A key element for a great smartphone has always been a truly innovative and top performing display, and the best leading edge smartphones have always flaunted their beautiful high tech displays.
Apple iPhones (and iPads) 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.
iPhone 4: 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 smartphone viewing distances of 10.5 inches or more. It was a brilliant technical and marketing innovation, and the competition was left in the dust.
iPhone 4s, 5, 5s: But then iPhone display innovation slowed almost to a crawl: in 2011 the iPhone 4s display remained the same (mid-cycle refresh). In 2012 with the iPhone 5, the new display enhancements were increasing the Color Gamut up to 100 percent sRGB and bumping up the display size from 3.5 to 4.0 inches. In 2013 the iPhone 5s display stayed the same (mid-cycle refresh). It's now four years since the innovative iPhone 4. This could be a touch of the Blackberry effect (the display is already perfect), or perhaps a bit like the tale of an intermittently sprinting hare losing to the steady progress of a tortoise. More on this in the conclusions.
Competition: While Apple display innovation slowed, many other manufacturers just steadily pushed ahead to take the lead. So recently Amazon, Google, HTC, Huawei, LG, and Samsung have been launching products with the best and most innovative mobile displays, as documented in our Display Technology Shoot-Out article series. The new iPad mini Retina display, for example, came in a distant third place finish due to backpedaling its Color Gamut down to 63 percent from 100 percent in earlier Apple products (and in many competing products).
iPhone 6: Now in 2014, four years after the introduction of the innovative iPhone 4, it's nice to see Apple once again significantly enhancing the displays for their iPhone 6 and 6 Plus. But there are now four years of catching up to do, and there are many more display issues in addition to screen size, which is the simplest one that has gotten the most attention. We'll examine how the new iPhone displays compare to their competition, which includes other full HD LCD smartphones and the OLED Samsung Galaxy S5, plus we just finished testing the Galaxy Note 4 and Note Edge, which have the latest OLED displays. We'll cover these issues and much more, with in-depth comprehensive display tests, measurements and analysis that you will find nowhere else.
High tech display enhancements
One particularly revealing point during the keynote announcement for the new iPhones were slides listing several technical display enhancements like photo aligned IPS, dual domain pixels, and improved polarizers. Interesting, but they really don't mean much because it is the lab tests that determine whether they actually improve display performance or are just sales and marketing puffery. We'll find out in our lab tests. In either case, it is significant that Apple wants everyone to know that display performance is important, and that they have been working to improve the displays on the new iPhones. And they did!
The use of sapphire to make the iPhone screens scratch proof was one of the most talked about rumors over past year as a result of Apple's $578M investment with GT Advanced Technologies to build a factory in Arizona. The likelihood of sapphire appearing on the iPhone 6 was close to zero because it will probably take at least another year for everything to come together. It is important to note that sapphire has some downsides over and above its much higher cost and manufacturing complexity. The most important issue for display performance is that sapphire has almost double the screen reflectance of glass (due to principles of optics), so it will be harder to read sapphire screens in high ambient light. That might be one reason why the recently announced Apple Watch Sport edition has a cover glass rather than sapphire like the other models—because it is much more likely to be used unshielded in high ambient light outdoors. Another reason is that while sapphire is very hard it is also brittle and is likely more prone to impact breakage, which is more common in sports situations. So, if given the choice, I personally would choose a cover glass with its better screen visibility and breakage protection. Others may find the scratch protection more important.
The display shoot-out
To examine the performance of the iPhone 6 and 6 Plus displays we ran our in-depth series of Mobile Display Technology Shoot-Out Lab tests and measurements in order to determine how the latest LCD 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 LCD and LCD 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.
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 iPhone 6 and iPhone 6 Plus 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 iPhone conclusions.
Display resolution and PPI
Both the iPhone 6 and 6 Plus are what Apple calls Retina displays, which simply means that the pixels cannot be resolved with normal 20/20 vision at the typical viewing distances for the displays, which for these screen sizes is typically 11 inches or more. That is the origin of the often misunderstood 326 pixels per inch (ppi). The iPhone 6 has a 1334x750 pixel display with 326 ppi and the iPhone 6 Plus has a 1920x1080 pixel display with 401 ppi.
While the display on the iPhone 6 has almost identical performance to the iPhone 6 Plus, it only has a 1.0 megapixel display, significantly lower than the 2.1 pixels on the iPhone 6 Plus, and the 2.1 to 3.7 megapixels found on all of the other leading smartphones. While its 326 ppi and 1334x750 resolution qualifies it as an HD Retina display, there are a number of other significant advantages for going to higher resolutions that exceed the limits set by normal 20/20 vision. For one, it is particularly important to have as many pixels as possible when digitally rescaling images from their native resolution to the display that they are being viewed on. Most images require rescaling and most rescaled images (from either higher or lower resolutions) with fine text and graphics look noticeably to considerably better in side-by-side comparisons on the iPhone 6 Plus with 2.1 megapixels compared to just 1.0 megapixels on the iPhone 6. Twice as many pixels to work with makes a noticeable visual difference. In addition, even with content at their respective native display resolutions, fine text and graphics look better on the iPhone 6 Plus. The display on the iPhone 6 is none-the-less still a very good display, and most buyers will be happy with its performance. We'll examine this in detail below.
There are some significant advantages in going higher than the visual acuity for 20/20 vision at typical viewing distances. For smartphones they include a closer match to digital photo resolutions, the ability to display standard full HD 1920x1080 images and videos at their native resolutions. For the iPhone 6 Plus no rescaling is required for full HD content, which always results in the best possible image and picture quality. In addition, if you really want (or need) to take advantage of the extra fine display sharpness and resolution above normal 20/20 vision, you can. If you study and stare at the image on the screen, move it closer and move it around, you'll be able to make out considerably more fine image detail because you are building an integrated visual map of the image in your brain. So, when you are looking at an image with very finely detailed graphics and small text, most people with reasonably good vision will be able to make out and take advantage of the extra sharpness and image detail if they take the time to do so. See our 2014 Innovative Displays and Display Technology article for more details.
Full sRGB Color Gamut and Absolute Color Accuracy
It was a relief to see the new iPhones stick with a full 100 percent sRGB Color Gamut after the iPad mini Retina display was launched in 2013 with a reduced 63 percent sRGB Color Gamut. Both new iPhones provide a very accurate sRGB and Rec.709 Color Gamut that is used in virtually all current consumer content for digital cameras, HDTVs, the internet, and computers, including photos, videos, and movies. So it's necessary for high color accuracy. We measured a nearly perfect 99 percent sRGB Color Gamut for the iPhone 6 and 101 percent for the iPhone 6 Plus, both impressively accurate. 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 iPhones both have very accurate Intensity Scales with a gamma of 2.22, however, they both have a slightly bluish white point, with a color temperature of about 7,300K, which is still (marginally) very good, and also somewhat better than the iPhone 5.
In our detailed lab tests the measured Absolute Color Accuracy for the for the iPhone 6 is 2.6 JNCD, and for the iPhone 6 Plus 3.1 JNCD. See this figure for an explanation and visual definition of JNCD and the Color Accuracy Plots showing the measured display color errors. Both are very good, among the most accurate mobile displays we have ever measured, and are very likely considerably more accurate than your living room TV. 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 iPhone 6 and 6 Plus have both. They each provide over 550 cd/m2 (luminance, which is a measure of brightness sometimes called nits), among the brightest that we have ever measured for a Smartphone, and considerably higher than the Full HD LCD Smartphones that we tested in 2013.
The screen reflectance for both new iPhones is 4.6 percent, close to the lowest value we have ever measured, and also considerably lower than the same Full HD LCD Smartphones. Our contrast rating for high ambient light quantitatively measures screen visibility under bright Ambient Light—the higher the better. As a result of their high brightness and low reflectance, the iPhone 6 and 6 Plus have a contrast rating for high ambient light of 121, among the highest that we have ever measured (and also the same as the much smaller iPhone 5). See the Brightness and Contrast, the High Ambient Light and the Screen Reflections sections for measurements and details.
Exceeding display specifications
All of the tested iPhone displays have almost identical Brightness, Contrast Ratio, Color Gamut, Intensity Scale, and overall calibration. This is unusual and is due to the detailed automated factory calibration performed on every individual display at the factory.
