Most of the initial tests on the D800/D4 conveniently avoid the HDMI issue, and the manual isn't making things helpful either. Unfortunately, there are contradicting reports all over the place and so far this is what I have got:

1. Output is video only, no audio
2. 8-bit only, not 10 or 12 bit, even though the signal might be encoded as 10-bit
3. Color sampling is at 4:2:2
4. 1080 output is 59.94i (for 23.98 and 29.97 fps) and 50i only - 23.98 via pulldown (but no clarity on which method - there are some reports of a non-standard method)
5. 720 can output 50p and 59.94p.
6. The HDMI stream from D4 is different to the D800. Is one 10-bit and the other 8-bit?

Regarding point 4, some reports also claim that 23.98p is possible via HDMI without the pulldown.

Has anyone here tested the HDMI out of either of these Nikons? If yes, please shed some light on this issue. I would love to see a comparison between the HDMI out from the D800 and the intraframe codec of the 5D Mark III.

On a side note, I think it might be time for Nikon to have its own place on this forum.

D800 HDMI video Test:

NIKON D800 HDMI V.S AVCHD TEST VIDEO Vol.01? - YouTube


Nikon D800 Atomos Ninja Test Clean HDMI:


Nikon D800 Atomos Ninja Test Clean HDMI on Vimeo

Nikon D800 test - internal video vs externally captured HDMI footage using Atomos Ninja. on Vimeo
clear advantage of Ninja

Thanks for sharing Oleg.

I see no advantage for the Ninja, actually. The video for the external source is brighter, but there's no DR improvement at all. I wonder whether the external recorder actually recorded 8-bit 4:2:2 or just 4:2:0.

There have been several recent D800 tests using Ninja recorder.
It turns out that there is more to this than one might expect.
Bottom line, property set up, the Ninja does bring out more resolution and detail.
As with any new camera, my standard strategy is to let others bleed on the cutting edge
and take all the information from what they find to make my own decision.

Once recent post from CML points to this link.

Nikon D800 Internal Recording VS. Atomos Ninja on Vimeo


Another from XL1 Watchdog Mike Pappas leads to another site - not sure if this is cool Mr. Hurd, but will remove it if you so deem.

More Nikon D800 1080P video tests (http://www.dvxuser.com/V6/showthread.php?278662-More-Nikon-D800-1080P-video) tests&p=1986112841#post1986112841