What is the function of the aperture in a camera?

The function of the aperture in a camera is to regulate the amount of light that is directed onto the film or the digital sensor. The aperture is an opening in the lens that can be adjusted to allow more or less light to enter the camera. This control over light is crucial in photography because it affects exposure, which is the amount of light that reaches the sensor. A wider aperture (a lower f-stop number) lets in more light, which is beneficial in low-light situations or when you want a shallower depth of field. Conversely, a narrower aperture (a higher f-stop number) reduces the amount of light and increases depth of field, making more of the scene in focus.

In addition to controlling light, the aperture also influences the photographic outcome by affecting the depth of field, which refers to how much of the scene is in focus. This is particularly important for compositional choices in photography, but the primary function of the aperture remains its role in regulating light exposure.