I thought the 1080 hdmi out from the d800 was interlaced, not progressive. I think the video on Nikon cameras is beholden to the will of Sony because of the way they license the sensors. Thus, Nikon will always be a step behind with video, not because of capability, but because Sony wants to protect their v-cams.
no. it is 1080p. You need the right recorder.
You are correct - D800 is only progressive at 720. 1080 is interlaced
nope. 1080p at 4:2:2 color. the claim the D800 could only do 1080i was because the atomos ninja could not, until their recent firmware, identify itself as capable of recording 1080p to the D800. So the D800 would send it a 1080i signal as most devices will understand that. However, once atomos worked the protocol out, the D800 sends it a true 1080p 4:2:2 color signal.
http://www.dslrnewsshooter.com/2012/04/22/nab-2012-nikon-d800-and-atomos-ninja-2-now-working-in-harmony/as you can see from the sample video in that page, the 1080p uncompressed ninja footage edits much more nicely. Unlike with compressed internal footage you can both grade it and be a bit more daring on sharpening which you can't do without sharpening artifacts on cameras like the 5DmkIII.
But although resolution is slightly better than on the 5DmkIII in both internal and external modes, it is still no true 1080p. Yes you can sharpen uncompressed video better but sharpening doesn't bring detail that isn't there. It just make you perceive more detail.
I like the set of stills below for comparison purposes. It also shows how bit-rate doesn't really create a sharper image. Folks hoping that a higher bit rate can cure the 5DmkIII resolution issues will likely be dissapointed since likely the issue is low level sensor readout and processing pre-encoding.
http://proofs.iamron.com/Personal/Atomos-Ninja-VS-D800-In-Camera/the second to notice is that you can all but eliminate codec artifacts in high motion scenes. every dslr to date falls appart in this regard, and the D800 is no different. However, by allowing you to record pro-res externally at much much higher bit rates, you can get an artifact free image impossible using internal codec based cameras.
I have a ninja 2 on order. But I'm left wanting more. So I'm all but convinced a Sony FS100 or FS700 is going to become my video rig. DSLR video is just not keeping up.