f-stop

• f stop, f/stop

f is short for focal.

f-stop (plural f-stops)

1. (photography) 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 rotating that ring or marked in the display of a digital camera and adjusted by buttons or touch-sensitive controls.
   • 2006, Michael Grecco, Lighting and the Dramatic Portrait, Amphoto Books, →ISBN, page 22:

     Before you know what f-stop you want, you first have to know what it is you are trying to accomplish in the photograph: Do I want to freeze action, or show motion, and consider shutter speed, or, do I need to get a cast of people in focus, or focus selectively, and cater to aperture?

   • 2008 May 23, Ted Kritsonis, “Six of one, half a dozen of the other”, in Globe and Mail, Canada, retrieved 26 Dec. 2008:

     If you're shooting at an f-stop of 2.8, then the lens will take in a lot more light than it would if the f-stop was at 22.

• f-number