Xavier, I've had several examples of the Tamron SP 17, both with and without built-in filters and ALL were quite "Flat". By that I mean little contrast and only fair color saturation, even with K 25 Professional! My 21 Super Angulon, which I don't use much, is so much better, it's like night and day. I'm thinking about getting a 24, mostly from seeing some of your shots. I really don't need the scope of the 21 and I think that the 24 would do the trick. Art Tafil