Originally posted by creampuff My question is have you even tried shooting fast-paced AF action shots with the K-5 & DA* 50-135mm before coming to your conclusion?
Yes, I have.
While the K5+50-135 is an improvement over the K7+50-135, I still would not consider it particular fast setup for fast action sports (or similar shooting).
Also, FWIW, my K5+60-250 outperforms the K5+50-135 in terms of AF speed.
EDIT: That said, I plan to use my K5+50-135 tomorrow to shoot my son's first karate "test". As I wouldn't call that "fast-paced AF action" (they are 4-year olds), I think the K5+50-135 should do fine.