BMCC 4K is Quad HD not 4K
 

Someone can correct me if I'm wrong about this, but yesterday at the Burbank show I grilled several of the top techs from BMD and they revealed to me that all BMD 4K enabled products (BM Cinema 4K, Hypershuttle Pro, etc) only process in 4:2:2 color space and at 3840 x 2160 not 4096 x 2160.

This is Quad HD and not 4K resolution.

I have no beef with this, as I feel there will be a broadcast market for Ultra/Quad HD, but many potential (cinema) users would be surprised as I was to find out that you are not shooting legitimate 4K with the BMCC 4K camera. The 6G SDI output only outputs 3840 x 2160 also, so no 4K love there either, and no support for 4:4:4 raw at all on that camera either internally or via the 6G SDI. As of yesterday, their 4K camera is only recording 4:2:2 Pro Res HQ. I could not determine if/when the Cinema DNG recording capability is enabled in firmware if that would be legit 4K resolution or not.

I still like the 4K camera and feel that it is a great, inexpensive camera tool for TV broadcast work in Ultra/Quad HD, but I would be hesitant to promote it to any clients expecting cinema 4K resolution footage.

Anyone with a different take on this, please correct me or chime in.

re: BMCC 4K is Quad HD not 4K
 

Are they Square Pixels? Frankly being this close to 4096 and matching the 2160 seems like no big deal. The 4:2:2 issue might be more significant but hey what are they competing against. I remember when HDCAM was 1440 x1080 etc. Of course it might be good to know the technical reason they have a sensor that size.

Re: BMCC 4K is Ultra HD not
 

That is a difference of 300 lines of resolution. I would love to see anyone who would consider that an issue to have to pick between unlabeled Quad and 4K versions of the same footage projected on any size screen. And if anyone is that much of a stickler, they shouldn't be shooting with a prosumer camera to begin with, one with a form factor that was not designed for professional use.

It's becoming something of a cliche to bring this up as a comparison, but Skyfall was shot at 2.8K and it's hard to argue with the results.

re: BMCC 4K is Quad HD not 4K
 

Just to clarify Bruce's issue, it is not whether the 3840 x 2160 provides a quality image but it is whether 3840 is 4K - or not. This is an important issue if one tells a client that you're shooting 4K but in fact it isn't.

To say one is shooting 4K when it isn't is misrepresenting the product and/or the work.

Its like "close but no cigar." Or you're pregnant or you aren't.

Can't remember the quote from Bill Clinton about dear Monika or I would use it.

Anyway, that's how I read it. What about 4K-ish?

On another note .... a couple years ago I was talking to someone who was shooting in 1440CBR and saving the files to the camera's SD card. He thought the files were 1440 but they weren't, they were SD. BUT they looked great and it wasn't until digging into the camera specs that this was discovered.

re: BMCC 4K is Quad HD not 4K
 

I see your point--in theory. In real life, it's nothing like being pregnant or not. It's more like being 8.5 months pregnant vs 9 months.

I was initially excited when the last build of the Alexa allowed for internal 2K recording vs HD, but when I did the calculations I saw that it would increase resolution by 6% (the same difference as between Quad and 4K). I have done blowups of 10, even 15% that are undetectable even projected. This should be even less of an issue with double the resolution.

This is splitting hairs and clients who are only budgeting for the use of a $4000 camera should absolutely not be making that kind of distinction. They insist on true 4K, they should be prepared to pony up real money. They are lucky to be getting anything over 1080 (and most likely, they don't even know the difference, they are just spouting rhetoric anyway).

As a point of comparison, I shot a feature coming out on which I was told by the producers that shooting Arriraw on the Alexa was out of the question, ProRes4444 was good enough. This was obviously not a limitation that prevented it from getting a substantial theatrical release and no-one has ever had a concern with the way it looks.

re: BMCC 4K is Quad HD not 4K
 

Is or is it not 4K is what I am musing about. For $4000 this is a great tool for broadcasters & UHD quality archiving of footage. But if I misrepresent it as true 4K then I'm misinforming my client (in my case many times its major studios) then thats not a good or fully honest policy.

