Understanding Anti-Aliasing

[SvennoJ]

daveJ said:

SvennoJ said:

20/20 vision is the limit at which you can determine detail, or read text. You will not be able to read pixel font text at 100 cpd. Yet you can still tell a difference, which probably also has to do with the grid pattern of display pixels. 

its a common misconception, 20/20 vision is not perfect hell its not even good, its adequate to get a drivers license or so, most teenagers eyesight (if they dont ware lens) is 20/12. That is nearly twice as good as 20/20. Somehow over the years cause I assume that 20/20 equals 1/1 equals 100% that people have misunderstood it to mean perfect. I can easily see the difference between pixels on a iphone's retina display from more than 12" away  

I checked their retina claim once and came to this:
"The iPad 4 retina display needs to be viewed at a distance of 43.4" to make it a true retina display."
At that distance you see it at 100cpd.

For comparison a 1080p 40" set needs to be viewed from 17ft4" away to see it at 100cpd. That's the upper limit and anti aliasing becomes irrelevant.