Official Nikon Announcement:

http://www.nikon.com/news/2012/0207_dslr_01.htm

A new Full Frame player in the field of HDSLRs.
If it has the essentials of the D4, its worth considering price wise.

It has the option to select FX or DX mode like the D4. Yummy.
The OLPF must be aggressive video wise since there is mention of releasing a D800E version without the OLPF.

Uncompressed HD and a 36MP still camera - what more does one need?

link to site with "official photos":
Google Translate (http://translate.google.com/translate?sl=pt&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fztop.com.br%2F2012%2F02%2F06%2Fnumeros-enormes-os-36-megapixels-da-nikon-d800%2F)

For those of you who know video, is 8 bit 4;2;2 a good signal.

its essentially very usable. ;)

and its now in DPreview;

Nikon D800 and D800E 36MP full-frame DSLRs announced: Digital Photography Review (http://www.dpreview.com/news/2012/02/07/Nikon_D800_D800E_launch)


OFFICIAL Nikon announcement: (updated first post)

http://www.nikon.com/news/2012/0207_dslr_01.htm

Hey Ted, thanks for that info. What do you think of the body without the AA filter for video.

Without the AA filter, it would have the apparent sharpness improvement since an AA essentially "softens" the image.

There are companies that do Filter removal for existing DSLRs and the improvement I saw is significant for stills.
However, the moire patterns can be seen especially in grills and bricks.

I have even installed a third party OLPF on my 5D just to reduce these moire and aliasing.

I wouldn't consider the D800E(w/o AA filter) if my usage is for video. But even in stills, you would not be greatly served without an OLPF under "conventional" uses like portraiture or weddings.

a couple of sample films posted with some whip pans and fast motion;

Nikon D800 D-SLR Camera | High Dynamic Range Camera (http://www.nikonusa.com/Nikon-Products/Product/Digital-SLR-Cameras/25480/D800.html)

I'm DSLR illiterate.
Is this camera better for video recording compared to a Nikon D4, Canon 5D, or any other DSLR?
Will it still be susceptible to overheating in video mode?
Will it still have moire problems?
Does it record in-camera in 4:2:2?
Are the audio levels manually controllable?

ETA - I think it records 4:2:2 to an external recorder through the HDMI port. Audio seems to be manually controlled.

Glen

So far on paper and based on their sample video..

I'm DSLR illiterate.
Is this camera better for video recording compared to a Nikon D4, Canon 5D, or any other DSLR?

On par with the D4 as video goes, Better than a "bare 5D". -bare meaning without magic lantern and OLPF, I have both in mine and has increased the 5D's usability immensely.

Will it still be susceptible to overheating in video mode?
So far I havent heard of overheating with the recent nikon offerings.

Will it still have moire problems?
D800 has a video optimized OLPF so this should be considered solved. The D800E has no OLPF

Does it record in-camera in 4:2:2?
I think so, H.264

Are the audio levels manually controllable?
Yes

plus 1080 HDMI out and simultaneous LCD and HDMI viewing.

Ted, if you are correct, this is quite the cinema DSLR. I like the broadcast quality video (assuming it is truly recorded in-camera). 4:2:2 is...wow. And for around $3,000.
All that's missing are XLR inputs.

Joy Ride on Vimeo

Joy Ride - Behind the Scenes on Vimeo

Some digs:

3 crop modes:
FX(35.9X24) in Video mode 91% of the width
1.2(30x19.9)
DX(23.4X15.6)

BOth CF SDXC cards

When recording from HDMI, the cards record below 720p resolution

PRIce: $3000!!!! $3200 without the OLPF

It's just one example (an on-line one at that), but I wasn't entirely impressed with the video on the web site (the biker/doctor). For a large sensor it didn't seem particularly sensitive to light (maybe slow lenses used?) Will have to see more to assess its potential obviously. The specs are pretty eye-catching. I wonder if this'll get the train rolling on a 5D Mark III.

