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ryan

June 21st 2012 8:04 pm

Crunching the numbers on Retina: what to expect in iMacs, MacBook Airs, and Thunderbolt monitors with Retina displays


Ready to geek out on pixel densities? Great, me too.

So when Apple announced its first computer with a Retina display, the revamped 15.4 MacBook Pro (gdgt.com­/apple­/macbook­-pro­/with­-retina­-display­/mid...), I think we all instinctively drew the conclusion that one day every Apple computer model -- like the iPhone, iPad, and iPod touch before them -- would have a Retina display. Seems pretty obvious, right?

Now, it's easy to assume that we'll just take the number of pixels in current models and multiply them by two in both directions to reach Retina-level resolutions, but I'm not so sure. The resolutions and PPI (pixels per inch) on Apple's current lineup actually vary -- sometimes greatly -- so I built a little PPI calculator to crunch the numbers.

As it happens, the new MacBook Pro exactly pixel-doubles the old MacBook Pro's 110 PPI, 1440 x 900 display (we'll ignore the optional 1680x1050 "hi-res" display option). As I started running the numbers on everything, it became apparent to me that around 110 PPI is Apple's sweet spot. Almost all of its current lineup of computers are between 108 - 113 PPI. This means Apple is teed up nicely to approach the iPad 3rd-gen's 264 PPI by simply pixel-doubling most of its displays' current resolutions¹.

Now, one area where things get a little wonky for Apple is in the MacBook Air line of devices (as you'll see below). The current, non-Retina display on the 13-inch Air actually has the same resolution as the 15-inch MacBook Pro (1440 x 900), thus giving it a much higher pixel density (127 PPI) than, say, the 13-inch Pro (113.48 PPI).

And as it happens, the humble 11-inch Air actually has the highest pixel density of all the non-Retina computers Apple currently makes, with a PPI of 135. That's pretty damn high for Apple's lowest-end laptop.

Although Apple could simply double the resolutions in the Airs, their final pixel densities would be significantly higher than necessary (especially in the case of the 11-inch, where it would get all the way up to about 260). Remember, the new 15.4-inch Pro has a pixel density of 220 PPI, and that is more more than necessary to look like a Retina display.

So, given the disparity in the pixel densities of the MacBook Airs vs. all other Macs, my assumption is that we actually won't see a straight pixel-doubling there. My guess is that the 13-inch Air's Retina display will actually be a pixel-doubled version of the current 13-inch Pro's 1280x800 display, which would make it a more reasonable 226 PPI (instead of an inflated 255 PPI). For the sake of comparison, I've included both sets of numbers below.

The 11-inch Air, with its surprisingly high non-Retina PPI, is even more of an anomaly as far as resolution-to-screen-size ratio is concerned, so I also included a reduced estimate that gets it right into the range of the expected ~220 PPI of the other devices.

Okay, still with me? Great. So here are your future Apple Retina resolutions (assuming screen sizes and aspect ratios² don't change in future device updates, which they may):


MacBook Pro 15 [example]
MacBook Air 13
MacBook Pro 13
MacBook Air 11 (16:9)
iMac 27 (16:9)
iMac 21.5 (16:9)
  • Current resolution: 1920x1080 via gdgt.com­/apple­/imac­/21­-5­-inch­/mid­-2011­/specs/
  • Retina resolution: 3840x2160
  • Current PPI: 102.51
  • Retina PPI: 205.02 [note: this is by far the lowest PPI of any expected Retina resolutions, don't be surprised if the Retina iMac 21.5 gets a resolution bump above 3840 x 2160]

Thunderbolt Display (16:9)Update: I mistakenly calculated the 11-inch Air's numbers based on 16:10 aspect ratio -- it's actually the only 16:9 laptop Apple makes, so I've updated my calculations to reflect the correct numbers.
¹ It makes sense that the MacBook Pro with Retina would have a slightly lower PPI than the iPad. For the same reason the iPhone has a much greater pixel density than the iPad, in most cases you're probably going to be using your laptop a little further from your eyes, so its pixel density really doesn't have to be extremely as high to be every bit as as effective.

² As you might notice, all of the current Mac portables on the market except the 11-inch Air sport 16:10 aspect ratio displays. However, Apple's desktop displays -- the iMac 21.5, 27, and Thunderbolt Display -- all use 16:9 displays. Apple could fairly easily change those to 16:10 in the future, but for the examples I've presented here I'm assuming they'll stay the same for the time being.

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43 replies
joelja

there's not much point in 220 dpi on a display you sit 3 feet or more from (27" display or imac) it's seems logical as more videos sources are 2 or 4 k pixels that the resolution would go up but it doesn't have to... 3996 × 2160 e.g. 16:9 4k resolution seems like a more reasonable step. the technology is driven by use case. and interacting with your phone vs a large data display is a very different activity
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doctorsub

Perhaps but if your doing photo especially it would be nice.
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jogdial

In footnote 2, you currently say that all the portables have 16:10 displays. This isn't correct - the 11-inch MacBook Air has a 16:9 display. This helps to keep the screen height dimension (and thus the overall size) down.
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ryan

You are correct, will fix that!
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kernco

I wonder if Apple might do something different here, and try to reduce the variety of resolutions on their computers. Maybe have one for the laptop-sized screens, and another for desktop-sized screens. The PPIs would be different between 13" and 15" screens, for example, but they'd still both be retina displays and I'm not sure the difference would be very noticeable.

Why would Apple want to do this? With desktop environments, the resolution of the screen has never been very important for developers because their programs run in a window which can be resized to any resolution. But with fullscreen apps being front and center now in OS X, it might be that developers will want to focus on designing their UI for fullscreen mode, and then it would be extremely helpful if they knew there were only a few resolutions they had to worry about (the huge variety of resolutions on Android devices has been one of the biggest complaints from app developers).

I think I'd still bet on the standard pixel doubling we've seen so far, but this is something to think about.
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ryan

I don't think we're going to see a single Retina resolution across multiple display sizes, personally. For one, higher pixel densities on smaller screens will equate to more expensive parts, but more importantly it would necessitate even more powerful graphics processors than might be necessary on devices like the Air where the power / heat envelope is highly sensitive. In the end, despite some of the resolution messiness between the 13-inch displays in its line right now, Apple really only has a handful of screen sizes to target for Retina: 11.6, 13.3, 15.4, 21.5, and 27. That's not too crazy.
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bb4u

I don't think that they would scale back the effective resolution on the airs (for non retina enabled apps). Most people would view that as a step backwards rather than forwards. I suppose they could still allow them to scale it to non optimal resolutions like they do with the retina Macbook Pro (in that case up to ~1080p scaled to match the 17" mbp resolution) but that wouldn't be the recommended setting or default.

Seems like it makes the most sense that the 13" Macbook Pro would be the next one in line to get the retina treatment before the Airs but the question becomes if they remove the optical drives like they did with the 15" MBP retina how would they differentiate it from the 13" Air? Maybe they could just replace the 13" version of the Air with the retina 13" MBP without optical drive especially if they can cut the weight down to the current 13" air? They might keep both available initially with the 13" retina MBP priced higher than the 13" air.
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ryan

I wouldn't be surprised if the 13-inch Pro gets axed before it gets a Retina display. There's simply no compelling reason to keep it in the lineup now that the Airs have become sufficiently powerful (and inexpensive).

Within the next 12-24 months I think the current fatty 15-inch Pro will be dead as well, but I think that will have more to do with yields on 15-inch Retina displays.
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johnswilson1

I disagree. I think you get rid of the 13" Air, keep the 11", and have 13" and 15" Pros. That's it. Three computers, all retina, and the Pro is again the top dog. They should be able to make a 13" retina Pro in the 3.2-3.6 pound range. The 13" Air is 2.98. So it's about comparable. And it'll be way more powerful.
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ryan

Really? Get rid of the 13-inch Air? I'm reasonably sure that's their best-selling computer right now -- possibly the best selling single computer anywhere.
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johnswilson1

It is hard to believe, but what's the point of having two 13" computers that are basically the same in specs? That's messy and not Apple's thing. Getting rid of the 13" Pro is unlikely to me because that's been the bestselling computer for years (yes, it may have been eclipsed by Air but I'm not sure). Also, I'm unsure if Apple can fit that massive battery required to drive a 13" retina into the Air's design.
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alejandro1398

This is why I am waiting for Hasewell next year :D
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marinelayer

I can see the 11" Air Retina getting a 2400 x 1440 (1.66:1, 241 ppi) display. I would hope it's not something lower like 2048 x 1280.

The 13" Air and MacBook Pro (if it's still around) should standardize on the same 2560 x 1600 display. Simple and already supported.

The 21.5" iMac uses a normal Full HD display. I agree with Ryan that the Retina display should be more than double Full HD. 4096 x 2400 makes more sense.

Of course, all of this is only possible if Apple works closely with Intel and nVidia/AMD to support these resolutions. The future is denser.
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ScottFrancis

For the purposes of this post you ignored the 15-inch MBP's optional 1680x1050 "hi-res" display option.

