Retina Display is designed to smooth the jagged edges of
pixels are provide a higher-quality image than previously available on mobile
devices. Apple claims that it's resolution is so good that it makes it
impossible to distinguish individual pixels. The effects of the display
technology are noticeable in many uses, but especially in text, where font
edges are curves are substantially smoother than on previous display
technologies.
Retina Display's image quality derives from a number of
factors:
A greater density
of the pixels that make up the iPhone's screen
Higher contrast
ratio than previous models for brighter whites and deeper blacks
In-Plane Switching
(IPS) technology to improve viewing angles
Chemically treated
glass over the screen and LED backlighting to improve the quality of the image
Resolution
The Retina Display, as used on the iPhone and iPod touch,
offers a resolution of 960 x 640 pixels. Since both devices have 3.5-inch
diagonal screens, this means they offer 326 pixels per inch.
It's this resolution--326 pixels per inch--that Apple claims
is the same as the human eye. The resolution was achieved on a relatively small
screen thanks to pixels that are just 78 micrometers wide, according to Apple.
Claims Disputed
Some experts disagree with Apple's claims that Retina
Display actually offers the same resolution as the human eye, pointing out that
the iPhone would need varying numbers of pixels per inch, depending on how
close it is to the eye, to mimic the human retina.
Steve Jobs first introduced the Retina Display when showing
off the iPhone 4. He explained it then as four times the amount of pixels in
the same amount of space. That’s what the key is right there, the amount of
pixels in how tight of a space.
To put it into number, the iPhone 3 comes with a 3.5 inches
screen and a screen resolution of 480 x 320. That is equivalent to 163 pixels
per inch (ppi). For the iPhone 4 and 4S, with the same 3.5 inches screen, the
screen resolution is now 960 x 640 ( 326ppi), double that of its predecessor.
As for the new iPad, the resolution is 2048 x 1536 on a 9.7 inches screen,
equivalent to 264 ppi.
This assertion was disputed by Raymond Soneira, president of
DisplayMate Technologies, who believes the human retina can see 477 pixels per
inch. This assertion was in turn disputed by the author of Bad Astronomy, Phil
Plait, whose has collaborated with NASA on the Hubble Space Telescope camera.
He believes that 300 pixels per inch will not be seen with a person who has
20/20 eyesight, and that only people with eyesight better than that would see
the individual pixels.
Going on the assumption that an iPhone or iTouch will be
viewed at a distance of approximately 12 inches, Apple made this 960 x 640
display (measured in pixels) 326 pixels per inch, just over the amount that the
eye should be able to detect. This means the naked eye shouldn’t ever see those
pixels, and should only see smooth text and images.
Apple then brought that same Retina Display technology to
their iPad. With a larger screen, 9.7 inches, it requires more resolution. They
have made the resolution 2048 x 1536, which is even better than a standard HDTV
display, a million more in fact, just to put it in perspective.
RetinaDisplay-iPad
Bear in mind, though, that this resolution is going to
depend on how it was originally uploaded. Take pictures on Facebook. If your
friends upload bad, fuzzy pictures with a very low pixels per inch to Facebook,
when you view them with your device that has Retina Display, it’s not going to
look any better. You can’t fix what’s already there. But if your friends upload
pictures that have a high pixels per inch, you will see them as intended.
Going back to the question if Retina Display is something we
need, it all depends on personal preference. Some people didn’t need to update
to CD players, because they were happy listening to their music on cassette
tapes. Similarly, some people won’t mind a lower pixel per inch display. It’s
not a necessity. However, if you’re wowed by great displays, you will enjoy
every single pixel, whether you can see them or not.
The new MacBook screen-resolution is 220ppi, but used
further away its display is claimed to have a similar appearance to a
smartphone. The one retina display in my life is on my iPad 3 – and I love it.
Photos, books and magazines look crisp and natural, indistinguishable from
their print equivalents. Along with the iPhone, the Galaxy S3 and HTC One X
smartphones also boast retina displays. Makers of Windows-based laptops have
been slower to produce high-resolution models, but the eye-popping MacBook Pro
will give them plenty of incentive to do so.
