Maximum human eye visual acuity and screen dpi *spawn
- Thread starter zed
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I'm afraid you can't, unless you have better than 20:10 vision and are looking at it from less than 2-3" away, or you are using a magnifier. The physics of the eye just doesn't allow it. You might be able to see some jaggies, like on the W of the on screen keyboard, but even that is iffy, and might be more the font design than the pixels. Try spotting the jaggies on the X, for instance. Note here I'm talking about the iPhone, the galaxy S3 with its pentile display may be a little different, especially since the green sub pixels are at half the dpi.
Do you have some data on how the physics of the eyes work?
aha, so youre talking about AA'd 2D graphics. I develop IOS stuff in 3d so have looked at it a lot, & with high contrasting things you can easily see the individual pixels.
edit - sorry had to go out
well I just tested. Turned on a 2d overlay in my game which draws debug info with lines and such, with 1 pixel width (no AA) & I could still see a single pixel at 35cm distance with one eye, prolly quite a bit greater with someone with 20/20 vision.
I can send an app if you dont believe me.
though do I enable AA in my game? No at 326ppi its not really necessary.
Actually that reminds me of arguments on these forums I used to have years ago over wether or not better resolution or better AA was more important. I was on the higher res camp, I betcha now we have these high resolution devices none of the higher AA > higher res guys still think this way
btw - this apple retina marketing thing (u cant see the pixels) is just pure PR BS pure and simple
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It is marketing, yes. But it's not BS. Here's a test: write an app (in 2D, pixel perfect, no scaling) that draws alternating 1px wide black and white lines. Then work out at how close it needs to be to look like individual lines and not just 50% grey. That's an absolute best case, since it's using the greatest possible contrast. At 20:20 vision, that change should happen at around 8-10" on the iphone. For anything lower contrast (say lines of 25% grey, 75% grey), it'll be even closer, or not discernible at all. Resolution is angular, so if you routinely hold your phone closer than 6-8" and you have 20:20 vision, then you will be able to resolve pixels if they are high enough contrast, otherwise there's very little chance. (If you write this app, make an ipad version and publish it, I have this conversation often enough that I would buy itaha, so youre talking about AA'd 2D graphics. I develop IOS stuff in 3d so have looked at it a lot, & with high contrasting things you can easily see the individual pixels.
edit - sorry had to go out
well I just tested. Turned on a 2d overlay in my game which draws debug info with lines and such, with 1 pixel width (no AA) & I could still see a single pixel at 35cm distance with one eye, prolly quite a bit greater with someone with 20/20 vision.
I can send an app if you dont believe me.
though do I enable AA in my game? No at 326ppi its not really necessary.
Actually that reminds me of arguments on these forums I used to have years ago over wether or not better resolution or better AA was more important. I was on the higher res camp, I betcha now we have these high resolution devices none of the higher AA > higher res guys still think this way
btw - this apple retina marketing thing (u cant see the pixels) is just pure PR BS pure and simple
)
It is marketing, yes. But it's not BS. Here's a test: write an app (in 2D, pixel perfect, no scaling) that draws alternating 1px wide black and white lines. Then work out at how close it needs to be to look like individual lines and not just 50% grey. That's an absolute best case, since it's using the greatest possible contrast. At 20:20 vision, that change should happen at around 8-10" on the iphone. For anything lower contrast (say lines of 25% grey, 75% grey), it'll be even closer, or not discernible at all. Resolution is angular, so if you routinely hold your phone closer than 6-8" and you have 20:20 vision, then you will be able to resolve pixels if they are high enough contrast, otherwise there's very little chance. (If you write this app, make an ipad version and publish it, I have this conversation often enough that I would buy it
I just thouht of something, but it might probably be stupid, but the math behind the resolution of a retina display, takes acount the horizontal/vertifcal width of pixels, or the diagonal? Because that could make a difference.
Indeed, and when they quote 326ppi, they're talking about the diagonal length. If the pixels are square, the horizontal or vertical ppi would be around 460.
Actually I just compared my 4S to a coworker's 5 and there's a very slight impression of raster lines on my phone's screen. You need to put it side by side with a 5 to really see it but the difference is there, even if it's literally a hair's width.
(((interference)))
Veteran
Actually, zed might have a point.
I took a screenshot of my iPhone 5 home screen and then edited it in Photoshop (on PC) to insert a white line a single pixel wide and also added a white pixel to the lower left corner of the Clock app icon.
