Motorola Droid X2 Review - A Droid X with Tegra 2
by Brian Klug on July 7, 2011 8:31 AM ESTDisplay - qHD RGBW PenTile
Probably the most significant change (other than Tegra 2) between the X and X2 is of course the display. As we mentioned before, that has been upgraded from a 4.3” FWVGA (854 x 480) IPS LCD to a qHD (960 x 540) LCD with the same diagonal size. What’s special about the X2’s screen, however, is that it comes with an RGBW PenTile subpixel rendering layout.
We’ve talked about the RGBG PenTile subpixel structure before in the context of devices which came with AMOLED or Super AMOLED displays. The chief complaint back then was that black text on webpages and UI elements didn’t always look super sharp. RGBW is a different layout with different purpose, and dare I say different results.
A 100% crop of the AT homepage on the Droid X2's RGBW display
As its name implies, RGBW PenTile includes a fourth, white, subpixel. The idea here is that light throughput for the panel can be vastly increased by simply adding a subpixel with no color filter. That increase in throughput then can be exploited to either get equivalent visual brightness with less backlight power, or you can crank things up all the way and get extreme brightness for the same backlight power. That translates to power savings most of the time, and extremely bright whites other times when you need it. It actually does make a lot of sense, especially when you consider things like browsing webpages which is still largely black text on a white background.
Left: Droid X2, Right: Droid X
On webpages, RGBW actually looks pretty good, with black text being nice and sharp on a white background. This is one place where RGBG just never could do a perfect job, but RGBW does. I actually have no problem with RGBW for black text on white backgrounds.
Droid X:
Droid X2:
The only place you can still dramatically tell that this is PenTile is either by looking at regions that are solid green, or red. At green in particular, you can see a bit of that grain from the subpixel structure - green is most visible because visual acuity peaks in the green. Red is also sometimes also shows a bit of that telltale grain, but nothing too dramatic. Human visual acuity isn’t very good for blue, so that looks pretty homogeneous.
In our tests, the X2 results definitely show how much having that white subpixel can help.
Motorola has had a pretty steady track record for putting great displays in their devices, going all the way back to the original Motorola Droid which included an IPS display. It’s nice to see that they haven’t compromised with the X2 either.
We’ve also been measuring display brightness and white point at 25% brightness increments on displays lately, and the X2 is no exception from this treatment. Alongside the Motorola Droid X, the X2 looks substantially bluer. Looking at the white point on the X2 it’s easy to see where that comes from. At 7500K it’s closer to sanity than the 8500K for Super AMOLED Plus, but still not quite perfect.
Moving onto the brightness (white and black) graph, we can see something finally reminiscent of a LCD, showing steady contrast as black and white both climb in a nice linear fashion as we ramp up brightness. The Droid X2 stays pretty contrasty, moreso than we originally measured the Droid X as being, but still not quite chart topping.
Viewing angles on the X2 seem subjectively better than the original X. You can see colors on the X fade off and turn strange at the extreme vertical angles and a bit as well at horizontal extreme angles. I don’t remember the X looking this bad, it could be that the device I borrowed has a worse panel than the original X we were sampled last year.
Outdoors the X2 seems pretty readable, no doubt thanks to having that white subpixel and extremely high brightness. Even in the extremely bright, direct Arizona sunlight the X2 seemed a bit more readable than other devices from recent memory.
Again the real nice thing about the X2 display is that qHD resolution which makes it able to both have a bit more text smoothing on webpages, and also just look better. I was especially thankful for that extra resolution when using things like remote desktop and maps from the X2, as a result, things on similarly sized WVGA displays look cartoonishly huge.
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NeoteriX - Thursday, July 7, 2011 - link
Again, the N8 is an unfair comparison, it's not even the same class of camera phone. Just like the other examples I cited, the Sony C-902, Nokia N82... these are cameras that happen to also be phones. The problem is that these are not apples to apples comparisons.The sensor on the N8 is 1/1.83″ -- by way of comparison, the Canon S95, a real point and shoot camera with very well-respected low light performance relative to its peers has only a slightly larger sensor of 1/1.7" Not to mention it has carl zeiss branded optics and a xenon flash (like the other examples I cited)
The iPhone 4 uses a mobile camera sensor of 1/3.2" and so does the HTC sensation.
