When I use the focus module I notice a couple of strange things. It could very well be that I don't know how to use it correctly (have some settings wrong).
Usually when the focus is complete the HFR is slightly larger than when it started.
On some occasions during the focusing it will make a big movement which takes it way out of focus. Usually it corrects itself on the next movement but I am wondering why it makes these big movements.
Maybe if someone could point me to some explanation of the what all the settings do that would help me get everything correct.
Your link explained it great. The only issue I have that is not answered in the documentation is why does it make such large adjustments. I will take a look in the code and see if I can understand what is happening.