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SvennoJ on 15 July 2020
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Pemalite said:
SvennoJ said:

20/20 vision is being able to distinguish 30 cycles per degree (at max contrast, it's lower for lower contrast) which is the same as 60 pixels per degree. 40 degree fov comes to 2400 pixels wide, thus 2560x1440p is more than enough for great immersion.

Most people sit more in the 20 to 30 degree fov range, 1200 to 1800 pixels width, 1080p is plenty for that. You do need descent anti aliasing since it's easy to pick up on (unwanted) patterns, aka pixel crawl and shimmer. However native 4K is not needed for great immersion.

Keep in mind that 20/20 vision isn't the maximum extent the human vision can go... You can have better than 20/20 and 30 cycles per degree.

I know, 40 to 50 cycles per degree is possible in younger people with the best visual acuity.

Which would be up to 4,000 pixels wide at 40 degree fov.
Yet at 20 degree fov 1080p is still sufficient.

I did all those calculations long ago

1080p
pixels per degree = (distance x 38.45) / diagonal
distance = (pixels per degree x diagonal) / 38.45
diagonal = (distance x 38.45) / pixels per degree

4K simply double the constant to 76.9 (pixels per degree is simply 2x cycles per degree)
720p the constant is 25.62, 1440p it's 51.24

So if you have the best possible young eyes, able to distinguish 50 cycles per degree and sit 6 feet away, your 4K tv needs to be 55" or smaller.
If you have normal good eyes (20/20) and sit 6 feet away, your 4K tv can be 92" diagonal. (anything smaller would be overkill)
If you're a regular person with 20/20 vision and sit 10 ft away, 1440p would be more than sufficient at screen sizes up to 102" diagonal.

My living room setup has me about 12ft away from the tv (eye distance), I'm 46 and wear glasses to correct to 20/20 vision.
1440p gives me 113 pixels per degree on my 65" tv, or 56 cycles per degree. No wonder I don't seen any difference between 1440p and 4K.
I do sit closer for racing, 6ft from the tv, 1440p still gives me 57 pixels per degree, just a few percent below 20/20 vision, enough for me to notice the actual difference between 1080p and GT Sports 1800p. From the couch, blu-ray or 4K streaming looks the same to me :/

To have benefits of native 4K you either need to have way better vision than most, a TV the size of a wall or sit right on top of a monitor.