The aperture is like the pupil in a human eye – it’s the hole in the lens which permits light to enter through to reach the camera’s sensor. The size of the aperture can be changed – just as a pupil shrinks in harsh sunlight and expands in the dark. A wider aperture lets more light in (causing a brighter exposure), while a narrower one restricts the amount of light that enters (for a darker exposure). Increasing the size of …