Question Difference in blurriness between different native resolutions

[annihilation]

I have read that if you use a lower resolution on a larger screen there can be blurriness or low image quality as less pixels are spread over a screen. So as you go above 24 inch it is recommended you have higher resolutions than 1080p.

Is there a difference in blurriness on a native 1080p 27inch /30inch over running 1080p on a native 1440p 27inch/30inch ?

 

[Obakasama]

The factor you're missing there is the distance from the eye of the viewer to the display. This sounds like the sort of thing Apple tried to address with 'Retina' displays; there's an actual formula for calculating at what distance the human eye cannot detect individual pixels (at 20/20 vision, I believe).

You may find this of interest: https://en.wikipedia.org/wiki/Retina_display

 

[SkyNetRising]

Is there a difference in blurriness on a native 1080p 27inch /30inch over running 1080p on a native 1440p 27inch/30inch ?

Yes there is.
Using native resolution of the display is always gives sharper image than, if you upscale it from lower resolution.
This is most noticeable with text.

 

[annihilation]

The factor you're missing there is the distance from the eye of the viewer to the display. This sounds like the sort of thing Apple tried to address with 'Retina' displays; there's an actual formula for calculating at what distance the human eye cannot detect individual pixels (at 20/20 vision, I believe).

You may find this of interest: https://en.wikipedia.org/wiki/Retina_display

Thank you. Now suppose the distance is the same, does "native resolution" have any effect on this?
Example:
Viewing/Resolution set to 1080p on a native 1080p 27 inch display
Viewing/Resolution set to 1080p on a native 1440p 27 inch display
At the same distance?

 

[annihilation]

Yes there is.
Using native resolution of the display is always gives sharper image than, if you upscale it from lower resolution.
This is most noticeable with text.

But what if you are down-scaling? Then does native resolution matter?

 

[SkyNetRising]

Native resolution always matters. On lcd screens using anything other than native resolution causes blurriness and/or pixelation.

When upscaling color of the original pixel gets distributed over multiple neighboring target pixels.
When downscaling, color of multiple original pixels get squeezed into less target pixels (and information is lost because of this).

Basically you can get precise scaling only when upscaling to multiples of original (1:2 , 1:3, 1:4 ratio e.t.c.), for example:

1280 x 720 -> 2560 x 1440​

1920 x 1080 -> 3840 x 2160​

This results original single pixel to become 2x2 target pixels. But resulting image may seem pixelated. There are various techniques to smooth out the result and minimize pixelation effect, but all of them cause more or less blurriness.

 

[Obakasama]

The formula associated with 'Retina' displays is for native resolutions. What SkyNetRising says will hold as well as the pixels are no longer in a 1-to-1 correspondence (as it were).