#10. "RE: What to do? Bad lens? Bad D7000 body?" In response to In response to 0
If it's a Sigma or a Tamron, send the lens back immediately. Although both companies have significantly improved quality control, both companies still produce lenses with too much sample variation. Still though, even Nikkor glass exhibits some sample variation that is occasionally extreme enough to produce a bad one. Whatever. I'd say exchange it.