Are there any comparisons between this lens with the Canon 70-200 F2.8 IS V1? I am just wondering why someone would buy the Tamron instead of the Canon V1 if they are equal in picture quality and af speed.
The Canon 70-200 F2.8L IS really wasn't that great of a lens. Both the older Sigma and Tamron were sharper than it. The old Sigma lacked IS, and the old Tamron in addition to no IS had an awful slow focus motor.
The newer versions of all three of these lenses are better than the old ones. Sigmas now has OS and further improved image quality. Tamron now has VC and USD focusing making it quicker.
Here's the old Sigma 70-200 f/2.8 HSM vs the Canon 70-200 f/2.8L IS
Here's the old Tamron 70-200 f/2.8 vs the Canon 70-200 f/2.8 IS