What is "f-stop"

alt. (context photography English) Any of the discrete steps or stopping points for adjusting the aperture of a lens, either marked on a ring on the lens and adjusted by rotate that ring or marked in the display of a digital camera and adjusted by buttons or touch-sensitive controls. n. (context photography English) Any of the discrete steps or stopping points for adjusting the aperture of a lens, either marked on a ring on the lens and adjusted by rotate that ring or marked in the display of a digital camera and adjusted by buttons or touch-sensitive controls.