Debunking the Retina Display Myth

Last updated: August 10, 2014

Although Steve Jobs’ claims the human eye can’t perceive detail beyond 300 pixels per inch were immediately debunked, to this day almost everyone believes that what he said is still true. I became interested in this topic after seeing what I considered to be obvious differences between the highest-resolution smartphone displays. If Jobs’ claims were true, this shouldn’t have been possible. I wanted find out why I could see a difference, and whether it was possible to scientifically prove that Jobs’ retina claims were false. More importantly, I wanted to learn what specs would be needed in a real retina display. But before we can answer these questions, we need to go back to the beginning of this myth.

WWDC 2010 was where the Retina myth began

WWDC 2010 was where the Retina myth began

Looking Back

Back in June of 2010, Apple introduced the iPhone 4. Although no one knew it at the time, this would be Jobs’ last iPhone launch. The iPhone 4 was a landmark product because it was the first phone with a “Retina” display. Since few people correctly quote Jobs on this topic, let’s revisit what he said. Steve Jobs’ exact quote was “It turns out there’s a magic number right around 300 pixels per inch, that when you hold something around to 10 to 12 inches away from your eyes, is the limit of the human retina to differentiate the pixels.” This seemed plausible at the time because the display on the iPhone 4 was a big step forward. It had with four times the pixels of the previous model and a resolution of 326 pixels per inch (PPI).

Experts immediately questioned Jobs' retina claims

Experts immediately questioned Jobs’ Retina display claims

Experts Cry Foul

Almost immediately experts questioned Jobs’ claims. “Wired” ran an article saying the iPhone 4′s Retina display claims were “false marketing.” This article quoted Raymond Soneira from DisplayMate Technologies, who is one the most respected names in display analysis. Soneira said, “The math just doesn’t add up,” and suggested the term Retina display was misleading. Soneira went on to say “it was inaccurate to measure the resolution of the eye in terms of pixels.” He added “…a more accurate Retina definition would have a pixel resolution of 477 pixels per inch at 12 inches.”

Soneria was the first to attempt to prove Jobs was right

This blogger was the first to attempt to prove Jobs was right

Bad Math?

A blogger named Phil Plait then redid Soneira’s equations based normal vision, instead of perfect vision. Based on these calculations, Plait suggested Jobs’ claims were vindicated, but when you refer back to Jobs’ original quote, he refers to a distance of 10 to 12 inches. Plait conveniently used twelve inches, because that created the response he was looking for. Using a distance of ten inches, Plait confirmed that someone with normal vision could see visible pixels on a Retina display and the Retina display myth was busted. But that wasn’t the only problem with Plait’s and Soneira’s logic. There were several other problems we’ll discuss next.

A Flawed Definition of Perfect Vision

If you carefully read Plait’s article, you’ll see that he admits someone with perfect eyesight would be able to see a pixilated image when holding a Retina display one foot from their eyes. This backs up Soneira’s claim that 300 pixels aren’t enough for a true retina display, but there several problems with the definition of perfect vision. First, it is inaccurate to refer to 20/20 vision as “perfect” vision. 20/20 vision does not correspond to the best possible vision found in humans. Second, the word perfect doesn’t really make sense when applied to eyesight. The maximum acuity of a healthy human eye is 20/16 to 20/12. Even those with “bad” eyes can have 20/15 (or better) vision with glasses. This in itself doesn’t mean too much because the percentage of humans with better than 20/20 vision is relatively small (around 10-15% not including corrective glasses).

Most teens hold their phones close to their face

Most teens hold their phones closer to their face than adults

Screen Size Matters, Distances Vary

Contrary to the suggestions above, not everyone holds their mobile device 10 to 12 inches from their face. I’ve noticed that some teens hold their phones only 7 to 8 inches from their eyes. This is an important because the closer a person holds their screen, the higher the resolution required so the pixels effectively disappear. Jobs suggested that 300 pixels per inch was the magic number which determined whether a screen was a retina display, but the truth is there is no one single magic number for both smartphones and tablets. This is because the distance consumers hold tablets to their face is further away than they hold their smartphones. Some experts use a distance of 15 inches for tablets, but I often hold my tablet further away than that. What is the impact of this? It’s simple. The further you hold your device from your face, the lower the resolution needed for the pixels to disappear. This debunks the above assumptions that a single number can be used to determine whether a mobile device has a retina display or not.

