Z Wami zgadza sie tez niejaki Lance Lee, ktory w dosc prosty i przystepny sposob to wyjasnia, aczkolwiek sugeruje drugie zrodla na tło.

There are two seperate lighting areas, the subject and the background.

On the subject there is one light to camera right about 35-40 degrees, with a good sized modifier, if I had to guess I would say a 2x3 ft softbox quite close to the subject, and no fill light or reflector. See how dark the shadow side is? That indicates no fill. His hand is only maybe 6 inches closer to the main light, but it is much brighter, that means the main light is close and inverse square comes into play. No hair/separation light.

The background, who knows. It all depends on what the material is. That could be a white wall that is 2.5 stops underexposed, it could be grey paper that matches the exposure, it could be a black wall that is 3 stops overexposed(not likely, but I'm just exploring the possiblities). Most likely grey paper with a light on either side bounced into umbrellas. The thing with backgrounds is, you decide how you want it to look then you make it look that way.