ON DI UNITS,IT SHOULD BE FAIRLY EASY TO SET UNIT AND SHOULD NOT HAVE TO CHANGE IT MUCH LIKE U HAVE TO ON SI,WHEN U GO OVER SOMETHING TO GET BEST VIEW ,FREEZE UNIT AND THEN ADJUST TILL U ARE SATISFIED THAT IT IS AS GOOD AS WILL GET,THEN GO OVER IT A FEW TIMES FROM DIFFERENT DIRECTION TO SEE HOW WELL IT IS DOING,ALWAYS ONE DIRECTION WILL LOOK BETTER THAN ANOTHER