How to determine if you can benefit from a 4K display

[Dusso Janladde]

Before I explain the math behind it, I'll sum it up:

Measure your viewing distance in inches. To get any benefit from a 4K display, the diagonal size of the display needs to be greater than half the viewing distance. To get the full benefit of 4K, the diagonal size of the display needs to be about equal to the viewing distance.

This is all based on pixels per degree. A person with average visual acuity (20/20 vision) can see about 80 pixels per degree. A display with fewer pixels per degree will be bad as you'll be able to distinguish the individual pixels, while a display with more pixels per degree is also bad as you won't be able to see all the detail. Pixels per degree depends on three things: Resolution, screen size, and viewing distance.

To better understand this, let's use a 60" TV as an example. Starting with the lowest resolution, 480p, you would see 80 pixels per degree at 23.3 feet away. At this distance, any resolution higher than 480p would look no better. However, if you were to move closer, you would start to be able to distinguish the individual pixels of a 480p image, and it would look worse and worse as you got closer, while higher resolutions would look better and better.

When you reach 17.8 feet from the TV, you would now be able to see all the detail in a 720p image - you would be seeing 80 pixels per degree. However, 1080p and anything higher would still look the same as 720p. Continue to move closer and you'll start to be able to distinguish the pixels of a 720p image and it will start to look worse and worse. Higher resolutions will still continue to look better and better.

When you reach 10.3 feet away, you'll be seeing the full benefit of 1080p at 80 pixels per degree, but higher resolutions such as 4K will still look the same as 1080p. Note that the viewing distance in this case is 123 inches, almost exactly twice the screen size of 60 inches.

And, likewise, if you get even closer, 1080p will start to look bad. 4K would still look better and better, until you get to just 4.9 feet away (that's 58.7 inches). That's almost the same as the screen size of 60 inches.

So, basically, in order to get any benefit from 4K, you need a bigger screen and/or you need to sit closer. If you have a huge projection screen, say 170", you would get the full benefit of a 4K projector at 13.9 feet, and the full benefit of 1080p at 33.3 feet.

The calculator I used for all this can be found here. All calculations were made for a 16:9 screen, with 3840x2160 for 4K resolution.

[ADWyatt]

I very much appreciate the time and work you've devoted to state your case, and its reasoning is well worth thinking about.

Unfortunately my eyes, like their owner, are mathematically challenged; they only know what they know. Almost on a daily basis I look at 4k TVs at stores like Best Buy and Wal-Mart, and it's as normal as rain for me to stand 20 feet away from a 55" 4k TV and see a 4k picture, shot from a 4k camera, that is significantly superior to the best that 1080p has to offer. From that distance, I may not get the full benefit of 4k, but it shines compared to HD.

As a test, I've watched 65" 4k TVs from 12 feet away, which will be my seating distance when I buy a 4k TV in April, and the effect is even more dazzling. And for the record, as an objectivist I will never believe in the King's new clothes.

All of this is really moot, though. Perhaps as early as 2018 all TVs sold will be UHD, probably using the 4k format. But again, I'm grateful for the work you put in to emphasize your point of view.

[Penton-Man]

Originally Posted by Dusso Janladde

A person with average visual acuity (20/20 vision) can see

average V.A. is better than ‘20/20’

How do I know this? Well for one thing, for the same reason, if queried, I can tell you the name of the tech at the beginning of the clip helping the patient enter the room loaded with retina diagnostic devices and the name of the surgeon behind the mask (and microscope) actually applying the implant (not Mark, although he is one of the geniuses and tireless professionals and teachers behind the development of the device)...

Seeing is Believing: USC Eye Institute's retinal prosthesis gives blind woman the gift of sight - YouTube

[DavePS3]

The numbers only tell half the story to me. Samsungs upconversion is better than the panasonics and its the processing that makes the difference. Sonys is pretty good too and im talking about regular sources like cable. See, this is like high rez computer monitors. Do you have to be following the numbers in order to see the difference? Of course not. The higher pixel count, added shdes of color and finer detail is apparent as soon as you can see an image.

4k will be akin to 1080p in that there will be top of the line processing down to the bottom of the line basic crappy panels that fit a lower budget. I have 4 year old top of the line plasma but id trade it in a heartbeat for the 9000 series 4k. Like 3d, theyre not expecting everyone to junk their 1080p panels and buy 4k, rather they are available to those who are buying now and down the road.

I sell all 3 of the brands mentioned above. 50" to 85" in 4k and while they all look great on 4k material, its the upconversion processing that sets them apart. Its not just about numbers and theory, you need to see them for yourselves when you ARE ready to huy a new set.

[Dusso Janladde]

Originally Posted by ADWyatt

Unfortunately my eyes, like their owner, are mathematically challenged; they only know what they know. Almost on a daily basis I look at 4k TVs at stores like Best Buy and Wal-Mart, and it's as normal as rain for me to stand 20 feet away from a 55" 4k TV and see a 4k picture, shot from a 4k camera, that is significantly superior to the best that 1080p has to offer. From that distance, I may not get the full benefit of 4k, but it shines compared to HD.

If your eyes are good enough (20/10) you should aim for 120 pixels per degree. In this case the ideal viewing distance for a 55" 4K TV would be 7 feet.

[ADWyatt]

Dusso, there will be people who want the very best display quality that 4k can deliver, and so your article is quite valuable and timely. But I'd like to take this subject a little farther, if I may, and touch on two other related subjects.

First, there will be people who cannot or will not sit within the zone of optimal visual quality for 4k. (I suspect this comprises most Home Theater enthusiasts.) Determining the value of 4k quality then becomes subjective, and the carefully-crafted math figures can be sent straight to the paper shredder. What a customer would need to do in that case is find a 4k TV on display that is the size he's going to buy, and then sit or stand at the same distance he would at home for what he feels is a reasonable period of time watching true 4k material. With that, he could decide whether or not to invest in 4k.

Unfortunately, as of this writing such testing may be handicapped, and that brings me to the second subject. From what I've read from several sources, manufacturers are apparently going to include the best visual enhancements in their 4k models, and pretty much ignore 1080p TV. These enhancements may include 10-bit color, High Dynamic Range and macro-dot technology. If my thinking is correct on this, it means that most of us haven't yet seen the best picture that 4k can deliver, and so our judgment may be skewed.

Your article, which I believe was only written with the intent of showing all of us how to get the best from a 4k display, I think can be used along side my reasoning to help potential customers determine if buying into 4k is justified.

[Auditor55]

4K TV was simply a misguided idea. Basically useless for the home market. If you need an 85 inch TV, which is simply impractical for 90% of the market, why bother, what's the true benefit to the end user/consumer.

I think 4K is a good idea for the front projection market, where rooms are set up particularly for large size viewing. If I had that situation, I would be excited about 4K.

However, for the TV market, OLED should have been the progression and not high res LED, I'm disappointed. I would like to see more OLED (all sizes) and less big LED/LCD 4K sets that offer no real benefit to the vast majority of the global tv buying public.

[Auditor55]

Originally Posted by Dusso Janladde

If your eyes are good enough (20/10) you should aim for 120 pixels per degree. In this case the ideal viewing distance for a 55" 4K TV would be 7 feet.

"Only about 35 percent of all adults have 20/20 vision without glasses, contact lenses or corrective surgery. With corrective measures, approximately 75 percent of adults have this degree of visual acuity while the other 25 percent of the population just doesn't see very well, Dr. Johnson says."http://www.uihealthcare.org/content.aspx?id=225702

If the above is the case, what percentage of adults have 20/10 vision? Again, what is the purpose of 4K TV other than to remove money from your pocket?

[ADWyatt]

Auditor55, you're asking what the purpose of 4k is, other than to remove money from our pockets. Well of course, your reasoning is exactly correct. 4k is a gimmick. But with that in mind, I will ask you to show me even one form of entertainment that has ever existed that was not a gimmick. And please feel free to go back to cave painting days, tens of thousands of years ago.

Regarding filmed or televised media, since the creation of moving pictures every new innovation has been at heart a device created to make money. If there's anything wrong with that, I have no idea what it may be.

Look, if 4k is a cheap gimmick that can't hold up in the long run, the buying public isn't going to accept it; you just can't fool all the people all the time. I've tested 4k probably more than most people, and I've found it to be a gimmick I want. Is it worth the money? To me it is. Somebody's going to make a nice chunk of money selling me a 4k TV this year, and I accept that. In return, I get a form of entertainment that I really want. With that in mind, I would tell developers to keep rolling out the gimmicks in their search for ever-greater profits. Some I'll buy into, some I won't. But it's always nice to see what's coming down the pike.

[AudioWarrior]

People with 80"+ TV's and projectors will benefit. I plan on getting no less then a 80" 4k TV to make sure I take full advantage of the extra resolution. The TV I'm currently eying is Sharp's beyond 4k "pseudo 8k" TV. If true 8k TV's don't come out by next Holiday season, then that's what I may end up getting. Gaming performance will also dictate which TV I get.

[Brian81]

Originally Posted by Dusso Janladde

Before I explain the math behind it, I'll sum it up:

Measure your viewing distance in inches. To get any benefit from a 4K display, the diagonal size of the display needs to be greater than half the viewing distance. To get the full benefit of 4K, the diagonal size of the display needs to be about equal to the viewing distance.

This is all based on pixels per degree. A person with average visual acuity (20/20 vision) can see about 80 pixels per degree. A display with fewer pixels per degree will be bad as you'll be able to distinguish the individual pixels, while a display with more pixels per degree is also bad as you won't be able to see all the detail. Pixels per degree depends on three things: Resolution, screen size, and viewing distance.

To better understand this, let's use a 60" TV as an example. Starting with the lowest resolution, 480p, you would see 80 pixels per degree at 23.3 feet away. At this distance, any resolution higher than 480p would look no better. However, if you were to move closer, you would start to be able to distinguish the individual pixels of a 480p image, and it would look worse and worse as you got closer, while higher resolutions would look better and better.

When you reach 17.8 feet from the TV, you would now be able to see all the detail in a 720p image - you would be seeing 80 pixels per degree. However, 1080p and anything higher would still look the same as 720p. Continue to move closer and you'll start to be able to distinguish the pixels of a 720p image and it will start to look worse and worse. Higher resolutions will still continue to look better and better.

When you reach 10.3 feet away, you'll be seeing the full benefit of 1080p at 80 pixels per degree, but higher resolutions such as 4K will still look the same as 1080p. Note that the viewing distance in this case is 123 inches, almost exactly twice the screen size of 60 inches.

And, likewise, if you get even closer, 1080p will start to look bad. 4K would still look better and better, until you get to just 4.9 feet away (that's 58.7 inches). That's almost the same as the screen size of 60 inches.

So, basically, in order to get any benefit from 4K, you need a bigger screen and/or you need to sit closer. If you have a huge projection screen, say 170", you would get the full benefit of a 4K projector at 13.9 feet, and the full benefit of 1080p at 33.3 feet.

The calculator I used for all this can be found here. All calculations were made for a 16:9 screen, with 3840x2160 for 4K resolution.

Your numbers have got to be way off. I can see individual pixels on a 130" screen sitting 8 feet away, and this is wearing glasses with a 3 year old prescription. For a 60" set @ 10.3 ft, I'd imagine the difference would be close between 720p and 1080p, and not fully taking advantage of the capability of 1080p resolution.

[Dusso Janladde]

Originally Posted by ADWyatt

First, there will be people who cannot or will not sit within the zone of optimal visual quality for 4k. (I suspect this comprises most Home Theater enthusiasts.) Determining the value of 4k quality then becomes subjective, and the carefully-crafted math figures can be sent straight to the paper shredder. What a customer would need to do in that case is find a 4k TV on display that is the size he's going to buy, and then sit or stand at the same distance he would at home for what he feels is a reasonable period of time watching true 4k material. With that, he could decide whether or not to invest in 4k.

The only way to do this test properly would be to view a 1080p and 4K TV side-by-side, both as similar as possible to each other, using equivalent settings and both showing native resolution content. Basically, the resolution needs to be the only difference.

If you are farther than a certain distance from these screens, they will both look identical. As you get closer, you will reach a point where the 1080p TV starts to look worse (you'll begin to be able to distinguish the pixels) while the 4K TV will continue to look better. This distance will vary from person to person, but if your home viewing distance is longer than this (assuming these TVs are the same size as yours) you will get no benefit from a 4K TV.

[ADWyatt]

Of course, you're exactly correct in your response. The big question is...What's the maximum distance one would sit from a 4k display so that it would still look impressive enough, compared to 1080p, to invest several thousand dollars in?

And naturally, you're also right when you state that a potential buyer should compare resolution differences between the two display formats in a store setting, if it's at all possible. I was fortunate enough to be able to do this in both a Best Buy and Sears environment, and I am now convinced that, on detail alone, viewing actual 4k material on a 65" 4k TV from 12 feet away provides an impressive enough picture for me to invest in the technology. But someone else might decide differently, as entertainment is always subjective.

However, at the risk of sounding redundant, I would again like to impress on you that 4k, presented by the best 4k TVs and using a 4k Blu-ray player, will provide a visual experience that is superior to 1080p quite apart from detail. This will be in terms of color gamut and extended dynamic range, and these enhancements are not to be taken lightly.

Nor, I'm afraid, will the price that will probably be required to get the best. I will have $4,500 to invest in a 4k TV this year, but I can't help getting an uncomfortable feeling that this will require compromising on my choice of a 4k TV.

[steve1971]

Originally Posted by Auditor55

4K TV was simply a misguided idea. Basically useless for the home market. If you need an 85 inch TV, which is simply impractical for 90% of the market, why bother, what's the true benefit to the end user/consumer.

I think 4K is a good idea for the front projection market, where rooms are set up particularly for large size viewing. If I had that situation, I would be excited about 4K.

However, for the TV market, OLED should have been the progression and not high res LED, I'm disappointed. I would like to see more OLED (all sizes) and less big LED/LCD 4K sets that offer no real benefit to the vast majority of the global tv buying public.

Well said Auditor55. But be careful you might upset the people that are falling all over themselves over the glory that is 4K. Dont get me wrong I dont hate 4K but I dont see the point in it unless you have a big tv or projector to see the difference. I dont want more pixels but better Contrast, Black Levels ect and OLED could give me that. But OLED seems to have been put on the back burner for 4K. What a shame if you ask me.

[Dusso Janladde]

Originally Posted by ADWyatt

However, at the risk of sounding redundant, I would again like to impress on you that 4k, presented by the best 4k TVs and using a 4k Blu-ray player, will provide a visual experience that is superior to 1080p quite apart from detail. This will be in terms of color gamut and extended dynamic range, and these enhancements are not to be taken lightly.

There is no reason those same enhancements couldn't be present on a 1080p TV. When I say to compare equivalent 1080p and 4K TVs, I mean TVs that are identical apart from the resolution.

[ADWyatt]

I understand what you're saying, and in theory you're quite right. It is entirely possible that I may have misinterpreted a report I'd read some time ago regarding 4k development, or conditions may have changed, but here's the gist of what I've read...

Developers are going to put the latest visual enhancements, such as HDR and 10-bit color, only in upcoming 4k TVs, and they are going to bypass 1080p sets completely. I don't know if that's true, and I'm afraid I can't pinpoint where I read that, but it would seem to make sense to me.

If indeed there is little discernible detail difference between 4k and 1080p at what many people might feel is a comfortable viewing distance, then manufacturers would need to find other means to separate the two technologies. For the sake of profit, it just naturally follows that all future enhancements would be put into 4k TVs.

If my line of reasoning is correct, the big question becomes this: Will the enhancements given to 4k exclusively merit the purchase of one of these sets? That, of course, is a purely subjective decision.

And considering this subjectively, my own experiences have convinced me that a 65" 4k TV viewed from 12 feet away provides an impressively more detailed picture than 1080p. And since I haven't yet seen HDR or 10-bit color, I can only wonder how much better the viewing experience is going to be when the best 4k models are released this spring. However, many other people may see 4k as nonsense, and not worth the price.

I have to wonder, though, how many of these naysayers also saw 1080p as nonsense, being perfectly content with DVD quality. Along that line, it may be for no small reason that the FCC in America mandated that 1080i broadcasting had to be implemented by a certain date, and did not allow the public a vote in the matter. Sometimes progress has to drag people along with it.

[steve1971]

Originally Posted by Dusso Janladde

There is no reason those same enhancements couldn't be present on a 1080p TV. When I say to compare equivalent 1080p and 4K TVs, I mean TVs that are identical apart from the resolution.

I agree with you Dusso. It might seem funny to some for what I am about to say but I will put my Sony 55w900a up against any 4K tv that is out there right now and it will look just as good as they do PQ wise. I have always said that to really enjoy the benefits of 4K you need a set that is 65inch or larger or go the projection route. Anything smalled then you will see no difference and I aint the only one who has said that. Tom Norton over at Sound And Vision Magazine has said it and so has David Katzmaier over at Cnet. Alot of people are being led to believe that 4K tv's are different then a 1080p tv and in truth they arent. The only real difference between the two technologies is the pixel count. It was just like back in the day when LED tv's first hit the scene. Alot of people were led to believe they were a brand new tv when again in truth they were the same as a CCFL tv and only the backlighting had changed. But that being said everyone see's things differently and to some 4K is the best thing out there and nothing will match it and thats perfectly fine. 4K is a beautiful thing but for me I will stick with what I have because Im perfectly happy with it and I know that I still have one of the best 1080p sets made by Sony. The only thing I'm looking for is a Blu ray player that is dependable and works for more then a month but thats a whole other story. .

[ZoetMB]

Originally Posted by Dusso Janladde

The calculator I used for all this can be found here. All calculations were made for a 16:9 screen, with 3840x2160 for 4K resolution.

I'm not buying it because the calculator you used is intended to do just the opposite of your intention. It's not to calculate whether a given screen size and distance will provide a perceivable benefit in 4K -- it's to calculate whether you'll still be able to detect aliasing at a given resolution and screen size. So by their calculation, you get a better picture (less perceived aliasing) by moving farther away from the screen. You can see this by setting the resolution and picture size and then decreasing/increasing the distance from the screen. Increasing the distance from the screen in that calculator increases the visual acuity and reduces the need for anti-aliasing. But it may also reduce the perceived benefit of a 4K display.

Besides, in the final 4K standards, there is going to be a major increase in color depth. That will probably increase the perceived quality of a picture more than the resolution increase. So it's silly to talk about 4K only in terms of resolution. As I understand your claim, you believe if you sit 8 feet from a 4K screen, you would need a 96" display. While my experience has been that only in terms of resolution on the early 4K sets, you can't see a difference from 8 feet on a 55" display, the resolution benefit is most definitely perceivable with a less than 96" display.

[Auditor55]

Originally Posted by ZoetMB

I'm not buying it because the calculator you used is intended to do just the opposite of your intention. It's not to calculate whether a given screen size and distance will provide a perceivable benefit in 4K -- it's to calculate whether you'll still be able to detect aliasing at a given resolution and screen size. So by their calculation, you get a better picture (less perceived aliasing) by moving farther away from the screen. You can see this by setting the resolution and picture size and then decreasing/increasing the distance from the screen. Increasing the distance from the screen in that calculator increases the visual acuity and reduces the need for anti-aliasing. But it may also reduce the perceived benefit of a 4K display.

Besides, in the final 4K standards, there is going to be a major increase in color depth. That will probably increase the perceived quality of a picture more than the resolution increase. So it's silly to talk about 4K only in terms of resolution. As I understand your claim, you believe if you sit 8 feet from a 4K screen, you would need a 96" display. While my experience has been that only in terms of resolution on the early 4K sets, you can't see a difference from 8 feet on a 55" display, the resolution benefit is most definitely perceivable with a less than 96" display.

For those of you still caught up on resolution as the determining fact in display quality, do as side by side comparison of a 1080p OLED vs a 4K LED and then you will understand.

[dobyblue]

Originally Posted by Dusso Janladde

There is no reason those same enhancements couldn't be present on a 1080p TV. When I say to compare equivalent 1080p and 4K TVs, I mean TVs that are identical apart from the resolution.

So less that 0.1% of TVs most likely?

Originally Posted by Auditor55

For those of you still caught up on resolution as the determining fact in display quality

But one of those people...is you!

Originally Posted by Auditor55

4K TV was simply a misguided idea. Basically useless for the home market. If you need an 85 inch TV, which is simply impractical for 90% of the market, why bother, what's the true benefit to the end user/consumer.

You've concluded it's useless based solely on resolution.