This is quite a nice lens if used for the right purpose. It’s extremely sharp (competitive with any 70-300mm lens on the market.) The vibration control is a full four stops and functions very well. But it does not have a panning mode, and you’ll have to turn it off if you want to pan or follow a moving target.

Autofocus is slow. Not unusably slow by any means, but certainly too slow for action sports. But then, that’s not what this type of lens is for. You might miss a shot or two if you’re trying to follow the kids around the yard or shoot a hummingbird, but it’s certainly not terrible.

So, we’ve covered the USM and VC initials. For those left wondering, the Di stands for “digitally integrated.” This means the lens elements are coated to minimize reflections. Of course, all lenses made after 1935 have coatings, and everything made in about the last decade has digital coatings. Mostly I think Tamron looked over at the the Sigma 70-200mm f/2.8 II EX DG APO Macro HSM AF and had an acute case of initial envy, so they slapped a Di on there.