you know how funny the f-stop scale is. All those weird numbers that make no sense.. (well, they do make sense if you look at the square roots of powers of two, but this is really not making anybody’s lives easier).
Griffin Hammond came up with a clever trick to remember the entire scale of F-Stops using only two numbers: 1 and 1.4.
The secret to the method is making a series of numbers that starts with those two numbers and then the next member is the prev-prev number times two.
So, it’s 1, then 1.4, then 1×2=2, then 1.4×2=2.8, then 2×2=4, then 2.8×2=5.6 and so on.
P.S. 1.8 is not a “round” f-stop number