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Eric Franklin/CNET
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
Here’s how we rank the phones in screen performance:
- Motorola Droid
- Palm Pre Plus
- Apple iPhone 3GS
- HTC Nexus One by Google
- 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.
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The numbersThe Droid had the lowest black level of
the phones that were not OLED-based. With a black level of 0.17cd/m2
and a 410cd/m2 peak brightness, the Droid achieved an impressive
contrast ratio of 2412. This is an exceptional achievement for a non
OLED-based display. The vast majority of non-OLED displays will top out
at 1000:1. There is some clouding visible on the edges when viewing a
black screen in a dark room, but it’s the least amount compared to the
iPhone and Pre Plus.
Test pattern results
White Level Saturation: The Droid got the closest to peak white of any
of the phones by displaying the 254 level of gray. This is the highest
any display is capable of. We also saw no color tint problems. This was
as perfect as you can get.
Low Saturation Colors: Of the five phones tested, the Droid’s 2 percent bar was the fullest and most visible.
Color Scales: The Droid was as good as the Palm Pre Plus here and
achieved a smooth transition from dark to light with no blending of
color intensities.
Color Tracking: The Droid was the only phone in the roundup to display
the gray-scale with accurate intensities with no noticeable color tint
problems.
Font: The Droid displayed fine, sharp text, that may be too small for some. White text on black looks great.
RGBW Smooth Color Ramp: A smooth transition from dark to light indicating the Droid’s capability to display 24-bit color.
Real world results
Coca-cola photo: The Droid achieved a vibrant red that was the closest
to the real-world coke can than any of it competitors.
Mars photo: A smooth sky and color transition from the Droid, although
we did notice some slight graininess that gave the Palm Pre Plus the
edge here.
Game: The Droid had the most accurate colors in games than any other
phone. The colors are full without being over saturated, and accurate
without looking washed out. Still, some may prefer the over saturated
look achieved by the Nexus One and Behold II for games.
Diffuse Reflectance: The only glaring performance fail for the Droid is
its extremely reflective screen. When outdoors, on a sunny day, details
can’t be seen from certain angles.
Conclusion
There you are. –>
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.
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The Numbers
The Palm Pre plus had an unacceptable, but not terrible contrast ratio.
With a brightness of 320 cd/M2and a black level of 0.46 cd/m2, it
achieved a contrast ratio of 628:1. Lower than the 1000:1 we’d like to
see, but better than the iPhone’s 130:1. It didn’t have nearly as much
clouding as the iPhone, but it wasn’t as dark as the Droid either.
Test pattern results
White level saturation: The Palm Pre Plus had the second best showing
behind the Droid in this test. It displayed gray up to the very high
253 level, but unfortunately had a slightly pinkish tint. This
indicates the Pre will not have the tendency to over saturate colors,
but may see some slight color tint problems.
Low Saturation Colors: The Pre Plus produced a full, solid, 2 percent
bar. More evidence that you won’t have to worry about the Pre Plus over
saturating colors, especially when viewed on a white background.
Color Scales: The Pre Plus achieved a smooth transition from dark to light with no blending of color intensities.
Color tracking: The Pre Plus saw a very slight greenish tint, but no color dithering problems like we saw on the iPhone.
RGBW Smooth Color Ramp: A smooth transition for the Pre Plus that indicates its ability to produce 24-bit color.
Fonts: The Pre Plus’s font performance was better than the iPhone but
not as sharp as the Nexus One or Droid. White or gray text on black was
easily legible.
Real world results
Coca-cola photo: The Pre Plus’ coke can, looks slight orange compared to the real thing, but the perspiration bubbles are clear.
Mars photo: The Palm Pre Plus delivered the smoothest sky of all five
phones, barely beating out the Droid. We think it’s safe to say there’s
little chance of false contouring appearing on this phone.
Game: Colors in the game were not as washed out as on the iPhone 3GS,
but were not quite as accurate as the Droid’s reproduction. No color
over saturation was present.
Diffuse Reflectance: The Palm Pre Plus had the least amount of diffuse
reflection on any of the five phones, only showing glaring reflection
problems at extreme angles. Even so, we found that we could always see
the screen no matter the angle.
–>
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.
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The Numbers
Unlike the Nexus One, the iPhone 3GS doesn’t use an OLED-based screen, but instead traditional LEDs to provide the backlight. Of the five phones, the iPhone 3GS had not only the highest brightness, at 431 cd/m2, but the highest black level as well with its 3.31 cd/m2 reading. This resulted in an extremely low 130:1 contrast ratio, the lowest of the phones compared. When looking at a black screen on the iPhone 3Gs, in a completely dark room, there is apparent clouding and backlight bleeding. While the same screen looked completely black on the Nexus One, on the iPhone 3GS it appears a light gray.
Test pattern results
White level saturation: The iPhone 3GS displayed up to 251, but unlike the Nexus One didn’t reveal any color tint problems. A good score that shows the iPhone 3GS’s ability to display the gray-scale fairly close to peak white.
Low Saturation Color: The iPhone 3GS displayed a very light 2 percent color bar, indicating that it has a tendency to slightly over saturate the gray-scale when displaying colors a white background. Identical performance to the Nexus One.
Color Scales: On the light end of the scale, the iPhone 3GS showed a clear distinction between all color intensities. At the dark end, the last three levels of each color blended together, showing no distinction. This indicates that the iPhone 3GS would have trouble reproducing dark color detail.
Color tracking: Consistent intensity scaling from dark to light gray, but a pinkish tint indicates a slight color tracking problem which may result in somewhat inaccurate color reproduction.
RGBW Smooth Color Ramp: A smooth transition in the scale indicating that the iPhone is capable of producing 24-bit color.
Fonts: The iPhone 3GS’s text is slightly blurry compared to the Droid, Nexus One and Palm Pre Plus. Its white text on black reproduction, while completely legible, wasn’t as sharp as the aforementioned phones.
Real-world results
Coca-Cola photo: The iPhone 3GS’s reproduction of the coke can’s red was slightly muted and not as vibrant as its real world counterpart.
Mars photo: Some graininess in the sky, but the colors transition smoothly. Dark detail on bottom of the photo is difficult to see.
Game: Colors in the game were not as vibrant as what we saw on the Droid and the lack of contrast between light and dark images was apparent on the iPhone 3GS.
Diffuse Reflectance: The iPhone 3GS’s screen reflects an acceptable amount of light and can be clearly seen from nearly every angle. Some extreme angles required to play games like Super Monkey Ball, sometimes resulted way too much glare to play effectively.
–>
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.
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The numbers
The Nexus One’s screen affords it a very dark black level. True black
can be represented as 0 candelas per square meter (cd/M2). The Nexus
One’s black level was so low, the Konica Minolta CS-200 ChromaMeter
wasn’t equipped to detect it. 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 then that the Nexus One
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. Given that our tested maximum brightness for the Nexus One was
225 cd/2–the lowest of the phones we tested–we can hypothesize a
contrast ratio of at least 46,000:1 and possibly over 65,000:1 using
Displaymate’s black level results. As such, with our naked eyes, we saw
no clouding or backlight bleed-through on the Nexus One when staring at
a completely black screen. Thanks to its OLED technology, which–unlike
normal backlight technology and less sophisticated LED technology–can
completely shut off when viewing a black image, the Nexus was able to
produce incredibly deep blacks and this a high contrast ratio.
Test pattern results
White Level Saturation: The Nexus One displayed up to 251; however,
most of the blocks had an obvious pink tint to them, indicating that
the display may be displaying an over abundance of red.
Low Saturation Colors: The Nexus One displayed a very light 2 percent
color bar, indicating that it has a tendency to slightly over saturate
the gray-scale when displaying colors a white background.
Color Scales: At the light end of the scale, several colors began to
show no distinction in intensity levels. Also, some colors didn’t
always scale uniformly from the dark end of the scale to the light end.
Color Tracking: Not only did the Nexus One show inconsistent intensity
scaling from dark to light gray, there were apparent pink and green
tints in several spots indicating a distinct color tracking error.
RGBW Smooth Color Ramp: Very visible “steps” in the scale instead of a
smooth transition, indicating that the Nexus One is currently not
capable of displaying 24-bit color.
Fonts: The Nexus One’s fonts were consistently legible, even with white and gray text on a black background.
Real world results
Coca-cola photo: The Nexus One over saturated the red of the can over
its real life counterpart and the perspiration on the can looked
dithered.
Mars photo: The Nexus One shows distinct evidence of false contouring.
The colors in the sky don’t follow a smooth transition and instead
looks like visible wave pulses emanating from the sun. Also, the ground
looks very dithered and lacks color.
Game: The Nexus One over saturates the colors and as a result the text
in the game looks bloomy. Overall, the colors don’t look natural, but
they have a definite pop to them, so some may prefer this over the more
natural look of games on the Droid.
Diffuse Reflectance: In the bright sun, the Nexus One reflects an
abundance of light making it very difficult in operate from most
angles. Not quite as bad as the Droid however.
–>
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.
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The Numbers
Like the Nexus one, the the Behold II’s black level was too low for the
CS-200 to read it. Once again however, we can estimate that the Behold
II has at least a contrast ratio of 63265:1, given its brightness of
310 cd/M2 and a black level that can be no higher than 0.0049 cd/m2.
This gives it the highest contrast ratio of any of the phones we looked
at. Not surprisingly we saw not evidence of clouding when viewing a
black screen in a completely dark room.
Test pattern results
White level saturation: The Behold II displayed gray up to the 247
level, which is the minimum acceptable level. Also, what were supposed
to be gray blocks, actually looked pink, indicating a color tint
problem.
Low Saturation Colors: The Behold II could not display the 2 percent
bar, a failure of this particular test. This indicates that the phone
will over saturate certain shades of colors to the point that they are
invisible when displaying on a white background.
Color Scales: At the light end of the scale, most colors began to show
no distinction in intensity levels. Also, some colors didn’t always
scale uniformly from the dark end of the scale to the light end.
Color tracking: A very green tint is apparent indicating an obvious
color tracking problem. Additionally, many of the blocks showed shadow
artifacts.
RGBW Smooth Color Ramp. Very visible “steps” in the scale instead of a
smooth transition, indicating that the Behold II, like the Nexus One,
is currently not capable of displaying 24-bit color.
Fonts: The worst font performance of any of the phones. White and gray test on a black background is nearly illegible.
Real world results
Coca-cola photo: The Behold II’s version of the can looks more orange,
than red and is slightly over saturated. Unlike the Nexus One, the
Behold II displayed the perspiration bubbles clearly.
Mars photo: A lot like the Nexus One, the Behold II shows distinct
evidence of false contouring. The colors in the sky don’t follow a
smooth transition and instead looks like visible wave pulses emanating
from the sun. We didn’t see evidence of color dithering like on the
Nexus One however.
Game: The Behold II over saturates the colors and as a result the text
in the game looks bloomy. Sound familiar? Yes, Behold II delivered
virtually identical performance as the Nexus One. The Overall, the
colors don’t look natural, but they have a definite pop to them, so
some may prefer this over the more natural look of games on the Droid.
Diffuse Reflectance: An abundance of sun refection in an outdoors
environment, making the screen appear very dim with difficult to see
text and details.
–>
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.
| Phone Name | Resolution | Brightness | Black Level | Contrast Ratio |
|---|---|---|---|---|
| Samsung Behold II | 320×480 pixels | 310 cd/M2 | (At most) 0.0049 cd/m2 | (At Least) 63265:1 |
| Motorola Droid | 480×854 pixels | 410 cd/M2 | 0.17 cd/m2 | 2412:1 |
| Apple iPhone 3GS | 480×320 pixels | 431 cd/M2 | 3.31 cd/m2 | 131:1 |
| HTC Nexus One by Google | 800×480 pixels | 225 cd/M2 | (At most) 0.0049cd/m2 | (At Least) 46,000:1 |
| Palm Pre Plus | 320×480 pixels | 320 cd/M2 | 0.46 cd/m2 | 628:1 |
“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.
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Low Saturation Colors: When producing a bright, white image,
many displays over saturate the gray-scale and the lightest grays of
the scale are lost in the white background. This screen is used to
evaluate color reproduction at the brightest end of the scale, closest
to white. Five bars are labeled with their percentage of color
saturation, ranging from 10 percent to 2 percent. The real test here is
to see which of the phones were able to display the 2 percent color
saturation bar.
–>
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.
DisplayMate
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.
NASA
