Recently, I have also this lens. It performs its tasks on a K7. The lens has excellent imaging performance is fast and quiet. The integrated luminosity of 4.0 is enough for most photographic needs in everyday life. By the focal length of 17-70mm, it is an appealing "Always top lens". I too, like many others, various tests made with various brands (Sigma, Tamron) and have come to the conclusion: PENTAX PENTAX is the optimal solution.
