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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    Can a Chromebook Pixel Compete with a MacBook Pro?

    Last updated on December 4, 2013

    Before the Chromebook Pixel, Chromebooks were all about value

    Chromebooks offer the best value in a laptop today

    Beyond Budget

    Until recently, Chromebooks were budget laptops that sold for as little as $199. Although they were great values, their hardware didn’t compare with high-end laptops from Apple and others. Google changed that when they released the Chromebook Pixel. It’s specs aren’t just comparable to a MacBook Pro, they exceed it in several areas. But hardware isn’t everything, we’ll see how it stacks up in the software department as well. We’ll also compare it with Windows, iOS and Android devices.

     Apple's claims that the MacBook Pro is the highest resolution notebook is simply not true

    The MacBook Pro is no longer the resolution king

    Why You’ll Love It

      An exceptional display – The display on the Chromebook Pixel is superb. It has more pixels than a Retina 13″ MacBook Pro and its pixel-per-inch resolution exceeds every MacBook — including the new 2880-by-1800 Retina MacBook Pro 15″ (220 PPI). Whether you can actually see a difference is debatable because the numbers are close, but you’ll love what you see. It’s noticeably better than any PC laptop I’ve ever seen. Text on the Chromebook Pixel is razor sharp — not blurry and distorted like you get on PCs running Microsoft’s ClearType.

      The Chromebook screen looks noticeably better than other PC displays

      The Chromebook Pixel’s screen looks noticeably better than most PC displays

      No waiting – The days of waiting for your laptop to boot are almost over. This is an instant-on device. When you lift the screen the Pixel is usable in less than a second. That’s impressive, but where it really kills PC laptops is the time it takes to fully boot from a cold start. The Chromebook only takes 8 seconds to get to the sign-on screen and 8 to 10 additional seconds to fully load the browser home page. This may not sound fast, but it’s literally 10 times faster than the boot time of my new SSD-powered Lenovo laptop.

      One terabyte cloud-based storage – Although my Chromebook Pixel only came with 64GB of local storage. You can easily expand the storage to match a MacBook Pro by adding a 64GB SD card. These cards cost as little as $29. However, with the Chrome operating system, local storage isn’t that important. Where the Chromebook Pixel really shines is in the area of cloud-based storage. Google gives every Pixel user one terabyte of storage for three years. That’s 1029 GB or more than 200 times more storage than Apple users get. I’m trying to fill up my 1TB Google Drive, but it’s not easy.

      A Chromebook is much more secure than a PC (Image courtesy of Nilesh Patni)

      A Chromebook is more secure than a Mac or Windows laptop (Image courtesy of Nilesh Patni)

      Almost immune to viruses and malware – When a Chromebook boots, it checks to make sure the operating system and firmware haven’t been tampered with. As a result, it’s not possible for keyloggers or other malware to run in the background. All data is encrypted, so no one can read your files. Each webpage you visit runs in a restricted environment, so visiting a site that’s been infected can’t affect anything else on your Chromebook. Apps you install run in Chrome’s sandbox as well, where they are isolated from the rest of the OS. Although browser extensions are allowed, you can’t install Java plug-ins or other software that opens up security holes.

      The touchscreen on the Pixel is very useful for some things

      The touchscreen on the Pixel is useful for some things

      A responsive touchscreen and trackpad – The Chromebook Pixel comes with a touchscreen that is responsive and doesn’t affect picture quality. Although not all software supports touch, there are times like using Google Maps when it is extremely useful. However, most of the time you’ll be using the glass trackpad on the Pixel. It’s the best trackpad I’ve ever used and supports multi-touch gestures, such as two-fingered scrolling.
      LTE3
      4G LTE support – Like a MacBook Pro, the Chromebook Pixel has dual-band 802.11a/b/g/n WiFi support. But Google goes much farther by including a 4G LTE modem, which is capable of download speeds up to 100Mbps. This is really useful when you’re not in-range of an open Wi-Fi network. For now I’m using the free 100 MB/month plan, but I’m considering upgrading to Verizon’s 1GB data plan, because it only costs $9.95 a month.

      thin

      It’s lighter and thinner than a MacBook Pro – Although no one is going to confuse a Chromebook Pixel with a MacBook Air. It’s thinner (16.2mm vs. 19mm) and lighter (3.35lbs vs. 3.57lbs) than a 13″ MacBook Pro. This is surprising because Apple is very good at making very thin and light products.

