A key element for a great tablet has always been a truly innovative and top performing display, and the best leading edge tablets have always flaunted their beautiful high tech displays.
Apple iPads (and iPhones) were up until recently at the leading edge of mobile displays: they were early adopters of high performance IPS LCDs, the full 100 percent sRGB Color Gamut, and full 24-bit color, all of which dramatically improve image and picture quality and display performance. Steve Jobs and Apple also made display-quality a central theme for their product marketing.
iPad 3
Their most famous and aggressive innovation came with the introduction of the Retina display in 2010 for the iPhone 4, where Apple doubled the pixel resolution and Pixels Per Inch (ppi) up to where the screen appeared perfectly sharp for normal 20/20 vision at typical tablet viewing distances of 10.5 inches or more. In March 2012 the iPad 3 got its first Retina display, plus a full 100 percent sRGB Color Gamut, which significantly improved color saturation and color accuracy. Up until that time almost all LCD tablets and smartphones had 55-65 percent Color Gamuts, which produced washed out, under saturated and distorted colors, so that red tomatoes, fire trucks, and Coke cans looked a bit orange rather than deep red, for example. In my 2012 iPad Display Shoot-Out I stated "with some minor calibration tweaks this new iPad would qualify as a studio reference monitor" and was "most likely better and more accurate than any display you own." These were brilliant technical and marketing innovations, and the competition was left in the dust.
iPad 4, iPad Air
But then iPad display innovation slowed almost to a crawl: in November 2012 the iPad 4 simply updated the hot, heavy and power hungry iPad 3 display and battery into a nicer package. In November 2013 the original iPad Air display was essentially unchanged and identical in performance to the iPad 4 introduced in November 2012. It's now two and a half years after the introduction of the innovative iPad 3. What happened next?
Competition
While Apple display innovation slowed, many other manufacturers just steadily pushed ahead to take the lead. So recently Amazon, Google, Microsoft and Samsung have been launching Tablets with the best and most innovative displays, as documented in our Display Technology Shoot-Out article series and discussed below.
iPad mini, iPad mini with Retina display, iPad mini 3
Originally spurned, then introduced (in haste) in 2012, the original iPad mini was a smaller version of the older 2011 iPad 2 with a 1024x768 resolution display and a reduced 62 percent Color Gamut, when the full size iPads already had a 2048x1536 Retina display with a 100 percent Color Gamut. In 2013 the mini was given a Retina display, but remained with a reduced 62 percent Color Gamut—the only current iPad or iPhone without a full Color Gamut. We'll examine in detail how much the iPad mini 3 has improved, if at all.
iPad Air 2
Now in October 2014, two and a half years after the introduction of the innovative iPad 3, it's nice to see Apple once again announcing a significantly enhanced display for the iPad Air 2. But there are now over two years of catching up to do, and there are many display performance issues to consider. We'll examine how the iPad Air 2 display has improved and compare to it to the competition.
We'll cover these issues and much more, with in-depth comprehensive display tests, measurements and analysis that you will find nowhere else.
The Display Shoot-Out
To examine the performance of the new iPad mini 3 and iPad Air 2 displays we ran our in-depth series of Mobile Display Technology Shoot-Out Lab tests and measurements in order to determine how these latest LCD Tablet displays have improved. We take display quality very seriously and provide in-depth objective analysis based on detailed laboratory tests and measurements and extensive viewing tests with both test patterns, test images and test photos. To see how far mobile displays have progressed in just four years see our 2010 Smartphone Display Shoot-Out, and for a real history lesson see our original 2006 Smartphone Display Shoot-Out.
Results highlights
In this results section we provide highlights of the comprehensive DisplayMate Lab tests and measurements and extensive visual comparisons using test photos, test images, and test patterns that are covered in the advanced sections. The main Display Shoot-Out Comparison Table summarizes the iPad mini 3 and iPad Air 2 Lab measurements in the following categories: Screen Reflections, Brightness and Contrast, Colors and Intensities, Viewing Angles, LCD Spectra, Display Power. You can also skip these Highlights and go directly to the iPad Conclusions.
