I have a Tamron 28-75 and during my last wedding, while it was focusing and I was looking through the viewfinder, it seemed to shift right and left. I don't know if I explained that right, but I would center focus and it would do that. Is that normal?? Also, Im fairly confident in my focusing ability especially when center focusing, using around 2.8-4 and shooting no slower than 1/60th on shutter. Sometimes the images are sharp and sometimes extremely soft and out of focus. Do you think this lense may be going bad?

Thanks
Jeff

What camera body are you using? It sounds like more of a camera issue to me. Possibly a settings issue. Did you have different results with other lenses?

Canon 30D... I haven't checked that out. All I have is the 50mm 1.4 and 18-55 to test with.

I would check to see if the 50mm is doing the same thing. Also try the lens on another camera body (with the same settings if possible) to try to isolate the problem.

Ok, thanks a ton Bill. I hope it isn't the camera. Ill let you know what I find out.

Jeff