Every photograph is the result of light hitting a sensor (or film) for a specific amount of time. Three settings control how much light reaches that sensor: ISO, aperture, and shutter speed. Together they form the exposure triangle. Get comfortable with all three and everything else in photography starts to click.
Aperture — Control the light and the look
Aperture is the opening inside your lens that lets light through, measured in f-stops (f/1.8, f/4, f/11, etc.). A lower f-number means a wider opening and more light. A wider aperture also produces a shallower depth of field — that blurry background effect called bokeh that looks so good in portraits.
- f/1.4–f/2.8 — Wide open, lots of light, very shallow depth of field
- f/4–f/5.6 — A good all-around range
- f/8–f/16 — Most of the scene in sharp focus, ideal for landscapes
Shutter Speed — Freeze or blur motion
Shutter speed is how long your sensor is exposed to light, measured in seconds or fractions of a second. A fast shutter speed (1/1000s) freezes motion. A slow one (1/30s or slower) can create motion blur — great for silky waterfalls, but bad for sharp handheld shots.
ISO — Sensitivity to light
ISO controls how sensitive your camera's sensor is to light. ISO 100 is the base — clean and detailed. Higher ISO values (800, 3200, 6400) make the sensor more sensitive so you can shoot in darker conditions, but they introduce digital noise (grain) into the image.
Modern cameras handle high ISO much better than older ones. Still, keep it as low as you can — raise it only when aperture and shutter speed aren't enough on their own.
Exposure Triangle Simulator
Balance ISO, aperture, and shutter speed to nail any exposure. See how each setting affects brightness, noise, and motion blur in real time.
Open tool →Balancing the three
Changing one setting always affects the others. Widen your aperture to let in more light and you might need to raise your shutter speed to avoid overexposure. Bump your shutter speed to freeze motion and you might need to raise ISO to compensate.
Start by setting the priority that matters most for your shot:
- Shooting portraits? Prioritise aperture (wide, for bokeh).
- Photographing sports? Prioritise shutter speed (fast, to freeze action).
- Landscape at dusk? Use a tripod and keep ISO low.
It takes a few shoots to get comfortable with the three-way tradeoff, but once it clicks, you stop thinking about settings and start thinking about the shot. The ShutterFox app has scene-specific cheat sheets for dozens of common situations, a useful reference while you're still building the instinct.