Why your Samsung Galaxy S22 Ultra's 108MP camera takes 12MP photos

Plus how to take full-resolution shots — and why you probably shouldn't bother

It's not unusual to see phone cameras with megapixel counts in the hundreds these days. Super-high-resolution cameras are even making their way downstream to mid-range devices: Samsung's upcoming Galaxy A73 is packing a 108-megapixel camera. By default, though, that phone will certainly take 12-megapixel photos, just like the ultra-premium Galaxy S22 Ultra does. Why is that, though? What's the point of all those megapixels if the cameras are still kicking out average-size photos?

Digital camera sensors are covered in thousands and thousands of tiny, discrete light sensors, or pixels. Higher resolution means more pixels on the sensor — and the more pixels a sensor packs into the same physical area, the smaller those pixels have to be. Because smaller pixels have less surface area, they're not able to gather as much light as larger pixels can, and that means crummy low-light performance. High-megapixel phone cameras typically employ a technique called pixel binning to get around this.

It's technical, but in a nutshell, pixel binning, er, bins groups of individual pixels into artificially larger pixels, boosting how much light data the sensor can collect when you press the shutter button. In the case of the Galaxy S22 Ultra (and presumably the forthcoming A73), groups of nine pixels are binned, which is how 108 megapixels translates to 12 (108 ÷ 9 = 12). Unlike Google's Pixel 6 and 6 Pro, which have 50-megapixel primary camera sensors that always kick out 12.5-megapixel photos, the S22 Ultra gives you the option to take unbinned, full-resolution shots right from the stock camera app. Let's take a look.

The shot above was taken outdoors just before sunrise — lighting was a little dim, but already too bright for pixel binning to have any meaningful impact on image quality. The photo came out practically the same regardless of how I took it.

Here, we start to see some image quality improvement in the second photo, which was captured with pixel binning. There's not much difference in terms of noise, but if you look closely, lines are more defined in the second photo — edges in the first, unbinned shot look a little ragged if you crop in, particularly in the shadows toward the lower right corner.

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Unsatisfied with the differences in performance in middling light, I also took a few samples in really, really poor lighting — conditions where I wouldn't expect most people to try taking photos at all. In this set, the unbinned shot (first) is clearly darker and noisier than the binned shot (second), even without cropping in to pixel-peep. Neither looks good, but it was very dark here.

Same story here: the first photo is pretty dramatically different from the second. The first photo, captured in full 108-megapixel resolution (which, again, has been downsized to 12 megapixels here), is way noisier than the one I took just seconds later with the S22 Ultra's default settings.

Taken in a very dark room against a dark-colored wall, these photos show the most dramatic difference I saw in my testing. The first image, captured without pixel binning and at 108 megapixels (downsized here to 12) is much noisier than the second, which was taken with the S22 Ultra's default settings. Ironically, some detail is also lost at 108 megapixels: the text near the bottom right of the poster (that says "NASHVILLE, TENNESSEE") is completely illegible in the first photo.

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Pixel binning is important for the physically tiny, high-resolution camera sensors shipping in many Android phones these days because it helps them make sense of particularly dark scenes. It's a trade-off: resolution is cut drastically, but light sensitivity increases. Huge megapixel counts also give you the flexibility to zoom with software when shooting 8K video — though that's not a use case normal people will benefit from for many years. And of course, it's also part marketing. A 108-megapixel camera looks much more impressive on a spec sheet than a 12-megapixel one — even if they're effectively the same most of the time.

Based on my experience here, it seems to take a really dark setting for binning to matter much, at least on the S22 Ultra in particular — in every example where I saw a big difference, the scene was so dark that I would never have thought to take a photo in the first place (if not for needing low-light samples, anyway). On the other hand, shooting at the Ultra's full 108 megapixels doesn't often wring much more usable detail out of the scene anyway, even in good light. Leaving the phone at its 12-megapixel default will yield the better experience most of the time, regardless of lighting.