K-5 and Tamron 70-200 f2,8
Nearly a year ago I acquired a Tamron f2,8/70-200mm (non VC version).
It proved to be very sharp practically from full aperture up to f8, it starts to deteriorate but very moderately to f16. It is interesting that focusing (on my K5) is not a problem at all - yes, I'm not doing low light dynamic sports such as ice hockey or basketball.
Here are some of my early samples: