Battle Royale 3: A tale of four smartphone screens

Editors' note: If you've already read "Battle Royale: Five smartphones face off" or "Battle Royale 2: The Quickening" (OK, it wasn't actually called "The Quickening"), then you may experience some deja vu when reading this article. We've used the same tests and presented the article in the same style. Only the phones in question and the details of their performance have changed. Because of some technical difficulties on the back-end our How We Test Smartphone Displays page isn't up yet, but hopefully, by Round 4 it will be.

In the last six months I've tested 10 different smartphone displays, including the three new ones presented today. The response from both Android and iPhone fans has been interesting, if not unexpected. I assume this round will be no different. Once again, using DisplayMate Multimedia Edition for Mobile Displays, I put each phone through a battery of tests.

In our last roundup, we received some reader complaints for comparing the iPhone 4 to the original Droid and HTC Evo and not the Droid X or Droid incredible. Both of which hadn't been released at the time of last round's testing.

Well, today is a new day and with that comes the promise of a more robust evaluation (or so the saying goes). For Round 3, not only do we have the iPhone 4, but also the Motorola Droid X, the HTC Droid Incredible, and the Samsung Epic 4G. These were the most-requested phones according to the comments and e-mails from the previous round.

Like in previous roundups, 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: 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 gallery 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 on 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 will soon be posting a more technically focused evaluation of the iPhone 4 and Samsung Galaxy S (same screen as the Epic 4G) screens that I'm sure will be worth checking out.

The bottom line
Here's how we rank the phones in screen performance:

1. Apple iPhone 4
2. Samsung Epic 4G
3. HTC Droid Incredible
4. Motorola Droid X

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. This has become a regular feature here at CNET, so don't in any way believe this is the last word on the subject. We'll likely be seeing "Battle Royale 10: The iPhone 5 vs. Droid 3" at some point in the not too distant future.

Lastly, though I hope consumers get something useful out of this, I'd also be happy if the 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.

Apple iPhone 4
The iPhone 4 was the best overall performer of the four phones we tested. Although it achieved the lowest contrast ratio of the four, the iPhone 4 was capable of displaying 24-bit color and was able to display colors in games and pictures with pop and life while still being accurate. The iPhone 4 won in most of our scientific tests and also had the best performance overall in our real-world tests. Once again, the iPhone 4 has the best smartphone screen on the market.

Samsung Epic 4G
The Epic 4G handled white-level saturation better than any of the other phones, displaying the highest level of gray. Like the Incredible, the Epic 4G achieved a very high contrast ratio, thanks to its AMOLED screen.

HTC Droid Incredible
The Incredible achieved the highest contrast ratio of the four phones, thanks to its AMOLED screen. Also, it was able to display the darkest colors in the color scales test, whereas the other phones weren't. Unfortunately, it suffered from some egregious false contouring problems.

Motorola Droid X
The Droid X had the worst overall performance of the bunch, epitomized by it's drab color and offensively obvious false contouring. However, because of its tendency to not oversaturate colors, the phone exhibited the least amount of color compression at the light end of the color scale.

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 Droid Incredible and Epic 4G'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 this method we were able to determine the estimated contrast ratio of both the Epic 4G and Incredible.

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 more likely it'll be to show certain colors when viewing a really bright screen. The Samsung Epic 4G barely nudged past the iPhone 4 by displaying up level 254. The iPhone 4 displayed 254 as well, but just not quite as clearly. The Droid X was third, barely displaying level 252 and the Incredible brought up the rear where you can barely see level 249.

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. The Droid X had the least amount of compression at the light end of the scale, showing the most distinct difference in color levels at that end. Nearly all four phones had problems displaying the next to darkest level. The Incredible was the sole phone able to display that level of color. However, the Incredible had the most compression at the light end of the scale, with the last two levels of the light colors meshed together. The iPhone 4 and Epic 4G had almost no color compression at the light end, but not as good as the Droid X.

Color tracking: This screen tests the LCD's capability to display the grayscale uniformly and accurately without any color tint problems. Like last round, the iPhone 4 had the best presentation here with an accurate grayscale and no apparent color tint problems. The Epic 4G has a couple bars with both pink and green tint problems. The Incredible was pinkish in the lighter grays and slightly green in the darker grays. The Droid X had very dramatic green and pink 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. The iPhone 4, Epic 4G, and Incredible were all able to display 24-bit color. The Droid X failed the 24-bit color test, as it wasn't able to show smooth scaling in its native Gallery app.

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. The phones had no problems when displaying text; however, with the iPhone 4's high resolution and relatively small screen, text--though sharp and crisp--was small and we had to strain our eyes to see it properly. The Droid X had the next clearest text , though not quite as clear as iPhone 4. The Incredible's text was slightly blurrier than the Droid X. The Epic 4G has bloomy text, especially with black text on light backgrounds.

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. Again, like in the previous round, the iPhone 4 achieved the closest approximation of the can, with a nice, deep red and a metal top that looked appropriately more silver than gray. The Epic 4G was second best, with a clear picture, but its red was oversaturated. The Droid X displayed a clear picture, but its color was bland and lacked pop. The Incredible displayed blurry and dithered bubbles and oversaturated the 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. Once again, on the iPhone 4 we detected virtually no false contouring in the sky. The Epic 4G saw some noticeable dithering near the bottom center of the pic, around the sun. Both the Droid X and Incredible had skies full of ugly, very noticeable false contouring.

Game: We used Raging Thunder 2 on the iPhone 4 and Raging Thunder 2 Lite on the others to evaluate each phone's color performance in a fast-moving game. The iPhone 4 had the best overall presentation with the most-accurate colors that did not oversaturate at all. The Incredible saw vibrant and colorful performance, but its colors were oversaturated. The Epic 4G saw very similar performance to the Incredible, but had a slightly blurry presentation. The Droid X's drab colors made the game look unexciting and because of this, was the worst overall performer.

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. For the sake of your eyes, I don't recommend testing this without sunglasses on. In this round, the Incredible, Epic 4G, and iPhone 4 saw about the same amount of reflectance under direct sunlight. Details on the Droid X's screen was noticeably more difficult to see under the same conditions.