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The F Number - Demystified :

In any camera that allows you to have control over aperture, the aperture setting is done using what is referred to as F stops.

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Every newbie, faces some confusions with these F numbers.

• They don’t seem to follow a linear series like 1, 2, 3, 4
• Notation keeps varying like f/2.0 or F2.0.
• The number is supposed to indicate a value of Aperture but there is no “A” in the notation!
• Any time there is a discussion about increasing or decreasing aperture, people don’t use these numbers. They talk about “stops”, like move up 1 stop or move down half a stop etc.

So what’s up with this numbers ? The concept behind these number is not that complicated, but the notations and varying terminology to describe the same thing leaves some room to explain.

You know, I probably learned all this stuff back in my photo journalism class, but it never really sank in, and I never knew where those numbers were coming from. Turns out, it’s a lot of math, but pretty simple at its core.