The focusing action feels very quick. Lenses like this tend to hunt a bit in complicated focusing situations, and that was true here, but it was nothing out of the ordinary. Focusing with a really long lens is a skill in and of itself. The actual focusing motion is fast, silent, and very smooth. It would be nice to have some buttons on the barrel the way Nikon does to help remember preset focus points or lock focus on the fly, because that can help getting things focused faster, which can matter a lot during sports or wildlife photography.