20/20 has little to do with pixel recognition

Visual acuity alone is not the best predictor of pixel recognition

Primitive Measurements Don’t Cut It

The chart many eye doctors still use to determine whether you have 20/20 vision is a crude method that dates back to 1862. Eye charts were created to test vision, but we’re talking about something that goes beyond just text. We’re trying to determine whether a human can see the pixels on a display — and more importantly whether there is a benefit of using displays with resolutions higher than 300 PPI.

When trying to scientifically determine whether our eyes can tell the difference between two things, our eyes do a much better job telling the difference between two lines than they do interpreting characters of the alphabet. How much better? It turns out the ability of humans to distinguish between two different lines is actually ten times greater than 20/20 visual acuity. This is referred to as Vernier acuity and is the reason a Vernier scale like the one shown below allows users to measure things more precisely than using a uniformly-divided straight scale. You can prove this to yourself by taking this simple yet ingenious online test. This test proves that differences between Vernier lines can still be judged when the gap of a so-called “Landolt C” can no longer be recognized. In most cases the difference between these two is very large. That means while someone with excellent vision cannot recognize the orientation of the small “c” on the right (which has a 0.5 pixel gap size at normal reading distance), they can distinguish the gap between two lines that are only 0.05 pixels apart — that’s a 10x improvement.

The Vernier caliper uses Vernier acuity for more precise measurement

The Vernier caliper uses Vernier acuity for more precise readings

Science Still Matters

None of the experts quoted above attempted to scientifically test their assumptions. Plait claims his work calibrating for the Hubble telescope made him an expert in ophthalmology, but his real claim to fame was debunking the Moon landing hoax. I wondered what a real expert would say about this topic, so I did some research and found a study by Michael Bach. Mr. Bach is a professor at a German university known for their Ophthalmology-related studies and the former president of the International Society for Clinical Electrophysiology of Vision. Bach set out to test the limits of human vision and the ability to discern differences in extremely high-resolution displays. What he found and published in a scientific journal earlier this year clearly debunks Jobs’ retina display claims. His study had 49 subjects evaluate displays with resolutions between 254 and 1016 pixels per inch. The results of this study proves people can see the difference between a 339 PPI display and a 508 PPI display. More surprisingly, his study also suggests that some people can also discriminate between 508 PPI and 1016 PPI displays. So it’s clear the human eye is capable of benefiting from displays with more than 300 pixels per inch, but what is the minimum size for a true retina display and when will we be able to buy one?

The Real Retina Numbers?

Using the same equations Soneira and Plait used, a leading display manufacturer suggests a true retina smartphone display would need to have a resolution of at least 573 pixels per inch. However, this is for someone with perfect vision. The number is lower for someone with average vision. For a tablet held fifteen inches away from your eyes, and using the same equations, a true retina display would need a resolution that is higher than 382 PPI. Sadly, that means for people with perfect vision there are no true retina display smartphones or tablets available today. Even the new iPad Air only has a 264 PPI display. That doesn’t mean it doesn’t have a great looking display, but it doesn’t meet the definition of true retina display for a person with average vision.

Notice how the pixels of these four flagship phones vary

Notice how the pixels on four flagship phones vary. Source: AnandTech

All Pixels Are Not The Same

Now that we’ve established numbers for a true retina display, I want to point out one potential problem. When a mobile display goes under a microscope, it’s easy to see major differences between the types pixels used. The size varies, the shape varies, the placement varies. Even the color varies because some displays are now including white pixels (in addition to RGB). Some have pen-tile displays, others don’t. Even the type of displays used on popular smartphones vary. Companies like Samsung use OLED displays, while Apple uses LCD displays. Each has its own advantages and disadvantages. You can even see differences in the pixels on Samsung phones that have Super AMOLED displays. Unfortunately this topic is outside of the scope of this article. Just understand that all pixels are not the same and this makes it harder to come up with a single retina number that applies to all smartphones (or tablets). Other factors come into play as well, like the quality of your display. The better the quality panel, the more likely you are going to be able to see the differences we are discussing here.