If jagged pixel-edges are being purged from your mobile
phone and computer screens, there’s also a determined effort to sharpen up your
TV and movie-watching experience. The advent of “full” high-definition has
amounted to a quiet revolution in the quality of TV images flashed at our
retinas. But the HD our eyes have adjusted to, known as 1080p, is relatively chunky
and low-resolution in the scheme of things. TVs and projectors shown at trade
fairs this year are capable of displaying “4K” resolution – four times what we
now call high-defi nition. New Zealand film-maker Nigel Stanford, who made a
fortune as a founding employee of Trade Me, this month released one of the
first films made available in the 4K format. The documentary Timescapes
features time-lapse and slow-motion photography of the US southwest.
The film treats you to panoramic views of the dazzling night
sky above the Arizona and Utah desert, luxurious shots of red windswept
landscapes and giant forests of redwoods. I watched Timescapes on Blu-ray and
was blown away. But Stanford, who produced and scored the film, has made
Timescapes available for purchase as a 21 gigabyte “4K” file. “When your eye
can’t see individual pixels, it’s like you’re looking out of a window,” say 4K
film-makers. Nature documentaries like Timescapes get the best out of the
technology – it’s why HD nature docos are always playing in TV showrooms.
The pursuit of realism and the elimination of the jagged
pixel will be a boon for 3D movies, which haven’t wowed audiences yet. Current
3D TVs that rely on passive polarised glasses cut in half the full HD
resolution each eye sees. With 4K you can get full HD on a 3D image, cutting
out the noticeable loss of quality that makes 3D so disconcerting. But this
resolution increase will force a technology upgrade once again. Your current TV
screen just won’t cut it in the 4K world. Nor will your Blu-ray player. It will
be another trip back to the electronics store. It’s enough to make your
eyeballs itch.
Power hungry
By area, every iPad is made primarily of battery - and the
new iPad has the biggest one yet, which is why it's slightly thicker and
heavier than its predecessor. Driving those extra LEDs requires lots of power,
and to achieve the same battery life as an iPad 2 the new iPad's battery has
been upped from 25 watt-hours to 42.5.
The new screen isn't the only culprit - 4G mobile broadband
radios, which are available in the new iPad, are infamous battery hogs too -
but there's no doubt that Retina displays are more power hungry than non-Retina
ones.
The quad-core graphics in the A5X processor and the RAM
increase from 512MB to 1GB are largely to drive the display too: without them,
the new iPad's performance wouldn't be anywhere near as impressive.
Retina apps can be hungry as well, not for power but for
storage space. Retina-friendly versions of apps can be significantly larger
than non-Retina ones: Pages went from 95MB to 269MB, Numbers from 109MB to
283MB and iMovie from 70MB to 404MB. The difference isn't just higher
resolution textures, icons and media, but there is a real danger that for
graphically rich apps, Retina-friendly content could quickly overwhelm even the
roomiest new iPad.
The problem is particularly annoying when an app uses
pictures, such as JPEG images, to render text. Not only is that bad for
accessibility - VoiceOver can't read it out, it can't be copied and so on - but
it's bad for app size: the new iPad has four times the pixels of the iPad 2,
and that means images need to be four times larger to look good.
That could be disastrous for apps such as some digital
magazines, whose creators export the whole publication as a series of images.
As Christopher Phin, editor of our Retina-friendly and distinctly un-bloated
sister title Tap! explains, "If you're rasterising text to pixels rather
than just letting it be text, your issues are going to bloat even more once you
adopt Retina. If your issue is 650MB now, an issue built for Retina display
could be 2.5GB."
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As Chris notes, apps will contain the graphics for both
Retina and non-Retina displays, so that 650MB app could easily go past 3GB.
Tap! doesn't use images to display text, and we sincerely hope other
publications follow its lead. Otherwise there are going to be a lot of unhappy
iPad owners out there.
Even if you don't subscribe to digital magazines, the Retina
display could cause you some storage problems: videos and photos that have been
optimised for previous iPads running 1024x768 resolutions don't look so good on
the new iPad, and that means you'll have to decide whether upping the quality
is worth sacrificing space for. If you think you'll be watching a lot of HD
video or storing lots of high-resolution photographs, you might regret buying a
new iPad with just 16GB of storage space.
It'll be interesting to see whether badly designed
Retina-friendly apps also cause problems for older iPad users. We hope not.