I agree that the 256 lines are not distinguishable on blowup to 4096, but one quick look at inspector gives the game away.

Still I like the camera and will probably add one to my kit.

re: BMCC 4K is Quad HD not 4K
 

If one has to turn camera originals over without processing, that would be the case, for better or worse. I can't see why edited deliverables couldn't be uprezzed 6% to 4K from Quad though.

Bruce, have you already experienced this? Clients making a distinction between the two? Or for that matter--a distinction between 1080 and 2K?

re: BMCC 4K is Quad HD not 4K
 

Just to avoid any potential confusion, I have edited the title of this thread...

from: BMCC 4K is Ultra HD not 4K

to: BMCC 4K is Quad HD not 4K

The potential point of confusion being the fact that 4K *is* Ultra HD, by definition.

I guess the real question at stake here is whether or not Quad HD counts as Ultra HD.

I'll have to agree with Charles here. Is there any other word that better characterizes the difference between 3840 and 4K (or for that matter, 1080 and 2K) than "negligible?"

Re: BMCC 4K is Quad HD not 4K
 

No not yet. But I would rue the day when Sony or WB post production calls to ask why they now have to blow up the footage

Its all theoretical at this point, but you know how anal post people can be at times and they can bury you when you are not there to explain.

I' ve always found brutal honesty to be the best policy at all times in this regard.

PS. Skyfall yes but remember Avatar, Hugo were both only 1080 & in 3D

Re: BMCC 4K is Quad HD not 4K
 

No argument from me on that. Purely academic, but still 256 lines & a necessary blowup to conform to a 4096 timeline in post. Someone is bound to bitch at some point, don't want to be on that receiving end.

And let's not overlook the 422 vs 444 issue either. Might not be a big problem in normal production but definitely would be a big issue in any compositing or VFX work.

So I say again, honesty is still the best policy here.

Re: BMCC 4K is Quad HD not 4K
 

Agreed on the anal thing! (although that phrase gives me pause for some reason)

Preaching to the choir with me on 1080p--I've certainly worked on plenty of features and episodic that have originated in that format. I didn't fight hard when I was shut down on the Arriraw request. In truth, the Codex recorders would have killed us. Now that it is available internally on the Alexa, I'm sure I'll be more likely to fight the good fight down the road.

Bruce, please update this thread when your first set of 4K specs comes down the road. I'd be curious to see what the studio requests are.

Re: BMCC 4K is Quad HD not 4K
 

HD cameras are used for 2k cinema release and have been for many years, there's no real difference.

Re: BMCC 4K is Quad HD not 4K
 

Unfortunately, as has been the case so often in the past, usage of nomenclature gets blurred, to the extent where it starts to cause confusion.

The key point is that the difference between 3840 and 4096 systems is far, far less one of "a bit of resolution", far more one of ASPECT RATIO. Quad HD is exactly that, and hence (like HD) it maintains the 16:9 aspect ratio that is considered the TV norm. It can also be expressed as 1.78:1.

The 4096 system has a wider aspect ratio - about 1.9:1, which is roughly the traditional norm in the projected cinema.

It's worth looking at Wikipedia which makes it a bit clearer - 4K resolution - Wikipedia, the free encyclopedia . Hence, both 3840x2160 and 4096x2160 can accurately be described as "4k" - but the former is primarily intended for TV displays, the latter for the cinema.

If something is shot 4096x2160, then making a quad-HD version is simple - just crop off either side to make the 3840x2160/quad-HD version. But the other way round is not so good. You have to crop vertically (to change 1.78:1 to 1.9:1) - but then additionally have to scale the frame up to 4096x2160.

