New Sigma 17-50 f2.8 OS on D7000. Backfocus?

Hi all,

I just bought a new Sigma 17-50 f2.8 OS from Amazon and did the battery test to see if there were any front/back focus issues.

I used a tripod + timer, and focused on the second battery from the left. The third battery appears to be more focused at 17mm and 26mm, while the correct battery is in focus at 38mm and 50mm.

I also took photos of a lens test chart, where again it appears to be backfocusing at 17mm.

I'm fairly new at all of this, so I'd like to get your opinions. Do you guys see a backfocusing issue as well? Would I be able to correct this using the AF fine tune in my D7000? Should I exchange the lens / send it to Sigma for calibratoin?

Any help is appreciated!

17mm

17mm crop

26mm

26mm crop

38mm

38mm crop

50mm

50mm crop

17mm

50mm