I took delivery of my D810 yesterday, having sold my D800E a few months back in favour of the Sony A7R, with which I have been pretty well satisfied apart from the recent discovery that the camera has too much shutter slap to use the FE70-200 F4 at anything lower than 2x shutter speed, which is not useful. I also missed tracking focus. So I thought I'd try the D810 for certain uses only, intending to still use the A7R most of the time.
I had kept hold of my Zeiss 21mm F2.8 and Samyang 14mm and I have repurchased a 70-200 F4 Nikkor. Additionally I have bought a Sigma 24-105mm F4 having previously owned Nikon 24-120 F4 and both Nikon and Tamron 24-70F 2.8 lenses. Ever hopeful of a good mid range zoom, it seemed worth an experiment...
Initial thoughts based on not having a D800 to hand for direct comparison:
The new camera seems a touch larger and for me, it is a shock to return to something of this size and weight though it does feel very grown up and professional. It has so much faster startup than the A7R that it feels immediately more serious and ready. I find it less comfortable to hold than the A7R and can discern no difference from my memory of the D800e.
The files seem to me to be a small increment over the D800e. Not so much in sharpness but at ISO 64 they feel a touch smoother and it also feels like there's more DR. Colour is hard to judge because I'm a RAW shooter and I am using a Beta Adobe DNG converter and then importing into Lightroom.
Shutter is quieter and less slappy than the D800e and is frankly in a totally different league to the A7R.
I like being able to see through the finder when the camera is switched off.
Controls are familiar and fall well to hand but honestly, there's not a great of difference, just for me, between the menu and button setups: the Nikon is clearly superior but I can get where I want quickly on either.
I have taken less than 100 frames and only used the Sigma lens.
That lens seems to me a good alternative to the Nikkor 24-70 F2.8 for my needs: it isn't great, and in fact I think it is a touch less good than the Sony 24-70 (a lens I like quite a lot) but it is very useful and seems acceptable at all focal lengths, given reasonable expectations, and has a longer range. It seems very sharp on centre. I haven't test it yet, though, so this is very preliminary.
I'm probably not going to do a lot of side by side comparisons because I intend to use the cameras for different purposes. But so far, all seems good and my initial view is that the camera, subject to lenses used, gives better results than the A7R and has a broader range of use-cases but that neither of these advantages is big enough to use it for any of the cases where the A7R is up to the job. So, because I have lenses I like for the A7R and because it is smaller and lighter, it will be my default go-to unless the job requires some of the D810'a special abilities...
Some not very interesting shots, from which you will not be able to tell much: