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4K vs HD TV


11 Jan 2016 3:55PM
My son has bought himself a 48" 4K TV and wanted to see how good a 4K picture is.

I produced two similar images for him, from the same ORF file.

1: 3840 x 2160

2: 1920 x 1080

Studying them very closely, at a couple of feet from the screen, the difference in small detail, can be seen. However, back at normal viewing distance, the images look virtually the same.

Has anyone else tried this ?
ChrisV 14 2.3k 26 United Kingdom
11 Jan 2016 5:16PM
Yes and that's why there's a law of diminishing returns on this sort of thing. It's the thinking behind the concept of the 'retina' display [as Apple brands its high resolution stuff]. There is some sort of algorithm which is resolution/viewing distance/level of details the average human eye can discern. Essentially the further away you get from an image, the less detail the eye can discern until I suppose you cover the entire field of view.

UHD is pushing on those limits - SUHD [32k] probably surpasses them by a fair bit. The only way that is going to be of use is for something totally immersive, so that the screen occupies your vision, including the periphery [where you can only detect detail in a very vague sense anyway - colour/shape/movement - that sort of thing. That and getting up really close to examine small portions of the picture.

It's estimated that even up close, most people can't see more detail than there is at 300ppi - displays that are higher than that may be of benefit in terms of dynamic range, colour saturation and so on, but the detail itself is pretty much redundant.

At the distances you're going to watch TV in the traditional sense, you'd need a really massive screen to get much more out of 4k than 1080p.

PS... It's very pertinent to my work because I'm a graphic designer. If you want a practical demonstration of the effect, next time you see a big billboard you like the look of, [I've done them with images I've shot myself on a 21Mp 5DII], remember how astonishingly low the resolution is when you're looking at something which is maybe 18 foot across. They work fine because unless you get up closer than the normal viewing distance, you're getting just about as much detail as your eye can take in.
User_Removed 6 1.0k United Kingdom
11 Jan 2016 6:17PM
I don't want to upset people but 4K is out and 8k and OLED, glad I don't try to keep up, all I do is watch the news

I have 50" plain HDTV but surely there is no point in 4k 8k etc if transmissions are not made in that format.

ChrisV Plus is 100% on his detailed analysis

I also wondered why my 100Hz tv only showed 50Hz, according to Panasonic it is the transmission not the TV
Dave_Canon 15 2.0k United Kingdom
11 Jan 2016 7:28PM
When I bought a new TV recently, I notice that Which? suggested that you will need at least a 60 inch screen to notice the difference between 4k and HD,

Dave
StrayCat 17 19.1k 3 Canada
11 Jan 2016 7:30PM
4K TV prices have come down drastically, not much more than a regular HD TV really. Haven't seen any 8K TVs or monitors about, but then, I haven't looked. I'm considering a 4 K monitor, but honestly, I'm happy with my 1080P videos. I don't know of anywhere to show 4K, let alone 8K; and let's face it, there aren't many free outlets of any quality for 1080p. I honestly don't think 4K is going to become the standard for a long time yet, for broadcast TV I mean.
11 Jan 2016 7:41PM

Quote:Studying them very closely, at a couple of feet from the screen, the difference in small detail, can be seen. However, back at normal viewing distance, the images look virtually the same.


Oh dear...that's blown it...

expect a call in the early hours from the "You must conform to the latest technical hype, must have product" police..
dcash29 16 2.4k England
11 Jan 2016 7:48PM
When I looked at an HD TV the picture quality was poor when you viewed non HD. Is this the same with 4K?
Chris_L 7 5.5k United Kingdom
11 Jan 2016 8:33PM
I've got a large photograph here, printed at 300ppi

It looks way more detailed than the TV next to it, which is a 1080p HDTV. I see no reason that a new TV with the same pixel density as the photograph shouldn't also look more detailed.

if I look out of the window there are trees and cars and people, further away than the TV, they are higher resolution than my TV screen and I can tell.

I'm quite happy to risk a more detailed TV screen.
ChrisV 14 2.3k 26 United Kingdom
12 Jan 2016 1:50AM

Quote:I've got a large photograph here, printed at 300ppi

It looks way more detailed than the TV next to it, which is a 1080p HDTV. I see no reason that a new TV with the same pixel density as the photograph shouldn't also look more detailed.

if I look out of the window there are trees and cars and people, further away than the TV, they are higher resolution than my TV screen and I can tell.

I'm quite happy to risk a more detailed TV screen.



Have you noticed they're also in 3D, have the richest blacks you've ever seen along with the greatest colour and dynamic range?

Funnily enough, if you took 34.7 thousand (yeah that's a number I've just made up) 27 gigapixel images of outside, stuck them all together and put them 30 yards away outside, you still wouldn't see any additional detail. You might see the joins.

Seriously, if you view a screen more than 10 foot away, you're probably not going to notice pixel density any greater than 90ppi - and probably considerably less. Get in a lot closer (people look at art books often within a few inches) and you'll see a lot more.

Obviously above I was talking about 32Mp when I said 32k (that's actually 8k). I can see a use for recording at that level - you'd get excellent stills pulled from it with room to crop too. But for video even massive screens aren't going to benefit that much unless you want total immersion or to go in close to examine detail -something you'd rarely do with a moving image - but perhaps we will alter the way we view things? I can't think there would be many applications for that sort of facility, but you never know - perhaps future viewing may be in a wraparound box...
keithh 17 25.8k 33 Wallis And Futuna
12 Jan 2016 8:03AM
And yet in the real world a UHD movie running at the side of a HD one on identically sized screens just looks better. Add HDR and it looks better still.

As for 8k. .....give it another 5 years minimum.
sausage Plus
17 704 United Kingdom
12 Jan 2016 9:02AM

Quote:When I looked at an HD TV the picture quality was poor when you viewed non HD. Is this the same with 4K?


No it's not. There was a big difference with HD and SD images - colour, dynamic range etc. But HD to UHD not a lot - that we can discern anyway!
ChrisV 14 2.3k 26 United Kingdom
12 Jan 2016 11:49AM
I've got a 4k TV btw - and it is good for viewing still images up close. It does handle HD content really well and of course there's a benefit to the smart menus in that text is rendered more smoothly - but you really do need to be up fairly close to see that. UHD screens may typically have better dynamic range and from a distance you would see that - what you wouldn't see [from a normal viewing distance] is any more detail.

SD looks pretty bad though and I think the clarity of the screen does actually help to highlight the shortcomings of old material. It's surprising how poor the DVD copy of The Wire [which is also filmed in 4:3] looks. It's probably no worse than it would appear on any screen of a similar size, but it suffers by comparison with modern material.
StrayCat 17 19.1k 3 Canada
12 Jan 2016 6:47PM
I bet the BBC documentary series on nature would look good using Blu Ray. Although it would be hard to beat 1080p viewed from a little less than 20 feet, and a 55" screen.
Chris_L 7 5.5k United Kingdom
12 Jan 2016 11:37PM
HBO are meant to be remastering The Wire in HD. Don't know if they have original high quality sources such as film or if they are upscaling.

The 4k tvs may look better because everything about them is newer not just the higher resolution?

Here's the thing, I look at 1080 on my laptop v 1080 on my TV. Laptop is sharper and punchier because those pixels are smaller or closer together or both. So if I were to join up four laptop screens in a square, two up and two down, I'd have a big highly detailed TV. Like one of em 4k ones.

I won't be happy until I have a TV set where if I look at curtains, wallpaper or ornaments on the screen they look as detailed as the curtains, wallpaper or ornaments physically in the room to the side of the TV.
ChrisV 14 2.3k 26 United Kingdom
13 Jan 2016 11:22AM

Quote:HBO are meant to be remastering The Wire in HD. Don't know if they have original high quality sources such as film or if they are upscaling.


I'm only just starting on season 2 - a mate at work has lent me them. There's so much good stuff I haven't seen [I've never watched The Sopranos for example, but in spite of the poor video quality it's still great stuff.


Quote:The 4k tvs may look better because everything about them is newer not just the higher resolution?


I think that's at least part of it - contrast seems to be getting better along with dynamic range. It would be interesting to see a top of the line HD vs a relatively modest 4k and see how they stack up side by side at a normal viewing distance.


Quote:Here's the thing, I look at 1080 on my laptop v 1080 on my TV. Laptop is sharper and punchier because those pixels are smaller or closer together or both. So if I were to join up four laptop screens in a square, two up and two down, I'd have a big highly detailed TV. Like one of em 4k ones.


That's perfectly true - I've got a retina macbook and also an iPad mini retina [the resolution of the latter stacks at 326ppi]. They are both sharper than my LG 4k TV because the pixel density is greater. But the key thing here is I'll look at those screens [especially the tablet] really close up - and no matter how close I get, I can't see the individual pixels. That means if the pixel density was further increased, I still wouldn't be able to see any additional detail because it's already gone beyond my ocular acuity. It might seem fairly obvious, but the further away you get from an artificial image, the less able you are to see the individual picture elements that make up that image.

Fine art books reproduce images typically with a 150lpi screen and printers usually ask that images are submitted at a minimum of 300ppi [you get more than 150 lines of resolution because there are four separate plates]. For most people that means the dots that make up the image have effectively disappeared - and the only way you would see them is to look through a loupe. As no one is going to do that except for technical purposes, it's pretty pointless reproducing with finer screens [there are also technical limitations, not least with dot gain, which is why the media printed to is also important at higher resolutions].


Quote:I won't be happy until I have a TV set where if I look at curtains, wallpaper or ornaments on the screen they look as detailed as the curtains, wallpaper or ornaments physically in the room to the side of the TV.


There's a lot to unpack with that statement. If you took a shot of your wallpaper and curtains with studio lighting and then viewed your image on screen in poor ambient light, you should of course see a lot more detail in the image than you will of the actual objects themselves in gloomy conditions. Similarly you could arguably get a perception of seeing more detail if you gave your image the HDR treatment. It is possible to reproduce the 'hyper-real' with these tricks or as suggested above, by using ideal lighting conditions. This is of course to some degree an optical illusion because there can never be more detail in a simulation of an object than the object itself [unless of course you add additional detail in which case it's no longer a representation of the thing itself].

So the long and short of it is that there are lots of ways to improve reproduction and resolution is only one of them. Unlike some of those other things there does seem to be a ceiling to the gains that can be made by upping screen resolution [given a correlation with viewing distance]. We're at the happy state where our technology is butting against that now - further advances would present themselves as something of a parallel to the 'megapixel wars' in digital cameras now [at least to the educated] largely discredited.

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