Aperture or F stop
This is how big the hole in the lens is to let the light onto the sensor. The bigger the F number the smaller the hole, the smaller the number the bigger the hole.
This is how big the hole in the lens is to let the light onto the sensor. The bigger the F number the smaller the hole, the smaller the number the bigger the hole.
The F stop also has an impact on the Depth of Field [DOF] (or how much is in focus in front and behind your subject). the Smaller the F stop (e.g. F2.8,F4) the smaller the DOF. The bigger the F stop (e.g. F11) the longer the DOF, meaning more will be in focus around the subject.
So when taking photos, you will need to think about if you want the background in focus or not and set the F stop accordingly .