Ok, so I don't have access to a D700 so I can't compare and maybe I'm spoiled because I've been shooting with a D3s for a couple of years now, but these don't look very good at 6400 to me. Just my opinion though.
I'd love to see some shots, side by side on the same tripod to really compare. I'd expect that there would be no way that a 36MPixel camera can compete at high ISO with a D3s and its 12MPixel sensor. Again, that's just the engineer in me saying so.
+1. Wow! I haven't kept up with the D4 talk (because it's way out of my league), but this makes me wonder what kind of a high ISO monster the D4 will be if Nikon can coax this kind of ISO performance out of a 36mp sensor.
I shoot at night a LOT, and high ISO is very important to me. My thinking is that if the D800 can give the same image quality at ISO 3200 as the D300 can at ISO 800, it could work for me. Those two extra stops have meaning for me. I can get away with a Nikon 16-35mm f4 instead of a Nikon 14-24mm f2.8, an $800 savings right there. I will no longer need any f1.4 lenses, and that saves me at least $500, maybe $1,000. I can sell my seven high powered White Lighting X3200 strobes and replace with much cheaper Alien Bees B1600. My suspicion is that current online samples from D800 are made of images that are relatively "easy" for a camera, not the hardcore night stuff I do. I'm definitely sitting tight, waiting to see some real shots from "everyday" photographers, not the ones hand picked by Nikon. Nikon is still likely to release another camera this Spring, maybe even a fourth one. What if it turns out that a D400 is actually as good or better than the D800 at ISO 3200? I don't think I can justify buying ANY camera now that doesn't shoot relatively clean at ISO 3200, let alone an FX one that's going to cost me some big bucks to change pro lenses from DX to FX. The D3s might work for me and will eventually be hitting the used market, but really, I want more than just 12mp. I sometimes find myself cropping quite a bit. I also don't like the large size of the D3s type cameras.
Cliff Mautner is saying it will perform close to a D700, and I passed on the D700 because I just didn't see that I was gaining that much with the ISO. I'll wait and see how things shake out, and see what else Nikon releases this Spring.
Lucky me? I have never used a D3s.
If the D800 does better at 12,800 than my D3 did, I will be very happy.
And if I buy the D800 instead of the D4, I will still have enough money left to get one of those "Old Cast Off" D3s bodies for those needed ISO 25,600 shots.