'Best' is a subjective term, especially when you're talking about smartphones. The battle may sometimes involve fancy new features or innovative software, but at the end of the day it always comes down to the screen that you're looking and tapping away at. Samsung provided DisplayMate, one of the world's leading display testing and calibration companies, with a pre-release production model of its Galaxy S5 smartphone for some serious screen performance tests.
The Samsung Galaxy S and Galaxy Note series of smartphones are flagship products for the company to show off its latest and greatest OLED displays and display technology. Samsung provided DisplayMate Technologies with a pre-release production unit of the Galaxy S5, so that we could perform our well-known objective and comprehensive display lab tests, measurements, and analysis -- explaining the in-depth OLED display performance results for consumers, reviewers, and journalists.
While many people have assumed that the Galaxy S5 has basically the same display as the Galaxy S4 -- but just a bit bigger -- that isn't the case. Our detailed lab tests show that there have been significant display performance improvements in almost every single test and measurement category,resulting in a number of new records for smartphone display performance. Based on our extensive tests and measurements, which we present in detail below, the Galaxy S5 is the best performing smartphone display that we have ever tested -- and it has raised the bar for top display performance up by another notch.
With the Galaxy S5, the emphasis has shifted from the traditional yearly increases in resolution, screen size, and pixels per inch (ppi), which have dominated the headlines for the last 10 years. These have now played out as far as is visually beneficial, so it's time for manufacturers, consumers and reviewers to shift their attention and concentrate on the many other even more important display performance issues that we will discuss in detail below.
The Galaxy S5 has the same 2K 1920x1080 full HD resolution as the Galaxy S4, which at 432 pixels per inch is higher than can be resolved with normal 20/20 vision at the typical viewing distances for smartphones -- so the display appears perfectly sharp, and there is no visual benefit to going higher. There are, however, other benefits in moving up to somewhat higher resolutions, so future generations of smartphones will likely go up to a 2.5K 2560x1440 resolution, as discussed in our 2014 Innovative Displays and Display Technology article.
There are many more important and challenging issues for displays than just pixel resolution. For the Galaxy S5, Samsung has instead concentrated on improving maximum brightness, screen reflectance, performance in high ambient light, absolute colour accuracy, viewing angles, display power efficiency, and battery running time.
While most mobile displays are still LCD-based, OLEDs have been capturing a rapidly increasing share of the mobile display market. The technology is still very new, with the Google Nexus One smartphone, launched in January 2010, as the first OLED display product that received widespread notoriety.
In a span of just a few years, this new display technology has been improving at a very impressive rate, now challenging and even exceeding the performance of the best LCDs. Most of the OLED displays in current mobile devices are produced by Samsung Display. We have published yearly articles following their progress in our Galaxy S I,II,III OLED Display, Galaxy S4 OLED Display, and Galaxy Note 3 OLED Display Technology Shoot-Out article series.
Mobile Display Technology Shoot-Out Lab tests and measurements are used 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 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, Colours and Intensities, Viewing Angles, OLED Spectra, Display Power. You can also skip these highlights and go directly to the conclusions.
Evolution of OLED Displays The Galaxy S5 has the latest evolution of Samsung OLED displays since we tested the Galaxy Note 3, which launched in October 2013, and the Galaxy S4, which launched in April 2013. Those results, together with the lab tests and measurements below, show that the Galaxy S5 display is a major improvement over the Galaxy S4 and a significant improvement over the Galaxy Note 3 in almost every single test and measurement category, which we cover below.
Impressive Brightness OLED displays had previously been somewhat dimmer than competing LCD displays, up until the Galaxy S4 and Galaxy Note 3. The Galaxy S5 continues the OLED brightness improvements in a big way. It's an impressive 22 per cent brighter than the Galaxy S4 and a solid 13 per cent brighter than the Galaxy Note 3.
For most image content it provides over 400 cd/m2 (luminance, which is a measure of brightness sometimes called nits), comparable or higher than most LCD displays in this size class. As discussed below, the very low screen reflectance of the Galaxy S5 further improves the effective screen brightness in high ambient light. Even more impressive is that when automatic brightness is turned on, the Galaxy S5 hits an incredible 698 cd/m2 in high ambient light, where high screen brightness is really needed, which is 47 per cent brighter than the Galaxy S4 and 6 per cent brighter than the Note 3 with automatic brightness turned on -- it's the brightest mobile display that we have ever tested. An impressive achievement for OLED technology! See the Brightness and Contrast section for measurements and details.
Super Dimming Mode The Galaxy S5 also has a new 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 colour and the picture quality remains excellent.
