I have a ball coming towards me. It is far and then it comes near towards the camera. I want the centre of the ball to be in focus while area near the circumfrance to be fuzzy. I have tried various combinations in the cameras> depth of filed options. Either I get everything completely blurry or slightly blurry. I can' get the combination of sharp focus near the centre and blurry as you go towarsd the outside :-) What settings should I use in-

focus distance
F stop
Focus region scale
Rough ratio so that I can experiment again. Or just an explanation of the 3 settings so that I am bit more well informed. Thanks