I may sound like a novice
but not sure what focus shift actually looks like. I did some shots when I looked at the lens and it seemed to have focused correctly.
The test is a little technical, but not a big deal to do, and it is worth knowing where your camera and lens actually focusses. Surprises do happen.
You need a tripod. Take a sheet of lined or squareruled paper and put a big line down the middle from top to bottom. Draw arrows on the two sides, pointing at the point at which you will focus. You might also make cross-marks at constant distances along your big line, above and below the focus point. (I usually do this every two lines of the pad.) Now put the piece of paper on a low table, set the lens focus to 4' (1.2m), put it on the tripod and position them so that the camera is shooting down at the paper from 4' away, at about a 45 degree angle (precision not too important here). Focus carefully on the line at the arrows -- this is quite precise with a rangefinder.
Just shoot it at, say 640 ISO and f/1.4, f/2, f/2.8, ... up to at least f/5.6 in aperture priority, and look at the resulting raw files in the developing software of your choice at 100%. It is very obvious where the sharpest focus is, and it is useful to see what sort of depth of field you get as you stop down. Focus shift is when the point that is sharpest moves as you stop down. It is a real problem if it moves faster than the depth of field increases. (CV35/1.4 exhibited this recently).
If you find that the sharpest part of the image is not on the arrows, first try again, more carefully. Then try with another (longer) lens, to see if the problem is the camera or the lens. If you have no problem, enjoy your summilux!
scott
