Aperture (n.) The opening in a lens through which light passes to reach the camera sensor, measured in f-stops — f/1.4, f/2.8, f/5.6, f/11, and so on. A lower f-number means a wider opening (more light, shallower depth of field), while a higher f-number means a narrower opening (less light, sharper background). On dedicated cameras, aperture is one of the three pillars of the exposure triangle. On phones, action cams, and drones? It’s mostly fixed — but understanding it still changes how you shoot.
Why Aperture Matters for Mobile Photography
Here’s the thing most phone photographers don’t realize: your smartphone’s aperture is fixed. The iPhone 16 Pro’s main camera sits at f/1.78. The Samsung Galaxy S25 Ultra’s wide lens is f/1.7. The GoPro HERO13 Black is f/2.8. You can’t twist a ring and change it like you would on a DSLR or mirrorless camera.
So why bother learning about aperture at all? Because it explains why your phone behaves the way it does. That wide f/1.7 aperture is why your phone performs reasonably well in dim restaurants — it’s letting in a lot of light through a tiny lens. It’s also why your phone’s “portrait mode” is computational rather than optical. The sensor is so small and the aperture so wide relative to focal length that nearly everything is in focus naturally. Your phone fakes the shallow depth of field that a large-sensor camera achieves optically.
How F-Stops Actually Work
The f-stop scale confuses everyone at first. f/1.4 lets in roughly twice as much light as f/2, which lets in twice as much as f/2.8, and so on. The numbers get bigger as the opening gets smaller — counterintuitive, but it’s because f-stops are ratios (focal length divided by the diameter of the opening). You don’t need to memorize the math. Just remember: smaller number = more light = blurrier background. Bigger number = less light = sharper throughout.
The standard full-stop sequence runs: f/1.0, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22. Each full stop halves or doubles the light. Modern cameras and phones also use half-stops and third-stops for finer control, but you’ll mainly encounter these in manual or pro mode on phones that support it.
Aperture on Different Devices
Smartphones: Most flagship phones in 2025–2026 have main cameras between f/1.5 and f/1.9. Ultra-wide lenses are typically f/2.2 to f/2.4, and telephoto lenses range from f/2.4 to f/3.5. Samsung’s Galaxy S-series experimented with variable aperture (switching between f/1.5 and f/2.4) on the S9 through S10, but most manufacturers abandoned this in favor of computational processing. The wider the aperture, the more light hits the sensor — critical when your sensor is the size of a pinky nail.
Action cameras: GoPro, DJI, and Insta360 action cams use fixed wide-angle lenses, typically f/2.0 to f/2.8. The wide focal length combined with a smallish aperture means nearly infinite depth of field — everything from a few feet to infinity stays sharp. That’s by design. When you’re mountain biking or skydiving, you don’t want to worry about focus.
Drones: The DJI Mini 4 Pro shoots at f/1.7, while the Air 3 offers f/1.7 on its wide camera. Higher-end drones like the Mavic 3 Pro include adjustable aperture (f/2.8 to f/11), giving aerial photographers real creative control — a rare luxury in the compact camera world. If you’re serious about drone photography, adjustable aperture is worth the upgrade.
Aperture and Depth of Field
Depth of field — how much of your image is in sharp focus — is directly controlled by aperture on traditional cameras. Shoot at f/1.4 and your subject’s eyes are sharp while their ears are soft. Shoot at f/11 and the entire scene is crisp. This is the creative magic of aperture.
On phones, this optical effect is minimal because of the tiny sensor size. That’s why Portrait Mode exists — it uses depth mapping (via LiDAR, dual cameras, or AI) to simulate the bokeh you’d get from a wide-aperture lens on a full-frame camera. The results have gotten remarkably good, but they’re still simulated. Look closely at edges — especially hair or glasses — and you’ll spot the computational seams.
Practical Tips
Even with a fixed aperture, understanding the concept helps you make better decisions. In your phone’s Pro or Manual mode, you can’t change aperture, but you can adjust ISO and shutter speed — the other two sides of the exposure triangle. Knowing your aperture is fixed at, say, f/1.78 helps you calculate what ISO and shutter speed combination you need for a proper exposure.
If you’re shopping for a new phone and low-light performance matters to you, check the main camera’s aperture. The difference between f/1.5 and f/2.4 is significant — roughly 2.5 times more light. That’s the difference between a usable handheld shot and a noisy mess. Pair that knowledge with sensor size and pixel-binning specs, and you’ve got a much clearer picture of what a phone can actually do in the dark.
