In the days of film cameras, ISO related to film speed. Film had a different number on it, based on how sensitive it was to light. In a digital camera, it serves the same function, but instead refers to how sensitive your camera’s sensor will be to light.

Cameras have come a long way in recent years, and sensors are better at handling dark situations than they’ve ever been. But it’s still very important to understand how ISO works, and what effect changing it will have on your images.

Have you ever tried to explain a simple idea to a friend only to find yourself at a loss for words?

Exposure is a concept that does that to a lot of people.

From a technical standpoint, exposure is the amount of light your camera’s sensor captures when an image is taken.

The question of what is correct exposure, though, is less technical, and more of the opinion of the photographer. It’s based on the type of image you want to create. A correct exposure is not too bright and not too dark, and that will be dependent on the result you want, not on any technical definition.