Xiaomi's foldable Mi Mix Fold brings the first liquid lens with 3x magnification

2021-03-30

Xiaomi’s cutting edge Mix series is back with the Mi Mix Fold – the company’s first foldable phone that is packed with innovative features. So much so that the folding display may not even be the most interesting component on the phone.

The large internal screen is an 8.01” OLED panel with 4:3 aspect ratio (1440p+ resolution). It’s a tablet-sized display and Xiaomi claims it is the largest display on a foldable smartphone, although Huawei may disagree with this.

Still, it’s large enough that Xiaomi enabled a desktop mode with multiple resizable windows. This mode is launched with a simple three-finger swipe.

Anyway, Xiaomi developed a U-shaped hinge that is 27% lighter than the hinges used by other foldables. The phone was put through 200,000 bends during reliability testing then pushed further to 1 million bends.

The OLED panel supports HDR10+ and Dolby Vision and offers great color accuracy (DCI-P3 color space). The display is rated at 600 nits of brightness with a peak of 900 nits.

The Xiaomi Mi Mix Fold’s external display measures 6.52”, it is an AMOLED panel with 840 x 2,520 px resolution. That is a rather wide aspect ratio of 27:9. Unlike the interior display, this one has a high refresh rate – 90 Hz, plus 180 Hz touch sampling rate. Also, it is slightly brighter with 650 nits typical brightness. It supports HDR10+ and Dolby Vision, plus it has excellent color calibration as well.

Those are good stats for a first generation product, but the camera overshadows the display in terms of innovation. First off, this is the result of a CNY 140 million investment in R&D and was in development for two years.

The Surge C1 image processing chip was developed by Xiaomi. It runs the 3A algorithms – Auto Focus, Auto Exposure and Auto White Balance – in a power efficient manner.

Even more impressive is the world’s first Liquid Lens technology in the telephoto camera. It is made out of a flexible film filled with transparent liquid. It can change its shape, just like the lens in the human eye, thanks to a precision motor. And don’t worry about the liquid – apparently, it can function in extreme temperatures ranging from -40ºC to 60ºC (-40ºF to 140ºF).

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The lens offers 3x optical magnification (80 mm equivalent focal length) and has an 8 MP sensor siting behind it, but there’s no word on optical stabilization. The advantage of the liquid lens over traditional designs is the ability to focus at just 3 cm for macro shots as well as focus at distant objects for zoom shots.

The main camera has a 108MP sensor, the 1/1.52” ISOCELL HM2, which sits behind a 7P lens. The sensor supports 9-in-1 binning for 2.1 µm pixels, but this cam lacks OIS. The ultrawide-angle camera has a 123º field of view and a 13MP sensor with 1.12 µm pixels (f/2.4 lens).

The phone is equipped with a 5,020 mAh battery that is split into two 2,460 mAh cells. It supports 67W wired charging, which completes a full charge in 37 minutes (no wireless though).

The Xiaomi Mi Mix Fold is powered by the Snapdragon 888 chipset, which is hooked up to 3,200 MHz LPDDR5 RAM and UFS 3.1 storage. The base configuration is 12/256 GB, then there’s a 12/512 GB option and the top-specced model with 16/512 GB memory.

High performance is ensured by the “butterfly-type” cooling system, a combination of a large vapor chamber, thermal gel and multiple layers of graphite sheets. All told, the Fold boasts 22,583 mm² of total heat dissipation area. It’s not just for the chipset, the cooling system also expels heat coming from the 5G antennas and the fast charging system.

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The visual spectacle of the large display is matched by the Harman Kardon tuned audio experience. It has a quad speaker setup, something reserved for tablets until now. The four 1216 super linear speakers have large “1.34 cc-equivalent” chambers. They are driven by 15V amps, which makes them 40% louder than the Mi 10 Pro speakers (which also used the 1216). Xiaomi developed a 3D spacial audio algorithm that creates an immersive experience using the four speakers.

The standard version of the phone has a Gorilla Glass back with a ceramic texture. There is also a Ceramic Special Edition, which has a black ceramic back (with laser engraving), plus gold mid-frame and volume buttons.

Both versions of the Xiaomi Mi Mix Fold are going on pre-order in China later today. The first units will be available from April 16. The 12/256GB model starts at CNY10,000 ($1,520/€1,300), the next step is 12/512GB at CNY11,000 and, finally, the top end 16/512GB model for CNY13,000.