Sony Xperia Z5 Premium is the first smartphone to feature a 4K display or UHD as it's also known. To be more specific it utilizes a 5.5" IPS panel of 2160 x 3840 pixel resolution. The resulting pixel density of 806ppi is well above anything we've seen on a smartphone or even a tablet for that matter.
4K is another name for UHD resolution or 2160 x 3840 pixels. That's an awful lot of pixels - something along the lines of 8.3 million of them. Phones so far had only been able to go as high as 1440 x 2560 pixels (3.7 million pixels). And Sony's own Xperia line has never gone higher than 1080 x 1920 pixels (2 million). So with this phone, we're essentially rocking twice or even four times the usual number of pixels on the screen. An insane jump in resolution, right?
The screen in the Xperia Z5 Premium is the first of its kind in a smartphone. It's an amazing engineering feat and it's surely a challenge for any sort of a mobile hardware to pump out so many pixels to the screen.
Sony made it possible by putting a 4K panel inside the Z5 Premium but rendering mostly everything in 1080p resolution. Yes, it's a concept that you may find a bit hard to grasp at first. The 4K panel the phone utilizes only reveals its benefits when you check out high-res images and video on it (it works with online video too).
When we approached the phone for a detailed test, we had quite high expectations. We expected to see an image that's infinitely better than what we had seen before. Long story short, that was hardly the case.
It turned out the screen worked just as advertised but the benefits of the higher resolution over say, a 5.5-inch QHD screen, are not readily noticeable with our bare eyes. We did notice an improvement over a 5.5-inch 1080p screen once the 4K high resolution mode kicked in but it was mostly in the way that textures looked smoother, rather than with higher detail.
What we did appreciate however is the fact that at no point did we notice any downsides to the upscaling from 1080p to 4K of the regular interface elements or the apps that don't run in 4K. You shouldn't have any concerns about the picture quality and sharpness when the 4K mode is not used.
In fact, the upscaling is so good, that there is no easy way to tell when the 4K mode has kicked in. The effect is hardly perceivable with bare eyes and the switch is instantaneous unlike what other reviewers would have you believe, so what we did is we hooked up the phone to the Android SDK and we inspected its events log just to keep track of the turning on and off of the high resolution mode.
It turned out that the Xperia Z5 Premium automatically changes the resolution output once proper content is detected. This means that if you open a high-res image with a proper app such as any gallery or image editor, you would be seeing it in the screen's native 4K resolution. The default gallery works this way for sure.
The default video player, as well as the popular MX Player, which we tried, receive the native resolution upgrade as soon as you load up any video higher than 1080p.
The YouTube app is also allowed to use the screen in its native 4K resolution even though the app settings only offer streaming video resolution of up to 1080p.
If there is a game that supports 4K resolution, we couldn't find one. The same goes for the few Google Cardboard style VR apps we downloaded for testing. The few games we tried all ran in 1080p.
Interestingly, the web browser didn't utilize the high resolution mode either.
So yes, the screen is indeed a 4K one and it's indeed capable of showing all those 8M+ pixels. It's just that you can hardly tell the difference over a phone with a QHD screen.
Nevertheless, Sony deservedly gets all the 4K screen bragging rights and there is no way anyone's taking those from them. We also think that handling the high resolution mode this way is an excellent balance of user experience, performance and battery life.
Besides the 4K side of things, we also subjected the Xperia Z5 Premium screen to our usual battery of tests and measurements. The maximum brightness of the screen (566nits) turned out quite in line with what we got from the regular Xperia Z5 (583nits) though this one wouldn't go anything higher than that in Auto mode even in bright environment. The level of blacks is similar as well, which works out to a similarly average contrast ratio (966:1) as the Z5's (986:1).
|Display test||50% brightness||100% brightness|
|Black, cd/m2||White, cd/m2||Black, cd/m2||White, cd/m2|
In terms of sunlight legibility, the Z5 Premium is again, pretty comparable to its Z5 sibling. Both get decent scores, but there is still a lot of room for improvement left. It's all down to the relatively high reflectivity of their screens.
Much like on the Xperia Z5, color rendering without image enhancements is off to a higher extent than we're used to see lately (Avg deltaE 7.1 for the primary colors plus black and white), but it's the white to blame as it has a relatively high bluish tint (deltaE 14.6). Still, you would certainly have a hard time noticing a color cast without a reference.
Color accuracy of course takes an extra hit when you turn on the screen image enhancements such as the X Reality for mobile mode but not as much on the Xperia Z5 (Avg deltaE 7.2 in the Z5 Premium) but the representation of the whites remains unchanged in this mode. The maximum brightness however is reduced in this mode - down to about a maximum of 535 nits.
As usual, display colors are a matter of personal taste and perception so if you don't need calibrated color output, you will probably be quite happy with the default settings of the Xperia Z5 Premium display.
You can fine tune the display color rendering to an extent as Sony gives you fine grain sliders for adjusting the Red, Green and Blue channel saturation, but the UI is far from user friendly and unlikely to produce any meaningful results without a reference point sitting side by side with the display. Even worse, as soon as you start fiddling with those sliders, the maximum brightness will take a hit. They also don't allow lowering of the saturation of each channel, but only an increase, which is the opposite of what we would try to do with this screen if we're after calibrated color accuracy.
The Sony Xperia Z5 Premium is powered by a beefy 3,430 mAh battery, sealed-in, as expected. It scored an overall endurance rating of 66 hours, which is above average and certainly impressive, having in mind there is a 8M+ pixels on this screen to light up.
The Xperia Z5 Premium definitely did alright in our call and web tests, but it did average on the video test and standby.
An endurance rating of 66 hours is still above average and it means that the Z5 Premium should be more than happy to offer that many hours of our test pattern usage - one hour of browsing, video playback and calls a day respectively and the rest - standby.
Such usage pattern is of course entirely artificial, but we've established it so our battery results are comparable across devices. And if it doesn't quite fit your bill, you can easily hop on to our battery life chart and adjust the pattern to your liking for an even more comprehensive comparison.
Sony is offering the Z5 Premium in both a single SIM and dual SIM variant, just like the Z5. The handset offers quad-band GSM/GPRS/EDGE/HSDPA support. LTE is enabled and Sony has multiple regional models to make sure the Xperia Z5 will work with the most widespread 4G networks at Cat.6 speeds.
Local connectivity features dual-band Wi-Fi a/b/g/n/ac and Wi-Fi Direct. There is also support for Bluetooth 4.1 with A2DP. Satellite navigation is also a given, with GPS and GLONASS or Beidou (market dependent) support.
The Xperia Z5 Premium also has an FM radio with RDS.
The phone doesn't offer an IR port, but it does come with NFC.
There is a microUSB 2.0 port for charging and data connections and now, and since the Z3+, it no longer needs to be covered by a flap to stay water protected. Media transfer mode is supported for accessing the phone's built-in memory and microSD card over the USB cable.
USB host functionality is present, but requires a little more work than simply plugging in a device with an USB OTG adapter. There is a special menu under Xperia Connectivity in the settings that allows you to "discover" a plugged USB device. It still works as expected, but it requires the extra legwork.
Being part of the premium "Z" line has a few other features to mention, like the MHL 3 TV-out support. You can also output your phone's screen wirelessly via the Miracast protocol or Sony's Xperia Connectivity Throw option.
The app also lets you share your media over DLNA by creating a media server, as well as connect to a PlayStation DUALSHOCK 3 (or 4) wireless controller.
Last, but not least, the Z5 Premium offers advanced active noise cancelling when paired with a supported handset like the Sony MDR-NC750.