Originally posted by duglew60
Would the K-3 give me better results? Most of the issues I see are with focus not adapting quickly enough.
I have the K-S2 which has the same sensor, same processor, same AF system, same frame rate as the K-S1. I also used to have a K-3 and now have a KP.
Compared to the K-S1/K-S2, the K-3 (and K-3 mark ii) has a faster processor, faster frame rate, 27 AF points rather than 11 and a better AF system. AF is faster and more responsive. But I doubt you will see an instant improvement unless you have reached the limits of what you can do with the K-S1. If you are not using the DA 55-300mm f4.5-6.3 PLM you have not reached those limits, because it is the fastest-focusing telephoto lens in the Pentax system. I would also say that perfecting focusing technique makes a big difference. If you are using one of the AF options that lets the camera choose the AF point, you can expect a lot of mis-focused shots. See how far you can get with single point AF and AF-S first.
If the sport you are shooting is at night or in poor light, you might want a camera that has better high ISO performance. The K-70 or KP are noticeably better than the K-3 in this regard.
If you want the one with the lot, it's the K-3 mark iii. Best AF system, best frame rate, best high ISO.