Damian McGillicuddy gave us a great demonstration of feathered lighting at a Society of Wedding and Portrait Photographers (SWPP) meeting in Bristol.
The way he explained it was by asking was there any landscape photographers in the audience. Then asked them what was the best time of day for the best light. So back came the answer, an hour after sunrise and an hour before sunset. This is where you get a nice soft light with gentle shadows.
So applying this to portrait lighting, the one main light is simply not pointed directly at the subject but to the space directly in front of the subject, resulting in a nice soft light with gentle shadows.
