Stop by Stop

Photography basics · Namibia camera coach

Basics 1 · Exposure

A photo is a measured amount of light

When you take a picture, a small door inside the camera opens and light falls onto the sensor. The sensor records how much light reached each spot. That amount of light is the exposure.

Too little light and the photo comes out dark and murky. That's underexposed. Too much and the bright parts turn flat white. That's overexposed. Your job is to land in between.

Three settings decide how much light you get

Aperture
How wide the opening in the lens is. Think of how far you turn on a tap.
Shutter speed
How long the opening stays open. Think of how long you hold a glass under that tap.
ISO
How much the camera boosts what it caught. Think of the volume knob on a quiet recording: louder, but with more hiss.

Light is counted in stops

One stop more means twice the light. One stop less means half. In this app every notch on every slider is exactly one stop, and sliding to the right always makes the picture brighter.

Each of the three settings also changes how the photo looks, not just how bright it is. The next chapters take them one at a time.

Reading the meter. Cameras show a little scale like the one under each photo, running from −3 to +3. The marker shows how many stops too dark (left) or too bright (right) the camera thinks the shot will be.

Aim for 0. You'll see this meter in every exercise.