.
2). I get FULL autofocus with a teleconverter on my 400 mm 5.6 prime lens.
5D MKIII is a full frame sensor, but the extra megapixels will allow me to crop in tighter without losing as much quality as I would do if I do the same crop with the lower mp files from my 40D.
However that model is nearly double the cost of the 7D MKII.
The main reasons to me for upgrading now to the 7D MK II are:
- the 7D MK II is the only prosumer body that will fully autofocus with the 400m and a teleconverter
- better autofocus, larger MP and 10 fps with improved buffer performance
- the 7DMKII is still a 1.6x crop factor body (unlike the 5DMK III)
The added file sizes and auto-focus improvements and 10 fps are all gravy at that point. Thankfully, living here in the US, ISO is not an issue since we have light here
Obviously trying to shoot a Lancy in a rainstorm on Shetland will require a higher ISO, so for instances like that, shooting at 1600 with a nice non-noisy file would be ideal. It looks as though the 7D MK II might be fine with that.
Anyway, my friend has a beta test version and will be sending me over some files. Proof will be in the pudding as they say, but I for one am hoping Christmas comes early!!