Aperture in photography is the opening in a camera lens that allows light to pass through it and reach the film or digital sensor. It is one of the three basic elements of photography, alongside shutter speed and ISO.
Aperture affects the exposure of the photo and how much of the image is in focus. A wider aperture (smaller number) will let in more light and create a shallow depth of field, meaning that only part of the image is in focus while the rest will be blurry. This can be used to create stunning bokeh effects. On the other hand, a narrower aperture (larger number) will let in less light but create a larger depth of field, meaning that a larger portion of the image will be in focus.
Aperture also has an impact on the overall look and feel of an image. A wide aperture gives photos a dreamy, soft look while a narrow aperture gives them a sharp, clear look.
So in summary, aperture affects how much light is let in, how much of the image is in focus, and the overall look and feel of the photo. It’s an important element of photography that every photographer should understand.