Samsung recently shared their screen roadmap with analysts

Samsung recently shared their screen roadmap with analysts

Can You Really See A Difference?

Whether you can see a difference between your current smartphone and a smartphone with a true retina display depends on what you are viewing. Low-quality videos like the ones we watch on YouTube, will continue to look bad. In fact, they will even look worse, because you’ll see the compression artifacts more clearly. Small text is one area where you are likely to notice a difference. Text will be razor sharp. You can really see the difference between a 300 PPI display and 550 PPI display when things like pen-drawn Kanji characters are displayed. True retina tablets with screens that are 12 inches or larger will make it possible to get a newspaper-style experience, without reformatting articles. You will also be able to always use the full desktop versions of all websites and view high-resolution photos and 4K video with no loss of resolution. That’s not important today, but it will be in the coming years.

Much higher quality displays are coming in 2014

Much higher quality displays are coming in 2014

So When Can I Buy One?

True retina displays that are better than any Apple product are available now. The LG G3 has a 2560 x 1440 pixel smartphone display with a pixel density of 534 ppi. The Samsung Galaxy S5 LTE-A has a 5.1-inch display with an incredible 576 pixels per inch. That’s higher than the number required for a true retina smartphone display. Sadly it’s only available in Korea at this time. Samsung is also planning a 4K screen for smartphones. Assuming a screen size of around 5 inches, that works out to be about 880 pixels per inch.

4K tablet screens are coming as well. These screens should have resolutions over 400 pixels per inch, which exceeds the 382 PPI number required for a true retina display. Qualcomm demonstrated the first 4K Android tablet back in February of 2014. Reviewers like this one claimed its 3840-x-2160 display “easily beat the performance of the iPad Air.”

The Bottom Line

  • Researchers have proven people can see the difference between a >508 PPI display and a 339 PPI display.
  • It’s impossible to create a single number definition for a retina display because that number changes depending on the distance, your vision and other factors. Smartphones and tablets with much higher resolution displays are available now.
  • Apple mobile displays are no longer the best. Experts say the Galaxy S5 is the best performing Smartphone display that they have ever tested. As a result, Apple will finally increase the resolution of their mobile displays later in 2014.
  • Whether you can tell the difference between these new displays and today’s best displays will depend on the panel quality, distance and type of media you are viewing, but you won’t need a scientist to tell you they look great. Tablets will benefit the most, because their resolutions were significantly lower than smartphones.
  • – Rick

    Copyright 2013-2014 Rick Schwartz. All rights reserved. Linking to this article is encouraged. This article includes my personal opinions and does not reflect the views of my employer.


    Follow me on Twitter @mostlytech1

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    Nexus 10 – First Impressions

    Last update: January 27, 2013

    Earlier today I received one of the first Nexus 10 tablets. Since I’m hoping to use it to replace my iPad 3, I’m comparing the two side-by-side. Here are my initial findings so far:

    First Impressions – Day One

    1. The process of setting up a Nexus 10 is easy. You don’t even have to enter your Google account email. Just enter your password, answer a few questions and all of your apps and other data will start syncing.
    2. The build-quality on the Nexus 10 is very good overall. This was a surprise to me, because I didn’t think the Nexus 10 looked very good in the reviews. The front is metal and glass like the iPad 4. The back of the Nexus 10 is plastic, not aluminum like the iPad, but it feels good in your hands. Because it’s corners are rounded, it doesn’t dig into your palm as much as the iPad 3. The only thing I don’t like about the plastic is the fact that it does flex a little when you squeeze it hard. This is something the iPad 3 doesn’t do.
    3. The Nexus 10 comes with 5 books, 3 magazines, 10 songs, an HD movie and a TV show

