How to disble Auto Focus for third party video apps on Samsung S7 Edge and A3 (2017)?

[Android Central Question]

I use the Samsung S7 Edge and A3 for Facebook live, via the rear camera. But while doing this, they constantly zoom in and out if there is any movement. Eg a presenter moves their hand and the camera would zoom in and out to focus, even though it was focused before. Anyone run into this problem or solution? I only want to record/stream videos. The track auto focus doesn't work in third party apps like facebook or facebook pages manager. Any help would be appreciated.