The Xiaomi 12S Ultra’s camera is a remarkable achievement: it’s one of just a few smartphones ever to offer a 1-inch-type sensor. Relatively speaking, that’s a huge sensor for a phone, and bigger sensors generally lead to better image quality.
Pitting the 12S Ultra side by side against some of the current class leaders in smartphone cameras, there are clear situations where the bigger sensor makes a difference. But more than anything, it highlights just how advanced imaging systems from Apple, Google, and Samsung are, even with smaller sensors. The future of mobile imaging won’t be won with better hardware alone.
First, let’s get some housekeeping out of the way. A 1-inch-type sensor is often referred to as a 1-inch sensor to make life easier, but that does not mean the sensor literally measures one inch across or diagonally. It’s an old naming convention that has something to do with TV camera tubes. What matters here is that a 1-inch-type sensor is a lot smaller than what you’ll find in a full-frame camera, but significantly bigger than the sensor in just about every other smartphone camera. It’s the same size as the sensors used by Sony’s RX100 series cameras — so putting a 1-inch sensor in a smartphone camera potentially puts it on level ground with the best traditional pocketable cameras money can buy.
And as for the other specs, the 12S Ultra’s main camera offers a 50.3-megapixel resolution with a stabilized f/1.9 lens. By default, it creates 12-megapixel images from those 50-megapixels. There’s also a stabilized 5x telephoto lens (a 120mm full frame equivalent) with a 48-megapixel sensor and a 48-megapixel ultrawide. Xiaomi says it co-engineered the camera with Leica, and the camera app offers two Leica-branded color processing profiles: Leica Vibrant and Leica Authentic. Video recording up to 8K / 24p is supported, and around the front, there’s a 32-megapixel selfie camera.
Oh, and there’s a phone attached, but we won’t get into that here. It’s only sold in China, and as such, I wasn’t really able to test it as a phone.
Why is sensor size so important? For starters, it allows for bigger pixels, which are better at gathering light. The depth of field is also a little shallower, so it opens up more creative control over how much is in focus in the background of your shot.
It also means that the lens it is attached to can be bigger, and the two combined will gather more light than a smaller lens / sensor combo. Smartphone cameras use multiple frames and computational methods to compensate for their comparatively small sensors and cameras. Even so, starting with more image information gathered by a bigger sensor could make a big difference in very dim light or how the camera copes with moving subjects in low light — major challenges for smartphone cameras.
Putting a big sensor together with the benefits of computational photography is kind of the promised land of smartphone imaging. A Google Pixel 6 Pro already takes impressive photos in very low light with Night Sight, but it could look even better if the system had better data to work with from a bigger sensor. The 12S Ultra is capable of some incredible images, but it’s not quite the promised land.
Taking a look at some comparison images from the iPhone 13 Pro Max, Pixel 6 Pro, and the Samsung Galaxy S22 Ultra, I have to look closely to see where the 12S is able to capture more detail. It’s easiest to see in areas of shadow detail, especially in the scene below, where more leaves are visible in greenery rather than lost to shadows. I also prefer how the 12S Ultra’s image is exposed; the ground-level lights aren’t blown out like they are in the Pixel 6 Pro’s image. The images in the sliders below are 100 percent crops for comparison.
The 12S Ultra does a little better than the iPhone 13 Pro Max, too. It’s subtle but fine details in the bottles are just a little clearer. The 12S Ultra also holds on to color detail in shadows where the 13 Pro can’t quite hang and crushes them with blacks.
The Samsung S22 Ultra uses a 108-megapixel sensor for its main camera, which it also uses to produce 12-megapixel images. Even when competing against the Samsung with twice the pixel resolution, the Xiaomi 12S Ultra does a better job of resolving very fine details, like the chain-link fence in the background of the image below.
This is all very impressive, but to see a noticeable difference, I have to look at both at 100 percent magnification. If you’re just taking snapshots and sharing them on social media, you’ll never see the difference. On top of that, the 12S Ultra faces a lot of the same challenges that all other smartphone cameras face. Mixed lighting can sometimes result in weird exposure choices.
And a 1-inch sensor is bigger, but it’s not going to naturally give you the kind of blurry background portraits that big-sensor cameras can unless you get really close to your subject. So it uses portrait mode, just like every other smartphone camera, and the results are inconsistent.
Sometimes they look fantastic. In moderate indoor lighting, I took some of my favorite portrait photos of my 10-month-old that I’ve taken with any smartphone. To be clear, I take a lot of photos of my kid with a lot of different phones. Portrait mode crops in by default, but you can choose from three different “pro lenses” with different color profiles preselected to change things up quickly: black-and-white 35mm, “swirly bokeh” 50mm, and soft focus 90mm. I thought they’d be gimmicky, but I like them more than I thought I would. If this is the product of Leica’s influence, then I guess I’m a fan.
In a different situation with a couple of people in the background, portrait mode photos look much worse. It has a tough time distinguishing my subject from the people in the background and catches a stray arm and leg in focus. The Samsung S22 Ultra does a lot better with the same situation, although its results certainly aren’t perfect. Portrait mode is a mixed bag for the 12S Ultra, like it is on basically every other smartphone camera we’ve seen so far.
Overall, though, I really liked shooting with the 12S Ultra, and I let myself trust it in more situations than I would with another smartphone camera. That might not be totally fair, either. I think knowing that I was working with a bigger sensor convinced me to use it in more ways than I would another phone camera. Even so, it stood up to a lot of these use cases surprisingly well, like taking a photo of my husband tossing our kid in the air or using portrait mode in less than amazing light with a moving subject. I got a lot more keepers than I expected in both of those situations.
It might be partially down to the color processing, which is actually very nice. I wouldn’t peg it as distinctly Leica, and there are a hundred ways you could get similar color on another phone camera through processing or third-party apps. But I’ll usually just take what I get from the native camera app, and I like what’s here.
But the biggest impression I’ve taken away from the experience is how good cameras like the iPhone 13 Pro Max, S22 Ultra, and Pixel 6 Pro are with significantly smaller sensors. It relegates most of the 12S Ultra’s benefits to pixel-level details visible at 100 percent. What these other phone cameras do with computational photography to make such a narrow gap is very impressive. If this 1-inch sensor makes it into Pixel and Galaxy phones with such strong computational imaging chops, well, that’s a very exciting prospect.
Photography by Allison Johnson / The Verge