Aperture value “F”

Basically, when you want to blur the background and make your subject stand out, set it to the open value

There are 9 diaphragm values

F1,2

F1,4, F1,6, F1,8

F2,0, F2,2, F2,5

F2,8, F3,2, F3,5

F4,0, F4,5, F5,0

F5,6, F6,3, F7,1

F8,0, F9,0, F10

F11, F13, F14

F16, F18, F20

F22, F25, F29

The smaller the aperture value, the smaller the focus range becomes.