What Does F-Stop Mean?
In photography, an F-stop is the ratio of the focal length of the lens to the diameter of the aperture. The number is expressed as a fraction. F-stop is a dimensionless number and gives an important measure of the lens speed.
Techopedia Explains F-Stop
F-stop is commonly notated by a hooked f (f). It is measured with the help of a scale called the f-stop scale. The larger the opening of the aperture, the smaller the f-stop, and vice-versa. A low f-stop number would be ideal for dimly lit areas, as the aperture would be opened to its largest size. F-stop is sensitive to light fall-off, meaning the closer the subject is to the camera flash, the whiter the image would be, and the farther the image from the camera flash, the darker the image would be. Significant light fall-off is shown by wide-angle lenses at the corners for large apertures.
