The number that matters is one inch. Not the 50 megapixels, not the Snapdragon, the sensor size. The Xiaomi 12S Ultra, which went on sale in China today, is the first phone to actually use the full surface of a one-inch Sony IMX989, and that is a physical fact no amount of computational trickery can fake. Sharp technically beat it to the sensor by a few weeks with the Aquos R7, but Sharp crops it; Xiaomi uses the whole thing and helped pay to build it.
Start with the red dot, though, because the branding is the real story. In May, Xiaomi announced a long-term imaging partnership with Leica, and the part nobody states plainly is where Leica came from. For years, that logo lived on Huawei’s P-series, and it was a big reason those phones shot the way they did. Huawei’s sanctions-driven unwinding left the partnership on the table, and Xiaomi walked over and picked it up. Poaching your fallen rival’s camera partner is not subtle, and I do not think Xiaomi wants it to be.
What Leica actually contributes falls into two categories. The lenses carry the Summicron name, and the camera ships with two color science profiles: Leica Authentic, which is the restrained German house look with contrast sitting deep in the shadows, and Leica Vibrant, which is the negotiated truce between that aesthetic and Xiaomi’s punchier instincts. Xiaomi calls the work co-engineering rather than a sticker, and for once, I am inclined to believe the marketing because the tuning genuinely looks different from last year’s phones.
The sensor economics are the part I keep rereading. On Weibo, Lei Jun said Xiaomi helped define the IMX989 and co-developed it with Sony, splitting the roughly fifteen million dollars in development costs evenly, and in exchange, Xiaomi got first-out rights in its home market. That is why it is not a global exclusive and why Sharp could ship the same silicon. One inch matters because sensor area is the one camera variable software cannot argue with: more surface gathers more light, holds more dynamic range, and pulls cleaner detail out of a dim room. There is a reason every serious compact camera chased this size for years.
Around that main camera sits a 23mm f/1.9 Summicron, a 48-megapixel ultrawide, and a 48-megapixel 120mm periscope, and the 12S Ultra is the first Android phone that can capture Dolby Vision. It is also the first flagship to carry two of Xiaomi’s own Surge chips at once, the Surge P1 for fast charging and the Surge G1 for battery management. Those are not a Surge S1-style application processor, just power-path silicon, but they show the in-house chip ambition never actually died after 2017, it just went quiet and specialised. The Snapdragon 8+ Gen 1, the 6.73-inch 2K 120Hz panel, and 1500 nits round it out, and frankly they are the least interesting things in the spec sheet.
I am not going to litigate whether this beats an iPhone 13 Pro in a blind pixel-peep, because the 12S series is China-only and most people reading this cannot buy one regardless. The camera bump is enormous, the kind of lens hump only a designer could love. And one inch in a phone is still a small sensor next to any real camera; the physics of a slim body cap how far that glass can reach no matter whose name is engraved on it.
What this really is, is Xiaomi buying credibility. The Leica name, plus the biggest sensor on the market, is a statement that the company wants to be out of the cheap-and-cheerful box it has been fighting to escape since the Mi MIX. The part that annoys me is that the boldest camera phone of the year is locked behind a border, and the rest of us get to read about it and wait.
Related: Five Years Inside the Xiaomi Ecosystem, my history of how Xiaomi built the machine that got it here.