The 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. But Tablet displays are more challenging to produce because their large screens are three to four times the size of a smartphone. Up until now tablets have been almost exclusively LCD-based—so while the Samsung Galaxy series of Smartphones are Flagship models for Samsung to show off its latest and greatest OLED displays and display technology, there haven't been any OLED tablets until now (except for a single 7.7 inch OLED model launched in 2012).
With the continuing advancement in manufacturing OLED displays Samsung has now produced the Galaxy Tab S series, which true to form, will be the flagship models for their line of tablets—with display performance widely expected to be comparable to the OLED Galaxy S5, which is the best Smartphone display that we have ever tested. Samsung provided DisplayMate Technologies with pre-release production units of the Galaxy Tab S tablets so that we could perform our well known objective and comprehensive display labb tests, measurements, and analysis, explaining the in-depth OLED display performance results for consumers, reviewers, and journalists.
To examine the performance of the Galaxy Tab S OLED Displays we ran our in-depth series of Mobile Display Technology Shoot-Out lab tests and measurements in order to determine how OLED 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 OLED 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 Display Shoot-Out Comparison Table summarizes the lab measurements in the following categories: Screen Reflections, Brightness and Contrast, Colors and Intensities, Viewing Angles, OLED Spectra, Display Power. You can also skip these highlights and go directly to the conclusions.
Our extensive lab tests and measurements presented in the detailed Comparison Table indicate that the Galaxy Tab S Tablet displays are (not surprisingly) almost identical in display performance to the OLED Galaxy S5 Smartphone that we recently tested and found to be the best performing smartphone display. See the Galaxy S5 article for additional background information on OLED displays. For direct performance comparisons with the leading LCD Tablets see our flagship tablet and mini tablet display Shoot-Outs.
Both Galaxy Tab S models offer Quad HD 2560x1600 pixel displays, currently the highest resolution for tablets, with 4.1 megapixels, double the number on your HDTV. The 10.5 inch model has RGB Stripe Pixels with 287 pixels per inch, and the 8.4 inch model has Diamond Pixels and Sub-Pixel Rendering with 361 pixels per inch (ppi). Both are higher than can be resolved with normal 20/20 vision at the typical viewing distances for tablets, so the displays appear perfectly sharp.
Most smartphones and tablets only provide a single fixed factory display color calibration, with no way for the user to alter it based on personal preferences, running applications, or ambient light levels. An important capability provided by the OLED Galaxy Smartphones and new Tab S tablets is the implementation of Color Management that provides a number of Screen Modes with different levels of user selectable color saturation and display calibration based on user and application preferences. The Galaxy Tab S models have 4 user selectable Screen Modes: Adaptive Display, AMOLED Photo, AMOLED Cinema, and the basic screen mode, which matches the sRGB/Rec.709 Standard used for most consumer content. See this Figure for the Color Gamuts of the different screen modes and the Colors and Intensities section for measurements and details.
The Adaptive Display screen mode provides real-time adaptive processing to dynamically adjust images and videos—for some applications it will vary the White Point, Color Gamut, and Color Saturation based on the image content and the color of the surrounding ambient lighting measured by the Ambient Light Sensor (which measures color in addition to brightness). The Adaptive Display mode also delivers higher color saturation, with 138 percent of the standard sRGB/Rec.709 Gamut, the highest that we have ever measured for tablets and smartphones. Some people like vibrant colors, plus it is useful for special applications and particularly for viewing in medium to high levels of ambient light, because it offsets some of the reflected glare that washes out the on-screen colors.
Most high-end digital cameras have an option to use the Adobe RGB Gamut, which is 17 percent larger than the standard sRGB/Rec.709 Gamut used in consumer cameras. The AMOLED Photo screen mode on the Galaxy Tab S provides an accurate calibration to the Adobe RGB standard, which is rarely available in consumers displays, and is very useful for high-end digital photography and other advanced imaging applications. The measured Absolute Color Accuracy of the AMOLED Photo mode for the Galaxy Tab S is 3.2 JNCD, which is very accurate. See this figure for an explanation and visual definition of JNCD and Color Accuracy Plots showing the measured Color Errors. There are very few consumer displays that can accurately reproduce Adobe RGB, so this is a significant plus for serious photography enthusiasts. See the Color Accuracy section and Color Accuracy Plots for measurements and details.
