I have the Tamron 70-200 f/2.8 on my Sony Alpha 580 and shot my grand daughter's high school play with it. Results were very good, better than I could have asked for. I used spot metering to get the exposure right on their faces and used that setting in manual mode so it wouldn't wander off. The lens is the original non-is model which sold for $700 and change. With our new bodies capable of acceptable high iso work (like D7100) that would likely work for you as well. I shot two rehearsals to find the best settings and locations. Actually the rehearsals were best because of shutter noise being an irritant for the nearby audience during performances. After the fact I built a blimp but she has graduated, so it sits in my closet. That lans is now my favorite, by the way.

I have the Tamron 80-200. Wouldn't recommend it to anyone. Took good photos while new.

Quickly got dust inside the lens. It's loose where it mounts to the camera. Moves up and down enough that it makes focus inconsistent from top to bottom of the image.

The lens worked pretty well until about the time the warranty expired, then so did the lens. I am saving money to replace it and will never buy another Tamron.

I have owned three because the first one took good photos while it was new. All three have broken at least once. they are light weight and not nearly as durable as the Nikon, Cannon, or Sigma.

I know they get good reviews, but if you use your equipment a lot or are hard on equipment in general don't get one.