How do people film skate promos with the circle around the camera???HELP!

Question

Im suppose to be filming one and wanted to know if its and effect or the camera is built like that.I need to know

Answer 1

That effect is called a "fish-eye". It can be achieved by using a "fish-eye" lens.

It is used primarily in skate videos to put emphasis on the board and it's rider- so the view is looking at the board and it's tricks and not the other things around it.