As blogger excitement reaches a fever pitch over the iPhone 4 — now
available for pre-order, if
you can get the website to work — confusion and rage are also
running wild. Why? Because of Steve Jobs’ claim that the iPhone 4’s new
"Retina" display offers higher resolution than the human eye does.
The mathapalooza began a few days ago when PC
World interviewed Raymond Soneira, who has a PhD in theoretical
physics and runs a firm that makes high-end software to test computer
displays. Soneira explained that it’s hard to test Jobs’ claims because
we see pixels only when we’re close enough to the screen. Sit 20 feet
away from your laptop or TV and no one can see the pixels — so at 20
feet, it is "better" than your eye. But sit 6 inches away and you’ll
certainly see them — so at 6 inches, it is not. "Better" is subjective
and dependent on distance.
And that’s the mystery of the iPhone
4: Jobs said that at a foot, the 326 pixels per inch that the phone
offers are better than the eye can parse. Soneira said that’s not the
case: At 12 inches, based on the "angular measurement" of how the eye
actually works (click PC
World's story for the full math, if you dare), the eye can really
manage 477 pixels per inch. Not until you’re 18 inches away from the
screen will the pixels entirely disappear.
Case closed? Not
quite. The folks at Discover
magazine busted out their protractors and reached a different
conclusion, that Jobs was right. How so? Because, as Discover notes, the
numbers used by Soneira assume you have perfect vision. Discover knocked the
estimates down considerably, saying that if you have "typical" vision,
you will not see pixels on the iPhone 4 when held 12 inches from your
face.
End of discussion? Certainly not. I pay a lot of money to
my optometrist to ensure I have near-perfect vision, but the quality of
glasses prescriptions, like eyes themselves, will vary widely. Even the
definition of "perfect" is subjective, as any Lasik enthusiast can tell
you. The bottom line is that some people are going to see the pixels on
the new iPhone,
and some are not. I also doubt that users will be holding rulers next
to their faces as they look at their cell phones' screen (although I
know I will, just to see) to hold Jobs to his word.
And what if,
in the end, he’s lying after all? Well, it’s not like anyone’s going to
throw lye in his eyes for his transgression.