Sony shows (and tells) us why 4K on a phone isn't crazy

At Sony Mobile's HQ in Tokyo, Kichiro Kurozumi is itching to go into detail about the new flagship Xperia Z2. The VP says it's "all in the details." We really hope so, because it's getting increasingly hard to tell Sony's recent smartphone iterations apart, especially when it comes to the Xperia Z2 and Z1. Kurozumi emphatically states that it's all the work done behind the scenes (reengineered frame, a 20.7-megapixel camera that records in 4K) that makes the Z2 stand out. "2014 is about premium smartphones, tablets and the smartwear experience but we... Sony has to do it differently."

Take the Xperia Z2's 4K-recording camera sensor. Sony's certainly not the only smartphone maker with a device capable of recording video in Ultra HD, but Kurozumi reckons the company's software-based "SteadyShot" stabilization keeps the Xperia Z2 ahead of the pack. Because of the relatively large camera sensor, it can compensate for more movement than its rivals -- up to 21 percent. He offers up a professional-level clip and his own real-world sample from a few weeks earlier in Barcelona, and (courtesy of a 4K Sony TV in the room) the level of detail is noticeably beyond that of 1080p video, but won't the lack of 4K screens (UHD TVs are still pretty rare) limit the usefulness? We asked Kurozumi exactly that.

No surprises -- the Sony exec didn't see it that way:

"There's no dependency on 4K TVs. [Video] will look best on those, but even when downscaled to 1080p, the higher-resolution video looks good -- better than simply recording in 1080p."

We got to test out the Xperia Z2's 4K recording for ourselves -- embedded below -- which should offer a good estimation of what you can expect. (You should be able to play it back in 1080p or 4K, if you've got the hardware.) We gave it a tough order: filming Tokyo's lit-up skyline at night. Sony is fairly proud of the still-photo capabilities of its top smartphone imaging sensor. We've already documented the performance of its predecessor, but this time there's image stabilization (a wish-list item from our last review), so it wouldn't hurt to try the Xperia Z2 before our review, right?

You can immediately check out the lack of bluish noise and haze in the video, despite the mostly pitch-black subject material. Those image-stabilization skills also appear to dramatically boost the low-light photos too, even in our short testing time, although it made some shots look a little unnatural -- Sony tells us that this Xperia Z2 wasn't the final retail model. Sure, it's got the same megapixel count as the camera inside the Xperia Z1, but it's different. (A lot of Sony people stressed this during our playtime with the sequel.)

The video results are surprisingly pleasing. The image stabilization smooths away our handshakes, and our biggest complaint is the sporadic refocusing. Once it does lock on, however, you can see the extra pixels there on the video -- if your monitor's got the resolution for it.

So when will we get a smartphone with a 4K display? Kurozumi and Sony's VP of Mobile Development Akihiro Hiraiwa both laugh. Hiraiwa says, "Some day! There was the idea that users wouldn't be able to discern any increases in resolution once it got to a certain level, but that's wrong. People can tell." Kurozumi adds, "We now need the right size for phones, the right processors capable of running 4K. We're looking for [these] solutions." Smartphones would also need enough battery power to run on such a high resolution for a respectable amount of time.

"We now need the right size for phones, the right processors capable of running 4K. We're looking for [these] solutions."

But back to the displays we're using right now. Sony has taken on board the criticism for its existing -- often middling -- smartphone screens. "Live color LED" is the solution, swapping out a blue LED and yellow phosphor for a combination of blue LED plus red and green phosphors. Sony reckons this makes the screen substantially brighter, and expands the color palette beyond previous models. The company had some of those weird color gamut graphs to prove it, but it's there for you to see on the new phone -- it's a substantial improvement on what came before.

Another change from the Z1 to the Z2 was to rethink how it made the smartphone's frame. Instead of three separate parts, Sony managed to craft the same structure in one piece, and in the process reduced the number of seams and weak points, making the phone easier to water protect. Oh and it made the entire thing lighter and thinner, too: there are those details.

Earlier in the day, Sony Mobile's CEO (and Kurozumi's boss) Kunimasa Suzuki told us how 2013 was Xperia's breakout year. However, Sony still hasn't breached the global top 5 smartphone sellers list yet. In its native Japan, it's the top Android manufacturer -- it sells more phones and tablets than Samsung. He says, "The best of Sony is realized in these products" -- something we've heard many times before, with mixed results. The Sony Mobile CEO elaborates on his MWC presentation: "But ... without being bolder, we cannot be a bigger player. We can't make better products."

"Without being bolder, we cannot be a bigger player. We can't make better products."

"This year, we're taking a bolder mindset." With a new lifelogging wearable on the horizon, that's the plan, but Sony could find it difficult to push its new Xperia Z2 as another big step forward, regardless of its attention to detail. "We think the similarities are a positive thing," says Kurozumi. "If you already owned the Xperia Z (or Z1), then you'll see the Z2 in stores and know what it is ... what it can do. You'll also see the extra features, like 4K recording and the free noise-canceling headphones."

"The issue is marketing. We need to show everyone these are great products and communicate this." Will that be enough to create a top-selling smartphone? "If we didn't have Apple, then we wouldn't be here. iPhones are still very innovative." (Earlier, he also said that Sony has no plans to introduce a fingerprint sensor -- not yet.) "...But we don't think that we're losing in this game, either."