Based on the excelent reviews across the net I decided for that lens. Unfortunately the Qality Control of Tamron clearly failed. The pictures in all apertures are significantly worse then from the $60 Canon kit lens. Hardly usable for the speed above F16. Unfortunately I bought it in during my brothers visit of US (using him as "messenger" - I'm living at the middle of Europe - Prague) so the return/fix process will be more complicated, if possible.
European Tamron headqurter, where I send the mail asking fix is not answering. Any hint? Please mail me to pva(at)centrum(dot)cz