ISO
ISO is the third pillar of exposure, next to aperture and shutter speed — how sensitive your sensor is to the light it's handed. The idea is refreshingly simple: when there isn't enough light, turn ISO up and keep shooting, no flash needed. The catch — there's always a catch — is grain, the faint speckle that creeps in when you push too far, so the real skill is knowing how high you can go before it costs you. It's the shortest tree here on purpose: three shoots, one honest trade-off, and the nerve to shoot in the dark.
3 lessons, easy to ambitious — free to read, free to shoot.
- 1Shoot in Low LightIn a dim room with the flash OFF, raise your ISO until you get a bright, shake-free photo — and notice how high you had to go.
- 2The Noise Trade-offPhotograph the same dim scene at a low ISO and a very high one, then compare the grain in the shadows.
- 3Freeze IndoorsIndoors and without flash, photograph something moving — a pet, a kid, someone cooking — sharp and frozen, by raising ISO enough to allow a fast shutter.
Shoot this tree, assignment by assignment.
A free account turns reading into doing — place your proof shots, earn the XP, and master ISO for the Low-Light Hero badge.