08-08-2010, 06:20 AM
My experience with Tamron 28-75mm with Canon bodies is that, except wide open performance, Tamron 28-75 was a good lens with 1,6 crop sensor body (20D). With 5D its it´s border resolution suffered too much, and I changed it to Canon 28-70 f2.8, which is, I think, the best zoom I have ever used. The older Sigma 24-60 f2.8 is not tested in PZ, but it has a good reputation and may also be a good alternative in cheaper zooms.