The GRIII is ever so slightly faster to focus than the II, but not to the point where it would be considered a speed demon. The addition of PDAF isn't that much of a help, especially since it has to move the entire lens assembly. When it locks, it's accurate, but you'll see it rack back and forth before locking. When taking pictures in an arcade, it struggled to focus on my daughter playing. Eventually when it focused and took the picture, the results were as fine as I could expect from a 2.8 APS-C, just the process of taking the picture was glacially slow. Comparatively the a6400 with the 20mm f/2.8 in a different setting (but also low light), had no issues with focusing. The GRIII is considerably sharper than the 20mm f/2.8 pancake though. Seems like we can't have both, there's tradeoffs. Either sharp and slow or fast and soft.