UPDATE: Just saw it again on this Vimeo link above and it looked better than the one on the web site (not so dark). Still want to see more though.

Ted, if you are correct, this is quite the cinema DSLR. I like the broadcast quality video (assuming it is truly recorded in-camera). 4:2:2 is...wow. And for around $3,000.
All that's missing are XLR inputs.

Pick up one of the PIX 220/240 recorders and you'll have 4:2:2 ProRes and XLR inputs to compliment the full-frame sensor.

I'm DSLR illiterate.
Is this camera better for video recording compared to a Nikon D4, Canon 5D, or any other DSLR?
Will it still be susceptible to overheating in video mode?
Will it still have moire problems?
Does it record in-camera in 4:2:2?
Are the audio levels manually controllable?


You can see a bit of moire on the bridge tiles at 0:47 in the 'Joy Ride' video. Whether that's from the camera itself or from the internet compression, we can't say just yet.

You can see a bit of moire on the bridge tiles at 0:47 in the 'Joy Ride' video. Whether that's from the camera itself or from the internet compression, we can't say just yet.

OLPF implementation is a tricky thing, for one, the fact that they decided to come out with 2 versions of this cam shows that it must be aggressive enough to soften the sensor for wide landscape work, also,
I think they had to balance it to be not too aggressive to be still sharp for most lenses and for most scenarios in 1080 mode.

I can see some images from Nikon dslrs where they remove the OLPF and its sharper but moire starts creeping in grills and such.

Also I can learn from the mosaic OLPF I placed in my 5D that its aggressive enough to remove aliasing and moire in almost all situations but some lenses 20mm and wider get problematic.

So looking at a lot of brick wall scenes in the Joyride video, I think the OLPF is useful enough for most but the most densest of patterns.

D800 has a video optimized OLPF so this should be considered solved.

Are you sure the OLPF is not optimised for hi resolution stills? And surely 4:2:2 is not recorded to H.264 internally, but only via HDMI to an external recorder like the Pix220? Of course I'd love to be wrong on both counts.

The biker video looks fine for low light to me, but it's impossible to properly assess moire/detail with that coarse Vimeo compression. If the picture is detailed and suppresses moire/aliasing it looks like a very promising camera at that price.

Are you sure the OLPF is not optimised for hi resolution stills?


The Nikon D800 has an OLPF and this must be optimized for video since they removed it in the D800E which is targeted to landscape photographers and those demanding very sharp looking highly detailed stills.

An OLPF, by its very nature, is intended to soften a bit high freq details to avoid aliasing and moire.

They are also releasing software that handles the moire that comes with these images.

The Nikon D800 has an OLPF and this must be optimized for video since they removed it in the D800E which is targeted to landscape photographers and those demanding very sharp looking highly detailed stills.

An OLPF, by its very nature, is intended to soften a bit high freq details to avoid aliasing and moire.

They are also releasing software that handles the moire that comes with these images.

I'm aware of the alternative version, but I think it's a big leap to infer the OLPF filter must therefore be optimised for video. Portrait photographers, wedding photographers and many others are more likely to go for the version with OLPF - highly doubt it would be optimised for video in a 36mp camera. If it were, I think Nikon would make a point of it in the marketing literature. Again, I'd be delighted to be proven wrong.

OLPFs exist even in cameras not meant for video. But in todays marketplace where video is common place in convergence devices, they probably had to deal with compromises. So i think they had to go aggressive on the d800 OLPF since they now give the buyer the option. I really which it would be like an ND filter implementation which you can flip on or off like the ND on the C300.

Is amazing that even in DX mode the resolution is 15+ megapixels (if I didn't make any calculating errors). On par with D4. In a way is a D4X with D700 price tag. The only thing that remains to be seen is how the achieved the downscaling of the pixels for the HD image.
Anyway right now is a serious contender for the price/performance crown.

