Waited for prices to come down and I've changed my mind since this last post. More or less decided to go with the 5D Mark III now. I've seen lots of D800 video footage with noise creeping in from as low as 2500ISO. Don't fancy constantly having to deal with that in post. A touch of sharpening of Mark III footage will be easier and quicker and I can now get it for £2399 locally. Also need a truly quiet shutter. Sad to miss that Nikon picture quality but Nikon won't cater for all-rounders in the smaller body.

Thanks very much Ron for your excellent concert footage! Best quality D800 concert footage I've seen, certainly at 3200ISO. This really encourages me although the light is white and appears fairly bright on each musician. Is this how it appeared to the eye? I've been to many a gig with much lower murky lighting, especially coloured lighting, where I suspect higher than 3200ISO would be needed.

Great quality audio, by the way, for the built-in mic! Can I ask how tricky you found the manual focussing? Was there a great deal of searching if you tried autofocus? I also noticed you filmed footage at 6400ISO which you say started to show some noise. Is there any chance of you uploading some of that 6400ISO footage just so we can see how bad the noise is and judge whether it's of usable quality if need be? Would love to see any other really low light footage at over 3200ISO. Thanks again for this video!

Mike I agree video doesn't require anywhere near as much light as stills but low/coloured light gigs may push ISO needs higher. Can't imagine needing much beyond 6400ISO though. I've decided to go ahead with my D800 purchase as I think I can just about live with the noise limitations on video. The D800 is superior to the 5DMark3 in too many ways to ignore, especially in sharper stills AND video. I'm still way down the line in the list at my local dealers but can't afford to pass up the early discount I secured and go elsewhere. Guess I'll have to be patient!

JustinTArthur said:
resulting in slightly more detail and significantly worse noise:

At the cost of greatly increased moire too. But one might argue that videos get so much light that high ISO isn't really needed.

Lynne, here is my first try with the D800 at a concert, ISO3200: http://photo.vanderkolk.info/photo-nikon-d800-video-high-iso.php Make sure to watch it in full HD. I was impressed by the quality.

Thanks again for posting Justin. That last vid certainly clarifies things! Lol Seriously, it's a shame Nikon decided to adopt this "line skipping" method for video instead of "binning" as surely extra detail is of no use when there's way too much noise. If there was any way Nikon could've given us clean video up to 6400ISO from the D800 on top of it's amazing stills performance, what an even more awesome camera it would've been.

I'm still not 100% decided but I'm thinking Nikon MUST at some point (maybe in a year or two) release a true upgrade to the D700 with stellar low light performance in stills AND video as such a camera in the smaller more economical body is in such huge demand. Nikon surely can't abandon all these customers to Canon long-term?! When they do I'm thinking it will be much easier to sell a D800 (at a smaller loss) & buy the new Nikon model than sell a 5DMark3 (bought for much more) plus Canon lenses. At present the 5DMark3 possibly might suit me more but long term I think I'd be happier in the Nikon camp. Until then hopefully video noise reduction software will help.

I don't have it yet, but here's yet another comparison that's popped up (not safe for work):
http://www.youtube.com/watch?v=AfA2mTMt0u8

According to LumoLabs, the poor ISO performance in the D800 is not a fault of the sensor, but a fault of how the sensor data is used to construct the 1080p video image. Apparently, the D800 employs line skipping where the 5D Mark III performs simple binning, resulting in slightly more detail and significantly worse noise:
http://falklumo.blogspot.de/2012/04/lumolabs-nikon-d800-video-function.html

Thanks for posting this low-light video Justin. The greater noise with the D800 at ISO 3200 and above is clear. There's another video on You Tube uploaded by zosiha on 28 Mar (sorry I have no idea how to post video or photos on this forum) which makes the noise difference between the two csmeras seem less but this is contrary to most footage I've seen.

Would love to hear Justin if there IS any way of improving noise performance via the settings but I'm not hopeful. I wouldn't be able to afford to keep renting the 5DMark3 for concerts and theatre so I AM still concerned about the D800. Wish it had slightly less MP and at least an extra stop in ISO. That would've been SO useful and made all the difference.

I'd love to see some examples of noise reduction software used on D800 video footage at 3200 ISO and above as this may be a task I'll need to perform quite often!

Here are some more low light samples on Vimeo, comparing the D800, D4, and 5D Mark III. This one taken at ISO 3200:
https://vimeo.com/39534499

The D800's noise is pretty bad when compared with NR turned off. With some NR on, it's more bearable, but still not quite as good as the 5D Mark III. I wondered how much of it was codec-related vs actual sensor noise... and the fact that the buzzing noise gets accentuated in DX mode may mean it's sensor—but what do I know?

