Any issues with Sigma 18-35mm?

[Sausage]

I use this lens with a Nikon D7100 and recently I realized I have that poor focus problem that many people talk about. I never noticed because all along I was using the center AF point and recomposing (but this means if you recompose drastically there will be some OOF areas in the corners since you focused on the center area). I wanted to try a new technique where I move the AF focus point off center and focus there, reducing the need to recompose, and now I realized that 90% of my shots have become OOF, and they aren't even focused on the off-center AF point.

In other forums they suggested using only the center AF point. Does anyone know if calibration will solve the problem, or do I have to work around it by just using the center AF point only?

 

[Ah Keong]

Sorry to hear this.

I used it on my Canon 7D. so far so good.
My experience so far:

try to use BBF and one-shot AF.
another way I have read is using the Sigma Dock to calibrate if the shot is consistently front focus or back focus.
if under warranty, you can bring it back to the service center (think is near Queensway Shopping Center) to calibrate once for free.