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Camera Lens Aperture

Photopedia

18 October 2007 14:44

Camera lens aperture is the variable opening inside a lens that governs how much light passes to the film or sensor. It works in conjunction with the camera shutter and light meter to produce exposures.

Numerically, apertures are known as f/numbers or f/stops. These are commonly arranged as f/2.8, f/4, f/5.6, f/8, f/11, f/16 and f/22, with f/2.8 letting in the most light and f/22 the least. More expensive lenses will often have 'wider' apertures than cheaper models. The benefit of this is the ability to shoot in low light conditions.

If you see the phrase ‘narrow’ aperture, this is referring to a small aperture such as f/11 or f/16. Conversely, an aperture that allows a lot of light in is often referred to as 'wide'.

The controlling of the camera lens aperture plays an integral role in the setting of an exposure and is a critical technique to learn for any newcomer to creative photography.

In our two sunflower images apertures at the opposite end of the scale have been selected to different effect. The wide aperture helps to blur the background, while the narrow aperture keeps everything in sharper focus.