The Sony Xperia Z5 Premium's 4K screen isn't actually 4K all of the time, it has emerged.
Some of the biggest smartphone news out of IFA was that the Sony Xperia Z5 Premium comes with an ultra-sharp 4K display.
But it turns out that Sony's 4K display isn't all that it seems.
In a statement passed to PhoneArena, Sony outlines that the Z5 Premium's 4K display uses the full 3,840 x 2,160 pixels only when you view photos and video.
Other content – such as the homescreen, websites, apps and more – will only ever be "displayed at 1080p or lower resolution".
It's even unclear whether virtual-reality apps will be given the full 4K treatment.
Sony explains that displaying all content in 4K would significantly reduce the phone's battery life and, by rendering the majority of content in Full HD instead, the Z5 Premium might keep going for up to two days.
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This is the second major phone feature that Sony has backtracked on in recent weeks.
Earlier this month, the company updated its support page on dust and water protection for Xperia devices, advising users not to submerge their devices. They're waterproof devices.
"Remember not to use the device underwater," reads one section.
"The IP rating of your device was achieved in laboratory conditions in standby mode, so you should not use the device underwater, such as taking pictures," it continued.
Sony's promotional materials for its Xperia devices in recent years have always pushed the fact that they work underwater.
What's going on, Sony?