Reducing screen reflections
A major innovation for the iPad Air 2 (that is not fully appreciated) is an anti-reflection coating on the cover glass that reduces ambient light reflections by about 3:1 over most other tablets and smartphones (including the previous iPads), and about 2:1 over all of the very best competing tablets and smartphones (including the new iPhone 6). We measured a 62 percent decrease in reflected light glare compared to the previous iPads (Apple claims 56 percent) and agree with Apple's claim that the iPad Air 2 is "the least reflective display of any tablet in the world"—both are in fact understatements. While everyone has been in situations where it is difficult or even impossible to see the screen in very bright ambient lighting, where this obviously helps, it turns out that even in moderate indoor lighting the image contrast and colors are being noticeably washed out from reflections as well. For example, the Color Gamut is typically reduced by 20 percent even at only 500 lux indoor lighting. To visually compare the difference for yourself, hold two tablets or smartphones side-by-side and turn off the displays so you just see the reflections. The iPad Air 2 is dramatically darker than any other existing tablet or smartphone. Those reflections are still there when you turn them on, and the brighter the ambient light the brighter the reflections. It's a major innovation and a big deal with visually obvious benefits!
The iPad Air 2 is the first iPad with an optically bonded cover glass—all previous iPad models had high reflectance air gaps under the cover glass—but they are simply catching up because almost all other leading tablets have had a bonded cover glass without an air gap for years. One minor but noticeable issue is that the screen Reflectance spectrum is heavily weighted towards blue, which is may be noticeable for dark images or in bright ambient light. See the Spectrum Figure and Screen Reflections section for measurements and details.
iPad display evolution
Other than the new anti-reflection coating and bonded cover glass, the display on the iPad Air 2 is essentially unchanged and identical in performance to the iPad 4 introduced in 2012, and is actually slightly lower in performance than the original iPad Air (for example 8% lower Brightness and 16% lower display Power Efficiency) – most likely the result of an obsession with producing a thinner Tablet forcing compromises in the LCD backlight. Similarly, the display on the iPad mini 3 is essentially unchanged and identical in performance to the iPad mini Retina Display introduced in 2013.
Color gamut and absolute color accuracy
In order to deliver accurate image colors, a display needs a 100 percent sRGB / Rec.709 Standard Color Gamut that is used in virtually all current consumer content for digital cameras, HDTVs, the internet, and computers, including photos, videos, and movies. We measured a slightly large 107 percent Color Gamut for the iPad Air 2 and a rather small 62 percent Color Gamut for the iPad mini 3, both almost identical with previous iPad models. See this Figure for the measured Color Gamuts.
In order to produce high Absolute Color Accuracy a display also needs an accurate (pure logarithmic power-law) Intensity Scale, and an accurate white point. The new iPads both have very accurate Intensity Scales with gammas very close to the 2.2 standard, however, they both have a slightly bluish white point, with Color Temperatures of 7,086K to 7,355K, which is still (marginally) very good.
In our detailed Lab tests the measured Absolute Color Accuracy for the for the iPad Air is 3.8 JNCD, which falls into our good (rather than very good) Color Accuracy rating. On the other hand, for the iPad mini 3, the much smaller 62 percent Color Gamut resulted in a much higher error of 6.8 JNCD going up as high as 22.6 JNCD, which resulted in a good to poor Absolute Color Accuracy rating.
See this Figure for an explanation and visual definition of JNCD and the Color Accuracy Plots showing the measured display Color Errors.. See the Color Accuracy section and the Color Accuracy Plots for measurements and details.
Screen brightness and performance in high ambient lighting
Mobile displays are often used under relatively bright ambient light, which washes out the image colors and contrast, reducing picture quality and making it harder to view or read the screen. To be usable in high ambient light a display needs a dual combination of high screen Brightness and low screen Reflectance—the iPad Air 2 has both. The screen Reflectance for the iPad Air 2 is 2.5 percent, by far the lowest value that we have ever measured due to an anti-reflection screen coating and optically bonded cover glass without an air gap.
Our contrast rating for High Ambient Light quantitatively measures screen visibility under bright Ambient Light—the higher the better. As a result of its high Brightness and very low Reflectance, the iPad Air 2 has a Contrast Rating for High Ambient Light of 166, the highest that we have ever measured.
On the other hand, the iPad mini 3 lacks the anti-reflection coating and has an air gap beneath the cover glass, which results in a moderately high screen Reflectance of 6.5 percent, almost triple that of iPad Air 2, so its Contrast Rating for High Ambient Light is 61, which further washes out its image colors in ambient light.
See the Brightness and Contrast, the High Ambient Light and the Screen Reflections sections for measurements and details.
