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Definition of Term

  • a fraction that measures of the size of the aperture opening on a camera.

Study Guide Resources

      • f-number is actually a fraction where the focal length of the lens divided by the diameter of the opening. For example a 100mm focal length lense with an aperture opening of 25mm (diameter) will be f/4.
      • Wide apertures are represented by low f/#, and
      • Small apertures are represented by big f/#.
      • Most lenses on the market capable of somewhere as low as f/1.2 and as high as f/22.
      • The aperture size effects DEPTH OF FIELD as shown below:

      YouTube Video