Triangle of Exposure

The triangle of exposure is a simple way to remember the three camera settings that control how bright or dark your photo is: aperture, shutter speed, and ISO. They always affect each other.

The three sides

• Aperture: A “hole” in the lens that gets bigger or smaller.

  • Big hole (small f-number like f/2.8) = more light, blurrier background.

  • Small hole (big f-number like f/16) = less light, more in focus.

• Shutter speed: How long the camera’s “door” stays open.

  • Fast (like 1/1000) = less light, freezes motion.

  • Slow (like 1/10) = more light, but moving things blur.

• ISO: How sensitive the sensor is to light.

  • Low (100) = needs more light, cleaner image.

  • High (3200) = works in darker places, but adds grain/noise.

How they work together

Think of a bucket you want to fill with water to the perfect level.

• Aperture is how wide the faucet is.

• Shutter speed is how long you leave the faucet on.

• ISO is like making the bucket “react” more to the same amount of water.

If you change one, you usually must change at least one of the others to keep the brightness similar. For example, if you make the shutter speed faster (darker), you might open the aperture wider or raise ISO to keep the picture from getting too dark.