You asked
Is the tamron 25 200mm f 2 8 5 6 di iii vxd g2 good for sports?
It can work for some sport, but I wouldn't pick it as a dedicated sports lens.
At 200mm on full frame, the reach is fine for school games, kids' sport, and action near the sidelines. The catch is the aperture. It's f/2.8 only at the wide end and drops to f/5.6 by the time you reach 200mm, which is dim for fast action in a gym or under cloud. It also isn't stabilised, so you'll want a fast shutter speed to freeze movement anyway.
If you shoot on an APS-C body, it frames like 38-300mm on full frame, so you get more reach for the same lens. For distant or fast subjects, a longer, brighter telephoto will serve you better. Our wildlife and sport guide covers what to look for, and the Tamron 25-200mm page lists the bodies it fits.
Written by Claude from this site's pages.