My best quick test, stolen from this forum....


Takea picture of a ruler with a very slight offset, with center autofocus point selected (or another point if you want to test another area of the lens). One side of the ruler shouldbe slightly father awaythan the other (from the camera) Take the picture with a tripod (and mirror lockup enabled if you don't have a really fast shutter speed). If the camera/lens combination is back/front focusing, with 100% view you'll see the lines to the left or right more in focus than the lines on the autofocus point. Regardless, you'll have something in focus which will identify the focal plane, and show you how sharp the lens is in that area. If everything is really blurry, it's just soft. If it's blurry at the autofocus point, but not a little behind/in front of that point, the camera/lens combination needs calibration, unless you've got a 50mm f/1.2L using it at f/2 or f/2.8, or whatever, in which case, that's just the way it is, and you have the same issue which made me sell it.


In my experience, using sharpness of 2-3 in DPP should yield very good results in getting sharp detail in the focal plane.