Battle Royale: Five smartphone screens face off

With the recent release of DisplayMate Multimedia Edition for Mobile Displays, a battery of tests to measure the quality of portable screens--and apparently because I'm a glutton for punishment--I thought now would be the perfect time to bring five popular smartphones back to CNET Labs for a down-and-dirty comparison of their screen performance.

The five phones I chose to put through the ringer (ahem) are the Samsung Behold II, the Motorola Droid, the Apple iPhone 3GS, the HTC Nexus One by Google, and the Palm Pre Plus. These five were chosen because of their relative popularity and similar feature sets.

We used three different types of tests to evaluate each phone:

Scientific measurements: We used the Konica Minolta CS-200 ChromaMeter to test the maximum brightness, black level, and contrast ratio of each phone and reported numbers for each of these three tests.

Test pattern screens: We used several DisplayMate Mobile test patterns to test for color-tracking errors, 24-bit color, and font legibility, among others.

Real-world: Finally, we conducted real-world anecdotal testing using 3D games, photos, and a little tool I like to call "the Sun" to test the diffuse reflectance of each display.

All test screens were viewed within each phone's native gallery application. Some phones may handle pictures differently--and even improve them to some extent--outside the application. That said, we believe that testing within the respective gallery applications is still a viable test as this is where most users will view pictures on their phones.

In order to diminish potential repetition, I'll dive right into the details of how each phone performed; if you'd like to know more about our tests, you can binge off nerdy details in our "How we tested" section at the bottom of this article. Please note that this is an evaluation of each phone's screen performance and nothing else. Check out the full reviews of these phones to determine which is right for you. Also, DisplayMate recently conducted a more technically focused evaluation of the iPhone 3GS' and the Nexus One's screens that I recommend you take a look at.

The bottom line

1. Motorola Droid
2. Palm Pre Plus
3. Apple iPhone 3GS
4. HTC Nexus One by Google
5. Samsung Behold II

Keep reading to find out why we ranked them this way.

I know everyone has strong opinions and usually fiery passions about their smartphone of choice, so I don't expect everyone to agree with my assessment or the methods used in drawing my conclusions. If there are any questions about how I came to my conclusions or anything relevant I may have left out, please leave a comment saying as much. Also, if you'd like to see even more detailed information of each phone's performance, let me know. If enough are interested, I'll do a follow-up post with that information.

Lastly, though I hope consumers get something useful out of this, I'd be just as happy if the respective manufacturers of the phones took a serious look at these results and at least considered them when making their respective hardware and software revisions. We all want these phones to continue improving, and I'm just attempting to contribute to the cause. 

Motorola Droid
The Droid achieved an incredibly impressive contrast ratio, given that it's not OLED-based. It also had the most-accurate colors of any of the phones as well as the sharpest text. Also, unlike the Nexus One, the Droid was capable of displaying 24-bit color. Its only glaring mistake was an overly reflective screen when viewed in a sunny, natural environment. Despite that, the Droid is clearly the performance winner, followed fairly closely by the Palm Pre Plus and the iPhone 3GS, which washes out color as a result of its superbright screen. Both the Behold II and the Nexus One have incredibly deep blacks, but they both oversaturate colors to the point that they're inaccurate and sometimes distracting.

Palm Pre Plus
The Palm Pre Plus was one of the best performers we tested, coming in right behind our overall best performer, the Droid. The Pre Plus' color was accurate and fuller than the iPhone's and not oversaturated like the Behold II and Nexus One. The color isn't as accurate as the Droid's, but it did show that it's capable of displaying 24-bit color. Its level of backlight clouding was the second highest, next to the iPhone, but it produced the least amount of diffuse reflection of any phone.

Apple iPhone 3GS
The Apple iPhone 3GS achieved the highest brightness of any of the five phones we tested. Unfortunately, this resulted in it having the highest black level as well. This translated into a disappointingly low contrast ratio. The iPhone 3GS showed no evidence of false contouring and is capable of displaying 24-bit color. Reflection on sunny days is only a problem at extreme angles. It doesn't have some of the glaring color problems that plagued the Nexus One, but its profuse backlight clouding means many of its colors look washed out.