Apple is one of the few remaining manufacturers to actually provide display specifications. They specify a "typical" Brightness of 500 cd/m2 for both the iPhone 6 and 6 Plus—we measured 558 cd/m2 for the iPhone 6 and 566 cd/m2 for iPhone 6 Plus, both about 12 percent greater than the typical, which is impressive because they significantly exceed it—often the reverse is true. Apple also specifies a "typical" contrast ratio of 1400:1 for the iPhone 6 and we measured a true contrast ratio of 1591:1, and a "typical" contrast ratio of 1300:1 for the iPhone 6 Plus and we measured a true contrast ratio of 1451:1, both about 13 percent greater than the typical, and also the highest true contrast ratios that we have ever measured for mobile LCDs. Note that the very high dynamic contrast ratios claimed by some manufacturers are meaningless and pure nonsense. And for those of you thinking of emailing that we got hand-picked units, these were purchased retail from Verizon Wireless. See the Brightness and Contrast section for measurements and details.
Display power efficiency
The iPhone 6 and 6 Plus have roughly the same display power efficiency as the iPhone 5, which is not that surprising since they all have low temperature poly silicon (LTPS) backplanes, which are currently the most power efficient available. They are 10 percent more display power efficient than the Full HD LCD Smartphones that we tested, impart due to the different ppi, which is a factor.
Comparing them to latest OLEDs: LCDs are typically more power efficient for images with mostly white content (like text screens, for example), while OLEDs are more power efficient for mixed image content because they are emissive displays so their power varies with the average picture level (average brightness) of the image content. For LCDs the display power is independent of image content. For mixed image content (that includes photos, videos, and movies, for example) with a typical 50 percent average picture level (APL), the latest OLED Galaxy Note 4 display is 21 percent more power efficient than the iPhone 6 and 6 Plus displays. On the other hand, for a full white screen with 100 percent APL, the iPhone 6 and 6 Plus are 45 percent more display power efficient than the latest OLED Galaxy Note 4 display. See the Display Power section for measurements and details.
Viewing angle performance
While smartphones 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 high tech display enhancements that Apple mentioned really show up with Viewing Angle. The iPhone 6 and 6 Plus have significantly better Viewing Angle performance than the iPhone 5 or any other LCD that we have ever tested. Particularly important and noticeable are the much higher contrast ratios and the lower brightness decrease with Viewing Angle. The color shifts with Viewing Angle are also very small. See the Viewing Angles section for measurements and details.
The iPhone 6 and 6 Plus provide very nice, pleasing and accurate colors, and picture quality. Although the white points are both (intentionally) slightly too blue, the Absolute Color Accuracy and Intensity Scales are very good to excellent. 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. But this only holds for viewing in low ambient light. We'll discuss high ambient light in the conclusions.
iPhone 6 and 6 Plus conclusions: Impressive smartphone displays
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.
iPhone display evolution
The iPhone 4 not only revolutionized the displays on smartphones but it also started a major unprecedented renaissance of new display technologies for smartphones, tablets, TVs, and entirely new classes of products like wearable displays. That approach impressed consumers and moved the entire display industry. Then for reasons we can only guess, innovation on the iPhone displays slowed down almost to a crawl, while many other manufacturers just steadily pushed ahead—so there was a fair amount of catching up to do.
The best LCD smartphone display
Now in 2014, four years after the introduction of the innovative iPhone 4, it's nice to see Apple once again significantly enhancing the displays for their iPhone 6 and 6 Plus. While screen size has gotten the most attention, there are many more important and challenging display technology issues that Apple needed to address and enhance. And they did!
iPhone 6 Plus: Based on our extensive Lab tests and measurements, the iPhone 6 Plus is the best performing smartphone LCD display that we have ever tested. It delivers uniformly consistent all around top tier display performance. The iPhone 6 Plus is only the second smartphone display (LCD or OLED) to ever get all green (very good to excellent) ratings in all test and measurement categories (except for brightness variation with Viewing Angle, which is the case for all LCDs) since we started the Display Technology Shoot-Out article series in 2006, an impressive achievement for a display.The iPhone 6 Plus has raised the bar for top LCD display performance up by a notch. See the main Display Shoot-Out Comparison Table for all of the measurements and details.
The iPhone 6 Plus matches or breaks new records in LCD smartphone display performance for: highest peak brightness, lowest screen reflectance, highest (true) contrast ratio, highest contrast rating in ambient light, most accurate (pure logarithmic power-law) intensity scale and gamma, most accurate image contrast, and the smallest variations with Viewing Angle for Brightness, Contrast Ratio, and color. Where the iPhone 6 Plus display does very well but does not break LCD performance records is in: resolution (1920x1080 versus 2560x1440), pixels per inch ppi (401 ppi versus 538 ppi), and Absolute Color Accuracy (3.1 JNCD versus 2.1 JNCD).
iPhone 6: The display on the iPhone 6 has almost identical performance to the iPhone 6 Plus—but it only has a 1.0 Mega Pixel display, significantly lower than the 2.1 to 3.7 megapixels found on all of the other leading smartphones. While its 326 ppi and 1334x750 resolution qualifies it as an HD Retina display, there are a number of other significant advantages for exceeding the limits set by normal 20/20 Vision. It is particularly important to have as many pixels as possible when digitally rescaling images from their native resolution to the display that they are being viewed on. Most rescaled images look noticeably better on the iPhone 6 Plus with 2.1 megapixels compared to just 1.0 megapixels on the iPhone 6. In addition, even at the native display resolution, fine text and graphics look better on the iPhone 6 Plus if you look carefully and closely at the screen (because you may want to or need to).
The display on the iPhone 6 is none-the-less still a very good display, and most buyers will be happy with its performance, but it's somewhat disappointing that Apple went for satisfactory as opposed to the best. Maybe that was done for intentional product differentiation with the iPhone 6 Plus, or perhaps to improve their margins. With a 1920x1080 display the iPhone 6 would have taken the crown.
Comparing the LCD iPhone 6 and 6 Plus with the OLED Samsung Galaxy S5 and Note 4 displays
LCDs and OLEDs are the two leading mobile display technologies. The technologies are significantly different and each one has its own inherent strengths.
The iPhone 6 and 6 Plus are the current best mobile LCD Displays and the Galaxy S5 and Galaxy Note 4 are the current best mobile OLED displays. The iPhone 6 with a 4.7 inch 1334x750 display with 326 ppi corresponds most closely with the Galaxy S5 5.2 inch 1920x1080 display with 432 ppi. The iPhone 6 Plus with a 1920x1080 display with 401 ppi corresponds most closely with the Galaxy Note 4 5.7 inch display with a 2560x1440 display with 518 ppi.
You can compare all four displays 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.
Another way to compare them is by the relative strengths of each technology, which are listed below. Then refer to the individual lab measurements links above in order to get the values for the categories of interest. The manufacturer dependent strengths are categories that are not directly related to LCDs or OLEDs, but rather depend on how well the manufacturer implements them.
Current LCD Strengths: Higher peak brightness with high average picture levels, no peak brightness variation with average picture level, wide Color Gamuts with Quantum Dots, smaller color shifts with Viewing Angle, higher power efficiency with high average picture levels, and much higher worldwide market share.
Current OLED Strengths: Higher Peak Brightness with lower average picture levels, easier to increase screen resolution and ppi, perfect blacks and infinite contrast ratios, wide Color Gamuts, smaller brightness shifts with viewing angle, better screen uniformity, faster response times and no display motion blur, higher power efficiency with lower average picture levels.
Manufacturer Dependent Strengths: Low screen reflectance, accurate factory calibration, high Absolute Color Accuracy, accurate image contrast, good screen uniformity, multiple Color Gamuts, and providing color management.
The best smartphone display
The iPhone 6 and iPhone 6 Plus are the current best mobile LCD displays and the Galaxy S5 and Galaxy Note 4 are the current best mobile OLEDs displays. Both are impressive and excellent displays with great state-of-the-art display technology. We recently gave the Samsung Galaxy Note 4 our overall best smartphone 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 smartphone or 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 LCD 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 iPhone 6 and iPhone 6 Plus based on objective lab measurement data and criteria. For comparisons and additional background information refer to these comparable Smartphone displays: Samsung Galaxy S5 Display Technology Shoot-Out, Samsung Galaxy Note 4 Display Technology Shoot-Out, Full HD LCD Smartphone Display Technology Shoot-Out, and the iPhone 5 Display Technology Shoot-Out. For comparisons with the other leading Smartphone, Tablet and Smart Watch 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 firstname.lastname@example.org.
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.