Have anyone tried either or both of the below macro lens. I am split between the two. Both are very similar in spec and price. The biggest difference (that I can see) is that the Sigma has a minimum aperture at F45 while the Tamron's min aperture is at F32. Any info or recomendation is appreciated :thumbup: . Sigma: MACRO 105mm F2.8 EX DG 1:1 http://www.sigmaphoto.com/lenses/lenses_all_details.asp?id=3253&navigator=5 Tamron: SP AF90mm F/2.8 Di Macro 1:1 http://www.tamron.com/lenses/prod/90mm.asp Thanks!