HTC Nexus One by Google
The Nexus One achieved an incredible contrast ratio, afforded by its extremely low black level. This low black level is a result of HTC and Google's decision to go with an OLED-based screen, instead of a traditional, LED-based screen. However, instead of delivering accurate, natural colors, the Nexus One oversaturates them, resulting in glaring color tint problems and inaccurate color reproduction. For example, red could possibly be confused with orange on the Nexus One. Also, false contouring is apparent in the Mars photo, lending evidence to a lack of 24-bit color support, and the phone's extreme outdoor reflectance makes it difficult to operate on sunny days. Though some may prefer the screen's ability to make colors pop in games and its high contrast ratio, don't expect any natural color reproduction.

Samsung Behold II
The Samsung Behold II is the second OLED-based phone in our roundup. Not surprisingly, we saw not evidence of clouding when viewing a black screen in a completely dark room. Unfortunately, it continues the OLED trend set by the Nexus One: it has disappointing performance. Plagued by various color inaccuracies, oversaturation, color tint problems, and an inability to legibly display gray and white text on a black background, the Behold II had a terrible time trying to keep up with its competitors. Even its incredible, OLED-afforded contrast ratio couldn't save it. Overall, the Behold II had the worst performance of the five phones we tested.

How we tested
We measured each display's brightness, black level, and contrast ratio using the CS-200 and test patterns provided by DisplayMate. All phones were tested at their maximum brightness with full battery charges. All readings were conducted in a completely dark room.

"At least/At most" explanation: True black can be represented as 0 candelas per square meter (cd/M2). Thanks to their OLED screens, the Nexus One and Behold II's black levels were so low, the Konica Minolta CS-200 ChromaMeter wasn't equipped to detect them. According to its specs, the CS-200 can only see black-level measurements as low as 0.005 candelas per square meter (cd/m2). Using simple logic, we can infer that both phones achieved, at most, a 0.0049 cd/m2 black level. Using more-sophisticated equipment, the guys at DisplayMate got a black-level reading of 0.0035 cd/m2 for the Nexus One. Given that our tested maximum brightness for the Nexus One was 225 cd/m2, we can hypothesize a contrast ratio of at least 46,000:1 and possibly more than 65,000:1 using DisplayMate's black-level results for the Nexus One and 63,000:1 for the Behold II.

Test patterns All test pattern tests were conducted in a completely dark room.

White-level saturation: This test includes a number of rectangular blocks on a bright, white background. Peak white is represented by the block labeled 255. The closer a screen gets to displaying 255, the less likely it'll be to not show certain colors when viewing a really bright screen.

Color scales: Tests the display's ability to show 25 distinct intensity levels for each of the 10 primary colors, from black to peak brightness. A perfect showing would have each color with 25 distinct steps.

Color tracking: This screen tests the LCD's ability to display the grayscale uniformly and accurately without any color tint problems.

RGBW smooth color ramp: This an excellent test for determining whether the LCD can display 24-bit color. If the scale is smooth, without visible "steps," the display should be capable of 24-bit color. If not, it's likely limited to 16-bit or possibly 18-bit color.

Fonts: We tested black, gray, and white fonts on different combinations of black, gray, and white backgrounds. Depending on how the phone handles things, certain combinations may affect the text's legibility. Most of the phones had little problem displaying text, but the Behold II had an egregious white text on black problem.

Real-world tests

Coca-Cola photo: A high-quality picture of a coke can can be used to test how close the phone can come to reproducing colors from the real world. We used a real Coke can as reference. Though the Droid achieved the closest color approximation of the can, the Nexus One's and Behold II's cans looked more orange than red.

Mars photo: We used a picture of a sunset on Mars to test the display's real-world false contouring threshold. The sky should appear to smoothly transition in color. If visible steps are noticeable, the phone has a false contouring problem. The Behold II and Nexus One had the most egregious offenses; the Palm Pre Plus' sky looked nearly perfect.

Game: We used Fastlane Lite on the iPhone 3GS, Asphalt 5 Free on the Pre Plus, and Raging Thunder Lite on the Nexus One, Behold II, and Droid, to evaluate each phone's color performance in a fast-moving game. The Nexus One and Behold II saw oversaturated colors; the Droid's colors were pinpoint accurate.

Diffuse reflectance: Some screens are more reflective than others, but what matters most is how reflective they are under extreme conditions; you don't get more extreme than a sunny day in San Francisco.The Pre Plus won this fight, with the iPhone coming in second.