    4. The Nexus 10 comes with lots of free content – Content varies by country. U.S. users get the following three free magazines, Conde Nast Traveler, Entrepreneur and House Beautiful. We also get five great books including “Great Expectations” by Charles Dickens, “The Three Musketeers” by Alexandre Dumas, “Pride and Prejudice” by Jane Austen, “Treasure Island” by Robert Louis Stevenson and “Alice’s Adventures in Wonderland” by Lewis Carroll. Like music? The Nexus 10 also comes with ten songs from The Rolling Stones, Cat Power, M. Ward, The Lumineers, Bob Mould, Eskmo and more. Last, but not least, the Nexus 10 also comes with an HD copy of the full-length movie “Ice Age” and the BBC TV show “Planet Earth.” Preloaded media varies by country, so your selection could be different from what I’ve listed above.
    5. The screen on the Nexus 10 is beautiful. Small text on the Nexus 10 is noticeably crisper than the same text on the iPad 3. The free ‘Entrepreneur’ magazine Google gives you is a great example how media on a tablet can look every bit as good as a real magazine. That’s probably because HD magazines in Google Play are 300dpi and the screen on the Nexus 10 is 300ppi. I’ve attached a screen capture here, but you can only really appreciate the way it looks if you have a Nexus 10 or iPad 4. It won’t look good on most computer displays. It’s worth mentioning the quality on the free Conde Nast Traveler magazine seems to vary. Some of the ads look grainy to me, while others look great. I’m not sure why. Resolution is just one important display parameter. It wouldn’t be fair if I didn’t acknowledge the fact the iPad 3 and 4 both have amazing displays that excel in some areas over the display in the Nexus 10 as well. I’ll detail some of those in my next article.
    6. Here is an example of a 300 dpi HD magazine. In order to evaluate this, it most be displayed at 2560×1600.

    7. The Google Magazine reader preloads pages in the background so there is no delay when you turn them. However, when you flick through the pages of an HD magazine as fast as you can, on the fourth page, you’ll start to have to wait 1-2 secs for them to load. This isn’t a flaw, just an observation.
    8. When you have a web page loaded with a white background, the Nexus screen has a slight yellow tinge to it, while the iPad 3 has a slight blue tinge. This is very subtle so it’s unlikely most people will notice this, but I thought I would mention it anyway.
    9. The Nexus 10 is noticeably lighter and thinner than the iPad 3. The lightness is good, but I’m not sure I’d want a tablet any thinner than a Nexus 10. It just wouldn’t feel right.
    10. The Nexus 10 is really fast. Scrolling and app load times are the fastest I’ve seen on any device, (and noticeable faster and smoother than the iPad 3).
    11. Syncing everything from my Google accounts and re-downloading all of my apps and data to the Nexus 10 took 45 minutes or less. That’s much faster than it took to download everything to my iPad 3.
    12. Here is the same web page on the Nexus (left) and iPad 3 (right)

    13. The screen on the Nexus 10 is noticeably longer than the iPad 3’s screen. At first I thought the Nexus 10 looked strange when held in portrait mode, because I was so used to the 4:3 aspect ratio of the iPad’s screen, but now I love it. The long screen displays quite a few more lines vertically as you can see above. It also displays more information horizontally, because text and images appear smaller due to the higher number of pixels per inch. The smaller text is not a problem for my eyes, but it could be a problem for others.
    14. I’m not thrilled with the new album art carousel on the Google Music app. I’d rather see more album covers at once.
    15. As others have noted, charging the Nexus 10 is slow when you’re using it. I plan to buy a third-party charger as soon as they’re available. Once I got on a cycle of charging all night with the power off, my charging issues seem to have gone away.
    16. When holding the Nexus 10 in portrait mode, it seems like the volume buttons are reversed. The top button is volume down and the bottom button is volume up. This is hard to get used to. I suspect they did this because they suspect people will use this product in landscape mode, but I prefer using it in portrait mode for everything except video playback and gaming.
    17. Like the iPad 3, the Nexus 10 has a screen that is very reflective. If you want an eReader that can be used in bright sunlight, or conditions where there is glare, you’re better off with a Kindle Fire.
    18. One of the reviews I read said the boot time of the Nexus 10 is 18.6 seconds, however I clocked a boot time of 24 to 25 seconds (from vibration to full home screen). By comparison, an iPad 3 takes 28 seconds to boot. The iPad 3 does shutdown much faster however (~4 seconds vs. 10-11 seconds).
    19. At first I thought the touch screen on the Nexus 10 wasn’t as sensitive as the iPad’s touch screen, but now I’m not sure. The only time I have problems is when I touch really small controls on the screen.
    20. Page load times in the Chrome browser vary. Sometimes the iPad 3 is faster and other times the Nexus 10 is faster. The Nexus 10 displays less bars when it’s located far away from a Wi-Fi access point than an iPad 3. It’s unclear whether this is a signal strengh display issue or a larger issue.

    That’s it for now. Make sure to check out additional Nexus 10 gripes in my next article.

    What About All of the Android 4.2 Bugs?

    If you’re wondering about all of the Android 4.2 bugs that sites like BGR are reporting. Random crashes? I’ve had several in five days, but it hasn’t been a major issue. Most of the things things these site are talking about are things that a typical user would not encounter — unless they are using Bluetooth audio, using lock-screen widgets, or trying to select December from the date picker in the People app. It’s worth mentioning that not a single one of the twenty authors who have written detailed reviews on the Nexus 10 pointed out any of the bugs we’re hearing about now. Here is what Gotta Be Mobile said about the stability of Android 4.2. “Fortunately, with Android 4.2 Jelly Bean, I haven’t experienced any major issues, nor have I seen any Nexus 7 owners complaining about a plethora of bugs. I’ve heard and see some users complaining about a Bluetooth issue as well as an over sensitive auto-brightness function, but thus far, neither of those bugs are affecting my device.”

    UPDATE 11/27 – Google pushed out an Android 4.2.1 update today which addresses the missing December issue.

    UPDATE 1/15 – A Google employee confirms the next Android update will contain a fix for the Bluetooth issue. Version number rumored to be 4.2.2.

    Summary After One Day

    It’s too early to say whether the Nexus 10 is better or worse than the iPad 3. I can say it’s better than I expected based on all of the reviews. I’m convinced it is the best value in a 10″ tablet today. My goal is to use it to completely replace my old iPad 3. It will take weeks to see if that is possible. Make sure to check my next article for the answer. Also check out my list of 50 Great Tips and Tricks for the Nexus 10 here.

    – Rick

    Copyright 2013 Rick Schwartz. All rights reserved. Linking to this article is encouraged.

    Follow me on Twitter @mostlytech1

    iOS 6’s Advantages Over Android 4.2

    Last updated: January 23, 2013

    [This article is still under construction. Please come back later to view the final version]

    Last year I wrote two articles that compared Android to iOS. One stressed Apple’s advantages, and the other stressed Google’s advantages. Both turned out to be extremely popular. Since each operating system has had a major new update since then, I’ve decided to update both articles. Android has come a long way since my first post, so far that some experts feel it’s reached parity, but iOS still has a few important advantages. Earlier this week I listed Android 4.2’s advantages over iOS 6. Here are the advantages that iOS 6 has over Android 4.2.

    The Top Ten Most Important iOS Advantages

    The App Store still leads based on quality and quantity of apps (App Store: Left; Google Play: Right)

    1. Better Overall App Quality – Google Play has almost caught up to Apple in the total number of apps, but there is no doubt that Apple still has the edge when it comes to the number of quality apps available — especially in categories such as games, media creation and children’s apps.

    Both of these phones run the same version of Android, but their graphic interfaces are quite different

    1. More Consistent User ExperienceSome reviewers have complained that Apple hasn’t made any major changes to iOS since the first version. That may be true, but it’s not entirely a bad thing. The user interface on every iOS device is very similar. By contrast, the Android user experience varies greatly from one manufacturer’s device to another due to skinning.

      Fragmentation is also a problem on the Android platform. Sixty percent of all iPhone users are running the newest version of iOS, while less than 5% of all Android users are running the newest version of Android. Because carriers and handset manufacturers don’t make all Android updates available on every phone, over half of all Android users are still running version 2.3, which was released back in 2010. Apple doesn’t allow skinning, and most of the time allows users with older devices to upgrade to the newest OS (although they may not always get access to all of the new features). This results is a more consistent user experience.

    Tablet-optimized apps look better on larger screens

    1. Tablet-optimized App Listings – The App Store displays iPhone and iPad apps in separate areas. iPad-optimized apps normally look better on tablets — because they have been modified to take advantage of the larger screen which tablets have. I wish Google Play had a filter for tablet-optimized apps.
    1. No Carrier Bloatware – Carriers preload their Android phones with loads of apps. Some promote paid services (e.g. VZ Navigator), while others are carrier-branded or third-party apps. Many preinstalled apps are things you don’t need and will never use. They clutter the screens of Android phones and often cannot be deleted. Apple doesn’t allow carriers to install bloatware on their products. While you could argue this isn’t an operating system-related advantage, it is an advantage that iOS users have over non-Nexus Android users.

    Siri has improved and has some advantages over Google Now and S-Voice

    1. A Better Personal Assistant – Although Google Now is pretty good, the version of Siri which is included with iOS 6 has some advantages — including more human-like and actionable responses. Here’s a good comparison between the two.
    1. More iOS-only or iOS-first Apps – By now you’d think all popular apps would be available on both platforms, but that’s not the case. Android is still missing some popular iOS apps. To make things worse, even when developers support both platforms, they often release their iOS apps first.
    1. Better HTML5 Support – Although Flash is still a popular way of handling multimedia on the Web, many people believe HTML5 will one day replace it. Instead of supporting Flash, Apple put its efforts into supporting HTML5 and it shows.
    1. Dynamic App Icons – iOS may not have widget support yet, but I love how the icon for the Calendar app displays the current day and date. Folders and apps like Spotify also are capable of showing notifications.
    1. Global Search – Swiping to the right displays a screen where you can search for Apps, Calendar, Mail, Music, Notes, Web and Wikipedia. This is a pretty big deal and Apple has shown they will litigate if anyone attempts to support this.

    Other Areas Where iOS is Ahead

    1. Better Voice Mail App – I think it’s ridiculous that I have to dial *86 to get voice-mail on my Galaxy Nexus. You’d think its 1998, not 2012. Apple’s phone app has dedicated voice mail button and its interface is excellent.
    1. Better Power Management – iOS devices seem to have power management than Android devices. Some of this may be a result of the fact that iOS doesn’t allow third-party apps to run in the background. Others might have to do with the fact that iPhone 4S has an under-clocked processor and no LTE support. Whatever the reason, it’s an Apple advantage.
    1. One-button Operation – Apple uses a single button to return to the Home screen, display the search box, and show recently opened apps. Is it intuitive? No, but once you learn it, it works well.
    1. Better Calendar app – Another thing I miss is the iOS calendar. I found it much easier to add appointments to the Apple Calendar than the Android Calendar.
    1. Better Cut & Paste – Although Android devices had cut and paste first, Apple has done a much better job implementing the feature. iOS devices have more region selection options and it’s much easier to quickly select text by dragging the region select handles around. Although this seems like a minor issue, it’s important to some users.
    1. iOS has better support for USB audio devices – iOS devices can play and record audio with standard USB audio devices using the camera connection kit. Android is saddled with a USB port that cannot host audio devices. Android 4.1 supports audio output only (no input) with accessory devices, but audio accessories have to be the USB host. [Source: Paul N.]
    1. You can enter phonetic pronunciations for Siri – iOS allows you to add phonetic pronunciations to your contacts which will tell Siri how to pronounce certain names.

    These are just some of the main advantages iOS 6 has over Android 4.2. Let me know if I left any major advantages out, and I’ll add them here.

    – Rick

    Copyright 2013 Rick Schwartz. All rights reserved. Linking to this article is encouraged.


    Follow me on Twitter @mostlytech1