I'm interested in purchasing a new wider-view lens for my DCS-3220.  The specs say that it supports CS type lenses, but I purchased one and it was blurry with no ability to focus or even come close to being focused.  When picking out lenses, what should I look for?  Does the 1/3" sensor size matter?  What about the F number (i.e. F1.2) that's on the lens?  Any help on purchasing a new lens is greatly appreciated.
--Levi