4k resolution on smartphone/phablet screen: necessary or fool?

[luquinhas0021]

Recently, Sony announces the Xperia Z5 Premium, the world first smartphone with 4k display.
But... The maximum ppi that human being see at 35 cm is around 350 - 500. This smartphone has around 800 ppi. Hence, you will see nothing in 4k.

[Groucho2004]

Recently, Sony announces the Xperia Z5, the world first smartphone with 4k display.
But... The maximum ppi that human being see at 35 cm is around 400 - 500. This smartphone has around 700 ppi. Hence, you will see nothing in 4k.
People will still buy it. Good marketing people have a way of targeting the part of the brain furthest away from the area responsible for rational thinking.

Also, don't forget the need to brag: My phone's screen has 4K resolution - how big is your penis?

[SeeMoreDigital]

Recently, Sony announces the Xperia Z5, the world first smartphone with 4k display.

As far as I'm aware, the Xperia Z5's 5.2" display has a resolution of 1920x1080 pixels. It is supposed to offer "4K video recrding"...

[Groucho2004]

As far as I'm aware, the Xperia Z5's 5.2" display has a resolution of 1920x1080 pixels.
Hm, this (http://blogs.sonymobile.com/2015/10/01/xperia-z5-premium-your-4k-display-technology-questions-answered/) page says otherwise.

[SeeMoreDigital]

Hm, this (http://blogs.sonymobile.com/2015/10/01/xperia-z5-premium-your-4k-display-technology-questions-answered/) page says otherwise.
Indeed... Your link refers to the 'Xperia Z5 Premium'.

Sufficed to say, there's also a 'Xperia Z5 Dual', a 'Xperia Z5 Compact' and a 'Xperia Z5' ;)

[Sparktank]

4K resolution on a phone, sounds like upscaling and using exaggerated bitrates on your youtube videos to get actual 1080p details for your uploads.

Even if you were to stream or hookup to a 4K display, I would imagine existing 4K players would be more powerful to play 4K videos (and not to mention no worry about battery power drainage).

Recording in 4K would be handy for uploading to youtube so you get a decent 1080p out of it.

I think it's too early to jump aboard this train for mobiles.
Although we're heading into 4K territory with the future UHD-BD's, they're probably the only things that will be delivering BT.2020 for UHD resolution while things like Netflix and other UHD streaming is using BT.709 (while there are some TV's out there that are ready for BT.2020 and wider gamut).

My friend's LG TV can do BT.2020 and wider gamut in the settings but have not really tried any of it.
I have to check if his LG bluray player is ready for BT.2020.

My friend might like this if he was still into Sony. Not really for the 4K (he knows it's useless for a small screen), but just to record in the colorspace and playback on his TV that supporst the colorspace (although not a 4K TV).

[wonkey_monkey]

Recently, Sony announces the Xperia Z5, the world first smartphone with 4k display.
But... The maximum ppi that human being see at 35 cm is around 400 - 500. This smartphone has around 700 ppi. Hence, you will see nothing in 4k.

You won't "see nothing."

If it was an plain old 1080p screen, that'd be about 350 ppi - below what the human eye can see at 35cm, according to your figures.

This 4K screen puts it above that figure. Therefore - in simplistic terms, based on your numbers above - this will be a noticeable improvement.

Yes, by your numbers you might say that it's higher than necessary. But no-one's going to bring out a 3K screen for nitpickers!

Also, visual acuity is about more than just how many "pixels" you can distinguish.

[foxyshadis]

4K is practically necessary if you're using it for VR, where the phone is an inch or two from your eyes. In your hand, no point at all, but it's an easy bullet point in a spec race, the same way screen size was a few years ago. (Remember 7" phones?)

[Asmodian]

I understand the phone only displays 4K media in 4K, everything else including the OS is rendered in 1080p for performance/battery reasons.

I imagine that indicates that 4K is not needed for its normal use case.

[nevcairiel]

Yes, by your numbers you might say that it's higher than necessary. But no-one's going to bring out a 3K screen for nitpickers!.

Actually there have been mobile screens with resolutions between 1080p and full-blown 4K. Noone calls it 3K or anything, but things like 2560x1440 on 5-6" with > 500ppi are to be found on recent high-end phones.
According to those rules, that would seem to be a sweet spot then? :)

[huhn]

there is a good reason for this it's hard to spot dead pixel!

[feisty2]

Magnifying glass is the new best tool to check dead pixels :)

[Sharc]

Video seems to take the same route as audio where marketing also wants to make us believe that humans can hear "audio" frequencies up to the the MHz range.... :devil:

[feisty2]

Video seems to take the same route as audio where marketing also wants to make us believe that humans can hear "audio" frequencies up to the the MHz range.... :devil:

that's very different stuff
humans can't hear sound higher than 20khz under ANY CONDITION, with any equipment
images with higher resolution are still distinguishable to human vision on larger screens
edit: typo

[pandy]

Well, based on Nyquist i would expect PPI twice of human eye PPI however based on fact that eye PPI is not uniformly distributed then it may lead to extreme PPI on uniformly distributed displays.

In other words - i don't understand people wiling to see pixels - i don't wanna see pixels - i really glad to see lines, curves, smooth gradients etc - this means high PPI may have sense to loose digital nature of computer graphics.

Video seems to take the same route as audio where marketing also wants to make us believe that humans can hear "audio" frequencies up to the the MHz range.... :devil:

Perhaps some human can hear above 20kHz (me not - i perceive quite well up to 16kHz).

[pandy]

autocombine?

[luquinhas0021]

In other words - i don't understand people wiling to see pixels - i
don't wanna see pixels - i really glad to see lines, curves, smooth
gradients etc - this means high PPI may have sense to loose
digital nature of computer graphics.
Originally posted by Pandy

If we consider pixels are points that generates image edges and texture, we will know that, if a screen have a ppi that is bigger than we can see, at a distance x, in that screen size and ratio, we won't see all details that image shows.
Minimal separable angle is, in optometry, the minimal angle between extremes of really adjacent two dots (Dots in gray scale) we can distinguish how being two dots, in a surface of size x, ratio y and at distance z from person, at contrast c (c is p/100).
How low contrast is, high minimal separable angle is, at same other metric conditions.
If we treat about colors (Not grayscale), the minimal separable angle is bigger, and changes with each color, so, because the human eye see luma and chroma components separately and because the minimal separable angle doesn't change with each scale of greyscale, the use of greyscale's minimal separable angle in order to evaluate maximum visible ppi in screens is acceptable.
If you want know more, google "contrast sensibility function".

[pandy]

If we consider pixels are points that generates image edges and texture, we will know that, if a screen have a ppi that is bigger than we can see, at a distance x, in that screen size and ratio, we won't see all details that image shows.
Minimal separable angle is, in optometry, the minimal angle between extremes of really adjacent two dots (Dots in gray scale) we can distinguish how being two dots, in a surface of size x, ratio y and at distance z from person, at contrast c (c is p/100).
How low contrast is, high minimal separable angle is, at same other metric conditions.
If we treat about colors (Not grayscale), the minimal separable angle is bigger, and changes with each color, so, because the human eye see luma and chroma components separately and because the minimal separable angle doesn't change with each scale of greyscale, the use of greyscale's minimal separable angle in order to evaluate maximum visible ppi in screens is acceptable.
If you want know more, google "contrast sensibility function".

All that true but once again - all those special assumption prevent universal display to be universal - additionally with sufficiently high PPI you can consider bitdepth unnecessary (especially high bitdepth) = sufficiently oversampled binary will be perceived as grayscale.

[wonkey_monkey]

Minimal separable angle is, in optometry, the minimal angle between extremes of really adjacent two dots (Dots in gray scale) we can distinguish how being two dots, in a surface of size x, ratio y and at distance z from person, at contrast c (c is p/100).


That measure is not the be-all and end-all of measuring human vision. The human eye can, for example, detect aliasing of a near-vertical/horizontal line even when the pixels are much closer than the minimally separable angle.

[Sharc]

that's very different stuff
humans can't hear sound higher than 20khz under ANY CONDITION, with any equipment
images with higher resolution are still distinguishable to human vision on larger screens

Yeah, but the OP's question was about smartphones and phablets.

[Spades45]

1440p for phablets, 1080p for phones is plenty IMO. I'd rather have the battery life that comes with a lower res display -- it's not like you need a bunch of screen real estate on these devices.