With that MP count they could have done 4k the c300 (or David Heath) way: (3840X2160)x4=33.1MP

From the BHphoto video overview:
Nikon D800 SLR Digital Camera (Body Only) 25480 B&H Photo Video

"Thanks to Nikon's latest image-processing optimizations, the monumental power of 36.3 megapixels transforms to sharp, exquisitely rendered videos. Expect exceptionally smooth gradation in blue skies, with minimum block noise and beautifully natural movement rendered clearly and sharply. The D800's intelligent image sensor reads out movie images at faster rates than ever, significantly reducing the rolling shutter distortion that can occur during panning shots or when shooting fast-moving lateral subjects like trains. Thanks to EXPEED 3, your movies will take on a distinctive look of their own, even with dimly lit scenes."

On the OLPF:
"Optical Low-Pass Filter Optimized for Sharpness... Finding the right balance between benefits and sacrifices is the key to higher image quality, and that is what the D800's optical low-pass filter delivers. As a result, the astounding 36.3 megapixels unleash their potential through an optimized balance between sharpness and effectively prevented moiré and false color. Furthermore, the multi-layer structure of the D800 low-pass filter utilizes layers of antireflective coating that have been optimized for the camera, contributing to sharper and clearer images"

The only thing that remains to be seen is how the achieved the downscaling of the pixels for the HD image.
...
With that MP count they could have done 4k the c300 (or David Heath) way: (3840X2160)x4=33.1MP

Well, Dpreview mentions that when in video mode, the D800 only uses about 91% of the sensor width (hence slightly changing the FOV). One has to wonder if that's not to make the number of pixels a more manageable total to allow a better downsampling to HD video.
I mean, just speculating here, but why 91%?

If Nikon could develop their own HD Codec they would dominate the video DSLR market. They are still limited to 24Mbps.

Are you sure the OLPF is not optimised for hi resolution stills? And surely 4:2:2 is not recorded to H.264 internally, but only via HDMI to an external recorder like the Pix220? Of course I'd love to be wrong on both counts.

The biker video looks fine for low light to me, but it's impossible to properly assess moire/detail with that coarse Vimeo compression. If the picture is detailed and suppresses moire/aliasing it looks like a very promising camera at that price.

Agree. It's 4:2:0 internal, or I'll eat my hat. If it is 4:2:2, it'd be an amazing feat - The AF100 and FS100 - true dedicated video cameras costing $2,000 more - don't even record 4:2:2 internally.

The moire issue is - as usual - way overblown. Moire might be the biggest non-issue in the camera world - "normal" people could care less. Don't shoot a movie about brick buildings or stripped shirts, and you're golden.

A bigger concern is the "video-ish" look of the footage. Some bits looks absolutely cinematic, other bits like pure video (like when he grabs his keys off the night stand). And that's something not happening b/c of video compression.

On paper, this looks like a great camera. But Nikon doesn't exactly have a stellar rep for shooting video... but here's hoping.

Nikon is bringing some heat to Canon. Competition is great news for the consumer.

If Nikon could develop their own HD Codec they would dominate the video DSLR market. They are still limited to 24Mbps.

There are plenty of good codecs out there already, it isn't like we're lacking on good codecs. ProRes, AVCHD, DNxHD, AVCIntra, XDCam EX, XF ... (each offer something different). If anything, Nikon should follow JVC's lead (HM series adoption of Sony's XDCam codec) & piggy back on an existing codec instead of trying to invent something new.

It is a lot more hardware & user interface issues that are the pain of HDSLR shooting life right now.

New music video using the D800, produced by Nikon (apparently):

EUZEN - You're On [Official] by NIKON - YouTube

Looks pretty darn good to my eyes...

Thanks for posting this John. This looks very nice and I bet they did use an external recorder.

I laughed at the very first comment below the video. Pretty much sums it up. This looks better than a 5DMKII to me. The moto-doctor video did not do much for me from a detail point of view.

Things are heating up for sure!

