I was looking at Amelia Rowcrofts process videos, she has her own likeness tutorials on her website. I noticed how little she adjusts the features back and forth after the initial foundation, so her method of measuring the face must be really solid with how little is being adjusted at later stages…
Additional to @pior 's comment ( :+1: ) ..see any of the comparing images when searching for "focal length affects facial features".. like for example: https://duckduckgo.com/?q=focal+length+affects+facial+features&iax=images&ia=images&atb=v340-1 ..so the "traditional" way of practicing portraits by using a "live…