When 1080p screens came to phones, the general consensus was that the resolution race could be coming to an end. After all, who needs more than full HD resolution on a phone? Whether or not we need it, LG took the stage a few months ago and announced the LG G3 with a quad HD (QHD) screen clocking in at 2560x1440 pixels. The G3 is the first device in the US market with a QHD panel, but LG had to make some sacrifices to get there. So is it all marketing nonsense, or did LG win the resolution race?
More Retina than Retina
The conventional wisdom has long been that anything north of 300 pixels per inch would be sufficiently high resolution that the average human would be unable to make out the individual pixels at arm's length (the G3 is 534 PPI). This is absolutely true if you're talking about picking out pixels, but reality is a bit more muddled than that.
While 300 PPI makes it impossible to see pixels for virtually everyone, the images displayed on the screen might benefit from a higher resolution. For example, the eye can detect very small changes in the angle of a line that are well below the normal "retina resolution." Likewise, the alignment of two parallel lines can be seen with a startling degree of clarity--on the order of 4-5 times that of normal visual acuity. So, you might conceivably need 1500 PPI to account for all these cases.
A QHD screen might also perform better when it comes to rendering curves--antialiasing, basically. The mathematical relationship between discrete points (pixels) and continuous elements (lines) is murky at best, but when you toss human vision into the mix, it can be hard to come to any firm conclusions. So what does this mean? A straight line made up of pixels you can't see is just a line. However, a curve made up of pixels exactly the same size might not look continuous as the pixels will produce a very subtle aliased (jaggy) edge. It would be up to software to clean that up, and having more pixels to work means better results.
The way the eyes and brain process this visual data probably varies from person to person, but some analyses of the numbers point to roughly double the resolution requirements to prevent visible aliasing. So we're talking about 600 PPI, and the G3 gets close with 534 pixels per inch.
The bottom line is that there's SOME basis for thinking that a QHD screen could offer a better viewing experience. Although, it's definitely not going to be a marked improvement in quality like jumping past 300 PPI.
The G3 Screen
Okay, so we've gotten the science out of the way, how does the screen on this phone look and perform? I'll tell you right now, I like the screen. I can't rule out confirmation bias, but some things on the G3's screen do look crisper and more fluid to me. It's particularly evident on icons with a lot of curves and tapers that come to a point. So it's possible to see more detail on a 1440p screen, but not always.
There's also the eyeball test, which I will grant is not realistic at all. If you bring the G3 right up next to your eye, you can't make out the pixels or any jaggies. On a 1080p screen like the one on the Nexus 5 (445 PPI), you can just a little. The Moto X with its 720p RGB AMOLED matrix (312 PPI) makes it a bit easier to pick out these imperfections close up. Again, this isn't a real world situation, just a way to pick out subtle differences.
So maybe it's a little more clear, but what do you have to give up? More pixels means a lower active area and smaller transistors. Because there are so many more pixels to illuminate, the G3 has to project more light for you to see, and that means increased power drain. You can certainly tell LG is cognizant of this fact as the G3's auto-brightness is tuned fairly low. The maximum brightness is also a little dimmer than other devices in its category. Blasting all those photons at the 1440p screen also makes blacks a little less black, but it's not awful.
Because more light is needed to illuminate a 1440p screen, it sucks down more power. That's evident from using the G3. It has one of the largest batteries in a mainstream smartphone (3000mAh), but its screen-on time is only average. With normal usage, you're looking at about four hours of screen-on time, or over six if you keep it on continuously until it runs dry. The standby time, however, is amazingly good.
LG has done a lot to minimize power usage in software beyond the lower brightness tuning. LG says it is still using panel self-refresh, which debuted in the G2. This is an optimization of the processor that takes into account what's going on with the screen at a given time. If the image being displayed is static, the screen can refresh itself from a small partition of dedicated memory. This allows the Qualcomm Snapdragon 801 to back off and save power. The display's refresh rate is also controllable through software and toggles between two states -- 60Hz and 50Hz. When the full 60Hz isn't needed, it steps down to 50Hz to save power. Interestingly, this means that future OTAs could have a marked effect on battery life.
LG really wants to show off how sharp this display is, so there's some rather aggressive post-processing going on to emphasize the sharpness.
The last consideration for LG's foray into the QHD world is more of a software quirk than something about the panel. LG really wants to show off how sharp this display is, so there's some rather aggressive post-processing going on to emphasize the sharpness. In practice, it looks a bit odd in some instances. For example, text on a darker background appears to have a halo effect between the letters. Right now there is no way to turn off this feature, but considering the response, I imagine it will be optional in a future OTA update.
So what's the verdict? The G3 screen is very good overall. It does seem sharper in some places and the brightness is reasonable. I find that my eyes are somewhat adjusted to the small details you can pick up on a QHD screen--it's not a dramatic difference, but it's there. The battery life, while not amazing, is actually pretty good considering the jump in resolution. There are a few annoying issues right now, but LG's push toward software control of the panel should allow it to alter the display characteristics with updates more dramatically than in the past.