The Top 10 Photography Lighting Facts You Should Know
Diffusion scatters light
3. Diffusion scatters light, essentially making the light source broader and therefore softer. When clouds drift in front of the sun, shadows get less distinct. Add fog, and the shadows disappear. Clouds, overcast skies, and fog act as diffusion—something that scatters the light in many directions. On overcast or foggy days, the entire sky, in effect, becomes a single very broad light source—nature’s softbox.
Tip: Materials such as translucent plastic or white fabric can be used to diffuse a harsh light source. You can place a diffuser in front of an artiflcial light, such as a strobe. Or, if you're in bright sun, use a light tent or white scrim to soften the light falling on your subject.