t’s pretty much the same thing that makes any camera good in low light… with a bit of extra software magic on top.
The first of these is image sensor size. The larger your sensor area, the more light you can collect. The iPhone 5’s single camera used a 1/3.2″ sensor, about 15.5mm² in area. The main sensor in the iPhone 13 is 1/1.9″, or about 35.2mm². So the iPhone 13 can capture 2.27x as much light, about 1.14EV more light, just based on the sensor. The Honor Magic4 Pro I have employs a main sensor at 2/3″, a number of recent phones have been 1/1.3″–1/1.2″, and Sony just introduced a 1″ sensor for phones. That’s collecting almost 4EV more light than the iPhone 5.
The next thing is the lens. A wider aperture lens — smaller f-number — is another way to collect more light. The iPhone 5 has an f/2.5 lens, while the iPhone 13 has an f/1.6 lens for its main camera. That’s an improvement just based on the lens of another +1.33EV, for a total of +2.43EV between the iPhone 13 and the iPhone 5.
Next is image stabilization. All that sensor size and fast lens stuff got you +2.43EV.. not bad. But the in-body-image-stabilization system on my latest camera (Olympus OM-1) can delver up to +8EV of stabilization. Of course, image stabilization can’t make your subjects hold still, but it can effectively make your camera or phone hold much stiller than you can on your own. It magnifies your personal stability. The Olympus system works by using precision electronic gyroscope to monitor your body’s micro tremors and move the camera sensor to offset that motion. Other systems use a moving lens element to offset body motion, but are generally less effective.
The iPhone 5 didn’t offer image stabilization. The iPhone 13 offers “sensor shift” stabilization, which sounds like much the same thing as my camera’s stabilization. This was first introduced on the iPhone 12 Pro. I have not found any definitive measure of the effectiveness of this, Apple seems to believe it’s about +1.6EV improvement over the optical stabilization in the iPhone 12. Even if the OIS itself was only +2EV advantage, this would make the iPhone 13 good for +3.6EV based on stabilization, so now just over +7EV from the iPhone 5.
Then we get to the software part. Apple’s camera app, at least as of a few years ago, always takes photos when it’s on. It’s alternating normal and underexposed shots until you press the shutter icon. At that point, it picks the best of four pair it’s buffered. That’s right… by the time you press the shutter icon, the photo is already taken. Those shots are merged to enhance dynamic range more than adding up light for an EV improvement. I suspect there’s an EV improvement as well, but I don’t have any numbers for that, so I’ll defer.
However, when you get into lower light, the app automatically goes into Deep Fusion mode. In that case, it’ll use all eight shots. So that’s four pair stacked for noise reduction and light boosting. I’d credit that with at least a +4EV improvement. So now we’re at +11EV over the iPhone 5.
Among today’s top phones, not every one has the same size sensor, the same lens aperture. Or the same magic to apply to AI-driven computational photography.
In the very dark, the iPhone adds an extra photo, a longer exposure at a lower ISO, just to get better color information. Higher ISO shots lose dynamic range and color information. Apple, Google, and probably most of the others employ AI agents to figure out decent color for things that can’t really capture in good color in a single shot.
Here’s a shot I took with the main camera on my Honor Magic4 Pro. It’s not a great shot, but read on. This phone doesn’t have image stabilization on the main camera, and yet, it’s not fundamentally blurry, once you get past all the crazy processing. Honor calls their AI + computational photographic system “Ultra Fusion” but they don’t offer up a huge number of details.
Here’s the thing… while I didn’t stand outside for 15 minutes to get my full night vision, when I stepped outside my office/he-shed to shoot this photo ten minutes ago, I couldn’t see a damned thing other than the street light and the moon.
I shot the same photo with my OMDS Olympus OM-1 with the M.Zuiko 12–40mm f/2.8 PRO lens. This was shot at f/2.8, ISO 6400, 5 second exposure, hand-held at 12mm. I shot in raw and made a few adjustments in Lightroom before printing the JPEG for upload. I’ll admit that I had a bit of condensation on the lens I tried to clear off, given that the camera and I are were in my air conditioned he-shed. Outside, even at 2:30am, it’s pretty humid here in southern Delaware in late July. That’s why there’s streaking. I will also point out that the Honor Magic4 Pro main lens is f/1.8, so it had at least that advantage over my f/2.8. I didn’t feel like going back to the house and grabbing an f/1.2 or f/0.95 lens. But I could have.
I included this particularly to put a few things into perspective. Smartphone photographers get truly amazing results in low light today, versus what they could get even a few years ago. There is all sorts of advanced software and hardware being thrown at phone cameras these days. These help a novice get a good shot, but they really do not compare that well to serious cameras in hands of experienced photographers. It’s true that no one in their right mind would normally shoot a photo of my back yard my moon-and-street light.
Mohit Kumar 
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