Finally, as if that wasn't confusing enough, then the 4:4:4 and 4:2:2 aspects are a complete red herring. Leaving aside top end cameras like the F65, nearly all 4k cameras at the moment have a 4k sensor - 4096 (or 3840)x2160 photosites with a Bayer filter. That will inevitably mean that luminance resolution after deBayering will be only about 80% of the sensor dimensions, and chroma resolution 50%. (Think about it - the red and blue photosite patterns are only 1920x1080 in isolation. There is no way the sensor can give "4:4:4", even if that's the recording system.)

Re: BMCC 4K is Quad HD not 4K
 

I have the Sony 84 inch 4K TV Sony specs. the TV 4K Ultra High Definition (3,840 x 2,160) resolution.
LG 4k TVs are the same resoulution Ultra HD 4K Resolution (3840 x 2160p).

So the 4K TVs are not really 4K? Quad HD

Re: BMCC 4K is Quad HD not 4K
 

I really need to add a "like" button, and a "thanks" function!

Re: BMCC 4K is Quad HD not 4K
 

And to think that once upon a time 4K used to mean 4K resolution, not 4K pixels. So very few of the 4K or Quad HD cameras can resolve anywhere near 4K. 4K pixels = 3.2K resolution on a good day.

But, then I'm also curious as to what 4K means in terms of the pixels on a TV screen. If it's 4K of individual pixels then the TV's won't show 4K of luminance resolution either. The TV/Monitor would need 4K x3, one of each R, G and B or around 25MP, so far I'm only seeing 8MP screens, but what does that mean, the TV manufacturers are deliberately vague. OLED technology looks very interesting as a single pixel can output R, G or B (although cheaper OLED's use 3 x white LED's each with a printed color filter above). About the only thing that is certain is that using todays definitions 4K is a bigger number than 2K.

Re: BMCC 4K is Quad HD not 4K
 

It's all marketing speak isn't it.

There's another 4K camera maker out there that ended up going to a 5K camera so they could at least get 4K of recordable resolution on the screen. Their first effort could only get to a smidge over 3K on an actual resolution chart and 3.2K theoretically when taking the debayer in account. But it was recording a 4K file with that 3K worth of information.....so they got to say it was 4K.

Meanwhile, as pointed out, we've been projecting 1920 as 2K for a long time as well. HDCAM output 1920 but was pre-filtered to 1440 and had even less chroma sampling PLUS compression. Sony always fibbed about it too.

The whole chroma subsampling argument is also a bit misleading. For starters, it only applies to encoded video. Raw sensor data shouldn't be used in association with that kind of description, though it's a convenient leap to make.

I'm pretty sure we'll see a compressed RAW option on the 4K camera as well as the already announced ProRes 422. Personally, I'd rather see the 444 ProRes, not for 444, but for 12 Bit. Something that makes a bigger difference in my view to the end result.


jb

Re: BMCC 4K is Quad HD not 4K
 

I think I am developing morbid depression from future-shock in contemplating all this 4K stuff and lately have been beset by these weird throwback dreams of childhood, seeing kids at school playing hopscotch on a courtyard of green,green,red,blue repeating block patterns which flicker at about 25Hz. - Too much pixel-peeking I guess.

The scramble after being up with the crowd is like running a barefoot race over double-gees. It can be done but there is usually some pain involved in the process for the leader and everyone trying to play catch-up.

I'll leave my shortsight eyeglasses off at the cinema and then I won't know what I am missing if the camera artist has done his job. I won't then see the "calico look" or the repetitive swirl patterns from the artificial grain.

( I will have to speak to my local multiplex manager about that dreadful voice channel in Cinema 5. A handheld cop radio breaking squelch sounds better. )

In short, I guess I am rabbiting on about not being able to see the real art if one stands too close to the painting.

Re: BMCC 4K is Quad HD not 4K
 

We should welcome clients who won't tolerate a 6% difference, and can't be bothered with facts. We should tell them they are absolutely right, and charge them 60% more for a 'true' or 'legitimate' 4K camera.

