I use clamshell lighting in my large format portrait work. Typically these are full face portraits with the lights, lens and subject all on the same axis. Most examples of clamshell lighting that I find online back this up. Is clamshell lighting typically only used in this set up and for full face views?
What if I want to turn the head slightly to get, say, a three-quarter view of the face (to the point where one ear disappears). Should the lights move with the subject? I could see this being the case with true butterfly lighting where there is a prominent shadow under the nose (lest the butterfly disappear). But with clamshell lighting where there is good fill from below and virtually no shadows, is this necessary? Or should I introduce a lateral key and fill at that point?