Simulations
Exposure Triangle Simulator
An interactive simulator showing how aperture, shutter speed, and ISO each shape a photograph — and how they trade off against each other.
A bird in flight over a mountain valley — the classic freeze-the-action test.
Controls depth of field
Moderate depth of field — most of the scene is sharp. The sweet spot for general work.
Controls motion
Safe handheld range — slight blur on anything moving quickly.
Controls sensor sensitivity
Mildly amplified — noise exists but is invisible in most output.
The Three Sides of the Triangle
Every photograph is a negotiation between three settings. Each one changes how much light reaches the sensor — measured in stops, where one stop doubles or halves the light — and each one leaves its own fingerprint on the image.
Aperture
The size of the opening
The aperture is an iris inside the lens. A low f-number (f/1.4) is a wide opening that floods the sensor with light; a high f-number (f/22) is a pinhole that admits very little.
Its fingerprint is depth of field — how much of the scene is in focus. Wide open, only your subject is sharp and the background dissolves into blur. Stopped down, everything from the grass at your feet to the mountains stays crisp.
Choose it first when the look matters: blurred backgrounds for portraits, front-to-back sharpness for landscapes and real estate.
Shutter Speed
The length of the exposure
The shutter is a curtain that opens for a measured moment. Fast speeds (1/2000) admit a thin slice of time and little light; slow speeds (1") gather light for the full second.
Its fingerprint is motion. Fast shutters freeze a wing mid-beat; slow ones let anything that moves smear into streaks — including your own hands, which is why slow shutters demand a tripod.
Choose it first when movement matters: freezing sports and wildlife, or deliberately blurring waterfalls and light trails.
ISO
The sensor's amplification
ISO doesn't change how much light comes in — it amplifies the signal the sensor already captured. Doubling ISO brightens the image by one stop without touching aperture or shutter.
Its fingerprint is noise. Amplifying the signal amplifies the static with it: grain in the shadows, mottled skies, and less dynamic range at high values.
Treat it as the last resort — the setting you raise only when the aperture and shutter you need can't deliver enough light on their own.
How they balance
The triangle is a zero-sum trade: brighten one side by a stop and you must darken another by a stop to keep the same exposure. Open the aperture from f/5.6 to f/4 (+1 stop) and you can shorten the shutter from 1/125 to 1/250 (−1 stop) — same brightness, but now with a shallower background and better-frozen motion.
That's why photographers think in terms of what to sacrifice: a portrait gives up depth of field to keep ISO clean; a sports shot gives up ISO cleanliness to buy shutter speed; a landscape gives up shutter speed (hello, tripod) to keep both a deep focus and a clean file. Use the presets above to feel each trade in action.