Lens Blur Effect in SideScroller Template

Hello everybody.
I searched but i think missing someting. I am studing on a side scroller template and need to have a focusing effect on the characters Matinee Cam.
In side scroller view i want to build the cam focus on the chracter and blur the close and far from character.
Thanks any help and comments!

This is the doc for the DOF

Good luck with that…

EDIT: After some fiddling, I see that a good combo is:

Current aperture 1.2
Current focal length 100 ( or the distance to your character )
Focal distance 250 ( the length of the non-fuzzy bit )

Here, the ball, which in mid-ground is the only thing in focus: