Talk with a hundred photographers, and you will get a hundred different recommendations how best to light the same subject. My current go-to setup for lighting head shots is a studio light (Bogen 15000 – yes it is ancient but still works) shot into a 45″ silver umbrella. The light comes back through a 7′ diffusing umbrella before it hits the subject. A 7 foot umbrella is big and bulky but gives a soft light with a nice catch light for the eyes. My studio has a 10 foot ceiling, so the umbrella is off of the floor by a couple of feet. I usually stand in front of the umbrella when shooting head shots, which can be seen if you look carefully at the catch lights. Currently, I am using two Nikon SB 910’s to light the white backdrop.
Peter Hurley, the instructor for the head shot workshop I just finished, uses Kino Flo’s which are four bulb fluorescent continuous lights on the subject and Porfoto strobes on the background. Westcott just came out with a continuous LED daylight balanced light source which sounds like a good alternative to using strobe. I will keep you posted on my preferred lighting as time goes on. These are several examples of recent head shots.