AF problems on 50mm 1.4?

Actually the focusing problems of this lens are extremely well documented and complained about all over the internet. There are a large number of people who have copies that they love and an equal number of people who say that theirs consistently mis-focuses. (Some of them use them anyway because the lens has qualities they like, and some of them apparently don't use them anymore.) And there are some who say they returned lenses until they got a good one.

And the way I determined that there were focusing problems was to set up the camera on a tripod, aim it at a ruled focusing target, take multiple exposures using a remote release, and compare (at 50% and 100%) the sharpest part of the image with DPP's little red box. I have repeated this in different locations with different light and the result is always the same. The aperture is irrelevant; the percentage of in-focus shots is always much smaller than the percentage of missed-focus shots.

The reason I started doing the testing is because my hand-held "real" shots were abysmally out of focus and I knew I wasn't that bad at using a camera. Unfortunately, I didn't find all the on-line complaints about the lens until after I experienced the problems myself.