Alright, the following are some shots taken with the D700 starting from ISO 200 up to ISO 12800. High ISO noise reduction in camera was set to low, photos shot as RAW, converted to DNG before importing to Aperture (since Aperture doesn't support D700's NEF yet) and then converted to JPEG via Adobe PS3 with no post-processing besides some auto-contrast/color/level if I thought it looked better with it. No noise reduction run on these (my regular photo workflow includes a pass through Noise Ninja at the end). Clicking on the photos below will display the full-sized JPEGs which may be a couple megs in size so you have been warned.
Devon, who pretty much ignores me these days when I'm taking photos of him, took an odd liking to the D700's shutter sound. I suppose because it was different from the 5D's that he's been hearing forever now. So the morning this shot and the following two below were taken was different because he would stare right into the lens with a goofy smile and then not move until he heard the shutter go click. Then he'd giggle and continue doing whatever he was doing.
It's a little odd to have ISO start at 200 instead of 100 but I don't think there's any difference whatsoever.
First thing I did was turn on and set up Auto ISO so that it would maintain a shutter speed of at least 1/80s (and then 1/125s in the later photos below). Hence some weird ISO settings like 280 or 1100 and such. But the auto ISO functionality on Nikon bodies is pretty darn fantastic.
I think tripod-mounted focus testing of the 24-70 lens is needed cause it appears to me that it may be front-focusing just a tad. Or could just be user error. Next set of testing should answer the question.
Hitting ISO 800 and still non-existent or very low noise. Some fine grain is starting to show up in the blurry areas but nothing that can't be handled easily in post processing.
Now the grain is starting to make its way into the foreground but still, nothing that can't be handled and some people even prefer the grainier look.
ISO 1600, my max on the 5D usually. Still looking very good overall here in good light.
This is ISO 2000??? Geez, sure there's grain but the noise is just really well contained so that it's easy to remove with something like Noise Ninja.
ISO 3200. I can still live with this after some post processing.
Ok, ISO 12800 looking a bit gnarly. But what amazed me about this shot was that the outdoor lighting at the time was getting pretty dim and the first thing both my cousin and I noticed when we looked at the shot on the LCD screen was, "What the hell? Where'd the shadows come from???" My eyes didn't even register the shadows at all while I was taking the photo because it wasn't as contrasty as it appears in the photo but the camera picked up bright as day. You won't be printing big photos shot at ISO 8000+ but with some noise reduction and post processing they can serve quite well online.