What percentage of Blackmagic Design's market will actually produce work that will find a theatrical release? I am happy the BMCC 4K camera conforms to 4K TV - it is so easy to scale down to 1920x1080. And it shoots RAW in 12-bit. And I really don't see how anybody with a '4K' camera can make imagery better than this gem just by it being '4K'.

Re: BMCC 4K is Quad HD not 4K
 

I guess some DV cameras were not SD because they shot 704 pixels instead of 720 pixels. Oh how I fooled my clients for years. Shame on me.

I'm sorry but 4k on a RED is still considered 4k regardless of the aspect ratio used. The BM is just limited to only one type of 4k. We used to shoot 16x9 4k on RED all the time.

Would an odd 6% anamorphic adapter help here? Honestly I don't think it is a big deal. Even film was shot at multiple aspect ratios. Even in a theater the amount of pillar boxing is so small I doubt anybody would notice.

Re: BMCC 4K is Quad HD not 4K
 

FWIW, here is CEA's definition of Ultra High-Definition display characteristics:

TV/Video - CEA

A display system may be referred to as Ultra High-Definition if it meets the following minimum performance attributes:

Display Resolution—Has at least 8 million active pixels, with at least 3840 horizontally and at least 2160 vertically.
Aspect Ratio—The width to height ratio of the display’s native resolution is at least 16:9.
Processing—Has at least one digital input capable of carrying 3840x2160 resolution video and supports presentation of 3840x2160 resolution video from this input in a 3840x2160 or higher format. A qualifying display may not rely solely on up-scaling high-definition video content for presentation in a 3840x2160 or higher format.

Re: BMCC 4K is Quad HD not 4K
 

While we are putting links in. Here is Wikipedia's definition. Seems to justify Blackmagic's use of 4K even if it is not the same as 4K as defined by other organizations.

4K resolution - Wikipedia, the free encyclopedia

Re: BMCC 4K is Quad HD not 4K
 

So we have 3 items in play here with the BMD 4K Cinema camera;

1. Quad HD resolution at 3840 x 2160
2. Aspect ratio of (16 x 9) 1.78:1 vs 4K aspect of 1.90:1
3. 4:2:2 color space

None of these are to me a deal breaker, but of the three issues listed I am most concerned about the limited color space at 4:2:2 which would be OK for general green screen compositing but not for serious VFX work.

I started the thread to inform that these were the actual facts, not fanboy hopes and dreams. This camera will be a very handy small tool in any camera kit. I'm most curious though about the timeline for any raw capabilities and what those specs might end up being.

BTW, the Scarlet shoots it's motion 4K at Quad HD frame size 3840 x 2160 also. At least the inspector of any Scarlet 4K footage I've seen indicates this. Seems most post supervisors I've talked to lately like this frame size because of the easy 2:1 squeeze down to 1920 x 1080.

Re: BMCC 4K is Quad HD not 4K
 

I posted that link a little while ago. And there is no question that 3840x2160 is a form of 4k - it may be somewhat down to semantics but 3840x2160 seems to be taken to mean "television 4k", 4096x2160 "cinema 4k" and (as I said before) the difference is aspect ratio more than resolution.

Hence, I think Black Magic are completely justified in using "4k", but a "4K cinema camera" could be considered misleading.

Does it matter? In real life terms probably not that much. But then is it acceptable for a company to market a product as something it may not justifiably be described as? A bit like selling meat as organic, even if it isn't, then saying "so what? hardly any difference in taste, and just as good for you in health terms."
As said before, irrelevant. The 4:2:2 figure applies to recording format. 4:2:2 is far better than what a 3840x2160 Bayer chip is capable of delivering, which in the same terminology is probably equivalent to about "3:2:0" Exactly the same applies to most of the 4k cameras on sale today, even such as the F5/55 - with 3840x2160 Bayer chips, they don't give what may be thought of as 4:4:4 4K. As Alister said earlier "About the only thing that is certain is that using todays definitions 4K is a bigger number than 2K"

Re: BMCC 4K is Quad HD not 4K
 

Does the Sony F65 have the capability to output true 4:4:4 4K in your opinion. I believe it has and 8K Sensor.

Re: BMCC 4K is Quad HD not 4K
 

The F65 has 4K of green, 2K of blue and 2K of red in each row (the rows are arranged diagonally). So the nearest analogy to this at 4K would be 4:2:2. But it's not as simple as that. No real world object is ever pure green, pure blue etc so there is always some overlapping response in the other pixels. That's why a 4K bayer sensor which only has 2K of green, 1K red and 1K blue can resolve well over 2K, typically 3.2K. Given the right subject it could resolve higher. So the F65 is more than capable of filling a 4:2:2 output with data.

Re: BMCC 4K is Quad HD not 4K
 

Alister thanks for that clarification. That would imply a definite benefit in capturing at 4:4:4, Now I need to get the workflow down for the F65 in the Adobe PP CS6 environment.

Re: BMCC 4K is Quad HD not 4K
 

I think it's important to add the clarification to that that what Alister describes (resolution of a 4k Bayer sensor to typically 3.2k) is true for LUMINANCE. Hence it will resolve white-black detail far better than if the same detail was red-black or blue-black, say. That's why it can never give a 4:4:4 output. That implies by definition equality of black-white and colour resolutions.
Hmmm. Not sure about that. The F65 is certainly likely to be capable of true 4k luminance resolution, and likewise for 2k chroma in the horizontal direction. (The requirement for 4:2:2) But vertically, I don't think so, We can take 4:2:2 to mean equal luminance/chrominance resolutions in the vertical direction and I don't see how the F65 can achieve that.

(For anyone interested in the F65 technology (Q67), there's a good link at Pixels vs. Pixels by The Sony Tech Guy . Looking at the initial diagram, the coloured squares represent corresponding coloured photosites, the white squares show how the output pixels are derived from them. So each pixel has it's green contributed by one unique green photosite, but the red and blue are an average of two each red and blue photosites diagonally either side of the green. That's why the chrominance resolution cannot be equivalent to luminance. To really get 4:4:4 4k, you would need either a 3 chip camera with 3 3840x2160 chips - unlikely to be practical - or something like a 40 megapixel Bayer chip with 7680x4320 photosites, processed on a 2x2 block basis. Practically, I doubt the improvement over Q67 would be worth it.)

Re: BMCC 4K is Quad HD not 4K
 

Don't forget that the Blackmagic 4K camera is not named a cinema camera. It's called Blackmagic Production Camera 4K. It really is semantics because the 2.5k camera IS called a cinema camera. Either way, we all agree that the final image is what matters most, not how it was achieved. Having said that, I can't wait for my Blackmagic Production Camera 4K to arrive!

Re: BMCC 4K is Quad HD not 4K
 

I've heard it referred to as an 8k sensor - but to do so requires a change of definition, and consequently I think it's misleading. Using the same terminology as "4k", "8k" implies 4x as many photosites, twice as many horizontally and twice as many vertically. (So if 4k is 3840x2160, 8k should be taken to mean 7680x4320, yes?)

Unfortunately, no - not here. The F65 sensor has TWICE as many photosites as such as the BlackMagic or the F5 etc - NOT 4 times as many. The link I referred to earlier makes it clear, and it is (as Alister has said) because the photosite rows are arranged on the diagonal. (See http://provideocoalition.com/sony/st...els_vs._pixels ) That makes it very difficult to give a simple AxB number. If you count 8k horizontally, the photosites will overlap, and without double counting, will mean it has 7680x2160.

It makes far more sense to refer to the F65 sensor just as a "16.5 megapixel" sensor. Using the terminology of "8k" would lead you to expect about 33 megapixels.