After months of speculation that Samsung might be releasing a 4K smartphone this year, it turns out that Sony has beaten the company to the punch, as it's just announced the Xperia Z5 Premium at its IFA press conference in Berlin, making it the world's first 4K smartphone.
Launching this November, the Z5 Premium will be arriving in UK shop shelves a month after its smaller siblings, the Xperia Z5 and Z5 Compact, which are both due to launch in October. I went hands on with the phone ahead of its official launch to see whether 4K really is the next step for flagship smartphones.
^ The Z5 Premium (middle) is the 4K big brother to the Full HD Xperia Z5 (right) and 720p Xperia Z5 Compact (left)
To help make the most of its 3,480x 2,160 resolution, Sony has fitted the Xperia Z5 Premium with a large 5.5in display, giving it an insanely high pixel density of 806ppi. That's more than twice as sharp as the iPhone 6 Plus, and 1.5x as sharp as the LG G4, both of which also have 5.5in screens but only with resolutions of 1,920x1,080 and 2,560x1,440 respectively.
At first glance, the Z5 Premium looks stunning, as Sony's refreshed version of Android not only looks pin-sharp, but its pre-installed 4K videos look absolutely amazing. Move the phone slightly further away, however, and it becomes harder to tell the difference, as it was only when I held the phone quite close to my eyes that I could really appreciate all the extra detail.
Sony told me that it should be able to upscale lower resolution content to make it look better, but I saw little evidence of this when I fired up a video trailer for Spectre, which I ran simultaneously on the Z5 Premium and regular Z5. Both phones looked nigh on identical in terms of detail as far as I was concerned, and I actually preferred the slightly warmer colour cast of the Z5's display over the slightly greenish overtones on the Premium.
^ As you can see here, the Z5 Premium's display (below) isn't quite as warm as the regular Z5 (above)
It's possible that Sony's upscaling software hasn't been finalised yet, but it does make me question the value of a 4K smartphone display, especially since it's currently unknown how it will impact the rest of the handset. For instance, while Sony's confident that its 3,430mAh battery will be able to sustain it for the same amount of time as the Xperia Z5 and Z5 Compact – with Sony claiming up to two days of normal use – I'll be very surprised indeed if it can reach anywhere near the same figures as its smaller brethren when I get one in for review and put it through our continuous video playback test.
Likewise, with the current overheating concerns surrounding its octa-core Qualcomm Snapdragon 810 processor, its 4K display may end up making it too hot to use for long periods of time. That said, I didn't notice any overheating problems with the Xperia Z3+, so I'll be keeping my fingers crossed the Z5 Premium doesn't end up becoming an impromptu radiator when I start testing it.
^ The Z5 Premium has a shiny, glossy finish and comes in gold, black and mirrored chrome models
Still, provided that the Z5 Premium doesn't have any overheating issues, it should be one of the fastest Android phones around, as the Z3+ (which shared the same processor) produced some of the best benchmark scores I've seen. Likewise, with 3GB of RAM on board, it should be able to multi task very efficiently. It also has 32GB of onboard storage which can be expanded up to 200GB via micro SD card.
The Z5 Premium also comes with Sony's brand new 23-megapixel camera sensor – the first new module we've seen on a Z phone since the Xperia Z1. With this, the Z5 Premium can also lay claim to another world record, as Sony says it has the world's fastest auto-focus as well, clocking in at just 0.03 seconds. This is thanks to Sony's new hybrid AF system, which uses both phase detection and contrast detection to snap onto subjects quickly while still producing super sharp photos. It also has a closed loop actuator for more precise lens control and video stabilisation.
^ With the Z5 Premium, you'll be able to watch 4K videos at their native resolution
Likewise, Sony's 5x Clear Zoom feature means you can still zoom in on subjects without losing quite so much detail, as the Z5 Premium supports Sony's Super Resolution technology to help improve the quality of your pictures. Of course, a 4K phone would be no good at all without the ability to shoot 4K video, but the Z5 Premium goes one further and lets you capture 4K photo stills straight from your footage on the phone itself, making it incredibly easy to get the photos you want from your home videos.
The Z5 Premium also borrows the same frosted glass design as the rest of the Z5 family, but it will also be available in a fully mirrored version as well to help set it apart from its smaller siblings. It's a shame the mirrored version is an absolute magnet for fingerprints, but at least it means you'll never have to use your front facing camera again to check your hair and make-up.
^ The chrome model's mirror finish is much more pronounced than the gold version
The Z5 Premium has a much glossier finish than its matt siblings as well, making it more slippery to hold than the regular Z5. The small lip round the edge of the phone helps provide a little bit of grip, but it's a shame that even the non-mirrored versions don't feel quite as secure in the hand as its little brother.
Still, the engraved Xperia logo in the bottom corner adds an extra touch of class to the handset, and Sony's capless micro USB port means you won't have to keep messing around with fiddly plastic flaps when you want to take the phone for a dip in the bath.
^ The Z5 Premium's reinforced corners stand out much more than the matt Z5
Likewise, the Z5 Premium takes full advantage of Sony's new integrated fingerprint sensor, allowing you to unlock the phone with a touch of its power button. While it's a little disappointing it doesn't unlock straight from sleep mode like the Honor 7, placing it on the side of the phone is a stroke of genius, as it means you don't have to keep feeling around for it on the back of the handset or perform an extra swipe in order to activate it.
It's just a shame Sony had to get rid of its round machined-finish power button in order to do so, as the Z5 Premium's new flatter power button doesn't provide very much tactile feedback when you press it down to turn the screen on.
^ Sony's new fingerprint sensor has been integrated directly into the phone's power button
However, for all its potential problems, the Z5 Premium and its 4K display certainly have my interest piqued. Of course, much of its appeal will no doubt rest on how much the phone will eventually cost when it launches in November, but Sony has yet to announce UK pricing at time of writing. Still, if it can get the price right and really show that 4K won't instantly kill your phone's battery life or performance levels, then it may will be on to a winner. I'll bring you my full review as soon as I get hold of a review sample.
