swift - Adjust camera focus in ARKit -

i want adjust device's physical camera focus while in augmented reality. (i'm not talking scncamera object.)
in apple dev forum post, i've read autofocus interfere arkit's object detection, makes sense me.

now, i'm working on app users close object they're looking at. focus camera has default makes blurry when closer object around 10cm.

can adjust camera's focus before initializing scene, or preferably while in scene?