With that MP count they could have done 4k the c300 (or David Heath) way: (3840X2160)x4=33.1MP
Thanks for the credit regarding a way of reading the sensor! :-) Now - can I turn it in to a patent.....? :-)

(I'm afraid I'm only reporting what has been happening for quite a while. It's just that Canon were the first (and so far only?) to publicly say what they were doing - and the first to do it properly, by which I mean with a quad-HD (3840x2160) sensor.)

But joking apart, when I saw the 33/36megapixel specs it was my first thought. It's pretty well understood now what Canon do in the C300, thanks to their openness. Each output pixel is formed from four photosites of a 2x2 block. Easy processing, (hence low power consumption) all photosites used (hence good sensitivity) and must give "true" 1920x1080 resolution.

The C300 uses 2x2 blocks. It's easy enough to see that a very similar process could be easily done with 4x4 blocks to get good 1080 video *IF* the sensor dimensions were (4x1920)x(4x1080). That magic photosite count becomes 7680x4320, or 33,177,600 photosites. A "33 megapixel chip".

BUT - that only becomes true for HD video - 16:9 aspect ratio. A still camera is likely to have a 3:2 chip and use a 16:9 window for video. Therefore I'd expect the full (3:2) dimensions to be more like 7680x5120 - or about 39 megapixel.

But according to the spec on the dpreview site, the max resolution still image from the camera is 7360 x 4912, which works out to be 36,512,320. Since the spec says "Effective pixels 36.3 megapixels" we can be pretty sure that is the actual sensor size. "So near and yet so far" is my reaction to that.......... :-)

As far as the OLPF goes, then if that was optimised for video, the camera would be effectively hopeless as a stills camera - and that is what it is primarily designed for! There is more than one way to skin a cat though, and reading EVERY photosite every frame of a multi megapixel sensor would change the rules significantly as far as moire was concerned. (It's because each output pixel would be formed by 8 green sites, 4 red, 4 blue - hence natural averaging of the too fine detail that would otherwise cause moire.)

The main reason DSLRs suffer from moire is that they (so far) all have to ignore a percentage of the photosites to achieve a fast enough frame rate - hence the averaging is much less than ideal, hence moire. Initially they would skip several lines at a time (really bad), more recently they directly read in 2x2 blocks (as the C300) but (unlike the C300!) skip every other block horizontally and vertically.

The other aspect of that is sensitivity. Missing 3 out of 4 blocks means the sensiitivity will be about 2 stops down on a camera where no skipping happens, after allowances are made for overall sensor size.

The main reason DSLRs suffer from moire is that they (so far) all have to ignore a percentage of the photosites to achieve a fast enough frame rate - hence the averaging is much less than ideal, hence moire. Initially they would skip several lines at a time (really bad), more recently they directly read in 2x2 blocks (as the C300) but (unlike the C300!) skip every other block horizontally and vertically.


A question: Does this mean the OLPF won't make much of a difference as far as video is concerned?

A question: Does this mean the OLPF won't make much of a difference as far as video is concerned?
An OLPF has to be just strong enough to allow the camera to resolve detail up to it's maximum resolution to avoid artifacts. With or without the filter, the camera is inherently designed to capture 36mp, compared to HD which is a mere 2MP.

The only way a camera with such high resolution could deliver an artifact free downsize, is if it read pixel data from every photosite, as David wrote in his post above. I highly doubt there are any cost-effective processors out there that could handle a 36mp signal @ 30fps and down-sample it to HD in real-time, using a quality interpolation method.

The moire issue is - as usual - way overblown. Moire might be the biggest non-issue in the camera world - "normal" people could care less. Don't shoot a movie about brick buildings or stripped shirts, and you're golden.

You're absolutely right about "normal" people John, but for me shooting DSLRs moire is *the* issue, along with its buddy aliasing.

The GH2 is the only DSLR I've used to date that adequately suppresses moire and aliasing, and produces a detailed image. I'm waiting for a FF camera that can offer the same detail with good control of artifacts.

