How do facial performance capture deals with close faces

Let’s say I have 2 actors with the head rig (including the little camera to track facial expressions), and I want to make a romantic scene where both actors kiss, how do I capture the facial expressions if the camera is interrupting the acting??
I’m sure there’s gotta be a way to make a realistic facial expression without having to manually animate it.

Example 1 (Uncharted 4): Uncharted 4 Thief's End: Elena Plays Dead Funny Scene (PS4/1080p) - YouTube

Example 2 (Avatar): - YouTube

How facial recording works: Avatar: Motion Capture Mirrors Emotions - YouTube

And I’m sorry if my english is bad, I’m still learning it :stuck_out_tongue: