It's important to remember this digital shot is just right of the 8x10 camera. On the 8x10 Bob is looking straighter into the camera.
This first backlight, on the shadow side of the face is set-up to just skim across Bob's cheek and light up the side of his nose. It also lights a bit of his forehead. On the 8x10 you can see the light on the nose to a greater degree.
I'm trying to create a three dimensional look to the image.