Thanks for your good reply. The reason I asked the question is because I have got both Tamron 28-75 and the Pentax FA28-70 lenses. I am trying to decide if I should sell FA28-70. If Tamron 28-75 performs as good (or better) on film, then I will sell FA28-70. But if FA28-70 performs better on film, then I will keep both lenses. I will use the Tamron on digital and FA28-70 on film.
If anyone else got any other opinions please feel free to comment!