Robin Smith , Jun 18, 2012; 10:54 a.m.
Not sure it's smaller really: the Tamron has 82mm filter vs 77mm on the ver 1. The Ver II Canon is lighter than the Tamron (803 vs 825 g - hardly significant) but the ver II has no IS. Initial reports on the Tamron are good - my only concern is with AF accuracy - I found the Tamron 28-75mm not so accurate on the long end and when at f2.8 this was irritating. The hood on the ver 1 made the lens+hood length always the same, the Tamron and the ver II have lost this hood arrangement so the lens+hood length changes with focal length. The ver I is 953 g - is the 128 g difference compared to the Tamron significant to you?