Originally Posted by leadbelly 
i was about to buy a 16-50 awhile ago, but thought about asking here first... what should i look out for in the store? obviously, if it focuses sharp, BF/FF issues and what else? i'll be purchasing the lens tomorrow morning, just want to see what you guys would suggest on how to test..
You must check:
1. Manual focus work.
2. Back and front focus (take the foto of plain text on the f2.8 by 45 degrees).
3. Sharp at f2.8 (take the photo of newspaper). Border of photo may by simple soft - it's normal for crop lens.
4. Auto focus work.