The exposure triangle

Aperture, shutter speed, and ISO together decide how bright your photo is, and each one shapes the look.

The three controls

Exposure is a balance of three settings. Aperture is how wide the lens opens, shutter speed is how long the sensor sees the light, and ISO is how much the camera amplifies it. Change one and you trade off against the others to keep the brightness you want.

Why it is a triangle

Open the aperture one stop and you can use a shutter twice as fast, or drop your ISO, for the same brightness. Every photo is a choice about which of the three matters most for the picture you want.

See it

Example photo coming soon

The same scene at one exposure reached three ways: wide aperture, then fast shutter, then low ISO, so the brightness matches but the look differs.

Try it

Put your camera in manual, pick a scene, and reach the same brightness three different ways. Watch what each choice does to motion, depth, and grain.