8K by 4K or Octo HD - the real SUHDTV technology - Page 10 - AVS Forum
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post #271 of 676 Old 09-25-2012, 03:15 PM
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Originally Posted by SoundChex View Post

Of course that's still only the difference between sitting with your head six feet or eight feet away from a 200" screen.
And it seems viewers would prefer something about 12.25 ft for 200 in screen (1.5 image heights).
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Originally Posted by Lee Stewart View Post

According to NHK's research, the Sense of Realness (spatial resolution/angular resolution)/visual fidelity determines whether viewers can distingush images from real objects. The higher the angular resolution, the greater the sense of realness and the sense saturates above about 60 cpd.
Isn't that from an older paper? Doesn't matter. Anyway, 60 cycles per degree = 120 pixels per degree.
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post #272 of 676 Old 09-25-2012, 03:29 PM
 
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Originally Posted by Randomoneh View Post

And it seems viewers would prefer something about 12.25 ft for 200 in screen (1.5 image heights)

But will fine detail be lost at that increased distance?

1.5 PH is the optomim seating distance (55 degrees FOV) for 4K.
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Isn't that from an older paper? Doesn't matter. Anyway, 60 cycles per degree = 120 pixels per degree.

Yes - Jan. 2011.

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post #273 of 676 Old 09-25-2012, 03:32 PM
 
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Originally Posted by Lee Stewart View Post

2012-02-21 15:40
Subjective evaluation of preferred viewing distance and psyhcophysical effects of extremely high resolution images using Super Hi-Vision 85-inch LCD
"We are currently researching a next-generation broadcasting system named Super Hi-Vision, which has 16 times higher image resolution than that of a high definition television. Using our newly developed 85-inch
liquid crystal display (LCD) for Super Hi-Vision, we performed subjective evaluations to quantify the preferred viewing distance and psychophysical effects of the sense of being there and sense of realness. The results of the first experiment indicate that the preferred viewing distance is 2.5H (H is picture height) on the average and is distributed between 1.5H and 4H regardless of resolution and content. The results of the second experiment indicate that the sense of being there and the sense of realness improve as the image resolution increases when viewing at less than 3H."
http://www.ite.or.jp/ken/paper/201202211ACn/eng/
1-1-1-1.gif

Here is the entire study/revisions - covers the above, increased frame rate to 120: and Wide color-gamut camera

http://www.nhk.or.jp/strl/english/aboutstrl1/r1-1-1.htm
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post #274 of 676 Old 09-25-2012, 03:32 PM
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Originally Posted by Randomoneh View Post

And it seems viewers would prefer something about 12.25 ft for 200 in screen (1.5 image heights).

Sitting at a distance of 150% screen height, you might be able to get by with a 4K2K screen rather than needing 8K4K resolution (will there be a 'cheaper-than-4320' 2880 line, i.e., 4x720 line, resolution?) and 4K2K [BD disk] material upscaled to 8K4K will be more than adequate.

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post #275 of 676 Old 09-25-2012, 03:34 PM
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Originally Posted by Lee Stewart View Post

But will fine detail be lost at that increased distance?
Don't we have answer the answer to that?
1-1-1-1.gif
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post #276 of 676 Old 09-25-2012, 03:45 PM
 
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Originally Posted by Randomoneh View Post

Don't we have answer the answer to that?
1-1-1-1.gif

That data is based on an 85" SHV LCD display.
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post #277 of 676 Old 09-25-2012, 03:48 PM
 
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Originally Posted by SoundChex View Post

Sitting at a distance of 150% screen height, you might be able to get by with a 4K2K screen rather than needing 8K4K resolution (will there be a 'cheaper-than-4320' 2880 line, i.e., 4x720 line, resolution?) and 4K2K [BD disk] material upscaled to 8K4K will be more than adequate.

Right - 1.5 PH is the optomim seating distance (FOV = 55 degrees) for 2160P
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post #278 of 676 Old 09-25-2012, 04:17 PM
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Originally Posted by Lee Stewart View Post

Right - 1.5 PH is the optomim seating distance (FOV = 55 degrees) for 2160P

This also has the advantage of 'working well' with the current 'equilateral triangle' placement of the L+R speaker pair and the MLP. (Moving to a 100 degree FOV might involve conflicts with 'screen edge' sound placement unless one adopts the Hamasaki '5 front speaker' geometry!)

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post #279 of 676 Old 09-25-2012, 05:59 PM
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Originally Posted by Lee Stewart View Post


Here is the entire study/revisions - covers the above, increased frame rate to 120: and Wide color-gamut camera
http://www.nhk.or.jp/strl/english/aboutstrl1/r1-1-1.htm


I don't quite understand this figure and the discussion related to it:   the statement is that the preferred distance is 2.5H, while the figure indicates (as I interpret it) that the best 'realness' and 'sense of being there' is for a viewing distance of 1.5H, at least for 4K.    What am I missing?

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post #280 of 676 Old 09-25-2012, 09:34 PM
 
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Originally Posted by millerwill View Post


I don't quite understand this figure and the discussion related to it:   the statement is that the preferred distance is 2.5H, while the figure indicates (as I interpret it) that the best 'realness' and 'sense of being there' is for a viewing distance of 1.5H, at least for 4K.    What am I missing?

Look at the graphs again. In both realness and being there, from a seating distance of .75 PH to 4.0 PH, 8K scored higher than 2K or 4K
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post #281 of 676 Old 09-26-2012, 07:57 AM
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Originally Posted by Lee Stewart View Post


Look at the graphs again. In both realness and being there, from a seating distance of .75 PH to 4.0 PH, 8K scored higher than 2K or 4K


Yes, I do get that.   But for both 8K and 4K they peak at ~ 1.5PH, and at 1.5 PH the 8K value is only a very modest amount above that of the 4K value.     For me that says that 4K at 1.5 PH is the sweet spot, certainly for the foreseeable future.

 

PS   I'm presently viewing at ~ 1.8 PH (11ft from a 6ft H screen) with the Sony 4K projector, so I may scoot up a couple of ft as soon as we get 4K source material!

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post #282 of 676 Old 09-26-2012, 09:28 AM
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Originally Posted by millerwill View Post


Yes, I do get that.   But for both 8K and 4K they peak at ~ 1.5PH, and at 1.5 PH the 8K value is only a very modest amount above that of the 4K value.     For me that says that 4K at 1.5 PH is the sweet spot, certainly for the foreseeable future.

PS   I'm presently viewing at ~ 1.8 PH (11ft from a 6ft H screen) with the Sony 4K projector, so I may scoot up a couple of ft as soon as we get 4K source material!
At 2.5 image heights (40 degrees horizontally, very pleasant and much more usual than 60 degrees (1.5 image heights)) - difference between 2160p and 4320p is pretty decent.
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post #283 of 676 Old 09-26-2012, 10:36 AM
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Originally Posted by Randomoneh View Post


At 2.5 image heights (40 degrees horizontally, very pleasant and much more usual than 60 degrees (1.5 image heights)) - difference between 2160p and 4320p is pretty decent.

Yes, agree with the last part of your statement, but viewing distance is of course a very individual thing.    My screen-size preference has gradually grown with time since I got my first HDTV (60" rptv) in '04.    Went from there to 73" rptv, then to a projector with 110"W screen, and now to one 136" W for 16x9 (and 144"W for 2.35), and that 's the limit for my room!

 

2.5 PH is clearly further back that I like it, though I certainly understand that it's fine with many.    As I said, at present ~1.8 PH (11' from a 6'H screen) is where I am now but who knows, maybe I'll work up to 1.5 PH if I live long enough!

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post #284 of 676 Old 09-26-2012, 11:11 AM - Thread Starter
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Originally Posted by Lee Stewart View Post

I disagree. The cameras and lenses will be very important. Think of how much video we watch that consists of capturing live subjects; sports, television shows, movies, etc.

That was referring to the discussion of the MTF with claims of Octo HD irrelevant because of the optics limitations. To which I said this is irrelevant as there is computer generated content.
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Do you really believe that in the year 2150 there will be no higher resolution than 8K? I don't.

I am optimistic about humanity getting rational already around 2025 and staying with the Octo HD forever biggrin.gif.

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post #285 of 676 Old 09-26-2012, 11:42 AM
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Originally Posted by Lee Stewart View Post


Here is the entire study/revisions - covers the above, increased frame rate to 120: and Wide color-gamut camera
http://www.nhk.or.jp/strl/english/aboutstrl1/r1-1-1.htm


For amusement, I did a finite diff interpolation of the points on these curves and find that both properties reach their maximum (optimum) values at PH ~ 1.9 (for the 4K data).

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post #286 of 676 Old 09-26-2012, 01:15 PM
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Originally Posted by irkuck View Post

with claims of Octo HD...
I see you really want this to catch on. Too bad.
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Originally Posted by millerwill View Post

For amusement, I did a finite diff interpolation of the points on these curves and find that both properties reach their maximum (optimum) values at PH ~ 1.9 (for the 4K data).
Interpolation from 4 points rolleyes.gif
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post #287 of 676 Old 09-26-2012, 01:25 PM
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I see you really want this to catch on. Too bad.
Interpolation from 4 points rolleyes.gif


It's all I had (gives a cubic fit).

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post #288 of 676 Old 09-26-2012, 02:13 PM
 
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Originally Posted by irkuck View Post

That was referring to the discussion of the MTF with claims of Octo HD irrelevant because of the optics limitations. To which I said this is irrelevant as there is computer generated content.

Which would be irrelevant because so little content that people watch is computer generated. Most of it is live action oriented.
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I am optimistic about humanity getting rational already around 2025 and staying with the Octo HD forever biggrin.gif.

100+ years from now, 8K will be nothing but a foot note in history wink.gif
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post #289 of 676 Old 09-26-2012, 06:40 PM
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Originally Posted by Owen View Post

With regard to the recent discussions about MTF I provide the following video links.
I suggest you view them in the order below, its gets a bit technical but stay with it and pay attention.
Seminar presented by John Galt (Panavision) and Larry Thorpe (Canon)
http://www.freshdv.com/2008/05/demystifying-digital-camera-specs-part3.html
http://www.freshdv.com/2008/05/demystifying-digital-camera-specs-part4.html
http://www.freshdv.com/2008/05/demystifying-digital-camera-specs-part2.html
http://www.freshdv.com/2008/05/demystifying-digital-camera-specs-part1.html
That does explain your opinion on 30% MTF though it does seem you went too far by stating that it was an "industry standard" since I didn't see any evidence for that in the 2008 Panavision presentation. And technology has advanced since 2008 so some of the information in that presentation is a bit out of date.

Also during the presentation it mentions that the limiting resolution in TV lines is "typically measured where the horizontal MTF has dropped to 5%". As such I didn't notice any comments that would go against the 20% MTF that the NHK used when determining the limiting resolution in TV lines for their 2006 camera.

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From the above a few things should become clear.
1. Pixels are not resolution.
Sure, but the number of megapixels in a CMOS sensor does give you a rough idea of its capability. All other things being equal a 20 megapixel CMOS sensor can record 4K video with better resolution than a 8 megapixel CMOS sensor. And several of your previous posts used pixel resolution as a way to measure the resolution capability of a camera. In my opinion there are some good arguments that can be made against 8K resolution for TVs but I think the current limit of CMOS sensors is not one of them due to the technological advancement of CMOS sensors.

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Until bandwidth becomes a non issue 4k with high frame rates and 10bit 4:4:4 color is a far better option than 8k IMHO.
I personally think that it would make more sense for the NHK to go with 4K UHDTV.

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Originally Posted by Randomoneh View Post

...
Even at 3 image heights (1080p: 56 ppd, 2160p: 113 ppd, 4320p: 226 ppd), there is a noticeable difference between 4K and 8K. How to explain that? If there is no difference between 2K and 4K, why is there a difference between 4K and 8K?
Well any study where you ask people to decide on a subjective value such as their "sense" of something can lead to strange results. For example that the values go down at .75 picture heights for 8K might have been due to nausea (from the type of video being shown and/or that the display was only capable of 60 Hz). In my opinion the graphs alone don't give enough information.

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That data is based on an 85" SHV LCD display.
That is an important point to make since from what I have read that 8K LCD is limited to 60 Hz.
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post #290 of 676 Old 09-26-2012, 08:56 PM
 
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Originally Posted by Richard Paul View Post

Sure, but the number of megapixels in a CMOS sensor does give you a rough idea of its capability. All other things being equal a 20 megapixel CMOS sensor can record 4K video with better resolution than a 8 megapixel CMOS sensor. And several of your previous posts used pixel resolution as a way to measure the resolution capability of a camera. In my opinion there are some good arguments that can be made against 8K resolution for TVs but I think the current limit of CMOS sensors is not one of them due to the technological advancement of CMOS sensors.

Aptina Unveils 1-inch Sensor with 1080p Video at 120FPS
Quote:
SAN JOSE, Calif. & COLOGNE, Germany-(BUSINESS WIRE)-Aptina, a global provider of CMOS imaging solutions enabling Imaging Everywhere™, announced today the release of the AR1011HS digital camera image sensor. The new 1-inch optical format sensor is ideal for enabling high quality bridge and mirrorless cameras and targets Tier-1 camera OEMs. The sensor provides 10-megapixel (MP) resolution, 3.4-micron pixels, with Aptina’s DR-Pix™ technology, delivering uncompromised low light and bright light scene image quality. The AR1011HS high-speed sensor architecture is capable of reading full 10MP resolution at 60fps, and enables a variety of video modes, including broadcast quality quad high definition (HD), oversampled 1080p for True HD resolution, 1080p video at 120 frames per second, and additional high frame rate modes for slow motion playback.

http://www.schubincafe.com/2012/09/24/aptina-unveils-1-inch-sensor-with-1080p-video-at-120fps/
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post #291 of 676 Old 09-26-2012, 09:17 PM
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Dear friends,

what I'm about to post is important for many of your future calculations.

Mathematically correct calculation of matching viewing angle for any resolution:
Code:
2*(arctan((horizontal resolution/angular resolution)/(360/pi))) in degrees

For example, if you believe 60 pixels per degree to be visual acuity angular resolution limit for you and you are calculating for "8K" TV (4320p), you'll use this (type into Google):
Code:
2*(arctan((7680/60)/(360/pi))) in degrees

Result is horizontal viewing angle - number of degrees TV can occupy and still match visual acuity of person in question.

Incorrect calculation of matching viewing angle:
Code:
horizontal resolution/angular resolution

Here are viewing angles for popular resolutions, based on conservative angular resolution measurement of 60 pixels per degree (1 arcminute):

1920x1080:
31.2 degrees or less

3840x2160 ("4K"):
58.4 degrees or less

7680x4320 ("8K"):
96.3 degrees or less

Hope we won't see any more mistakes like this: "Acuity limit is 60 pixels per degree. There are 3840 horizontal pixels in 4K. Therefore, 4K TV can occupy 3840/60 = 64 degrees."
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post #292 of 676 Old 09-27-2012, 01:09 AM
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Originally Posted by Richard Paul View Post

That does explain your opinion on 30% MTF though it does seem you went too far by stating that it was an "industry standard" since I didn't see any evidence for that in the 2008 Panavision presentation. And technology has advanced since 2008 so some of the information in that presentation is a bit out of date.

35% MTF is where the image is judged to be out of focus by a camera operator so less is hardly useful wouldn’t you think? I very much doubt there is any “standard” written in stone, I'm sure most in the industry want the best they can get but wisely concentrate on what matters. High MTF at low to mid spatial frequency is very important, high limiting resolution is not.
The digital sampling laws that applied in 2006 still apply today and high end lens performance has changed little in the last 10 years and I doubt it will in the next 10.
Some of the NHK diagrams already posted show the theoretical performance of an 8k camera and how it relates to measured performance, they are not much different.
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Originally Posted by Richard Paul View Post

Also during the presentation it mentions that the limiting resolution in TV lines is "typically measured where the horizontal MTF has dropped to 5%". As such I didn't notice any comments that would go against the 20% MTF that the NHK used when determining the limiting resolution in TV lines for their 2006 camera.

Sony seem to use the 45% MTF point to measure their HD cameras and still camera gear is normally measured at 50% MTF. The 5% used by some is good for nothing more than marketing.
Remember that textural detail in an image typically has low contrast to begin with, after that already low contrast is degraded 70% due to a system MTF response of 30% we are not left with anything useful. I therefore think 30% MTF as a minimum is being overly generous, Sony seem to agree even when it would look better on the spec sheet to use 5%. They obviously realise that the professionals who buy high end video cameras are not impressed by silly numbers
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Originally Posted by Richard Paul View Post

Sure, but the number of megapixels in a CMOS sensor does give you a rough idea of its capability. All other things being equal a 20 megapixel CMOS sensor can record 4K video with better resolution than a 8 megapixel CMOS sensor. And several of your previous posts used pixel resolution as a way to measure the resolution capability of a camera. In my opinion there are some good arguments that can be made against 8K resolution for TVs but I think the current limit of CMOS sensors is not one of them due to the technological advancement of CMOS sensors.

Super sampling does improve MTF, all else being equal, but resolution can never equal the pixel count in any digital capture system, which will come as a shock to many people. When we downscale to a lower output pixel format a new lower Nyquist limit is imposed and low pass filtering must be used to stay within this new lower limit or nasty aliasing can occur.
As we move to more and more pixels lens performance becomes critical, 8k is much more affected than 4k and thats the reason 8k looks no where near twice as good as 4k.


As consumers we should not be concerned about cameras and numbers, just on what we can see with the screen size and viewing distance combination we use or expect to use in the future. At 1.5 x image height I know I cant see the deference between 8k and 4k so unless I get a much larger screen or am prepared to sit much closer to get under 1.5 x image height I just don’t care about 8k and never will. I consider more temporal resolution (higher frame rate) a better way to go then more pixels, 4k is plenty for motion pictures as super high resolution is too difficult to capture in a motion picture environment, its hard enough for stills.
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post #293 of 676 Old 09-27-2012, 07:46 PM
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Originally Posted by Owen View Post

35% MTF is where the image is judged to be out of focus by a camera operator so less is hardly useful wouldn’t you think?
It is important to note that being out of focus means that it is out of focus for that particular resolution which was explained in the presentation. Information can come through at low MTF values which is why camera manufacturers typically measure their limiting resolution at 5% MTF.

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The digital sampling laws that applied in 2006 still apply today and high end lens performance has changed little in the last 10 years and I doubt it will in the next 10.
The camera lens might be a longer term argument than CMOS sensors but it is still a technological limit that can be solved by advances in technology.

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Some of the NHK diagrams already posted show the theoretical performance of an 8k camera and how it relates to measured performance, they are not much different.
Which diagrams are you referring to? I have seen diagrams based on the 2006 NHK camera but I haven't seen any diagrams based on the limits of current technology.

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Sony seem to use the 45% MTF point to measure their HD cameras and still camera gear is normally measured at 50% MTF. The 5% used by some is good for nothing more than marketing.
In part 5 at 7:40 it shows the limiting resolution for both the Ikegami and Sony cameras and it looks like they used a 5% MTF for their limiting resolution. In part 5 at 8:30 it is mentioned that the limiting resolution is "typically measured where the horizontal MTF has dropped to 5%". As such it looks to me like the NHK used a higher MTF than what is typical when they measured the limiting resolution for their 2006 camera.

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As we move to more and more pixels lens performance becomes critical, 8k is much more affected than 4k and thats the reason 8k looks no where near twice as good as 4k.
UHDTV was designed with the idea that it would last for decades so I can understand why they would not have designed it based on current technological limits. Personally I am skeptical that 8K UHDTV will make sense for the mass market even 10 years from now. At some point in the future I think it will happen but it may require a revolutionary advancement in technology (such as printable OLED TVs at very large sizes).
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post #294 of 676 Old 09-27-2012, 08:19 PM
 
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The camera lens might be a longer term argument than CMOS sensors but it is still a technological limit that can be solved by advances in technology.

Like all things is life, there are tradeoffs. A camera lens is a highly complex device. Make an improvement in one spec - it degrades the performance in another spec, or multiple specs. It would not surprise me in the least if someone from Panavision joined this thread and said that the % of improvements in camera lenses for motion pictures hasn't improved more than 20% in the last 50 years. And that is just me "shooting from the hip" - a wild guess, based on using 65mm film 50 years ago for movie productions which required improved, high quality camera lenses.
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UHDTV was designed with the idea that it would last for decades so I can understand why they would not have designed it based on current technological limits. Personally I am skeptical that 8K UHDTV will make sense for the mass market even 10 years from now. At some point in the future I think it will happen but it may require a revolutionary advancement in technology (such as printable OLED TVs at very large sizes).

LOL - 10 years from now? I strongly doubt the USA will even have 8K 10 years from now. Japan will. But then again, Japan is more "high tech" when it comes to CE than the USA is. They were broadcasting HDTV years before the USA. They had HD LD, something the USA never had.

If they can maufacturer an 85" 8K LCD TV today, which Sharp did, then they can easily manufacture them in the near future (say 5 years from now) in lesser sizes like 70", 75" or 80." And probably much cheaper than 8K OLED.
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post #295 of 676 Old 09-27-2012, 09:44 PM
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Originally Posted by Richard Paul View Post

It is important to note that being out of focus means that it is out of focus for that particular resolution which was explained in the presentation. Information can come through at low MTF values which is why camera manufacturers typically measure their limiting resolution at 5% MTF.

I can see I am wasting my time, you seem to have completely missed the message that John Galt and Larry Thorpe went to some effort to convey. A high limiting resolution is of no use for cinema applications and they both stress that point. Thats why Panavision tests its lenses at quite low spatial frequencies equal to about 1k as high MTF there is whats important for perceived image sharpness.
“Resolution” without high MTF is useless because we cant see it, and since most detail in a scene normally has low relative contrast to begin with a large loss of relative contrast due to low system MTF makes that detail invisible. At 5% MTF the system is only conveying 5% of the scenes original contrast at that spatial frequency, you may consider that “resolved” but I sure don’t. For audio this would be like turning the treble control all the way down, not exactly accurate. The high frequencies are still there but so low in level we cant hear them.


When we look at the image below from a distance we can clearly see that at lower MTF it becomes much harder to distinguish the high frequency lines on the right side, and thats with an input signal that has 100% relative contrast to begin with (a test pattern). If the original scene has details with only 30% relative contrast (very common) and the system MTF is 30% we end up with 10%.
I can just see individual lines at the right edge of the 100% scale at 10' on my 27” monitor but I have to move in to about 4' to see them at 10% MTF.
So if I view from a distance that would allow me to see 8k resolution with 100% scene contrast and 100% MTF (about 0.75x image height) most of the fine textural detail in the scene captured with a camera and delivered in a 8k digital format will just be a blur.
No properly designed digital imaging system should have more than about 10%MTF at Nyquist (spatial frequencies equal to the pixel grid), so even if we had 100% scene contrast and a perfect lens the low pass filtering required for an 8k system makes 8k visible resolution completely impossible at anything like a reasonable viewing distance.

mtf1000.gif
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post #296 of 676 Old 09-28-2012, 02:32 AM
 
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Owen:

In all your posts involving 8K and MTF have you ever taken into account how much the sharpness of displayed images increases by doubling the frame rate from 60 fps to 120 fps? For movies, it would be a 5X increase (24 to 120).
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post #297 of 676 Old 09-28-2012, 04:59 AM
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24fps film with its slow shutter speeds has terrible motion resolution so a lot can be gained by higher frame rates and the higher shutter speeds it allows within the limits of available light. However, lock a camera down on a still scene and you can use as many frames per second as you want, each frame will have the same MTF and image sharpness is governed by MTF. Displaying the same image data over many frames displayed quickly is no different to displaying a single frame constantly for a still scene. Low MTF equals a soft picture and low visible resolution no matter how you dice it.

A high frame rate enforces a fast shutter speed, which also requires a lot of light or the image will be under exposed. Added to that the more pixels we pack into an image sensor the smaller each photo site becomes and the less light sensitive the camera. Its often not possible to use high shutter speeds due to lack of light and shutter speed is limited by the frame interval. When the shutter interval needs to be longer than the frame interval the frame interval must be made longer and the frame rate lowered or no image can be captured.

Then there are artistic considerations, the director my call for a shot with a large depth of field which requires a small lens aperture, problem is a small aperture gathers very little light and the shutter speed must be lowered to compensate. If the frame rate is too fast the shutter speed cannot be lowered and the shot cannot be captured.

All in all, high frame rates are very impractical and for content not shot outside on a sunny day often impossible.

A video camera is still a camera and it has to live by the same laws and limitations that govern still photography, plus a few more.

Its completely impractical to alter the frame rate during the video-movie so its not likely to ever happen, therefore the lowest frame rate required for the darker scenes will be the frame rate used for the entire movie.
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post #298 of 676 Old 09-28-2012, 05:27 AM
 
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Originally Posted by Owen View Post

24fps film with its slow shutter speeds has terrible motion resolution so a lot can be gained by higher frame rates and the higher shutter speeds it allows within the limits of available light. However, lock a camera down on a still scene and you can use as many frames per second as you want, each frame will have the same MTF and image sharpness is governed by MTF. Displaying the same image data over many frames displayed quickly is no different to displaying a single frame constantly for a still scene. Low MTF equals a soft picture and low visible resolution no matter how you dice it.

Did you read about this demo?

NHK-SHV-120-Hz.jpg
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Another NHK Super Hi-Vision (SHV) demo involved shooting and displaying at 120 frames per second (fps) instead of 60. At far right above is the camera used. Just above the lens is a display showing 120-fps images and to its left one showing 60-fps. The difference in sharpness was dramatic. But to the right of the 120-fps images and to the left of the 60-fps were static portions of the image, and they looked sharper than either moving version. At the left in the picture above is the moving belt the SHV camera was shooting, and it looked sharper than even the 120-fps images.

http://www.schubincafe.com/tag/super-hi-vision/

You can click/save on the image above in the link. It opens up to a much larger image.
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A high frame rate enforces a fast shutter speed, which also requires a lot of light or the image will be under exposed. Added to that the more pixels we pack into an image sensor the smaller each photo site becomes and the less light sensitive the camera. Its often not possible to use high shutter speeds due to lack of light and shutter speed is limited by the frame interval. When the shutter interval needs to be longer than the frame interval the frame interval must be made longer and the frame rate lowered or no image can be captured.

And yet we have people like Douglas Trumbull who says they could shoot at 1000 fps:

“Digital cinematography can effortlessly go to 1,000 frames a second,” he said, though the human eye can’t perceive that much information. “So no more raw stock, no more film, no more film processing; the camera is silent, it doesn’t care what frame rate it goes at."

http://www.nytimes.com/2012/02/05/movies/awardsseason/douglas-trumbull-honored-for-technology-hes-still-creating.html?pagewanted=all&_r=0
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Then there are artistic considerations, the director my call for a shot with a large depth of field which requires a small lens aperture, problem is a small aperture gathers very little light and the shutter speed must be lowered to compensate, if the frame rate is too fast the shutter speed cannot be lowered and the shot cannot be captured.

Are you famaliar with this camera?

Phantom HD GOLD

http://www.visionresearch.com/products/high-speed-cameras/phantom-hdgold/
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All in all, high frame rates are very impractical and for content not shot outside on a sunny day often impossible.
A video camera is still a camera and it has to live by the same laws and limitations that govern still photography, plus a few more.
Its completely impractical to alter the frame rate during the video-movie so its not likely to ever happen, therefore the lowest frame rate required for the darker scenes will be the frame rate used for the entire movie.

And yet Peter Jackson is filming his Hobbit movies at 48 fps (and in 3D) and I sincerely doubt all the cinematography was done in bright sunlight.
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post #299 of 676 Old 09-28-2012, 06:36 AM
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Originally Posted by Lee Stewart View Post

Did you read about this demo?

Yes, it says parts of the image where moving.
If there is no motion every frame is exactly the same, down to the pixel. Flashing the same image 120 times a second is no different to 12000 times per second or on continuously.
If we view a still image on refreshing monitor like a CRT does 120Hz look sharper than 60Hz?
LCD monitors are updating displays they don't refresh, the image is displayed constantly until pixel data is altered. They therefore don't flicker and if consecutive frames have the same data nothing changes on screen.

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Originally Posted by Lee Stewart View Post

And yet we have people like Douglas Trumbull who says they could shoot at 1000 fps:

Sure you can, IF you have enough light. Have you ever used a camera that shows you the shutter speed?

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Originally Posted by Lee Stewart View Post

Are you famaliar with this camera?
Phantom HD GOLD

According the specs its rated at 600iso, you would need a massive amount of light to shoot at 1000fps (over 1/1000th sec shutter speed) or more with 600iso. You can crank up the gain but then you get noise.
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Originally Posted by Lee Stewart View Post

And yet Peter Jackson is filming his Hobbit movies at 48 fps (and in 3D) and I sincerely doubt all the cinematography was done in bright sunlight.

48fps is not exactly fast and allows a shutter speed of about 1/48th of a second on a digital camera if needed, which coincidentally is what a cinema film camera uses. (24fps, 180 degree shutter for 1/48th shutter speed)

1/120th needs 2.5 times more light than 1/48th.
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post #300 of 676 Old 09-28-2012, 07:28 AM
 
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Originally Posted by Owen View Post

Yes, it says parts of the image where moving.
If there is no motion every frame is exactly the same, down to the pixel. Flashing the same image 120 times a second is no different to 12000 times per second or on continuously.
If we view a still image on refreshing monitor like a CRT does 120Hz look sharper than 60Hz?
LCD monitors are updating displays they don't refresh, the image is displayed constantly until pixel data is altered. They therefore don't flicker and if consecutive frames have the same data nothing changes on screen.

Yes, I know that HFR has no effect on static images. I was addressing movement, something that is a real world happening. Something that cameras have to capture, be it movies, sports, whatever. What I am saying is that MTF is not the only thing that affects what we see on the display when it comes to resolution.
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Sure you can, IF you have enough light. Have you ever used a camera that shows you the shutter speed?

Are you asking me if I ever owned and used a quality 35mm SLR camera? If so, the answer is yes.
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According the specs its rated at 600iso, you would need a massive amount of light to shoot at 1000fps (over 1/1000th sec shutter speed) or more with 600iso. You can crank up the gain but then you get noise.

You lost me. The higher the ISO number the more sensitive it is to light. The lower the ISO number, the less sensitive it is to light as in requires more of it. ISO 600 is fast. ISO 50 is slow. . . . right?
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48fps is not exactly fast and allows a shutter speed of about 1/48th of a second on a digital camera if needed, which coincidentally is what a cinema film camera uses. (24fps, 180 degree shutter for 1/48th shutter speed)

Right - compared to some of the numbers I introduced, but still twice as fast as normal 24 fps cinematography. This will definitely have a positive effect on the spatial resolution of images projected in theaters.
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