As I was taking headshots of colleagues from the mathematics department for their website (in case it is not obvious, the photos in this post are not of them), couple of things became apparent: (a) many math professors wear glasses; and (b) glasses are a big part of people’s image, and they are attached to them. From the photography standpoint, glasses are problematic because they reflect light and produce glare, which obstructs the eyes.
However, if removing the glasses is not desirable (see observation (b) above), it is useful to take into account the direction of the dominant light source. Specifically, it is easier to avoid the reflections in eyeglasses, is the subject is illuminated by broad lighting, where the most illuminated side of the face is the closest to the camera. In this case, the subject is facing away from the dominant light source, so the reflections of this light source are directed away from the camera. Broad lighting is the opposite of short lighting, where the most illuminated side of the face is farthest from the camera. It is more difficult to avoid the glare in eyeglasses in the case of short lighting.
