On paper, the D800’s biggest differences with the D700 are: the resolution has been tripled, the auto-focus has been improved and the Advanced Scene Recognition System is now much more advanced. Finally, the LCD display can swivel on two-axis (versus one for the D700). Pretty much everyone would agree that the D800 isn’t as good as the D4 in low-light (which is my favorite feature on cameras), but on the other hand, those who work in a studio won’t care that much about low-light capabilities, so this is definitely covering a corner of the market.
The megapixel count is not going to be useful to everyone as well: even enthusiasts may not be keen on having images that can be 200MB+ big. I also wonder if the existing lenses can match the level of performance of a 36 Megapixel sensor – we’ll see soon enough. In the meantime, with the introduction of the Nikon D800, Canon will probably follow-up with a 5D Mark III relatively soon… [Nikon press release]