F-Stops Explained — Camera Lens Tutorial

From the comments:

Tip: Heres something to know for fixed lens manuals. If you are doing meet+greets, you don’t want to be fiddling with your focus all the time as you might miss something. 

In this case. Set your aperture to f8 and move towards it by changing the ISO and Speed to get the correct exposure. Then focus on an object slightly in front of your main subject area - - - and because your depth of field is extended (using f8) everything behind that point will be in focus. You’ve just created a focus zone. So boshboshbosh!!!. Goes the same for flash photography, use f8 and adjust flash heads accordingly. 

Thing is everything is autofocus nowadays and most people rely on the camera and TTL flashes. What im showing you here is a sure way to take quick photos without thinking. All the best -DiyEcoProjects

 

Guy Photo:  In Classes I teach to beginning photographers I always tell them to think of f stops as fractions:  e.g., 1/2 is more that 1/4 and 1/4 is more that 1/8.  I show them with examples like you did but I leave the complex math out of it, they relate to fractions much better.  1/2 a pie is more that 1/4 of a pie, etc.  Anyway,  that's just my way of explaining f stops and why the larger numbers mean smaller f stops.