There's crazy moire at 3.30 in the music vid... I'm hoping this is something to do with Youtube... but it looks disturbingly like 5DII style moire to me - compression doesn't do this does it?

A question: Does this mean the OLPF won't make much of a difference as far as video is concerned?
Let's be clear, I don't know what the characteristics of this filter are, so can only speak in generalities. But as said before: "As far as the OLPF goes, then if that was optimised for video, the camera would be effectively hopeless as a stills camera ".

By that, "optimised for video" implies reducing the definition to something suitable for 1920x1080. Great for video - but your expensive 36 megapixel DSLR then starts to simulate a 2-3 megapixel in stills mode!
The only way a camera with such high resolution could deliver an artifact free downsize, is if it read pixel data from every photosite, as David wrote in his post above. I highly doubt there are any cost-effective processors out there that could handle a 36mp signal @ 30fps and down-sample it to HD in real-time, using a quality interpolation method.
Yes, but that's assuming reading the sensor, doing a full deBayer (for 36 megapixels!), then a quality downconversion - at 30/60 times a second. But, the other possibility is SIMPLY and DIRECTLY reading the sensor to derive the 1080 signal directly with does away with any need for deBayering and down or up conversion. This is exactly what the C300 does - "problem" is that a 8 megapixel sensor is nowadays considered inadequate for high quality stills. Since the C300 is a video camera, period, it's a non-issue, but a completely different story for a DSLR!

Hence the thought of the 33.1 megapixel 16:9 sensor. Yes, all the photosites need to be read every frame, but it should be possible to use binning techniques to reduce that workload without compromise. Most importantly, no deBayering or up/downconversion are necessary to get a 1080 signal.

The moire issue is - as usual - way overblown. Moire might be the biggest non-issue in the camera world - "normal" people could care less. Don't shoot a movie about brick buildings or stripped shirts, and you're golden.
There's crazy moire at 3.30 in the music vid... I'm hoping this is something to do with Youtube... but it looks disturbingly like 5DII style moire to me - compression doesn't do this does it?
Ah that it was so simple as avoiding striped shirts etc! :) Josh has the key with the comment about compression.

I heard a great analogy recently whereby moire was compared to food going off (!) Leave some food past it's sell by date and you may get two effects. First is a change in appearance/taste/smell - the analogy here is moire you can easily see with the eye. Second is growth of something which will give you food poisoning - but may not be obvious when you eat it.

And it's the same principle with moire. You can get artifacts which are hardly visible on camera footage - but can play havoc with compression systems further down the chain. Hence footage can look great straight off the camera - but degrade far worse than expected down the production chain. Exactly as some bad food may seem OK to eat - but make you seriously ill a few hours later.

That's why "normal" people DO need to care about moire and food hygiene - even if they don't seem a problem at first viewing or eating!

(If all that seems unlikely, then the characteristic of moire which can cause many problems is that it "ripples backward" in the opposite direction to the object it's associated with. That can confuse coders at low bitrates which use motion analysis - an object can seem to be moving two ways at the same time - and waste bitrate in the coding. Put simply, the end result has the appearance of what it would have been if no moire and a lower bitrate used for the encode.)

Great insight David. Why it pays to go a bit deeper and know the tech behind stuff in this day and age.

This camera is exactly what a ton of people hoped Canon would do and is exactly WHY I am so disappointed with Canon.

Okay, so the D800 isn't perfect - but for $3K? Compared to the Canon C300 for $16K?!!!

Come on folks, what I saw on those clips looked darn good to me.

AND, though this is far from a done deal, there will be tons of hackers and programmers getting inside
and *possibly* having some cool D800 mods. The camera has USB 3 out. If enabled, we could be recording RAW at 12bit or maybe 10bit S log. Who knows? The thing is, at $3K, that means for around $10K I can put together a whole kits that will do just fine.

It really sticks in my crawl that Canon, with what it has done with both the price points of both the C300 and DSLRs, has FORCED me to move to Nikon. That is not what I wanted, but there it is.

Congratulations Nikon. Not to understate it, but you just handed Canon its *$$.

The ball is definately on Canon's side of the net,


Well Canon ??????



P.S. C300 footage looked much better.

"P.S. C300 footage looked much better. "

Jeez, it better - it costs more then 5 times as much.

Well, Dpreview mentions that when in video mode, the D800 only uses about 91% of the sensor width (hence slightly changing the FOV). One has to wonder if that's not to make the number of pixels a more manageable total to allow a better downsampling to HD video.
I mean, just speculating here, but why 91%?
I've not been able to see that reference - could you point me to it?

As to "why 91%", then I suspect if so it is actually 91.3%. :-) No, not a joke, it's just that 91.3% will be 6720 - and that is 3.5x 1920. It's hard to believe that's a coincidence, and may be a strong pointer to the internal workings in video mode. It would infer 960x540 7x7 blocks of photosites, and various ways of dealing with them could be worked which would all give direct 1920x1080 output - no up or down conversion.

Theoretically, that should give pretty good results. Not as good as my hypothetical 7680x4320 chip, and certainly not as good as the C300 (for video!) - but possibly better than much other video from "designed for still" sensors.

Regarding moire/aliasing etc, then after what I said previously about the REAL problems with moire being it's ability to screw up compression, then it's worth mentioning again that it's the MOTION of the aliases that really causes the problems, the way they move counter to the real objects. For STILL images this is obviously nowhere near as big a problem, any aliases may just make edges look a little "busy".

This camera is exactly what a ton of people hoped Canon would do and is exactly WHY I am so disappointed with Canon.

Okay, so the D800 isn't perfect - but for $3K? Compared to the Canon C300 for $16K?!!!

Come on folks, what I saw on those clips looked darn good to me.

To me those clips don't surpass 5DII quality - would anyone be surprised if a 5DII had shot those? On paper the D800 is great, but image-wise it appears like Nikon is playing catch up.

The clips benefit from high production values, but the video quality itself looks soft with fairly clear moire/aliasing issues. The C300 is priced at a premium, but for that you get detailed, artifact free images. The D800 images (to my eye) don't convince, but I'm really hoping this is Vimeo/Youtube at fault because I can't afford a C300!

Canon is about to bring the 1DX to market (annoyingly without a headphone jack and clean HDMI). The 5DIII is surely just around the corner. They've had more than 3 years to come up with serious improvements to their original DSLR video implementation and they have promised (in the literature) much improved suppression of rolling shutter, moire and aliasing, along with superior internal codec; I'm quite optimistic the new generations of Canon DSLRs will handily beat the image quality we're seeing here.

I've not been able to see that reference - could you point me to it?

Nikon D800 Preview: 3. Key Technology: Digital Photography Review (http://www.dpreview.com/previews/nikond800/page3.asp)
"Movies can also be shot at two different crops from the sensor, FX and DX. This makes it easy to vary the field-of-view for grabbing footage, even if you’ve got a prime lens mounted. However, the ‘FX’ size is a significantly cropped version of the full sensor (it’s 91% of the sensor’s width), so the field-of-view will be a little narrower than you’d expect for any given focal length."

However, DPreview also reported in its D4 preview that the 16mp camera also employs a 91% crop in FX video mode, so it's not sensor specific...

In terms of potential for better image quality in video, the D4 then seems to be superior as it has a more sensitive sensor (with similar technology), far less pixel count, thus much less raw data for the IP (similar or identical) to deal with.

Whatever the tech behind the D800's video is, I can see no reason why Nikon can't do better with the D4 for about twice the price.

To me those clips don't surpass 5DII quality - would anyone be surprised if a 5DII had shot those? On paper the D800 is great, but image-wise it appears like Nikon is playing catch up.


The uncompressed 8-bit 422 is the big difference, isn't it? We'll know soon enough whether its worth anything in a few months.

Won't the D800 in DX mode equate to the D4 in terms of video quality? Wouldn't the sensor readout be approximately the same, if the technologies were developed together?

Is it safe to presume that the D800 will be 'sharper' in DX mode?

It might have the same number of pixels, but each photosite would be smaller. Smaller photosites collect less light and therefore have higher noise.

The uncompressed 8-bit 422 is the big difference, isn't it? We'll know soon enough whether its worth anything in a few months.

That's the great hope: it will be a huge difference if the image being output via HDMI is largely crisp and artifact free. But simply capturing direct to ProRes via HDMI isn't going to rid footage of moire, aliasing and softness due to poor scaling.

Does anyone seriously think that Canon, after introducing a $16K camera, is now going to shoot itself in the head and put out a 5DMkIII that isn't seriously hobbled? I am happy to be proven wrong, but ... it just wouldn't make any sense for Canon to do that.

Time will tell what the D800 is all about. I am invested heavily in Canon, but my current hopes are centered on Nikon now. If I had $16K it would buy a Scarlet or used RED ONE package.

Canon might - the C300 is still a niche camera. I can see only rental houses, highend big city shooters, and perhaps TV productions buying into the camera - in other words, it will hit it's sales ceiling relatively quickly. Don't forget lots of people still LOVE the Alexa and have no plans of diving into the C300. Bigger productions will still either go RED, high end Sony, or (gulp) film.

There's another factor as well, and that's lens sales. If they're selling the Mark III like hotcakes, then they're also selling lenses, batteries, grips, etc in big numbers. While a $16,000 camera won't sell in anywhere enough numbers to generate substantial lens sales, a $3,000 Mark III likely would.

One other thing - it'll still be a DSLR. That means short battery life, no XLR or SDI ports, no internal 4:2:2 50Mbps recording, no built-in ND wheel, no lanc, and of course, the love/hate DSLR form factor.

Does anyone seriously think that Canon, after introducing a $16K camera, is now going to shoot itself in the head and put out a 5DMkIII that isn't seriously hobbled? I am happy to be proven wrong, but ... it just wouldn't make any sense for Canon to do that.
I think it's tending to be overlooked that the 5DMkIII is first and foremost a camera designed for high quality STILL PHOTOGRAPHS. In that case, it is anything but "hobbled"!

I also think the engineering issues of getting video from a sensor designed for still use are not being taken anything like seriously enough. The more you learn about it, the more you appreciate the challenges, and in many respects far from "hobbling" the surprise may be that video from DSLRs is as good as it is, without compromising the still performance.

Price differentials normally have to do far more with economies of scale than absolute tech. From what I'm hearing, C300 sales are already pretty high - but are inevitably going to be small compared to the DSLR market. But that's because so many people buy DSLRs for stills!
Is it safe to presume that the D800 will be 'sharper' in DX mode?
No, impossible to say without knowing a lot more. That may not seem logical, but AFAIK at the moment *ALL* such cameras with multi-megapixel sensors have to ignore a percentage of the photosites to get a high enough read/processing speed. It's conceivable that in full frame mode only (say) 25% of the sites are read, in windowed mode it may be (say) 50% of the window. (Which may be more than 25% of the total!)
The uncompressed 8-bit 422 is the big difference, isn't it? We'll know soon enough whether its worth anything in a few months.
It may be a big difference in terms of ease of connectivity, but don't read too much into it. Any HDMI signal is going to be uncompressed and 422 by definition (and may be 10bit) but that by no means says that all HDMI signals will be the same! It would be quite possible to have a rubbish front end, which could still give an uncompressed 8-bit 422 output. It's quite conceivable that a good front end feeding an internal H264 codec will outperform a bad front end feeding uncompressed 422.

To continue with the food analogy, if you start with poor really ingredients, the best chef in the world will struggle to cook an exquisite meal. That's why "uncompressed 422 output" means little in itself.