In photography, the aperture or f-stop is the hole in the middle of a camera lens. It controls how much light enters the lens, which affects exposure and sharpness.

Wider apertures (lower f-numbers) allow more light in, allowing you to shoot with a faster shutter speed and/or a lower ISO. They also have a shallower depth of field.

Smaller apertures (higher f-numbers) have greater depth of field. These can be beneficial for landscape photography.