Understanding the different qualities of light is fundamental. Hard and soft light sources produce such different results that most all photographers spend a great deal of time thinking about (obsessing about) quality of light. Generally, we spend our time trying to find ways to soften light by diffusing light through surfaces or bouncing light off of surface — or my favorite, shooting on a cloudy day.
Bottom Line: Hard versus soft light is the most basic concept in lighting; get the light source larger and closer to get a softer light.
For this sequence we placed a 24" softbox 16 feet away from Nicole, then moved it closer and closer. The closer the lightbox, the larger it looms; hence the softer the shadow it creates. Every shot was done at f8.
More about this sequence: the first time we shot this in a white room we got a result that proved the exact opposite of my theory: the further away the light box went, the softer the look! This happened because the white walls and low white ceiling bounced the light, creating a larger light source as I moved away. Duh. Finally, we shot this in my dark-walled basement.