If you have controlled lightning in more than 50% of your sessions get the canon 24-70 mk2. If you are like me an enthusiast who wants quality and versatility of IS (vr) get the tamron. I read many reviews that all say the tamron is only a bit less sharp than the canon at 24 to about 40mm and has a little mire distortion on the wide end (what is anyways the case when you go less than 30mm.
Id get the tammy if i wouldnt be so prime addicted 