Display power efficiency
The iPad Air 2 has 16% lower display Power Efficiency than the (original) iPad Air—most likely the result of an obsession with producing a thinner Tablet forcing compromises in the LCD backlight. Other LCD Tablets have much higher display power efficiency. For example, the Kindle Fire HDX 8.9 (with a Low Temperature Poly Silicon IPS LCD) is 27 percent more power efficient than the iPad Air 2 for the same Luminance and screen area. See the Display Power section for measurements and details.
Viewing angle performance
While tablets are primarily single viewer devices, the variation in display performance with viewing angle is still very important because single viewers frequently hold the display at a variety of viewing angles. The angle is often up to 30 degrees, more if it is resting on a table or desk.
The iPads all have IPS LCD displays, so we expected them to show very small color shifts with Viewing Angle, and our lab measurements confirmed their excellent Viewing Angle performance, with no visually noticeable color shifts. However, all LCDs, do have a strong decrease in Brightness (Luminance) with Viewing Angle, and the iPads all showed (as expected) about a 60 percent decrease in Brightness at a modest 30 degree viewing angle. Note that the iPads do not perform as well with viewing angle as the iPhone 6 and iPhone 6 Plus, which have higher performance dual domain pixels and improved polarizers. See the Viewing Angles section for measurements and details.
Viewing tests
The iPad Air 2 provides very nice, pleasing and fairly accurate colors and picture quality. Although its White Point is (intentionally) slightly too blue, the Absolute Color Accuracy is mostly very good except in the blue to magenta regions, which decrease its overall Color Accuracy rating. Nonetheless, the very challenging set of DisplayMate Test and calibration photos that we use to evaluate picture quality looked Beautiful, even to my experienced hyper-critical eyes.
On the other hand, for the iPad mini 3, the much smaller 62 percent Color Gamut produced visibly washed out, under saturated and distorted colors, so that red tomatoes, fire trucks, and Coke cans looked a bit orange rather than deep red, for example. See Figure 1 and Figure 2 and the Colors and Intensities section for quantitative details.
iPad Air 2 and iPad mini 3 conclusions: One major innovation and one major disappointment
The primary goal of this Display Technology Shoot-Out article series has always been to point out which manufactures and display technologies are leading and advancing the state-of-the-art of displays by performing comprehensive and objective Lab tests and measurements together with in-depth analysis. We point out who is leading, who is behind, who is improving, and sometimes (unfortunately) who is back pedaling, all based solely on the extensive objective measurements that we also publish, so that everyone can judge the data for themselves as well. See the main Display Shoot-Out Comparison Table for all of the measurements and details.
iPad Air 2: A very good display with a major innovation
A major innovation for the iPad Air 2 (that is not fully appreciated) is an anti-reflection coating on the cover glass that reduces ambient light reflections by about 3:1 over most other tablets and smartphones (including the previous iPads), and about 2:1 over all of the very best competing tablets and smartphones (including the new iPhone 6). We measured a 62 percent decrease in reflected light glare compared to the previous iPads (Apple claims 56 percent) and agree with Apple's claim that the iPad Air 2 is "the least reflective display of any tablet in the world"—both are in fact understatements. While everyone has been in situations where it is difficult or even impossible to see the screen in very bright ambient lighting, where this obviously helps, it turns out that even in moderate indoor lighting the image contrast and colors are being noticeably washed out from reflections as well. For example, the Color Gamut is typically reduced by 20 percent even at only 500 lux indoor lighting. To visually compare the difference for yourself, hold two tablets or smartphones side-by-side and turn off the displays so you just see the reflections. The iPad Air 2 is dramatically darker than any other existing tablet or smartphone. Those reflections are still there when you turn them on, and the brighter the ambient light the brighter the reflections. It's a major innovation and a big deal with visually obvious benefits!
The iPad Air 2 is the first iPad with an optically bonded cover glass—all previous iPad models had high reflectance air gaps under the cover glass—but they are simply catching up because almost all other leading tablets have had a bonded cover glass without an air gap for years. One minor but noticeable issue is that the screen Reflectance spectrum is heavily weighted towards blue, which is may be noticeable for dark images or in bright ambient light. See the Spectrum Figure and Screen Reflections section for measurements and details.
However, other than the new anti-reflection coating and bonded cover glass, the display on the iPad Air 2 is essentially unchanged and identical in performance to the iPad 4 introduced in 2012, and is actually slightly lower in performance than the original iPad Air (for example 8% lower Brightness and 16% lower display Power Efficiency)—most likely the result of an obsession with producing a thinner tablet forcing compromises in the LCD backlight.