      A better auto-update system – The Chrome operating system (OS) handles software updates much better than any other OS I’ve used. Whenever a new security patch (or OS update) is available, the Chromebook Pixel automatically downloads and installs it in the background. No user-intervention is required. On major updates, the entire OS and browser are updated together, but they won’t be active until after you restart. Chrome keeps two copies of the OS around, so it can revert to an earlier version if something goes wrong. The best part is you won’t be constantly bothered with update requests like you are on Windows, iOS and Android.

      Google's office apps are better than anything you'll find on iOS or Android

      Google’s office apps are better than anything you’ll find on iOS or Android

      Better office apps – Google office apps have improved and are now better than most of the office apps you’ll find on iOS or Android. Some people even prefer Google Docs and Google Sheets to Microsoft Word and Excel, because of their value and real-time collaboration abilities.

      Great sounding stereo speakers – Even though the speakers on the Chromebook Pixel are hidden under the keyboard, they sound better than most other laptop speakers. I’ve got one small beef however, when you hold your fingers above the keyboard it acts as a filter and changes the sound slightly.

      Extra features – The Chromebook Pixel has a lot of nice extras like an integrated HD camera and noise cancelling mics, an anodized aluminum case, and a backlit keyboard that responds to ambient lighting and type of usage. I also can’t say enough about its keyboard, which feels wonderful and isn’t noisy as most laptop keyboards. Another nice extra is the twelve free GoGo Inflight Internet sessions Google gives you.

      Trouble in Paradise

      Although the Chromebook Pixel’s hardware stands out in many areas, the Chrome operating system and app ecosystem seems a little rough around the edges when compared to Windows, iOS or Android. Here are some of the limitations in software and hardware which I’ve experienced so far.

      Only a limited number of Chrome apps work offline

      Only a limited number of Chrome apps work offline

      Over-dependence on the Internet – Although a few Chrome apps work offline, you need Internet access to take full advantage of this product. LTE support helps in places without Wi-Fi, but there are many places that don’t have access to any Internet. Apps like Google Music are useless when you are offline. Chrome could cache media files you’ve played recently but it doesn’t. Although you can download songs for offline use, you can only do this twice (see the screen capture below) — even though Google’s PC-based Music Manager has no such restrictions. Google desperately needs to adopt a strategy like Dropbox, which keeps track of the changes locally, and syncs them after you get a data connection.

      Chrome has download restrictions that PC-based apps don't have

      Some Chrome apps have download restrictions PC-based apps don’t have

      Intel inside is no longer always a good thing

      Intel inside is no longer always a good thing

      Disappointing battery life – You can thank Intel for the relatively poor battery life of the Chromebook Pixel. You barely get 4 hours on LTE and although some claim 5-6 hours on Wi-Fi, I’m not seeing anything close to that. To add insult to injury, the i5 processor doesn’t feel as fast as the processors in the newest tablets. Heat is another serious issue. The metal case on i5-powered Chromebooks gets warm quickly, and the fan kicks after only a few minutes of video playback. Just how warm? I measured 120-128 degrees Fahrenheit on the bottom on the Pixel’s aluminum case. I’m confident all these issues would go away if this product had a Qualcomm Snapdragon mobile processor instead.

      Few great apps – Chrome’s dirty little secret is the fact that most of the so-called Chrome apps are not really apps at all, they’re shortcuts to existing web pages or browser plug-ins. This is my single biggest disappointment with Chrome OS. The few popular apps that are available in the Chrome Store are often missing important functionality found on other platforms. For example, Google Music on Chrome is missing EQ and advanced settings found on Android. Spotify for Chrome is missing many features found in their iOS mobile app. Google needs to encourage developers to create real apps, which don’t feel like they are running in a browser. There is some hope in this area. Last summer Google announced Chrome browser-based “Packaged apps” that look and behave like native apps. Packaged apps are closer to apps that are native, since they can run offline, display in a borderless browser that resembles an app window and can use APIs to gain access to a device’s hardware and other functionality. However, the creation of packaged apps isn’t happening nearly as fast as it needs to. Here are some of the best packaged apps that are available today.

      Notice how many more settings Google Music has on Android

      Notice how many more settings Google Music has on Android

      Microsoft Office compatibility issues – Although Google Drive is supposed to open documents created with Microsoft Office, it doesn’t always work. I tried to open a presentation created with PowerPoint 2010 and could not. Even after I manually imported the slides, there were issues with font sizes and the screen background didn’t look the same.

      Limited internal storage – Although it’s great that Google gives you one terabyte of cloud storage, the entry-level Chromebook Pixel only ships with 32GB of internal storage. This makes it hard to store a large collection of photos, music and movies locally so you can access them offline. Maybe this isn’t a problem yet, because I’m told you still can’t download movies to a Chromebook for offline viewing.

      Chrome was not designed with touch in mind like Windows 8 was

      Chrome was not designed with touch in mind like Windows 8 was

      Designed with touch as an afterthought – The touchscreen on the Pixel is nice, but touch seems like an afterthought on Chrome. Some apps don’t work well when you try to only use the touchscreen. Chrome doesn’t have a touch-friendly user interface like Windows 8, with its large tiles. Due to the high resolution screen, buttons on some web pages are hard to accurately click with your finger. Android has special logic to detect this, and zooms in so you can easily select the right thing.

      Not entirely intuitive – Chrome has some Windows-like user-interface concepts and some Android-style interface concepts, but is not near as intuitive as it should be. It also wasn’t obvious how to access app settings, update the OS, or do other basic things like right-click.

      The trackpad is nice, but missing dedicated buttons

      The trackpad is nice, but missing dedicated buttons

      Trackpad issues – One of the things I miss on this product is a right-click button. To get right-click commands to appear, you have to press with two fingers on the trackpad — which is louder than a dedicated button would be. You probably won’t notice this in a normal office environment, but it’s annoying in a quiet room. There is a good workaround however: You can touch the trackpad lightly and it still works.

      Limited I/O – I was surprised the Chromebook Pixel doesn’t have an HDMI out or a USB 3.0 port like Samsung’s Chromebooks have. It’s also crazy that you cannot plug-in a fast Ethernet cable when you are in environments with poor wireless connectivity. I purchased a USB-to-gigabit LAN adapter and DisplayPort-to-HDMI adapter to address these limitations.

      The Chromebook Pixel bests the MacBook Pro is many areas

      The Chromebook Pixel bests the MacBook Pro is many areas

      Can It Compete with a MacBook Pro?

      In terms of hardware the answer is yes. The Chromebook Pixel’s screen is better than the display on the Retina MacBook Pro. Both laptops use Intel i5 processors and the Pixel goes way beyond any Apple laptop with 4G LTE support, a terabyte of cloud storage, great sounding speakers and faster boot times. It’s also thinner and lighter than a 13″ MacBook Pro. Were this product falls short is mostly related to its operating system and applications, which can’t compete with Mac, Android or iOS devices today.

      Is It Worth the Money?

      Based on the issues listed above I wouldn’t recommended you pay $1299 to $1449 for a Chromebook Pixel. As good as the Retina-quality touchscreen is, it simply costs too much for what it does. For less money you could buy a Samsung Series 9 Ultrabook, MacBook Air or MacBook Pro and do much more on it. You’ll have a much better selection apps, fewer hardware-related issues and better battery life. Chrome OS is good for some things, but it’s not ready for prime time in some areas.

      Hope for the Future

      Although I’ve made it clear Chrome hardware and software needs work, I’m not giving up yet. I’m planning to keep my Pixel, because I’m enjoying learning the Chrome OS and I hope the software will improve in the future. By giving thousands of Chromebook Pixels to top developers, Google wants to encourage programmers to create new and improved Chrome apps. I hope a year from now we’ll see better Chrome apps available. I would also recommend a Chromebook to anyone who is looking for a computer for web browsing, email and writing. The next computers I buy my children and parents are likely to be Chromebooks.

      Google wanted to make a statement with this product that a Chromebook can be every bit as good as the best laptops. Influential tech writer Kevin C. Tofel of GigaOm affirmed this by saying “The hardware is on par with, if not better than, the MacBook Air I owned prior.” On this metric, I consider the Chromebook Pixel to be a success.

      – Rick

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

      Follow me on Twitter @mostlytech1