I plan to mimic Gizmodo's test with a night skyscape once I get my D800 (by May), maybe fiddle with the settings to see if there's a way to kill that noise. If it's too bad, I may be looking at renting a 5DmIII for concerts.

Many thanks for your reply @CaryTheLabelGuy. You provide some reassurance though you don't say how low-light the conditions were on your tests. Would love to see some footage. Seems to me the D800 high ISO video performance is only of concern in really low light conditions with chroma noise in the shadows.

There's a camera comparison of high ISO video on Cameratown(...)It's of limited value as again not very low light conditions & only quarter screen size. That footage suggests slightly worse video noise on the D800 (compared to the D4, 5DMark2 & 5DMark3)at 3200ISO and 5000ISO becoming much more pronounced at 6400ISO. It's the red in the chroma noise which is the main difference although sharpness and dynamic range look better so the D800 footage at 3200ISO to 6400ISO might clean up better than the rest in post if you have the advanced software for that.

Still needing to see more very low light D800 video samples. Would particularly like to see any low light/coloured light gig footage. CaryTheLabelGuy, you mention that the in-camera High ISO Noise Reduction works in Video Mode too and makes considerable difference. I'm assuming that all D800 video samples so far posted on the internet are without in-camera Noise Reduction? Please could you or someone else post low-light high ISO D800 video footage both with and without the in-camera High ISO Noise Reduction turned on so we can see how much it improves noise or affects sharpness?

Eagerly awaiting more low light footage!

I finally got mt D800 and have spent several days testing and getting to know the body. I can tell you that high-ISO noise in video is very impressive!! It's decently clean all the way to ISO-3200 and usable to ISO-6400 with proper exposure and good editing, maybe even higher. It rivals my D3s for noise in video up until about ISO-4000, then the D3s takes off, especially when you enable "High Sensitivity Movie Mode" on the D3s.

The D800 video is very sharp, so cleaning it up in post should be a breeze without much loss of detail.

EDIT: I just figured out that High-ISO Noise Reduction works in video mode. The difference is very noticeable. That is all for now.

Thanks for the reply Justin. Good to know someone else shares my concerns. It's true that blacks on D800 stills look great so can't understand why they wouldn't on video too. Gizmodo are more of a latest gadget site than a photography site so I'm hoping the poor quality of their D800 footage is more down to user error but we really do need to see more D800 low light video samples all you lucky people who have their D800 already so please please do upload some clips.

I plan to buy the new imac when it comes out and hopefully get my hands on a copy of Final Cut Pro from somewhere. I see that the Topaz Enhance plug-in to Final Cut Pro and Premiere Pro does an excellent job of cleaning up noise on video without losing much detail so it's reassuring to know that can be done. Whether cleaned-up D800 footage would be as sharp as 5DMark3 footage who knows? However, for this price tag, I wouldn't expect to be having to spend time cleaning up every bit of video at 800ISO upwards. Please calm my fears someone!

It's one of my biggest concerns as well. I've got all my Canon gear on the market and a D800 on preorder—and then this video comes along. The noise at ISO 1600 and above is just horrid. By the time I might have cleaned that up in post with a fancy plugin, I might as well have the softness of the 5DMIII. I'm hoping the Nikon footage from that video was just a setting away from looking at least as good as the 5DMIII. In the studio still samples on DPReview and other sites, the D800 looks like it has BETTER blacks. Fingers crossed for more info.

I'm currently planning to buy the D800 and, after viewing the increasing number of samples available, I have been very impressed with image quality after initial concerns about high ISO performance. Once images are down-sized I'm happy noise performance is on a par with the D700 but with superior image detail.

By contrast, there are still very few samples of true low light video from the D800 at different ISOs. The D800's video quality in decent light has already been demonstrated to be impressive. Inevitably we know the D800's performance in low light video will lag behind both the D4 and the Canon 5DMark3 but I'm keen to see just how much of a difference there is. Besides weddings and portrait photography, I intend to use the D800 for theatre and gig photography and video in reasonably low light. Some will say I might be better off with the 5DMark3 but I've really fallen for the fantastic resolution and also the amazingly useful crop modes of the D800 and I really want to switch to Nikon. (The D4 is not an option for me price-wise or size-wise)

Re low light D800 video samples - The official "Joyride" promo video has only some fleeting really dark scenes which show some noise. The first proper D800 low light "night scene" video comparison with the 5DMark3 has been posted on Gizmodo(...)
For some reason all the D800 footage has a red glow with no true blacks compared with the 5DMark3 footage (Wondering if incorrect white balance or other settings is to blame for this as not noticed this in other video samples?) Surprisingly to me chroma noise is clearly evident from 800ISO upwards in this D800 footage. I was hoping for decent noise performance in true low light conditions at least up to 3200ISO.

Does anyone have any more true low light D800 video footage as this is one of my main D800 concerns right now and video samples are still few and far between?