Much more significant is that the iPad Air 2 does not have the same high performance display technology enhancements that we measured for the new iPhone 6 and iPhone 6 Plus, which we rated the best performing Smartphone LCD Display that we have ever tested. While the iPad Air 2 has an all around very good top tier display, and most buyers will be happy with its performance, the displays on the Amazon, Google, Microsoft and Samsung tablets that we have tested (see below) have better display performance in Absolute Color Accuracy, Brightness, Contrast Ratio, Viewing Angle, and Power Efficiency. However, the iPad Air 2 matches or breaks new records in tablet (and smartphone) display performance for: the most accurate (pure logarithmic power-law) Intensity Scale and Gamma, most accurate Image Contrast, (by far) the Lowest Screen Reflectance, and the Highest Contrast Rating for Ambient Light. See the main Display Shoot-Out Comparison Table for all of the measurements and details.
Hopefully, Apple (and other manufacturers) will apply the same (or similar) anti-reflection coatings that are on the iPad Air 2, and the same or similar display technology enhancements on the iPhone 6 and 6 Plus to all of their displays. As we discuss below, the most important future advancements for displays will come with the implementation of very wide Color Gamuts with Color Management that will dynamically compensate for the loss of color saturation in ambient light. For LCDs that will requite Quantum Dots.
iPad mini 3: A major disappointment
The iPad mini can only be described as the perpetual runt of the litter. Originally spurned, then introduced (in haste) in 2012, it was a mini version of the older 2011 iPad 2 with a 1024x768 resolution display and a reduced 62 percent Color Gamut, when the full size iPads already had a 2048x1536 Retina display with a 100 percent Color Gamut. In 2013 the mini was given a Retina display, but remained with a reduced 62 percent Color Gamut—the only current iPad or iPhone without a full Color Gamut. Now, in 2014 the new iPad mini 3 still only has a 62 percent Color Gamut, plus it was denied the new enhanced anti-reflection coating and bonded cover glass of the iPad Air 2. So in addition to washed out, under saturated and distorted colors (red tomatoes, fire trucks, and Coke cans look a bit orange rather than deep red, for example) it continues with a moderately high screen Reflectance of 6.5 percent, almost triple that of its favored littermate, which further washes out its image colors in ambient light.
The mini size tablets from other manufacturers like Amazon, Google, and Samsung that we have tested (see below) have excellent and significantly better mini displays. On top of that Apple charges a premium $399 for the mini 3, just $100 less than the much larger and higher performance iPad Air 2, and considerably more than other competing mini tablets. For a company like Apple that prides itself on producing great products, the iPad mini 3 is embarrassingly mediocre and way overpriced.
Comparing the iPad mini 3 and iPad Air 2 with other tablets
You can compare the iPad mini 3 and iPad Air 2 display performance with other tablets in detail by using a tabbed web browser with our comprehensive Lab measurements and analysis for each of the displays. Click on each Link below. The entries are mostly identical with only minor formatting differences, so it's easy to make detailed comparisons.
iPad mini 3 and iPad Air 2 Lab Measurements Comparison Table
Samsung OLED Tab S Lab Measurements Comparison Table
Microsoft Surface Pro 3 Lab Measurements Comparison Table
2013 Flagship Tablets Lab Measurements Comparison Table
2013 Mini Tablets Lab Measurements Comparison Table
The best tablet display
While the iPad Air 2 has an all around very good top tier display, the displays on the Amazon, Google, Microsoft and Samsung tablets that we have tested have better overall display performance as discussed above. We recently gave the Samsung Galaxy Tab S our overall Best Tablet Display award, and for the time being that continues for all of the reasons originally mentioned there. In particular, for implementing Color Management to provide multiple Color Gamuts, and then using the Color Management to provide the Highest Absolute Color Accuracy for Standard (sRGB/Rec.709) consumer content of any tablet display that we have ever measured (in one of its four available screen modes, which many reviewers seem to overlook). As we discuss next, dynamic Color Management is something that every display will need to provide in the future.
With display technology advancing rapidly on many different fronts, things can change again in the next generation of displays—so best wishes to all of the manufacturers and technologies in innovating and developing the next generation of even higher-performance displays!
