Portrait-0011.png
Again, no one can stare perfectly straight into the camera, intentionally or not.
Assuming a perfect angle often leads to misread proportions and perspective.
Even a slight tilt, yaw, or roll can rotate the Loomis sphere and its equator lines along with it.
Box the head.
That is the best way to get a good sense of how the head is oriented.
Unfortunately, it is an extremely hard skill to master.
cwkLoomis v1
Pippa and I created cwkLoomis for that purpose: boxing the head. The 3D Loomis head automatically adjusts to the box.
But again, the Loomis method is just another tool, not a hard-and-fast rule.
Do not force it onto the reference.
Do the opposite: use it to read what the reference is actually doing.
Portrait-0011-loomis.png