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After we announced Xperia Z5 Premium as part of the Xperia Z5 Series unveiling at IFA, we’ve seen a raft of excitement and some speculation on the 4K display technology and how it’s used within the device…

So, we’d like to take the opportunity to answer a few of the most common questions around the world’s first 4K smartphone*.

Here goes…

How is (and isn’t) Xperia Z5 Premium’s 4K display used?

Xperia Z5 Premium uses its 4K display when you’re viewing either the 4K content you’ve captured using your device or third-party 4K content from streaming services – all other content (including the homescreen and apps) are displayed in 1080p Full HD or lower resolution to simply optimise performance, power consumption and battery stamina so you can use the device for up to two days without charging.

There are many 4K content streaming and subscription services, but these have not yet been fully optimised for mobile. So, we integrated an automatic upscaling feature in Xperia Z5 Premium – so you can enjoy all video and image content within Sony’s Movie and Album applications and popular video streaming services such as Netflix and YouTube in 4K.


Why is the 4K display only used for Sony’s Album/Movie apps and everything else (Home screen, apps, browsing etc) is rendered in Full HD 1080p?

There’s a few reasons – first up, after extensive user research and testing we found that rendering entertainment content in 4K, but still being able to access and use all the other great Sony smartphone features as normal without compromising on battery life, was an absolute priority for users.

Secondly, many third-party apps are not designed or capable of running at 4K resolution (yet), but as Xperia Z5 Premium’s display hardware has a 3840×2160 resolution (4K SID standard) with 806ppi, we feel we’ve created a future-proof device for the imaginations, developers and apps of the future.

Are screen shots captured in Full HD resolution or 4K?

At present, Android Lollipop (Xperia Z5 Premium’s launch OS) doesn’t support 4K screen capture, so all screen shots are rendered in Full HD.

Doesn’t the 4K display, upscale processing and content capture affect device performance; memory and battery life anyway?

Xperia Z5 Premium has been designed from the ground up as a high-performance mobile device. We’ve looked to focus on the best performance in two key areas with Xperia Z5 Premium – firstly it brings a high capacity 3430 mAh battery that will last for up to two days and quick charge capability, which eliminates the need for regular charging. What’s more, Sony’s Battery STAMINA Mode optimizes how your battery is used by automatically limiting processes and connectivity when it’s not needed, and the added option of Ultra STAMINA Mode will keep Xperia Z5 Premium running on its core functions for a week if needed.

Secondly, Xperia Z5 Premium features a large 32GB internal memory, with the capability to take a 200GB external microSD card, which offers extra room for 4K videos and movies, and images too. Also in terms of memory, we’ve also looked to optimize Xperia Z5 Premium’s memory on display feature – the data transfer between processor and device is optimized so Xperia Z5 Premium’s display memory technology remembers the display of images seen on your smartphone and caches the image or video so that you don’t need to reload the full image each time you view it – saving on battery power in the process.

Z5_Premium_white_groupWhy would I need a 4K display in a smartphone – what’s the benefit?

Xperia Z5 Premium features a sharp, vivid 5.5” Ultra HD display, bringing Sony’s 4K BRAVIA technologies to a smartphone for the first time. It offers a viewing experience four times the resolution of Full HD, delivering a more lifelike, richer viewing experience achieved in three core areas: a dense 806ppi resolution; vivid colour with TRILUMINOS Display for mobile, Dynamic Contrast Enhancer for contrast and X-Reality for crystal clear clarity

Why does this matter? We know from our research that brightness and colour is linked with memory in the human mind. The more vivid the memory, the brighter we remember it, and as engineers we always try to create on-screen experiences that mirror the way we experience the real world.

We also believe Xperia Z5 Premium is capable of offering the clearest, sharpest Virtual Reality platform – we’re working on a few things here internally, so stay tuned for more news soon.

Xperia Z5 Premium will start rolling out from November – if there’s anything else you’d like to know, feel free to drop a question in the comments below.



*4K smartphone refers to 4K Ultra HD display in combination with 4K video capture, reproduction and sharing (via MHL). Specifications verified by Strategy Analytics SpecTRAX service as of 1st September 2015. For more information on Strategy Analytics test results, go to:

Takao Yagi

Display Engineer

After five years at the heart of Sony’s Bravia TV department, Takao Yagi moved to focus on mobile technology in 2004. Since then he has been a core part of the team that has delivered some of the world’s leading mobile displays.