Thanks for the reply, Jan.


I would like to bring the lens in to Sigma some time this summer when I get some free time. Until then, I have e-mailed Sigma support on my issue and am awaiting a reply. I'll keep you informed.


By the way, when I purchased the lens last year, I went thru 3 copies. All seemed to have front-focus issues. Since my 50D had micro adjust capabilities, it didn't concern me too much. It wasn't until later I realized the problem fluctuated with focal length.


I recently upgraded to a 7D, and the Sigma has the same problem on this body, as well.


John