Now I'm all for big sensors in cameraphones--the better the image quality the better, as the best camera is ultimately the one you take with you. And the N8 shows that you can shove real point and shoot sensors into a phone, but let's face the reality -- the market of phones with REAL camera sensors and optics is a very, very, very small niche market (they cost $$$ to put in those sensors) and doesn't reflect the mass market of advanced smartphones.
Again, the iPhone 4 represents the best candidate of this balance, and I'm really hoping others HTC, Motorola, etc. step up their game here, but I don't plan on owning an Apple device in the near future.
munky - Thursday, July 7, 2011 - link
It's a valid comparison, the N8 is a smartphone like all the others you mentioned, in the same form factor. I'm not comparing something the size of a DSLR to something that fits in your pocket.Yes, it has a bigger sensor, just like the S95 has a bigger sensor than average pocket cameras - does that mean the S95 is not qualified to be the gold standard of pocket cameras? Doing so is just a refusal to acknowledge a superior product in favor of the lowest common denominator.
NeoteriX - Thursday, July 7, 2011 - link
I agree, but I think the distinguishing factor is that the S95 performs better than anything in its class by any dimension.The large sensor camera phones are still a "niche" in the sense that you have to singularly want exceptional photographic performance to buy one of these phones -- and in return, you have to make several compromises as to the user interface, CPU performance/technology, software ecosystem, etc. The phones are geared towards an audience willing to deal with that.
However, if you look at the other major powers in the phone OS ecosystems (iOS, Win7, Android, WebOS?), none incorporate the large sensor into any phone, much less the kind of flagship phone that you would expect them to pull all the stops out for.
Believe me when I say I would go out and immediately buy the first Android phone with all the furnishings -- dualcore CPU, etc. that *also* included a large sensor and quality glass.
Exodite - Thursday, July 7, 2011 - link
That's a bit of a red herring considering that the vast majority of these so-called 'camera phones' aren't lacking in other desirable features.Indeed, a good camera is becoming something of a hallmark of high-end smartphones in general, HTC being the exception to the rule.
As for the cost you mentioned before, the N8 - undeniably the best-equipped smartphone today when the camera is concerned - is a mid-range phone.
Brian Klug - Thursday, July 7, 2011 - link
I'm a huge optics nerd (it's what I studied in college at least) so I always try and find out everything I can about the cameras in here. Usually that ends up being very little because it either isn't documented, or there's no information in the place I look.For the sensor type, it's easy enough to just run dmesg and scan through there. HTC lately has been initializing the camera and leaving the part number right there. I searched through on the X2 and couldn't find any camera sensor part numbers even in the sections where they're clearly starting to init the camera. It's unfortunate, because otherwise we could get a better feel for what sensors are usually very good and which ones usually aren't.
It's interesting that Apple did such a good job marketing backside illumination with the iPhone 4, when essentially every sensor at or over 8 MP needs to be backside illuminated (and thinned) due to skew effects. That said their camera is indeed very good.
-Brian
jamyryals - Thursday, July 7, 2011 - link
Love the video review format. My favorite smart phone reviewer on the net, keep it up Brian.munky - Thursday, July 7, 2011 - link
Why do the graphs always compare the usual Samsung and Motorolla phones, the old practically irrelevant iphone 3gs, Nexus One and Dell Streak, but not more variety of modern phones, like the Nokia N8, for example? Instead of grouping tablets and phones in the same graphs, separate the two categories so that each one has a better selection of relevant entries.Exodite - Thursday, July 7, 2011 - link
Regarding Motorala and their use of FWVGA over WVGA, they're not the only Android handset manufacturer who went that route as Sony-Ericsson also uses FWVGA on the X10/arc/neo/play.BryanC - Thursday, July 7, 2011 - link
I might consider buying this phone if not for the terrible pentile screen door effect, which is simply unacceptable in today's day and age.The iPhone4 has 960x640x3 subpixels in 5.65in2 area. The Droid X2 has 960x540x2 subpixels in 7.90in2 area. The iPhone has 2.5X the subpixel density of the Droid X2! And it's immediately obvious when you look at the displays - the iPhone4 display is so detailed the image looks printed on, it's in a completely different class.
Too bad.
JayQ330 - Thursday, September 1, 2011 - link
what does that have to do with any of this? oh i see, wipe your chin there's still some iphone honey left.