Multiple Screen Modes and Colour Management Most smartphones and tablets only provide a single fixed factory set display 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 more recent Galaxy S and Galaxy Note smartphones is the inclusion of a number of screen modes that provide different levels of user selectable colour saturation and display calibration based on user and application preferences. The Galaxy S5 has 5 user selectable screen modes: adapt display, dynamic, standard, professional photo, and cinema, which we discuss below and include detailed measurements for three of the modes. The screen modes require the implementation of colour management in order to adjust the native colour gamut of the display, plus additional factory calibrations for each screen mode. See the colours and intensities section for measurements and details.
Cinema Mode and High Colour Accuracy The Galaxy S5 cinema mode provides the most accurate colour and white point calibration for the standard sRGB/Rec.709 Colour 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 Colour Accuracy for the cinema mode is an excellent 2.2 JNCD, the most colour accurate display we have ever measured for a smartphone or tablet. See this figure for an explanation and visual definition of JNCD and Colour Accuracy Plots showing the measured colour errors. Use the cinema mode for the best colour 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 colours that you are familiar with, and also for viewing online merchandise, so you have a good idea of exactly what colours you're buying and are less likely to return them. See the colour accuracy section and colour accuracy plots for measurements and details.
Professional Photo Mode Most high-end digital cameras have an option to use the Adobe RGB Gamut, which is 17 per cent larger than the Standard sRGB/Rec.709 Gamut used in consumer cameras. The Professional Photo Mode on the Galaxy S5 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 applications. The measured absolute colour accuracy of the professional photo mode for the Galaxy S5 is 3.0 JNCD, which is very accurate. See this Figure for an explanation and visual definition of JNCD and Colour Accuracy Plotsshowing the measured colour errors. There are very few displays that can accurately reproduce Adobe RGB, so this is a significant plus for serious photography enthusiasts. See the Colour Accuracy section and Colour Accuracy Plots for measurements and details.
Adapt Display Mode The Adapt Display mode provides real-time adaptive processing to dynamically adjust images and videos -- for some applications it will vary the white point, colour gamut, and colour saturation based on the image content and the colour of the surrounding ambient lighting measured by the Galaxy S5 RGB ambient light sensor (which measures colour in addition to brightness). The Adapt Display mode also delivers higher colour saturation, which appeals to some, and is also a better choice for high ambient light viewing conditions, which wash out the on-screen colours and contrast from the reflected light, which we examine next.
Performance in High Ambient Lighting Mobile displays are often used under relatively bright ambient light, which washes out image colours 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 S5 has both. For screen reflectance, the Galaxy S5 (with 4.5 per cent) is effectively tied for first place with the Galaxy S4 for the lowest screen reflectance of any mobile display that we have ever tested. As discussed above, for most image content the Galaxy S5 provides over 400 cd/m2, comparable or higher than most LCD displays in this size class. See the Brightness and Contrast and Screen Reflections sections for measurements and details.
Contrast Rating in Ambient Light: Even more impressive is that when automatic brightness is turned on, the Galaxy S5 hits an incredible 698 cd/m2 in high ambient light, where high brightness is really needed -- it's the brightest mobile 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 S5 has a contrast rating for high ambient light that ranges from 75 to 155, also the highest that we have ever measured. See the Brightness and Contrast and High Ambient Light sections for measurements and details.
Screen Shots in Ambient Light: This article with screen shots shows how many smartphones and tablets degrade in high ambient lighting. On the Galaxy S5 the brightness can be set much higher for automatic brightness so that users can't permanently park the manual brightness slider to very high values, which would run down the battery quickly. This extra high level of brightness is only needed for high ambient light.
Colour Washout in Ambient Light: The adapt display mode delivers higher colour saturation, which appeals to some, and is also a better choice for high ambient light viewing conditions, which wash out the on-screen colours and contrast from the reflected light off the screen. For example, in 0 lux absolute darkness the adapt display mode has a colour gamut that has 129 per cent of the standard colour gamut, but at 1,000 lux ambient light, which corresponds to high indoor or low outdoor lighting levels, the colour gamut falls to 99 per cent, while for the cinema mode it falls to 84 per cent at 1,000 lux, so the higher colour gamuts are best in high ambient light. See the Colours and Intensities section for measurements and details.
2K Full HD 1920x1080 Display
The Galaxy S5 has the same 2K 1920x1080 Full HD resolution as the Galaxy S4, which at 432 pixels per inch is higher than can be resolved with normal 20/20 vision at the typical viewing distances for smartphones, so the display appears perfectly sharp and there is no visual benefit to going higher. For an in-depth discussion see our visual sharpness and display resolution section, which explains the many issues that come into play.
A high resolution screen shot of the Galaxy S5 and S4 (provided by Samsung) shows an interesting design and sub-pixel arrangement, which Samsung calls diamond pixels. First of all, the red, green, and blue sub-pixels have very different sizes -- blue is by far the largest because it has the lowest efficiency, and green is by far the smallest because it has the highest efficiency. The alternating red and blue sub-pixel arrangement leads to a 45 degree diagonal symmetry in the sub-pixel layout. This allows vertical, horizontal, and particularly diagonal line segments and vectors to be drawn with reduced aliasing and artifacts. In order to maximise the sub-pixel packing and achieve the highest possible pixels per inch (ppi), that leads to diamond rather than square or stripe shaped red and blue sub-pixels. But not for the green sub-pixels, which are oval shaped because they are squeezed between two much larger and different sized red and blue sub-pixels. It's a form of high-tech display art.
The Galaxy S5 display delivers 22 per cent higher brightness than the Galaxy S4 with the same display power. Taking into account its 4 per cent larger screen area, the Galaxy S5 has an impressive 27 per cent improvement in display power efficiency over the Galaxy S4. Turning this around, for the same screen brightness the Galaxy S5 uses 18 per cent less display power than the Galaxy S4, which helps improve the running time on battery. The Galaxy S5 also has 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. See the Display Power section for measurements and details.
While LCDs remain more power efficient for images with mostly white content (like text screens, for example), OLEDs are more power efficient for most other content, which are typically darker, because they are emissive rather than transmissive like LCDs. In fact, the Galaxy S5 is 27 per cent more power efficient than the Full HD LCD Smartphones we recently tested for mixed image content (that includes photos, videos, and movies, for example) with a typical 50 per cent Average Picture Level, APL.
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.
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's resting on a table or desk. While LCDs typically experience a 55 per cent or greater decrease in brightness at a 30 degree viewing angle, the Galaxy S5 shows a much smaller 22 per cent 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 colour shifts with viewing angle are also relatively small. See the viewing angles section for measurements and details.
The Galaxy S5 Cinema mode provides very nice, pleasing and accurate colours, and picture quality. Although the image contrast and colour 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 cinema 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 adapt display mode has significantly more vibrant and saturated colours. Some people like that. It is also particularly recommended for medium and high levels of ambient light viewing because it offsets some of the reflected glare that washes out the images.
Galaxy S5 Conclusions: An Impressive Display
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 backpedaling, all based solely on the extensive objective measurements that we also publish, so that everyone can judge the data for themselves as well.
OLED Evolution: What is especially significant and impressive is that Samsung has been systematically and significantly improving their OLED display performance with every single Galaxy generation since 2010, when we started tracking OLEDs, summarized in our Galaxy S I,II,III OLED Display, Galaxy S4 OLED Display, and Galaxy Note 3 OLED Display Technology Shoot-Out article series. The Galaxy S5 continues the rapid and impressive improvement in OLED displays and technology. The first notable OLED smartphone, the Google Nexus One, came in decidedly last place in our 2010 Smartphone Display Shoot-Out. In a span of just four years OLED display technology is now challenging and even exceeding the performance of the best LCDs across the board in brightness, contrast, colour accuracy, colour management, picture quality, performance in high ambient light, screen uniformity, and viewing angles.
Newest Performance Improvements: The Galaxy S5 has the newest generation of Samsung OLED displays since the Galaxy Note 3 smartphone, which launched in October 2013, and the Galaxy S4 smartphone, which launched in April 2013. While many people have assumed that the Galaxy S5 has basically the same display as the Galaxy S4, but just a bit bigger, that isn't the case. The Galaxy S5 display is a major improvement over the Galaxy S4 and a significant improvement over the Galaxy Note 3 in almost every single test and measurement category -- a good reason to consider upgrading.
Best Smartphone Display: Based on our extensive Lab tests and measurements, the Galaxy S5 is the best performing smartphone display that we have ever tested. It has a long list of new records for best smartphone display performance including: Highest Brightness, Lowest Reflectance, Highest Colour Accuracy, Infinite Contrast Ratio, Highest Contrast Rating in Ambient Light, and smallest Brightness Variation with Viewing Angle. The Galaxy S5 has raised the bar for top display performance up by another notch -- an impressive achievement for OLED technology.
Display Shoot-Out Comparison Table
Below we examine in-depth the display on the Samsung Galaxy S5 based on objective lab measurement data and criteria. For comparisons with the Galaxy S4 and Galaxy Note 3 and additional background information see the Galaxy S4 Display Technology Shoot-Out, the Galaxy Note 3 Display Technology Shoot-Out, and the Galaxy SI,II,III Display Technology Shoot-Out that compares and analyses the evolution of the OLED displays on theGalaxy S I, II, and III. For comparisons with the other leading smartphone displays including LCDs 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.
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 colour 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 protected]