Erik,
Your camera is generally considered a very good one, so
even fully open you should get sharp pictures when well focused. So, try landscapes : with everything far away, with distance set on infinity, you cannot have DOF issues. So if the pictures are unsharp, some mechanical adjustment may be wrong.
here I wrote a paper on "adjusting and using folders" (however in french), this could help ?
Paul
Oops, there are two Eriks here, this post was meant for Erik Petersson