4K Lite, Phase 1 or Fat free Milk in a 30 YearTransition to the Ultimate UHDTV System or 4K Heavy Cream. - Page 2 - AVS Forum
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post #31 of 60 Old 05-05-2014, 08:51 AM
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Here is a good paper on bt1886 for anyone.

http://www.spectracal.com/Documents/bt.1886.pdf

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post #32 of 60 Old 05-05-2014, 11:25 AM
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I think on my recent calibration of my X700 using a Klein K-10A meter (that can actually reliably read blacks with the JVC) BT 1886 set my gamma for black at about 1.8 or 1.9. My overall gamma curve ended up near about 2.34 for an average despite the 2.4 target and this was setting the dE target as 0.

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post #33 of 60 Old 05-05-2014, 11:49 AM
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What's not to believe? The divide by 1.001 is an artifact of the analog color carrier wave. It's not needed at all on digital. Your 60p is also really 59.94hz.

If you try forcing sync of 24 hz when the tv expects 23.97, about every 17 seconds you will notice a slight stutter. There are some blu-ray players where the engineers were idiots and don't do 1080p24 correctly, and literally do 24.00hz.

So, yes it's needed because that's how the signal is encoded and sent(because of legacy issues), but if the standard were developed right now from scratch, the signal sent would be exactly 24.00hz.
Yes, I'm well aware of the drop frame. There are really Blu-Ray players that play discs at 24FPS when the format is clearly defined as 24000/1001 FPS?
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post #34 of 60 Old 05-05-2014, 12:39 PM
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Yes, I'm well aware of the drop frame. There are really Blu-Ray players that play discs at 24FPS when the format is clearly defined as 24000/1001 FPS?

 

I think it was one of the early Samsung models. Which is why I waited for a source direct model on the cheap, my Denon 1611.

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post #35 of 60 Old 05-05-2014, 02:00 PM - Thread Starter
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I filled my wife's car with high test, its a turbo.

Now please back to the subject of the thread. I am curious. Who here actually has read the article and understands it fully?

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post #36 of 60 Old 05-05-2014, 02:05 PM
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Originally Posted by mark haflich View Post

Now please back to the subject of the thread. I am curious. Who here actually has read the article and understands it fully?
I read the complete article. I think I have a reasonable understanding of it. It has some interesting ideas, not all of which are practical or good. Like transporting compressed video streams to the display and having them decoded there.

Trying to build a futureproof connection method is a good idea, but extremely hard to realize. Analog connections were never futureproof. Every new connection whether is be composite, s-video, or component left people and gear behind. DVI, DVI w/ HDCP, HDMI, etc are no different.
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post #37 of 60 Old 05-05-2014, 08:17 PM
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Originally Posted by mark haflich View Post

I filled my wife's car with high test, its a turbo.

Now please back to the subject of the thread. I am curious. Who here actually has read the article and understands it fully?

 

Hey teach, is there going to be a pop quiz?

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post #38 of 60 Old 05-06-2014, 06:10 AM - Thread Starter
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Though I taught engineering at a university for 4 years many years ago, I do not believe in quizzes in this forum, pop or otherwise, because I don't enjoy seeing some people flunk. Particularly newbies ho actively participate and wish to become a respected member but whose score would be so low that it would fall off the bell curve, Just saying in general and with respect to no one here.. Hope you understand.. BTW I would prefer to limit this discussion to the points in the article and that requires the article to be read by those participating and that posters have at least a modicum of understanding and intelligence.

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post #39 of 60 Old 05-06-2014, 09:13 PM
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Ok, I have three issues with the article, so far.

 

Perception of color has nothing to do with the reality of color. Otherwise we get into a whole nother can of worms about subjectivity.

 

It's not size, it's viewing distance, which is about 0.8x the screen width for UHD.

 

He needs an editor badly.

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post #40 of 60 Old 05-06-2014, 09:54 PM - Thread Starter
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take your time, I can wait, I understand, for some, its a long read and contains topics difficult to comprehend.

Your first comment needs further elucidation. A color can scientifically defined. How we see that color as scientifically defined is entirely another issue, and a real issue. Color blindness, eyes with aging cataracts that impose heavy yellow filtering etc though JK is talking about other things.

It is fairly clear that JK is basing his screen size on a viewing distance of 10 ft, the distance the general populations views their flat panels from. Translating to a 12 ft wide 1.78,, , .8 of the width would be about 10 ft.

i am curious about your viewing experience with UHD or 4K. Do you own a 4K panel or 4K projector?

WSR no longer has a video technical editor and I suspect no much of an English editor either. . JK does have a tremendous amount of video knowledge. Much more than I have and much more than you have demonstrated so far with your total 26 posts, perhaps that will change.

Would you care to state your training and experience in the field of video displays upon which you base your assessment of J'ks article?

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post #41 of 60 Old 05-06-2014, 10:17 PM
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Originally Posted by mark haflich View Post

take your time, I can wait, I understand, for some, its a long read and contains topics difficult to comprehend.

Your first comment needs further elucidation. A color can scientifically defined. How we see that color as scientifically defined is entirely another issue, and a real issue. Color blindness, eyes with aging cataracts that impose heavy yellow filtering etc though JK is talking about other things.

It is fairly clear that JK is basing his screen size on a viewing distance of 10 ft, the distance the general populations views their flat panels from. Translating to a 12 ft wide 1.78,, , .8 of the width would be about 10 ft.

i am curious about your viewing experience with UHD or 4K. Do you own a 4K panel or 4K projector?

WSR no longer has a video technical editor and I suspect no much of an English editor either. . JK does have a tremendous amount of video knowledge. Much more than I have and much more than you have demonstrated so far with your total 26 posts, perhaps that will change.

Would you care to state your training and experience in the field of video displays upon which you base your assessment of J'ks article?

 

For the most part, color is scientific. You have no idea what color issues an individual has, so a scientific approach is required. Although sometimes your equipment for one reason or another doesn't show reality because equipment isn't perfect, but few know how to deal with that or even recognize when such problems arise.

 

No one has ever complained about my 10.67 foot wide screen.

 

No, I'm waiting for a 4k projector which uses a solid state light source to replace my CRT which I've been using for the last ten years. The blue tube died.

 

Self taught.

 

The article isn't hard to understand. His phrasing and sentence structure is strange.

 

I'm at page 13. 

 

He's right about master quality. What's the point of more pixels, if the source isn't perfect. That's kind of counter productive to the whole selling point behind UHD. Something other than HDCP needs to happen. Lots of people choose SD on their HD sets because then they no longer deal with issues, such as lock ups.

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post #42 of 60 Old 05-07-2014, 12:40 AM
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I've recently come back to this site after a long absence because my 60" Pany DLP rear projection from 2005 is starting to randomly cycle the bulb .. so I figured that if I need to replace it, I should start looking into an upgrade to UHD .. specifically the Sony 500/600. However, I've also been a faithful watcher of Scott's podcasts and have seen JK before. Although I don't know of his history in the industry, he has always come across as having a very balanced view of the whole industry .. from content creation to consumer consumption.

I agree with previous posts that he badly needs an editor .. there are spelling mistakes; incorrectly used words; etc that make it a tougher read .. but I can also appreciate that he has attempted to organize it into a fairly logical progression of sections and he comes at it from a very wide view. But to be honest, it scares the hell out of me that an industry this large is this far out of control on the whole UHD implementation. I know that there are some standards group(s) and I would have hoped that saner heads would have prevailed but given the number of stakeholders (ie content producers; media distributors; TV/cable channels; TV manufacturers; etc); and the large numbers of each, each with their own agenda and desire for a competitive advantage, maybe I was naive in my assumption that there was a well thought out plan.

I think back to when I made the leap from SD to HD with the purchase of my DLP rear projection TV. Back then, I was worried about picking the right TV technology (plasma vs LCD vs DLP vs LCOS, etc) and BD players hadn't yet made their appearance IIRC .. sort of like the situation today with UHD BD players. And at the time, people were buying HD tvs and returning them (much like what I hear with UHD TVs) because they hadn't really thought thru the fact that there was little HD content. But at the time, I was able to get a few HD cable channels and things improved over time. With the TV, I also bought a Pany DVD player with the Farouga upscaler which helped boost DVDs to near HD quality. I also bought a Sony HD camcorder (because I wanted to capture my daughters wedding in HD, plus family vacations) which gave me add'l HD content which I burned onto regular DVDs and then used an imported IODATA AVEL Link player which had an MPEG2 decoder and would overspin the DVD to get the necessary data rate to play the HD content. So, I wasn't really 'bleeding edge' .. but do have some scars from the HD rollout.

And here I am 8 years later and we've been through the transition to 1080p; BD players; media streamers; lots of HD channels ... but the TV/cable distributors are still stuck at 720p/1080i. It's been at least an 8 year journey so I'm not sure why people get upset with a phased UHD implementation schedule that supposedly rolls out in less time. But, since TV/cable isn't even on the current state of the art today for HD, I'm not real hopeful they're going to be really for UHD any time soon. However, I do think that JK is right and this is now a new world and the internet is going to lead this time with dist'n.. not the cable companies.

However, I don't recall there being some of the same technology obsolescence gotchas with the HD implementation that there seem to be with UHD. Sure there was the connector evolution thing before HDMI became the standard and there might have been some issues when HDCP was rolled out .. and later the whole HDMI 1.1, 1.2, etc thing but with UHD it seems some early adopters (maybe just 2013 versions) could be SOL since the specs are in such a state of flux. JK makes a good case that if there's going to be any future proofing of the UHD rollout, then the content creators should have a stronger say that they appear to have had so far. I have worked in IT for many years and the term we use is to 'architect' a solution .. which is a form of thinking through how best to interface and integrate the pieces so that they can evolve in a more controlled way over time. It appears to me that no-one (other than maybe JK) has attempted to 'architect' the UHD solution. His observation that the pipe should carry compressed signals and the decoder function should be in the TV makes a lot of sense on a number of fronts.

The whole discussion about skipping 4k and moving straight to 8k doesn't make a whole lot of sense for a number of reasons .. (1) the content creators don't even have 4k masters today let alone 8k, and (2) no one is going to sit 5 feet from the tv which is what you're going to need to do in order to appreciate the benefits. I have heard Scott and others suggest that it's much more important to enhance the color gammut and dynamic range to give the consumer more value and JK seems to make the same case.

Just my $0.02 worth. Sorry for the long post. I really enjoyed the article and some of the very informative threads on AVSFORUMs. I'm not as smart or experienced as some of you guys but I'm an electrical engineer with lots of IT and geek background so I'm doing my best to get up to speed.
...Ian
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post #43 of 60 Old 05-07-2014, 05:16 AM - Thread Starter
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A great post Ian. Welcome

And thanks for the response Debonaire. What projector are you using for your large screen and what screen material is your screen made from? Thanks

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post #44 of 60 Old 05-07-2014, 08:30 AM
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Quote:
Originally Posted by Debonaire View Post

It's not size, it's viewing distance, which is about 0.8x the screen width for UHD.
You're talking first principles which I've noticed JK sometimes skips over.
The reason he talks about size is because the formula doesn't scale well for smaller screens due to other human factors. There is a minimum distance where extended viewing becomes uncomfortable, which varies depending on the person.

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post #45 of 60 Old 05-07-2014, 08:49 AM
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I didn't even know Widescreen Review was still publishing! eek.gif

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post #46 of 60 Old 05-07-2014, 09:00 AM - Thread Starter
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Man I have to tell you everything. Its a shell of what it once was but there is still a lot of good stuff to be found there.

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post #47 of 60 Old 05-07-2014, 09:25 AM
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Man I have to tell you everything. Its a shell of what it once was but there is still a lot of good stuff to be found there.

On it. Thanks for the info. smile.gif

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post #48 of 60 Old 05-07-2014, 01:06 PM
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On JK's point about perhaps using a lower color temp (e.g., 6000K), that may make sense.

When outdoors with direct sunlight the color temp varies from about 5500K to 6000K, a noon in the summertime at low to mid-latitudes, to closer to 6500K at higher latitudes, such as northern Europe, where the light must pass thru more atmosphere. A color temp of 6500K corresponds to the temp of light outdoors on a cloudy day at mid latitudes. So if we want our video of outdoor scenes to appear more natural, perhaps 6000K is a more reasonable value to use.

By the way, I've subscribed to WSR for the past two decades, and over the years t really has been one of the best HT related mags available, but as Mark said, it's a lot thinner than it used to be (as are most all print magazines today).


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post #49 of 60 Old 05-07-2014, 10:11 PM
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A great post Ian. Welcome



And thanks for the response Debonaire. What projector are you using for your large screen and what screen material is your screen made from? Thanks

 



An HD-700. About four cans of gesso spray paint. Hey, at the time I spent so much money on the system nearly ten years ago. The difference between a real screen and gesso is so slight in a dark room.

I'm thinking about getting that new Sony laser 4k short throw, if it does what they promise.
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post #50 of 60 Old 05-07-2014, 10:59 PM
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I went back and found the last interview Scott did with Joe Kane (http://twit.tv/show/home-theater-geeks/180) and was surprised at how much it mirrors his recent paper that this thread started with. Granted it's an hour long so people may find it to be an even greater slog than reading the article .. but both Joe and Scott do a good job of explaining things that don't get covered in the article. It doesn't give much additional insight into the UHD standards evolution process .. mostly just an expansion of his paper but in a dialogue format.
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post #51 of 60 Old 05-10-2014, 10:40 AM
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I strongly recommend that all read the latest Science of Imaging article, " 2160p and UHDTV Update", by Joe Kane in the April-May 2014 issue of Wide Screen Review. It is long and not an easy read. It is very informative and the factors discussed through implication help explain what the delay by the 4K Forum in establishing 4K Bluray standards. There is much food for thought here including why Joe doesn't think 2020 color space should or will ever happen and why we might be moving from 6500 K to a 6000 K standard .
Joe Kane literally doesn't know how DCI P3 video is encoded for digital cinema. DCI P3 video is encoded using the XYZ color space so over 80% of the data is wasted (the idea was that a wider color gamut could be used in the future). The XYZ color space is larger than the Rec. 2020 color space so 12-bit video is more than sufficient for UHDTV. In fact 12-bit video is sufficient for HDR video using a perceptual gamma curve which is explained in this article. That is the biggest mistake in the article since it causes Joe Kane to reach a wrong conclusion about the bit depth needed for UHDTV.

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When outdoors with direct sunlight the color temp varies from about 5500K to 6000K, a noon in the summertime at low to mid-latitudes, to closer to 6500K at higher latitudes, such as northern Europe, where the light must pass thru more atmosphere. A color temp of 6500K corresponds to the temp of light outdoors on a cloudy day at mid latitudes. So if we want our video of outdoor scenes to appear more natural, perhaps 6000K is a more reasonable value to use.
It would be expensive to change the white point, since it would require real time white point rebalancing, and there isn't a benefit in changing the white point since our perception of it is based on the light we are viewing (which is why it is possible to have white points at different color temperatures). In a light controlled environment it makes sense for UHDTV to use the 6500K white point which has been used for SDTV, sRGB, and HDTV.
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post #52 of 60 Old 05-11-2014, 04:23 PM
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On JK's point about perhaps using a lower color temp (e.g., 6000K), that may make sense.

When outdoors with direct sunlight the color temp varies from about 5500K to 6000K, a noon in the summertime at low to mid-latitudes, to closer to 6500K at higher latitudes, such as northern Europe, where the light must pass thru more atmosphere. A color temp of 6500K corresponds to the temp of light outdoors on a cloudy day at mid latitudes. So if we want our video of outdoor scenes to appear more natural, perhaps 6000K is a more reasonable value to use.

By the way, I've subscribed to WSR for the past two decades, and over the years t really has been one of the best HT related mags available, but as Mark said, it's a lot thinner than it used to be (as are most all print magazines today).


.

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It would be expensive to change the white point, since it would require real time white point rebalancing, and there isn't a benefit in changing the white point since our perception of it is based on the light we are viewing (which is why it is possible to have white points at different color temperatures). In a light controlled environment it makes sense for UHDTV to use the 6500K white point which has been used for SDTV, sRGB, and HDTV.

Richard -

I was just attempting to provide some rational for JK;s suggestion for a white point of 6000K, more or less as part creating UHD from a clean sheet. I agree this is very unlikely to happen since 6500K is well established and in any case would be of marginal value.

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post #53 of 60 Old 05-11-2014, 04:32 PM
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Joe Kane literally doesn't know how DCI P3 video is encoded for digital cinema. DCI P3 video is encoded using the XYZ color space so over 80% of the data is wasted (the idea was that a wider color gamut could be used in the future). The XYZ color space is larger than the Rec. 2020 color space so 12-bit video is more than sufficient for UHDTV. In fact 12-bit video is sufficient for HDR video using a perceptual gamma curve which is explained in this article. That is the biggest mistake in the article since it causes Joe Kane to reach a wrong conclusion about the bit depth needed for UHDTV.

I suggest you submit the above comment for Joe Kane's article (revised as appropriate) to Gary Reber, the editior of Widescreen Review. Gary's email address is: editorgary@widescreenreview.com

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post #54 of 60 Old 05-12-2014, 06:08 AM - Thread Starter
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Quote:
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Joe Kane literally doesn't know how DCI P3 video is encoded for digital cinema. DCI P3 video is encoded using the XYZ color space so over 80% of the data is wasted (the idea was that a wider color gamut could be used in the future). The XYZ color space is larger than the Rec. 2020 color space so 12-bit video is more than sufficient for UHDTV. In fact 12-bit video is sufficient for HDR video using a perceptual gamma curve which is explained in this article. That is the biggest mistake in the article since it causes Joe Kane to reach a wrong conclusion about the bit depth needed for UHDTV.
It would be expensive to change the white point, since it would require real time white point rebalancing, and there isn't a benefit in changing the white point since our perception of it is based on the light we are viewing (which is why it is possible to have white points at different color temperatures). In a light controlled environment it makes sense for UHDTV to use the 6500K white point which has been used for SDTV, sRGB, and HDTV.

I think for movies everything boils down to what is encoded in the Academy color Encoding system which boils down to a very wide encoded color space with CIEx and CIEy of Red (0.73470, 0.26530), Green (0.00000, 1.00000), and Blue (0.00010, -0.07700) and requires 16 bits for that space and for the greater than 25 stop dynamic range the system encodes. This mean P3 occupies about 20% of the space encoded. That space encompasses all colors that can visibly be observed. How many bits are required to encode the data that falls within the range defined by the UHD standard whatever that may turn out to be is another issue. Certainly it would be less than 16 bits There is no way we are going to get 25 bits or a space anywhere as large. P3 for a variety of reasons is all we are going to get. Dynamic range ? I really have no clue but it is presently extremely limited by display technology as well as what for legacy sources (film) to about 5 stops if I remember correctly.

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post #55 of 60 Old 05-12-2014, 07:14 AM
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I think for movies everything boils down to what is encoded in the Academy color Encoding system which boils down to a very wide encoded color space with CIEx and CIEy of Red (0.73470, 0.26530), Green (0.00000, 1.00000), and Blue (0.00010, -0.07700) and requires 16 bits for that space and for the greater than 25 stop dynamic range the system encodes. This mean P3 occupies about 20% of the space encoded. That space encompasses all colors that can visibly be observed. How many bits are required to encode the data that falls within the range defined by the UHD standard whatever that may turn out to be is another issue. Certainly it would be less than 16 bits There is no way we are going to get 25 bits or a space anywhere as large. P3 for a variety of reasons is all we are going to get. Dynamic range ? I really have no clue but it is presently extremely limited by display technology as well as what for legacy sources (film) to about 5 stops if I remember correctly.


Mark -

Info from THIS article says:

"Vision3 is the latest (last?) stock from Kodak, and is available for 8mm, 16mm, 35mm and 65mm film. Kodak presents detailed data sheets which charts MTF, granularity, color temperature and sensitivity information, like this one for 5219.

Kodak states Vision3 has a maximum dynamic range of 13 stops."

......

"The point is, sensors are linear devices, while film is non-linear in its exposure response to light. As I’ve explained in Dynamic Range of the Human Eye, the human eye is strictly neither (or more than both) linear or non-linear – it has its own rules. Furthermore, the way in which film is developed and scanned has a huge role to play in its contrast response. In this respect it behaves closer to the eye, which too, can change its behavior to the intensity of light.

For this reason, when comparing film to digital tests, it would be wise to give film an extra stop of ‘latitude’, if you will. Therefore, I have equated Vision3 with a dynamic range of 14 stops."

.................................................

"Red carried out a test between the Epic and the Alexa back in 2010, when everyone (including me) was going gaga over the impending demise of film. In this test, the Red Epic checks in at an impressive 13.5 stops of dynamic range, while the Alexa does 14 stops (to my eyes at least)."



The article (link above) has a table listing the manufacturer's claimed dynamic range for a number of digital cameras. The highest DR is for a Red camera with the upgraded Red Dragon Senor which has 18 stops of DR while the Sony F55/F5 has 14 stops and the Red Epic has 13.5 stops. Quality consumer DSLRs range between about 9 and 12 stops of DR.

Since each f-stop represents a factor of 2, then 14 stops would represent a 2E14 = 16,384 or a ratio of 16K to 1 for brightest to darkest.


.

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post #56 of 60 Old 05-12-2014, 03:40 PM - Thread Starter
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At least I was only off by less than a factor of 3. My number was from the days when I shot slide film. Five stops would be pushing it and often we would need a graduated ND filter. Print film gave us about 6 stops.

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post #57 of 60 Old 05-12-2014, 09:58 PM
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Originally Posted by Highjinx View Post

No doubt.....!

For JK to mention a screen size without a viewing distance is just ridiculous.....or carefully crafted statement to move larger screens. A mention of a 17degree horizontal viewing angle or viewing from .75 screen widths or so would have been more meaningful.

I presume that this issue has been settled by now, though I haven't seen it stated explicitly. Anyway, JK is very specific about what he recommends for viewing distance and screen size: for the full benefit of 3840x2160 he recommends (in Appendix 2) a viewing distance of no more than 1.5 picture heights. For my 6 ft H screen this is thus 9ft, and I'm actually sitting at ~ 10.5 ft; I'll have to try scooting up a bit closer.
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post #58 of 60 Old 05-13-2014, 05:50 AM - Thread Starter
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Its not settled at all and it never will be. Most like to sit at about 10 ft from a screen no matter its size up to about a 12 ft wide screen or so. If one wants to see the pixel grid projector from 4K chips, those with average eyes would have to move closer than 1.5 I would think. Obviously .8H will give one brain more pixel detail than 1.5. But like other things, personal preference trade offs come into play. One can usually sit where they like the trade offs. Sitting at 1.5 may lose some of the 4K detail but be preferable to some. There is no ideal There is no right that some organization can validly specify. Sony set a .8 for its 4K panels. Small consumer sets with the largest being a 84 inch diag, 1.78. Marketing. You want to see 4K resolution improvement enough to sell a 4K set at 4:2:0. rec 709, limited DR etc. You have to sit close. It changes with larger screen sizes. Why. I don't really know. For commercial theaters with rows from very close to far, should SIMPTE etc specify one row for people to sit in to maximize their experience. No there will be a range and theaters will have seats closer and further than the recommended range as well. Me. I like 1.5 for my seating distance regardless of whether 2K or 4K.

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post #59 of 60 Old 05-13-2014, 08:26 AM
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By 'settled' I meant settled on what JK had to say about screen size/viewing distance (in response to an earlier poster criticizing JK for not having specified viewing distance when he mentioned screen size).

IIRC, Sony's 4K promotional literature touted 1.6 pic ht as the optimum viewing distance for 4K material; very close to JK's 1.5 recommendation.
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post #60 of 60 Old 05-16-2014, 05:55 PM
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Quote:
Originally Posted by mark haflich View Post

I think for movies everything boils down to what is encoded in the Academy color Encoding system which boils down to a very wide encoded color space with CIEx and CIEy of Red (0.73470, 0.26530), Green (0.00000, 1.00000), and Blue (0.00010, -0.07700) and requires 16 bits for that space and for the greater than 25 stop dynamic range the system encodes. This mean P3 occupies about 20% of the space encoded. That space encompasses all colors that can visibly be observed.
ACES uses 16-bits but it has an incredibly large dynamic range (it uses OpenEXR) and has a precision far better than what a human can perceive (it was designed for professional production work so excess precision wasn't considered a problem).

Quote:
Originally Posted by mark haflich View Post

How many bits are required to encode the data that falls within the range defined by the UHD standard whatever that may turn out to be is another issue. Certainly it would be less than 16 bits
If HDR takes off than I think it will be 12-bits since that allows for up to 10,000 nits with the Dolby perceptual gamma curve. If HDR fizzles out than it might be 10-bits.
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