Its a step up from the D7000 for video - The 1080 30p is a welcome addition, so is 720 60p. Live histogram, audio meters, headphone jack - its getting there. Video quality is much better - D7000 would start breaking up around 640 ISO and the D800 is still relatively clean at 1600. The clean HDMI leaves room for expansion in the future if needed. For photo, its ridiculous - so much range/resolution - it will take me some time to acknowledge this cameras capabilities and use them to their full extent. The ergonomics aren't as good as the D7000 - The ISO button placement is worse - awkward to get at it (should of been somewhere around the shutter) and the function buttons by the mount would of been great if I was able to assign some usable functions to them such as ISO or a record button (like in the D7000). Overall, happy I got my hands on one and hope to have something to show soon, though I keep grabbing the EX1 instead :O.
So far so good. The image is great, with a few caveats, but it's still a DSLR and for the price I think it's great. The user experience is way better than with the Canon's for me. Maybe that's because I always shot stills with Nikon. Haven't used the clean HDMI out yet because I'm getting good results using the internal codec. The lowlight performance is probably better than you'd expect, but if that's something you need I'd look for another camera. On top of the solid video it's the best stills cam I've ever used. By far.
I'd put the low light performance between the 5D2 and 5D3. In fact, we're about to sell off some 5D2 & 7D bodies, just as soon as we can locate another D800 or two. The files stand up well enough and the image is sharper than the 5D2. the 5D3 wins on some other scores, like timecode in the files and the ability to change the volume while recording (the D800 requires you to stop recording to change the volume - crazy!).
For me, 720p has too much aliasing and is unusable, but I suppose that's going to depend a lot on the subjects you shoot.
I've still to find a good hue balance I'm happy with, but I'm sure we'll get there.
For stills, the D800 is head and shoulders above the 5D2 & 7D.
I have played with the HDMI out and honestly you are unlikely to see any difference between the HDMI and internal recording unless you are shooting something that has the potential to overload the internal codec. However, you are unlikely to be shooting that kind of material with a DSLR in the first place.
I have to admit, before taking some lens test shots for a film-shoot I was not even the slightest bit interested in the photographic capability of the camera. But when testing a Zeiss lens man the results were pretty amazing. As a filmmaker, I've shot with Arri, Red, Sony and Panasonic cameras and the 5D. So far, I'm finding the D800 the best jump between the larger cameras and the DSLR's. Maybe I should've spent more time with the Canon, but I feel I have more control over the image with the D800 versus the 5D. I also like the sharpness and being able to switch it up with the lens of choice. In regards to low-light situations, I'm not a documentary filmmaker - I'm a commercial and features guy so it's rare that I have an image that is naked of light or without some artificial illumination. Sure I need performance but I don't need to find solutions in darkness like non-fiction filmmakers often do. I also like the heft of the D800, something I'm sure photographers understandably hate. But filmmakers like the stabilizing weight and it fits well with all my gear ( Letus rails, Birns & Sawyer Matte Box, Lamparte follow, Vinten tripod, etc.). It holds it's own amongst my rig. The 5D feels a bit too light for what I use it for. The only complaint I have is the ISO adjustment is as contorting as people say it is and the fact that I can't find a spare battery anywhere. That's been a real bummer on my shoots so far. Also, if anyone has a good suggestion for what kind of cards I should get for it that would be cool to know - either SSD or Compact Flash. While we're on the subject, is there a big difference between SSD and Compact cards? If that's an idiot's question, I apologize in advance. And finally, since I'm writing it, does anyone know a good HD field monitor I could use ( and no, I'm not interested in a Atomos Ninja)? Thanks in advance for any replies.
Over-all, I'm having a blast with the D800. Great filmmaking tool that's versatile, portable and capable. And guess what, it takes really neat photos too.