Tell me with your own words how to use defocus

Support Basics & Interface
1

I cannot see how to use defocus. I have seen many pics with defocus and they are, for example blurred for sides or the far away-objects ate blurred. But when I try defocus, the whole picture is blurred or full of some kind of weird hectagons :smiley:

So can you tell me simple advices to defocus?

2

http://wiki.blender.org/index.php/Manual/Compositing_Nodes_Filters#Defocus

It’s a two-step process. Set up your camera, then set up the node.