Originally posted by Khoff2 All pics are subject moving towards me with slight panning. The pics have been aggressively cropped for subject isolation. My tests have shown that the DA* 200 was actually better than the Sig with subjects moving towards me, even though reviews with other cameras say different. On the K-30, the Sig is faster, but on the K-3, not much difference.
Perhaps Pentax has made a dramatic firmware fix to speed up the DA*200 focusing on a K-3. If not, you'd have to have a miracle DA*200 to get fast focusing in demanding situations.
In any case, when I had the DA*200 for that brief 1-2 weeks the athletes were significantly closer to me than in your shots, and they were running directly at me (at race speed). Since you're doing a fair amount of cropping, the DOF at that distance is enough that much less focus adjustment should be required, and small errors in focus may not even be that noticeable.
Every type of shooting has its own challenges - I wouldn't consider one to be "easier" than another. But since you're having to crop, you'll get a better ROI in IQ with any of the *300 AF lenses. Neither of the lenses you're using here has quite the same IQ as a *300, and for the cost of the Sigma you could have the 300 instead. Furthermore, professional photographers frequently use 400mm and 500mm lenses (on FF) for sports, and a *300 on the K-3 gives you a similar FOV. In AF lenses I go from 135mm (DA*50-135 - also slow AF - or FA135) to 300mm (F*300), without anything in between. I just don't seem to need anything in the middle. In fact, usually I can work with just the F*300 and the FA*85.
If you have a 200 with you, you'll think you don't need a 300, but if you have a 300 you'll think you don't need a 200. Since the 300s are better lenses, get one of those.