Series of default?

I have already sent a copy which had as failure to do me a slight vertical spun at all focal lengths, F2.8 aperture, visible from even before 1/80, activated stabilization. The autofocus was not very good, made me focus a little back or front, I do not know. I got much better results to manual control, confirming that in mind, it is very good.

So I sent my first copy for a second. And well ... it still spun, this time especially visible at 70mm opening! Well, I won the autofocus seems to me more accurate. Still, still not satisfied.

There is another proposal similar objective to + 900 euros on Amazon. Do we not try refourguer a bad run?

I will do tests by more pros than me before returns, maybe I'll go through the SAV Tamron. I will give a more enthusiastic appreciation when I would be sure to have a copy in the hands flawless.