The f-stop is the apertureThe aperture is basically a hole in the camera’s lens that lets light pass through it to the shutter and ultimately the film or censor. The aperture not only influences picture brightness but also regulates depth of focus. Most cameras are equipped with an iris aperture that can be freely adjusted or set according to pre-selected values. More opening of a camera lens, which allows light to come in. The f-stop is the focal lengthThe optical distance in millimetres between a camera lens and the film (or sensor on a digital camera). It determines the height and width of the scene being captured, known as the field of view. More of the lens divided by the diameter of its opening. Each consecutive f-stop halves the opening of the previous. For example, an 80mm lens with its f-stop set to f/8 means that the optics inside the lens create a diameter equivalent to 10mm. Changing the f-stop to f/16 creates a diameter of 5mm.