To bring it back into the discussion, do you think Apple will do a "Retina-optimized" version of this resolution (3360x2100), or do you think they'll deem scaling the 2880x1800 resolution to be good enough? The "1680x1050" setting looks pretty good on the Retina MBP, but it is a noticeable degradation from the "Best" (1440x900) setting.
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ryan

I don't think they need to. At 220 PPI there are more than enough pixels to simulate the scale of 1680 x 1050 while retaining the crispness they're looking for. But I haven't spent a ton of time with it on that setting, so for the moment I'm gonna have to take your word on it!
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zkarj

I'm not going Retina any time soon because I bought only my MBP 15" in October last year. I bought the hi-def screen because it equalled the pixel count of my old iMac 20" and effective screen area is important to me. I'm yet to be convinced that the Retina MBP can give me the same effective area without looking like crud. Scaling small bitmaps with non-integer multipliers sounds like a really bad idea to me, so I expect all developers are going to have to create much larger artefacts and always scale down appropriately - sounds like a lot of work for both developers and the GPU.
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williamdowell

Thanks a lot for adding the iMacs and not just the MacBooks! I read endless discussions about the latter, as if the iMac doesn't exist anymore!

I have a humble 21" since the last aesthetic change came out in autumn of 2009, so ready for a new one - just waiting for the magic increase in screen res. Or perhaps they will jump for touch display, but that possibility seems to have faded for now..
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LunaticSX

Good overview. Now how about one doing the same thing focusing on the change to battery capacity in Apple's laptops? Apple had to bump the battery on the 15" MacBook Pro from 77.5 Wh to 95 Wh to support the new Retina display. That's a 22.58% increase.

One could imagine the 13" MacBook Pro getting a ~23% battery increase via the same treatment as the 15", by dropping the optical drive and switching the spinning hard drive to Flash RAM. It's much harder to see how either the 11" or 13" MacBook Airs could get such a battery increase needed to support a Retina display. There's nothing you could take out of them to reduce their power consumption or free up more room for a larger battery. They'd either have to get significantly thicker, or their runtimes would be reduced by a lot. Apple could do a little bit of each, but that's not a very Apple-like "no compromises" type of solution. The 11" MacBook Air already only has an official 5 hour runtime, and I don't think they'd ever want to go below that.

A reason for keeping both the 13" MacBook Pro and the 13" MacBook Air, then, could be that the 13" MacBook Air (and the 11" one) simply can't get a Retina display due to power consumption issues, at least in the near term. So the differentiation between them would be that Retina displays are "Pro" features only available on the 15" and 13" MacBook Pros.
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Fanfoot

Agree completely. This is one of the more interesting problems with "Retina" displays, their increased power consumption. On the new iPad the battery had to be doubled in size, but of course its got a very low-power ARM core, where the new MacBook Pro has a powerful Intel CPU, a serious GPU etc all consuming significant power so it was a smaller percentage increase. Still...

Although the rumors that Apple would turn to Sharp for their IGZO panels with this generation turned out not to be true, one has to hope that something like this still happens in the long run. I don't know how much better transmissivity the IGZO panels are going to have, but any technology that allows for higher resolution with lower increases in power draw has to see some adoption given the kinds of increases we are seeing with these devices.

I too would like to hear Ryan's opinions on these issues. Perhaps he has some ideas how much more efficient IGZO might be...?
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Kannon778

We sit further away from a 27" ACD or 27" iMac than a MacBook Pro. The "retina" PPI will likely be significantly lower than the 220 of that retina MBP. Similarly the 11" MBA should have a significantly higher PPI because the working distance, it will likely be closer to that of the iPad 3.
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AllanCaeg

Great topic!

One important consideration is distance between eye and the display. That's affected by monitor size and form factor.

Air 11" has both a smaller monitor and a great form factor that allows it to be close to the body. That's probably why it's the Mac with the highest non-Retina ppi.
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ryan

I disagree, I think the 11-inch Air has such a high PPI because 11.6-inches at 110 PPI (that of the old MBP 15) would net out to roughly 1100 x 700. That's a pretty freaking low resolution to run a desktop OS on these days. I think Apple had to bump up that PPI to actually fit a reasonable amount of stuff on the 11.6-inch Air's tiny screen. They can equalize it the PPI later once they get all their models to Retina.
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brownlee

You say the 11-inch Air would get a Retina display with 2100-2200 x 1300-1400 to maintain a 210ppi, but that doesn't really make any sense: there aren't any graphical display resolutions in that range. The closest one that stays within the 11-inch Air's 16:9 display ratio is 2048 x 1152 QWXGA display, which would result in a ppi of 202.57, the lowest of any of the PPIs listed here. Still, it's way more than is needed to fit Apple's definition of Retina: a 1680 x 1050 display on the 11-inch Air would technically be Retina.