The next generation of best mobile displays
The best performing LCD and OLED displays are now delivering impressive sharpness, brightness, low reflectance, high color accuracy, accurate image contrast, and great viewing angles. So what comes next? Essentially all published display specifications and factory calibrations are based on performance in absolute darkness 0 lux, but mobile displays (and even TVs) are seldom viewed in the dark. Even low levels of ambient light significantly affect the image and picture quality. For example, the 100 percent sRGB Color Gamut specified by many manufacturers only applies at 0 lux. At 500 lux, which corresponds to typical indoor office lighting, the on-screen colors are washed out by the reflected ambient light, typically reducing the on-screen Color Gamut from 100 percent down to 80 percent, plus the image contrast is also significantly affected. And it gets worse as the ambient light levels increase. So here is what needs to come next.
The most important improvements for both LCD and OLED mobile displays will come from improving their image and picture quality and screen readability in ambient light, which washes out the screen images, resulting in reduced image contrast, color saturation, and color accuracy. The key will be in implementing automatic real-time modification of the display's Color Gamut and Intensity Scales based the measured Ambient Light level in order to have them compensate for the reflected light glare and image wash out from ambient light as discussed in our 2014 Innovative Displays and Display Technology and SID Display Technology Shoot-Out articles. LCDs will need Quantum Dots in order to implement the necessary wide Color Gamuts. The displays, technologies, and manufacturers that succeed in implementing this new high ambient light performance strategy will take the lead in the next generations of mobile displays. Follow DisplayMate on Twitter to learn about these developments and our upcoming display technology coverage.
Display shoot-out comparison table
Below we examine in-depth the LCD displays on the Apple iPad mini 3 and iPad Air 2 based on objective Lab measurement data and criteria. For comparisons and additional background information refer to these comparable tablet displays: Samsung OLED Tab S Display Technology Shoot-Out, Microsoft Surface Pro 3 Display Technology Shoot-Out, 2013 Flagship Tablet Display Technology Shoot-Out, and 2013 Mini Tablet Display Technology Shoot-Out. For comparisons with the other leading tablet, smartphone, and smartwatch displays see our Mobile Display Technology Shoot-Out series.
Below is a partial excerpt of the table; you can see the full comparison at DisplayMate.
This article has been republished with permission from DisplayMate.com , where it can be read in its entirety.
About the Author
Dr. Raymond Soneira is President of DisplayMate Technologies Corporation of Amherst, New Hampshire, which produces video calibration, evaluation, and diagnostic products for consumers, technicians, and manufacturers. See www.displaymate.com. He is a research scientist with a career that spans physics, computer science, and television system design. Dr. Soneira obtained his Ph.D. in Theoretical Physics from Princeton University, spent 5 years as a Long-Term Member of the world famous Institute for Advanced Study in Princeton, another 5 years as a Principal Investigator in the Computer Systems Research Laboratory at AT&T Bell Laboratories, and has also designed, tested, and installed color television broadcast equipment for the CBS Television Network Engineering and Development Department. He has authored over 35 research articles in scientific journals in physics and computer science, including Scientific American. If you have any comments or questions about the article, you can contact him at dtso.info@displaymate.com.
About DisplayMate Technologies
DisplayMate Technologies specializes in proprietary sophisticated scientific display calibration and mathematical display optimization to deliver unsurpassed objective performance, picture quality and accuracy for all types of displays including video and computer monitors, projectors, HDTVs, mobile displays such as smartphones and tablets, and all display technologies including LCD, OLED, 3D, LED, LCoS, Plasma, DLP and CRT. This article is a lite version of our intensive scientific analysis of all types of displays – before the benefits of our advanced mathematicalDisplayMate Display Optimization Technology, which can correct or improve many of the display deficiencies. We offer DisplayMate display calibration software for consumers and advanced DisplayMate display diagnostic and calibration software for technicians and test labs.
For manufacturers we offer Consulting Services that include advanced Lab testing and evaluations, confidential Shoot-Outs with competing products, calibration and optimization for displays, cameras and their User Interface, plus on-site and factory visits. See our world renownDisplay Technology Shoot-Out public article series for an introduction and preview. DisplayMate's advanced scientific optimizations can make lower cost panels look as good or better than more expensive higher performance displays. For more information on our technology see the Summary description of our Adaptive Variable Metric Display Optimizer AVDO. If you are a display or product manufacturer and want to turn your display into a spectacular one to surpass your competition then Contact DisplayMate Technologies to learn more.
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