Kind of like playing Darts when you have the dart in front of you and focusing on the target you dont really see the dart or pay attention to it?
ORIGINAL: bawanajim
Just a very simple way to eliminate any concerns you might have with your sight.
If you place a dime on the front lens of a rifle scope it will block a huge portion of your viewing area,or so you would think,because when you raise the rifle and look thru the scope the dime will not be visible to you.