Cut the chase – back to reality
Here is a visual size comparison between the approximate individual pixel sizes we would expect from modern panels, ranging from the 11″ in a MacBook Air, to 24″ and 27″ desktop monitors and finally a large screen TV.
In numbers, the above diagram would look something like the following table:
Looking at the above table, we realize that the PPI between the available monitors varies a big deal. But just like with prints, aiming for 300 ppi/dpi is not a realistic expectation as far as today’s hardware goes, but that is actually OK.
We are far closer to “perfection” than we think.
By solving the visual acuity’s “magic formula” you saw above, we could actually calculate the approximate “optimal distance” for viewing each panel. And I should specify the term “optimal”:
Optimal Distance: The distance from the panel, after which it will be nearly impossible for a person with “clinically” perfect vision to distinguish between individual pixels.
What do the above numbers teach us?
- The “absolute ideal” 300ppi rule of thumb for large panel screens, just like with large format prints is a huge overstatement. Within reason, all available screens today can look nearly perfect – if you sit reasonably far from them! Of course for handheld devices, or magazines that we often hold up close, 300 ppi – or for some, even more – are a realistic expectation for a perfect looking screen, while future products like the iGlass and Project Glass from Google, will probably reach a much higher than 300 ppi resolution as those will be meant to sit a couple of inches at most from our retinas.
- Scaling up a panel, by which I mean maintaining pixel count and aspect ratio the same, we force ourselves to move further back in order to maintain the impression of a sharp image, and in fact the minimum viewing distance from the panel, maintains the same ratio to its diagonal.
- The 15″ rMBP screen, despite having 227ppi and more than 40% the pixels a 27″ 1440p panel packs, is in theory not that much superior sharpness in real life applications. Deriving from the visual acuity calculation, both panels similar image sharpness when we would position ourselves at 1.0~1.2x the screens diagonal or further. Something that feels perfectly natural due to the inherit viewing angles human eyes provide us. A 27″ 16:9 panel with just “2960 x 1665p”, would actually come close to the rMBP’s “perfect 1.0”.
The reality is, that the optimal viewing distance for most desktop and laptop monitors is not something we have complete control over, as other factors are prevailing: we are forced to position our monitors pretty close to us, usually within a few dozen in/cm regardless of having a 27″ or a 22″ – again due to minimal space limitations on our desktop surfaces, and/or hold our laptops on our laps, or when rested on a desk as close as we can while balancing visual and typing ergonomics.
From all the above, we can also see that opting for a screen panel that is bigger than 22-23″, while sticking to 1080p is actually a “bad” move. The pixels will be too big, and too easy to distinguish in typical viewing distances for a desktop monitor. Both gamers investing a lot of money for running their FSAA and textures @ ultra, and designers after a sharp, clean image, are literally shooting themselves in the foot, opting for a 1080p 27″ that was looking great behind the shop’s window (i.e. being far), which in reality will deliver both a far less sharp image than either much cheaper 22-24″ 1080p panels, or worse color clarity and viewing angles than closely priced 24″ 1200p IPS panels.
Page 5: Conclusion