Xiaomi’s retractable lens promises huge phone camera improvement

Chris Davies - Nov 5, 2020, 8:39am CST
Xiaomi’s retractable lens promises huge phone camera improvement

Xiaomi is working on a retractable lens for smartphones, promising a big increase in quality by borrowing strategies from traditional cameras that phones have in so many cases replaced. The Retractable Wide-aperture Lens Technology sees the lens normally collapsed inside the body of the phone, but when you need extra low-light performance it can unfurl to deliver a significantly larger aperture.

Camera aperture is basically a reference to the size of the hole through which light enters and hits the sensor. A larger aperture means a larger opening, and thus more light reaching the sensor. Unfortunately for phone camera-makers, physics and the behavior of light places certain demands when it comes to size: if you want a large aperture smartphone camera, it typically ends up being fairly bulky.

Device-makers have developed workarounds, using things like pixel clustering – where multiple adjacent pixels on a camera sensor combine their data for more overall sensitivity – and longer exposures to gather more light. There’s nothing, though, quite like just having that bigger aperture to begin with. Samsung experimented back with the Galaxy S9 series with a Dual Aperture camera, that could switch between two different sizes of opening, but it was still constrained by the need to fit the lens assembly entirely within the body of the phone. That’s where Xiaomi’s new lens tech comes in.

By telescoping out from the phone, it can increase the amount of light captured by 300-percent, Xiaomi claims. It also introduces a new image stabilization system, apparently, with a larger anti-shake angle. As a result, the company says, you’re looking at less blur from things like hand-shake, and a 20-percent improvement in overall image sharpness.

The result is better portrait photography, Xiaomi says, along with a bump in quality from night photography. The former is presumably because, with a larger aperture (or a lower number in f/stop terms), the depth of field is narrower. That means the sort of background bokeh that looks so good in portrait shots, without having to resort to artificial blurring.

As for night photography, any increase in light capture is a good thing for pulling out stars and other details in extreme low-light situations. Current smartphones can use exposures lasting several minutes to deliver that, but Xiaomi’s lens tech could improve on that significantly.

The downside, of course, is the potential for bulk, and the usual concerns about more moving parts in a device and the possibility of them breaking. Xiaomi hasn’t said how large its Retractable Wide-aperture Lens Technology is, and has only shared one prototype image of the system, so we’re still unsure just how bulky it might make a phone overall. The company hasn’t given a timeline for when we might see it appear in commercial devices.


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