Hands on with Sony’s new Xperia Z5 phones, including that ludicrous 4K display

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ars.AD.queue.push(["xrailTop", {sz:"300x251", kws:["bottom"], collapse: true}]);BERLIN—Forget QuadHD displays: the new hotness is 4K. At IFA 2015, Sony took the wraps off its new Z5, Z5 Compact, and Z5 Premium phones, with the flagship Z5 Premium sporting a 5.5-inch 4K (3840×2160) display, which works out to a ridiculous 806 PPI. The jury's still out on whether you actually need a 4K display in a phone, but—in Sony's demos, at least—it looked ridiculously good, with vibrant colours and deep blacks.

4K content is still thin on the ground, though, and while Netflix's Android app does support 4K, it only does so for a limited number of devices—it's not clear yet whether the Z5 Premium is one of them. There's also the worry of how much of an effect that 4K screen will have on battery life. Sony's Xperia series has historically had great battery life (up to two days in the case of the Z3 Compact), so it'd be a shame to see that disappear because of a crazy high-resolution screen. For its part, Sony says the Z5 Premium's beefy 3430mAh battery will be good enough for two days of use.

Aside from a 4K display, the Z5 Premium also features a blingtastic mirrored glass back in black, gold, or chrome. No doubt it will need constant cleaning to keep it looking shiny. Sadly, while we didn't get any hands-on time with the Z5 Premium, we did get to play with the Premium's little brothers. Aside from the 4K display and glossy finish on the Premium, all of the Z5 smartphones have near-identical specs.