Aperture refers to the size of the iris in the lens.The bigger the whole, the more light gets in. Aperture refers to the access given to light from the lens to the camera sensors. The size of your aperture controls the amount of light entering your lens. Using the aperture of your lens is the simplest way to control your depth of field as you set up your shot.
F/11- Large shutter speed
F/4-Medium aperture
F/2-Small aperture
This diagram shows the F stops on how much or less light gets in. The greater the F number (f/11 or f/16) the less light gets into the camera lens however the smaller the F number (f/1.4 or f/2) the more light gets into the camera lens. This ensures that you get the right amount of lighting in your image so the picture can come out expected.