Hello fellow TPF'ers - I have a question. I've been looking at the tamron 90 2.8 but apparently there's a few diff models. Searching on various sites, I see a AF model ( assuming its a screw drive), one that's Di without VC ( I think it has a BIM) and the last has vc. Anyone have experience with the screw drive model? I tried to see if I could find reviews but unless I've typed in the wrong keywords - I get a lot for the Di ( with and without vc.) Thanks!