>>4120286The AF tracking and especially the approaching subject problem is related to slow AF drive in lens. Most screwdrive lenses have slow gearing but I have one (DA 50-200 WR) that has fast gearing and can track subjects surprisingly well. The image quality is of a turd though. The DA 55-300 (WR) is slow gearing, panning tracking is fine but if it loses the tracking it is slow to find it again, at least image quality is excellent.
The new AF drives are just getting introduced but mostly on star lenses and the older SDM drives are still lacking in AF speed. My 70-200/2.8 has screwdrive AF and is faster focusing than my 60-250/4 or 16-50/2.8
The first new and fast AF drive in consumer lenses was the 55-300 PLM and funny enough it was faster than the AF algorithm could manage, needed several firmware adjustments and by the time the K-3III came out it was tracking well on all KAF4 compatible bodies.
By now there are good lenses with fast AF in the Pentax lineup but most of them are pricey
