This is a very early quick look about the new camera that I have had now for 3 days. I don't have a good enough connection to fact check so I apologize ahead of time. 36MP Sensor: It has been said before but I am going to say a few things here anyways. The sensor is no doubt incredible but it will indeed punish camera users who's skill set has not been refined, and for those who have been it will just simply make you a better photographer. I try to explain, the sensor because it has so many pixels will make the flaws within your photographs stand out / magnify them. The problem is hard to explain but similar to the effect of a telephoto lens and a slow shutter speed. Not the same nor the reason why but even with speeds that should be fine the images are not tack sharp. This is simply due to the fact that you are provided with so much information. The same settings on a different camera (with less MP) would look much better but once again this is due to the fact that the information is not available. So once again there are other ways to explain this but I'm not in the right place to do so. If the image was scaled down it would look the same, the problem is not a major one for most uses.
So in conclusion chimps will be chimpier and photographers skills will be refined over time.
Autofocus: As far as I can tell there is really no difference. It still focuses very quickly and in a couple of occasions I was able to focus under moonlight, maybe that will be rare or maybe I'll just get used to it. The new way to change between auto and single point is taking the most time to get used to. I usually end up scrolling the wrong wheel but I'm sure with time I'll get used to it.
Metering: I know it has it's big brothers AF and metering so I know it's an improvement. In normal usage I don't see a difference but then again colors are usually a bit different with newer sensors. Also every once in awhile the camera will render a scene as if it's already been post processed, its something that you just have to see Nikon is known to have the best images straight out of the camera and I love them... But I feel as I get to know this camera better I will learn to control the beast.
LCD: When they announced the D800 I was bummed that they didn't upgrade the pixel count on the display. Little did I know that the amount of pixels that wasn't holding it back but it appears that it was the files itself being viewed. Images on the display are incredible but still keeps a realistic impression of what the image truly looks like (cough unlike another company cough). They say that they moved the panel backwards to make it better in bright lights but it looks the same as the D700 in my opinion. I see the issue now more that I am shooting video and having to stare at the display more. It's not bad, but I just dont see the improvement.
Video: New to the camera obviously but there are a few quirks. Settings being used before switching to live view are not retained. I haven't had the time to figure out or pay attention to what's going on but I saw a post online with someone saying the same thing. The internal mic is quite good compared to previous on camera mics. I am going to go off topic for a bit and talk about the rode videomic pro. It's incredible to be able to monitor this fine piece of equipment while recording. I picked up a dog barking from 250 feet away and the slightest move of my feet on the ground. I just can't wait to record something serious with it. A very nice addition to the video department is that the native 1080P files play back on an iPad without any tricks over the camera connector.
New Settings: Even years after owning my D700 I would find a new setting or set up a better way to shoot with the camera. I don't think the D800 will be any different. I'm going to list a couple of settings that I have not seen mentioned online. First the self timer setting now has an option to fire off a set amount (up to 99) with another setting for how long in between shots. I have been using this to bracket 3-9 images. Another option was to give the command wheel the ability to change ISO when in certain modes. For example in aperture priority the front wheel changes aperture while the back wheel does nothing, now it has the ability to change ISO by just scrolling. I feel that simple steps like these end up saving time and shots when there are less presses involved.
Lenses: Nikon has actually made an approved list of lenses on their site for their camera. This is because the camera can potentially out resolve the glass in the lens. This is a potential bummer because the sensor would show off all of the flaws of the lens. Honestly I have a whole range of consumer to pro glad and do far I haven't seen issues with any of them. I have noticed that I have been incorrectly shooting my 70-300VR lens, I guess it needs a faster shutter than what I had thought. It's probably a reason why Nikon added an additional setting to auto ISO to match the focal length. Without zooming once again you can't tell but if you want to double check behind door number zoom you can see if you have a winner. Also I have not noticed any diffraction yet with smaller apertures. When I finally review these images on the computer I'll find out the truth.
File Size / CF Cards: 4GB cards were what I survived on with the D700. RAW files are nice and thin compared to the D800. When a card is formatted in the camera it still underestimates the amount of photos that you could fit onto the card. Although it is quite funny to see the D800 quote you 50 RAW images on a 4GB card where it used to get me over 200. I'm sure that amount would lurk near 100 but still it's laughable. I saw it online a few times that people were having issues with their old memory cards just not working with the D800. I tested each of my cards with photo and video after a fresh format and I didn't have an issue at all. Although some of the cards processed the images very slow. So far I have been shooting a Sandisk Extreme 16GB 90Mbs card alongside a Patriot 32GB class 10 SDHC card. No issues (glances around for wood).