Off the top of your head, do you know how much more light f/2.8 lets in compared to f/5.6? Do you know the f-stop number that comes after 11? This 1.5-minute video reveals the simple pattern used by the scale.
If you didn’t know, f/2.8 lets in four times as much light as f/5.6. That’s because the aperture is bigger by two stops. As shown by freelance filmmaker Griffin Hammond in the video, the scale revolves around twos.
All you have to remember are the numbers 1 and 1.4. From there, you can build out the scale by doubling (and rounding):
1, 2, 3, 4, 8, 16, 32, 64
1.4, 2.8, 5.6, 11.2 (11), 22.4 (22), 44.8 (45)
It’s that simple! Check out the video at the top if it’s still not clear.