There is a funny thing going on with this new Tamron SP AF 17-50mm 2.8 XR Di II VC LD Asp IF. Sometimes it does not focus.
What happens is this: I try to make an image, I recognize that the camera does not focus, i.e. I get no AF confirmation beep (yes, Ken Rockwell says that’s unmanly, I know :)), I turn the camera off, on again, half-press the shutter release, and it works. Perfect autofocus.
It doesn’t happen all the time. I can’t yet tell when it happens and when not. Due to the way I work, it does not really bother me, but I recognize that it may bother other people to the point where it renders this lens useless for them. Just think of someone using it to photograph children or animals. This is the kind of photography where you can’t accept that a lens sometimes needs a hard reset.
As I said, so far I have not found out if there is a certain pattern, and if so, what the pattern is. Those things need time, but I currently look into it, consciously try to find it out. The only thing that’s for sure at the moment is, that there is indeed a problem.
If you have such a lens (I am talking of the new, stabilized version), regardless of what your experience is, if it works for you or not, please drop me a line. I’m really interested to find out.