That said, what Apple's doing is HiDPI pixel doubling to maintain current desktop sizes while upping clarity. It's pretty unlikely Apple will do anything but make the resolution 2772 x 1736. Anything else requires a lot of weird scaling or increasing or deceasing the size of the desktop.

PS: I wrote a pretty accessibke article about Retina display science, if you're interested: www.cultofmac.com­/173702­/why­-retina­-isnt­-enough­-fe...
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ryan

I'm not clear on why you think Apple is going to stick to "standard" resolutions. Before the MBP Retina 2880 x 1800 didn't exist.

I'm not sure if 1680 x 1050 would qualify as Retina on a 11-inch Air -- PPI would be 175, and while I'm not 100% sure on this, I seem to recall Schiller saying that given average distance of use, Retina resolutions on a laptop would start at about 200 PPI.

Either way, in the case of the 11-inch Air, there's just no need to pixel-double. Nothing in OS X is scaled specifically for the 11-inch Air's screen, there aren't any technical dependencies I'm aware of.

Great looking piece by the way, looking forward to reading it!
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brownlee

Ryan, good point about 2880 x 1800. You're right: that is new.

I still think you're putting way too much stock in 200+ PPI and not enough in what Apple has clearly signaled what it strategy is going to be across all devices: straight up HiDPI pixel doubling of existing screen resolutions. They've done it for the iPad, the iPhone and the MacBook Pro at this point. I really don't see them changing that strategy.
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ryan

Could be. To summarize my takeaways:
  1. The 13-inch Air and Pro have disparate resolutions; if the 13-inch doesn't get the axe, I'd expect them both to get the same res Retina display based on a pixel-doubled version of the lower-density 13-inch Pro's display.
  2. The 11.6-inch Air's display pixel-doubled might be unnecessarily resolution-dense, so they may ratchet it down. We'll see, though. (I wouldn't swear by that strategy, which is why I included both sets of numbers.)
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jkibuule

A huge thing everyone is missing is the lack of a label on the bottom of the Retina MacBook Pro. There's also not much difference between a 13" Air with Retina Display and 13" Pro with Retina Display after you take out the optical drive. I predict sometime in the next year or so all laptops are just called MacBooks as there's no reason to call one Air and another Pro.
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ryan

That's not a bad point. I can see that happening at some point down the line, especially if they get rid of the overlap between the 13-inch Air and Pro.
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marinelayer

At Instapaper creator Marco Arment's blog, he tried to predict how quickly we'd see Retina iMacs and Thunderbolt displays. For the latter, a "2X" Retina Thunderbolt display would require so much bandwidth (5120 x 2880, 24-bit color) that the current implementation of Thunderbolt (20 Gbps) is not fast enough to handle the stream! That's the kind of scale Apple is dealing with. No wonder the company didn't announce any desktop machines, there's already a bottleneck.

www.marco.org­/2012­/06­/22­/predicting­-mac­-desktops
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ryan

Yeah, that's a very good point. I think his numbers might be ever so slightly off, but the larger point is spot on: the stack required to deliver Retina is still nascent, especially on larger scale devices like computers, so I'd expect this to be a slow rollout.
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zkarj

The way to fix that problem is to put a GPU in the Thunderbolt display. That way, the Thunderbolt cable only needs to carry instructions and not the whole image. It also means you can easily power a Retina TB Display with something as lowly as an 11" MBA.
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homli

While text on the current MacBook Pro with Retina display appears the same physical size as on the non-Retina version by default, the retina display also supports scaled resolutions equivalent to 1920 x 1200, 1680 x 1050 (same as upgraded Pro 15 display), 1280 x 800, and 1024 x 640.

I agree the MacBook Air 13 with retina display will be 2560 x 1600--pixel doubled from the current MacBook Pro 13. It will also support a scaled resolution equivalent to the MacBook Air 13's current 1440 x 900 resolution... the best of both worlds I think.
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hogsdill

So based on this analysis, what would be the supported scaled resolutions on the 13" MacBook Air? i can't decide whether to get the rMBP or wait for the retinal MacBook Air. if I get the rMBP, i'd run it at 1920x1200 the entire time.
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homli

I think the 13" Retina will support 1680x1050, 1440x900, 1280x800, and 1024x640--the same resolutions as the 15" Retina minus 1920x1200. This will mean text remains about the same size across MacBooks, as outlined below.

