Put simply, the ‘aperture’ is the hole in the lens that lets the light through, and for a long time camera lenses have had adjustable apertures so that you can control the amount of light.

The aperture refers to the size of the iris (hole) within the lens. The bigger the hole, the more light gets into the camera. Aperture is measured in F-stops. A low number like F1.8 or F2.1 means ...