The basic screen mode provides the most accurate color and White Point calibration for the standard sRGB/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. The Absolute Color Accuracy for the basic screen mode is an excellent 2.1 JNCD, the most color accurate display that we have ever measured for a Smartphone or Tablet. See this figure for an explanation and visual definition of JNCD and Color Accuracy Plots showing the measured Color Errors, and also this regarding Bogus Color Accuracy Measurements. Use the basic screen mode for the best color and image accuracy, which is especially important when viewing photos from family and friends (because you often know exactly what they actually should look like), for some TV shows, movies, and sporting events with image content and colors that you are familiar with, and also for viewing online merchandise, so you have a very good idea of exactly what colors you are buying and are less likely to return them. See the Color Accuracy section and Color Accuracy Plots for measurements and details.
Both of the Galaxy Tab S displays have very good to excellent screen brightness, but are not as bright as the brightest LCD Tablets. The current record holder for tablets is the Nokia Lumia 2520 with 684 cd/m2 (nits), while the Tab S has 546 nits with Automatic Brightness On and 415 nits under manual Brightness (10 percent lower for mixed content with 50 percent Average Picture Level (APL) and 25 percent lower for an all white 100 percent APL screen). High screen Brightness is only needed for High Ambient Light, so turning Automatic Brightness On will provide better screen visibility and also a longer battery running time. As discussed below, the record low screen Reflectance of 4.7 percent for the Galaxy Tab S further improves its effective Screen Brightness in high Ambient Light. See the Brightness and Contrast section for measurements and details.
The Galaxy Tab S Tablets also have a Super Dimming Mode that allows the Maximum Screen Brightness to be set all the way down to just 2 cd/m2 using the Brightness Slider. This is useful for working comfortably without eye strain or bothering others in very dark environments, or affecting the eye's dark adaptation, such as when using a telescope. The display still delivers full 24-bit color and the picture quality remains excellent.
Mobile displays are often used under relatively bright ambient light, which washes out 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 Galaxy Tab S displays have both. They have 4.7 percent Screen Reflectance, the lowest of any tablet display that we have ever tested. 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 low Reflectance, the Galaxy Tab S have a Contrast Rating for High Ambient Light that ranges from 59 to 116, among the highest that we have ever measured. See the Brightness and Contrast section for measurements and details.
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. OLEDs have been rapidly improving in their power efficiency. For example, comparing the OLED Tab S 8.4 to the LCD Apple iPad Air: the OLED Tab S with Diamond Pixels is 27 percent more power efficient (for the same screen size and Luminance) than the LCD iPad Air for mixed image content (that includes photos, videos, and movies, for example) with a typical 50 percent Average Picture Level. See the Display Power section for more details. The Galaxy Tab S displays also have an Ultra Power Saving Mode that lowers the screen Brightness and also sets the background to Black, both of which significantly reduce display power and can double the running time on battery.
One subtle but important advantage of OLEDs is their excellent screen uniformity compared to LCDs, which often show hot spots and shadows from the edge LED lighting.
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's resting on a table or desk. While LCDs typically experience a 55 percent or greater decrease in Brightness at a 30 degree Viewing Angle, the OLED Galaxy Tab S displays show a much smaller 21 percent decrease in Brightness at 30 degrees. This also applies to multiple side-by-side viewers as well, and is a significant advantage of OLED displays. The Color Shifts with Viewing Angle are also relatively small. See the Viewing Angles section for measurements and details.
The Galaxy Tab S Basic screen mode provides very nice, pleasing and accurate colors, and picture quality. Although the Image Contrast and Color Saturation are slightly too high (due to a slightly too steep Intensity Scale), 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. The Basic screen mode is recommended for indoor and low ambient light viewing of most standard consumer content for digital camera, HDTV, internet, and computer content, including photos, videos, and movies. The Adaptive Display screen mode has significantly more vibrant and saturated colors. Some people like that. It is also particularly recommended for medium to high levels of ambient light viewing because it offsets some of the reflected glare that washes out the images.
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.
Based on our extensive Lab tests and measurements, the Galaxy Tab S is the best performing tablet display that we have ever tested, not surprisingly with performance that is almost identical to the OLED Galaxy S5 Smartphone that we recently tested and found to be the Best Performing Smartphone Display. The Galaxy Tab S establishes new records for best Tablet display performance in: Highest Color Accuracy, Infinite Contrast Ratio, Lowest Screen Reflectance, and smallest Brightness Variation with Viewing Angle. Both Galaxy Tab S models offer Quad HD 2560x1600 pixel displays (with 287 to 361 pixels per inch), currently the highest for tablets, with 4.1 megapixels, double the number on your HDTV. Where the Galaxy Tab S does very well but does not break performance records is in maximum display Brightness—the current record holder for tablets is the Nokia Lumia 2520 with 684 nits, while the Tab S has 546 nits with Automatic Brightness On and 415 nits under manual Brightness (10 percent lower for mixed content with 50 percent Average Picture Level APL and 25 percent lower for an all white screen). High screen Brightness is only needed for High Ambient Light, so turning Automatic Brightness On will provide better screen visibility and also a longer battery running time. Its record low Screen Reflectance of 4.7 percent further improves the effective screen Brightness, resulting in a very high Contrast Rating for High Ambient Light with Automatic Brightness On. See the Brightness and Contrast section for details. Comparisons with the leading LCD Tablets are examined below.
Most tablets only provide a single fixed factory display color calibration, with no way for the user to alter it based on personal preferences, running applications, or ambient light levels. Samsung's implementation of Color Management for their OLED smartphones and tablets allows them to provide multiple Screen Modes with different Color Gamuts and color calibrations—other tablets only provide a single fixed screen Color Gamut and calibration.
The Galaxy Tab S Basic screen mode has the most accurate colors for standard (sRGB/Rec.709) consumer content of any smartphone or tablet display that we have ever measured (even slightly better than the Galaxy S5 the previous record holder—also see this regardingBogus Color Accuracy Measurements). Color Accuracy is especially important when viewing photos from family and friends (because you often know exactly what they actually should look like), for some TV shows, movies, and sporting events with image content and colors that you are familiar with, and also for viewing online merchandise, so you have a very good idea of exactly what colors you are buying and are less likely to return them.
Most high-end digital cameras have an option to use the Adobe RGB Gamut, which is 17 percent larger than the standard sRGB/Rec.709 Gamut used in consumer cameras. The AMOLED Photo screen mode on the Galaxy Tab S provides an accurate calibration to the Adobe RGB standard, which is rarely available in consumer displays, and is very useful for high-end digital photography and other advanced imaging applications. The large screens on the Galaxy Tab S makes them especially useful for photographers to check their Adobe RGB photo shots and for showing them off.
The OLED display's native Wide Color Gamut in the Adaptive Display screen mode has significantly more vibrant and saturated colors, with 138 percent of the standard sRGB/Rec.709 Color Gamut, the highest that we have ever measured for tablets and smartphones. Some people like vibrant colors, plus it is useful for special applications and particularly for medium to high levels of ambient light viewing because it offsets some of the reflected glare that washes out the on-screen colors.
In 2013 the Amazon Kindle Fire HDX Tablets became the top performing tablet displays in our Display Technology Shoot-Out series, leapfrogging the competition with cutting edge displays using Quantum Dots and Low Temperature Poly Silicon. But with the ever continuing and impressive improvements in display technology the Samsung Galaxy Tab S has now taken the lead for the best tablet displays. The Apple iPad Air, which came in second after the Kindle Fire HDX 8.9, now moves into third place for Flagship Tablet models, and the iPad mini with retina display, with a very disappointing 63 percent of the standard sRGB/Rec.709 Color Gamut and poor Color Accuracy moves further down the pack for the mini tablet models. You can directly compare all of the display performance measurements and results by referring to these and other articles in our Display Technology Shoot-Out article series.
With display technology advancing rapidly on many different fronts things can change again in the next generation of displays for tablets and smartphones. So a strong Congratulations to Samsung, but please don't rest on your laurels—and best wishes to all manufacturers in developing their next generation of even higher performance displays!
The most important developments for the upcoming generations of both OLED and LCD mobile displays will come from improvements in their image and picture quality in ambient light, which washes out screen images, resulting in reduced readability, image contrast, and color saturation and accuracy. The key will be in dynamically changing the display's color management and intensity scales with the measured Ambient Light in order to automatically compensate for reflected 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. The displays and technologies that succeed in implementing this new strategy will take the lead in the next generations of mobile displays.
Below we examine in-depth the OLED displays on the Samsung Galaxy Tab S 8.4 and 10.5 models based on objective Lab measurement data and criteria. For comparisons and additional background information see the Galaxy S5 OLED Display Technology Shoot-Out, the Flagship Tablet LCD Display Technology Shoot-Out, and the Mini Tablet LCD Display Technology Shoot-Out. For comparisons with the other leading tablet, smartphone and smartsatch 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 email@example.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 mathematical DisplayMate 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.