If you save it to your phone and view full screen, and even from 2 feet away I can clearly see the line and can just make out the single pixel (though it is extremely faint).
But I am quite young and do have at least 20/20 vision, if not better (got my eyes tested a month ago).
So maybe the Retina displays on the iPhone aren't at resolution independence yet, but i'm sure the upcoming Sharp 1080p 5" displays, with 446 ppi will be for all intents and purposes.
I took a screenshot of my iPhone 5 home screen and then edited it in Photoshop (on PC) to insert a white line a single pixel wide and also added a white pixel to the lower left corner of the Clock app icon.
If you save it to your phone and view full screen, and even from 2 feet away I can clearly see the line and can just make out the single pixel (though it is extremely faint).
But I am quite young and do have at least 20/20 vision, if not better (got my eyes tested a month ago).
So maybe the Retina displays on the iPhone aren't at resolution independence yet, but i'm sure the upcoming Sharp 1080p 5" displays, with 446 ppi will be for all intents and purposes.
that is similar to what I had, though green & grey but still at ~35cm I could see the gap between the lines (only right eye since my left has an astigmatism, also after ~35cm my vision gets blurry)
from a google, try this
http://willmore.eu/retina/
on my retina 326 display Im still able to see at 35cm which are vertical/horizontal at the edges (horizontal easier must be some evolutionary trait)
(((interference)))
Veteran
That's strange, you're saying the iPhone 5 has better resolution than the 4S?
That shouldn't be, since the only difference resolution wise with the iPhone 5 display is the added pixels with the switch to 16:9 aspect ratio, besides that dpi remains identical at 326 ppi
http://www.displaymate.com/Smartphone_ShootOut_2.htm
A single line will always be discernible. Use the test in the post above and see at which point you can't tell the difference. A better test would be to randomize the circles, and have you choose which is horizontal. Otherwise you get confirmation bias, like in audio. On my iPad 3, it's at about 16" that I lose the ability to tell.Actually, zed might have a point.
I took a screenshot of my iPhone 5 home screen and then edited it in Photoshop (on PC) to insert a white line a single pixel wide and also added a white pixel to the lower left corner of the Clock app icon.
If you save it to your phone and view full screen, and even from 2 feet away I can clearly see the line and can just make out the single pixel (though it is extremely faint).
But I am quite young and do have at least 20/20 vision, if not better (got my eyes tested a month ago).
So maybe the Retina displays on the iPhone aren't at resolution independence yet, but i'm sure the upcoming Sharp 1080p 5" displays, with 446 ppi will be for all intents and purposes.
No, it's more like you can 'feel' the grid between the individual pixels somehow on the 4S. The pattern is only 'visible' on bright areas.
So the difference is more about the better quality and in particular the higher brightness of the 5's display, and not related to resolution.
Just found this image:
Ok, what I really wanted to know if you have any data that actually supports your statement about regarding the maximum resolution the human eye can see.
There isn't none as everyone is difference, I can see the difference between 720p and 1080p on a 50" TV from well over 20 feet away....
Yes there is. It's derived from the human anatomy of the eye, the density of the visual receptors, the optical characteristics of the lens and the pupil at different diameters. There'll be a degree of variation, and maybe even a few fringe mutations that increase rod or cone density in some individuals, but the generalisation of human visual acuity is well studied and documented. eg. : http://wolfcrow.com/blog/notes-by-dr-optoglass-the-resolution-of-the-human-eye/
2190 dpi at 4 inches for a young child taking visual acuity at 0.4 arc minutes, through to 300 dpi at 2.5 feet for 0.4 arc minutes acuity, or at 1 arc minute for the more conservative measure, 115 ppi.
http://www.cultofmac.com/173702/why-retina-isnt-enough-feature/
yes as shifty geezer writes
apple define retina as 1.0 arc minute, but its accepted that in reality its less than that
thus roughly 900 ppi
yes as shifty geezer writes
apple define retina as 1.0 arc minute, but its accepted that in reality its less than that
Apple did not make that definition, that is the definition of 20:20 visual acuity. 1 arc minute. The iphone pixels are ~0.5 arc minutes at 12" (a little smaller, actually). Perfect human vision has been recorded at about 0.6 arc minutes, and I'm sure some people have slightly better, but not by much.