On a 15.4" display, 1920x1200 is 147PPI.
On a 13.3" display, 1680x1050 is 149PPI.

On a 15.4" display, 1680x1050 is 129PPI.
On a 13.3" display, 1440x900 is 128PPI.

On a 15.4" display, 1440x900 is 110PPI.
On a 13.3" display, 1280x800 is 113PPI.

On a 15.4" display, 1280x800 is 98PPI and 1024x640 is 78PPI.
On a 13.3" display, 1024x640 is 90PPI--between the two but keeps it a standard resolution. Or Apple could go with 1152x720 and 960x600 (102 and 85PPI).
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sillymansamOCN

Wonder how this would affect the rest of the Industry. I predict a panic for high resolution screens and OEMs pump out AMOLED displays which will mostly be crap. Right now we're stuck with 16:9 and 1080p displays which I think isn't the best for computing. From a user who using all the above, this will peak my interest in what Apple has to offer.
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kolebee

Potentially helpful for flipping around... colbyjordan.com­/dpi
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This post has been removed.

sejoki

Don't think they'd bring retina to the pro only and keep the other ones as high resolution? They have great screens as it is, and the benefits of the retina display shown at WWDC were definitely more aimed at the pro user (with the exception of Diablo 3).
Maybe it'll be just the pro laptop line, with a separate thunderbolt retina display. But then again, I know professionals who use an iMac (quite a lot) and then you could combine your Air with the retina TB display which would just cause confusion and what about the mac mini and…
Maybe not. If they can keep the costs low, sure. But I think 13" pro is next, as well as a new mac pro and the thunderbolt display.
The air is definitely last, and I'd say it's about time they drop the "Air" and make it just the MacBook. Maybe on the iMac, it'll just be an extra option.
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dennyc69

It would make you wonder if Apple would actually make a 27 inch version of the iMac considering the clarity the display would give off. Other then video editors, (and myself) most people I think would be happy with the 21 inch display if it looks that great, not to mention the cost factor.

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trixxxter750

I seriously doubt Apple will be doubling all of these... Laptops yes, but the iMacs would be insanity... a 50% bump on those would be more than enough to get rid of any noticeable pixels. Remember, Apple has went out of their way to explain retina as how it looks, not a certain pixel density spec.
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kernco

If they increased by 50%, any graphics that haven't been updated would look terrible. It's not that bad when the pixels are double, because then each pixel in a graphic just becomes a block of 2x2 pixels. If they had to scale it up 50%, then there'd be some weird distortions unless they antialiased everywhere. What they might do is increase by 50%, but drop the "effective" resolution back so that the 50% increase is a doubling of a lower resolution than was being used...if that makes any sense.
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zkarj

My thinking too, but the MBPwRD already allows for non-integer scaling when you set it to 1920x1200. The question remains – is it practical?
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freshjulius

I am surprised so many people are perfectly content to write-off the 17" MBP.

The 15" Retina MBP can do the 1920x1200 resolution, but it is insanely small (most people squint when they see that at 17"!) and the Screen size of a quality laptop is major selling point for Apple's supposed core target: creative professionals!

If anything, a Retina 17" MBP is the most logical usable Retina MBP size!
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RohanBhade

The thought process behind Apple moving to "retina" displays on "legacy" devices is not with the intention of merely providing a sharper image. That thinking is true in case of their iOS devices where the user interface distance is much closer than traditional notebooks and desktops.

On iOS devices, higher density displays have resulted in sharper images and the fact that the human eye cannot distinguish between individual pixels.

On the Mac, the normal distance at which we interact with these displays is long enough that our eye cannot distinguish the pixel. A look at the new MacBook Pro proves this point, while the image is visibly sharper, Apple is scaling up all the icons to ensure that they don't look miniscule on the retina panel.

The idea for now is to offer media professionals pixel for pixel accuracy while working. An example is uncompressed 1080p view in the Final Cut Pro editor, there are similar examples that can be found in Aperture and iPhoto. The target is to offer screen real estate for now, the panel "natively" offers the same desktop space as the now defunct MacBook Pro 17 used to offer at its native resolution.

If the MacBook Air is the new "MacBook" it shall retain the display resolutions now, the higher end iMac configurations for both the 21 and 27 inch versions will go retina alongwith the thunderbolt display.

There was a case for the MacBook Pro to go "retina" but I don't see the point of the other products in the line going along the way, although we are all pretty certain at this point that the roadmap points that way.
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