It is possible that I got a better 77 and you have a better 50-135
and I guess both are happy. That is great.
But back to photo zone: on K5, DA18-135, 24MM, center: F4: 2598, 5.6: 2683. I can hardly find any MTF number better than that from any other Pentax lenses, zoom or prime:
FA 31: F2.8: 2596, F4: 2563, F5,6: 2485.
After quick check, I found only DFA 50 2.8, a bleeding sharp lens, reaches that MTF at its best: F4: 2668, still < 18-135's 2683.
clackers: your posted photos are really nice. what they show are very nice contrast in general, from back to white in the frame, and very vivid and saturated color, not micro contrast, which makes the image crystal clear, but not as contrasty as DA coating.
I believe that is the difference of FA and DA lenses in general. Some prefer DA lens' more contrast and saturated color, some like FA's taste better. Or in other words, DA is better for some situation, FA is better in other. -- we should be happy as pentaxian, we have choices, and both are great.