Back in the good old days of… the year 2014, the resolution 1080 x 1920 pixels (also referred to as 1080p) was the screen resolution associated with most high-end smartphones. Everyone seemed to be happy with it thanks to a high pixel count and density sufficed for every task, especially games. But then came phones like the Oppo Find 7 and the LG G3, which broke the 1080p barrier with their 1440 x 2560 pixels (Quad HD) screens. All of a sudden, 1080p screens weren’t good enough. It was Quad HD displays that produced the most detailed, sharpest image one could possibly see on a smartphone screen. At least that’s what we were told.
Today, just one year later, there are no less than a dozen smartphone models rocking Quad HD screens – from the exotic Sony Xperia Z4v and Meizu MX 4 Pro to the hugely popular Galaxy S6 Edge and Galaxy S6 Active. And their number is only going to rise in the foreseeable future. But honestly, do we really need a Quad HD Phone? What’s the practical benefit from having such an insanely pixel-dense display on your smartphone? And, in case of being convinced, can users really see the difference between Quad HD and Full HD 1080p resolution on a device of average size?
Different types of displays
HD stands for high definition. It simply means a measurement of pixel of 1280 x 720 pixels. Regardless of the screen size, if the pixel stays at this measurement, it’s a HD display. So, it can be assumed that the smaller the screen, the higher pixel density, and it will have better picture. For instace, 4.3 inches screen will come with 342 ppi pixel density, 4.7 inches will drop to 312 ppi. However, it is not a matter because according to Apple when it launched iphone 4, 300 ppi is human “sweet spot” in a certain distance.
This one is the higher step of smartphone standard display. The definition of Full HD is 1920 x 1280 pixels. With the smartphone around 5 inches, the pixels will be 441 ppi. Once again, pixels will be adjusted basing on the screen size. The pixel will spread out more on a larger screen. Similarly, it will squish on smaller screen.
QHD / Quad HD or 2K
QHD is the abbriviation of Quad HD. Its measurement is 2560 x 1440 pixels. That is the reason why it called 2K, which measured over 2,000 pixels. Those resolution often defined by its mesuarement. Therefore, in the same way, HD will come sometimes called 720p, and Full HD called 1,080p. Then, a 5.5 inches QHD display has a pixel density of 538 ppi. For instance, 5.5 inches LG phablet form is G3 with 1440 x 2560 a resolution hit the same pixel density of 534 ppi.
Full HD vs Quad HD, When we start to notice pixelization?
In order measure the ideal distance between you and your smartphone screen, you will need a perfect vision of 20/20 that only few are gifted with. A person with 20/20 vision is one who can discern detail of 1 arc minute (1 arc minute = 1/60 of a degree = a circle has 360 degrees, so 1 arc minute = 1/21600th of a full circle). Most people have worse vision than that – for instance someone with 20/40 vision can only discern detail of 2 arc minutes, while the rear few (think jet pilots) with 20/10 vision can discern detail of 0.5 arc minutes. The actual limit of human vision is around 20/8, so again, we’re assuming a fairly optimistic 20/20 vision scenario.
So with all that in mind, how close do you need to be start seeing those pixels and details on even a Quad HD smartphone?
- Typical 480p phone (4” display like Galaxy S III Mini): eye starts to notice pixelization from 14.73” (37.4 cm)
- Typical 720p phone (4.7” display like Nexus 4): eye starts to notice pixelization from 11” (28 cm)
- Typical 1080p phone (5” display like Galaxy S5): eye starts to notice pixelization from 7.8” (19.8 cm)
- Typical 1440p phone (5.5” display like expected LG G3): eye starts to notice pixelization from 6.44” (16.4 cm)
Screen resolution and battery drain
More pixels are put in a display will make the CPU work harder in order to render the high definition images faster. Therefore, this will have a severe impact on the battery. Based on our purpose of needs, we can wisely choose between crystal clear screens, or the long run battery life. It’s up to your personal preference.
It is important to remember that the human vision is more complex and the actual way we see things is a lot about how the brain processes images. And that’s something that is hard to measure right now. With this in mind, we’ll keep things simple: at regular viewing distances, it is practically impossible to notice the difference in sharpness between say the 1080p Galaxy S5 and the future Quad HD flagships.
But regardless of whether people can see the difference, Quad HD displays are only going to get more prevalent among smartphones. After all, a Quad HD screen makes a strong selling point. And we have a feeling that the resolution race won’t stop here, as smartphones equipped with 4K screens might not be far from been announced.