F stop

F stop , F stop is the way you can blur out the background when you are taking a picture and when you focus on the object right in front of you then it unfocused the background.This is to make your object in the picture more focused on and emphasize that is it the main point and object in the picture because the foreground completely gone. To explain this more and in better detail , you can go to the link below.





http://www.picturecorrect.com/tips/aperture-and-shutter-science-of-the-f-stop/