In a previous article we looked at how lenses work.  We learned about the focal length.  Today we’ll focus on camera lenses and what the term f-stop means.

The term f-stop is a ratio.  It has no dimensions.  You don’t measure an f-stop in meters, inches, kilograms or even degrees Fahrenheit.  An f-stop is the ratio of two distances.  It’s the ratio of the focal length of a lens to its diameter.  In figure 1, the f-stop is f/d _where _f is the focal length and _d _is the diameter.

© 2022 Aijaz Ansari
The Joy of Hack by Aijaz Ansari is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
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