Forgive me for cross posting, but I just realized I might get a better answer in this thread.
I picked up an a6500 to us with a hand held gimbal. I also bought the $600 18-105 lens. My main camera is the FS7, and when I did a shoot yesterday with the 18-105 lens and the autofocus was intermittent at best.
Anyone else experience this problem?
Bruce Yarock

Make sure your 18-105 has the latest firmware version which is currently v4.

https://esupport.sony.com/US/p/swu-download.pl?mdl=SELP18105G&upd_id=11236&os_group_id=3

This upgrade helps improve the auto focus and vastly improves the manual focus. Not that that would be hard because it was a shocker before. NOTE! You cannot install the lens firmware via the FS7 but you can do the installation via your 6500.

Sony's auto focus on the FS7 is there but it's not a Canon DPAF by any means. The closest to the Canon is probably your 6500 because it has so many focus points. Sadly not so with the FS7. If I'm using the 18-105 on an FS7 I just normally zoom in frame up and use the momentary focus function which can be assigned to a button on the handle. Rare I zoom while recording so this works for me far more efficiently than trying to manually focus the 18-105, or worse still relying on it to work 100% in auto. With reasonable amount of light and the latest firmware on both the FS7 (v4.1 from memory) and v4 on the lens the auto focus is okay... sort of :)

Good luck!

Chris Young
CYV Productions
Sydney

Thanks, Chris
I loaded the latest firmware on my fs7 (4.2, I think)
Also loaded v4 with lens attached to the 6500.
Bruce Yarock
Videoproductionfortlauderdale.com

Forgot to ask-Where is the "momentary focus " button?
I don't use the handle
Bruce

Hi

If you don't have the handle on the camera you use the button down on the left hand side adjacent to where the 'auto / manual' focus selector switch is. It's just in front of that on the side.

Chris Young

Thanks, Chris
I’ll try it
Bruce Yarock