I have no idea. If you go to say dpeviews.com they give you the skinny on the iterations of this lens starting with the latest version with notes going back in time to what they improved on. All others versions previous have been discontinued, I believe. Also go to the Sigma site and look at what all their nomenclature means for their lenses...I'm not entirely sure ( do not want to mis-speak) so someone might be able to add to this...the version you are looking at might not have been desgined for digital, although even some of the old Canon 70-210's do work on a Canon DSLR too.