Direct light, light coming mainly from one direction, produces relatively high contrast between bright highlights and dark shadows. Diffused light bounces onto the subject from several directions, lowering contrast. Contrast, in turn, affects the brilliance of colors, the amount of visible texture and detail, and other visual characteristics. In direct light you may have to choose whether you want highlights or shadows to be correctly rendered because image sensors can accurately record only a limited range of contrast between light and dark areas. In diffused light, colors tend to be softer than in direct light and textures are also softened because shadow edges are indistinct.
Direct light comes from a point source, such as the sun on a clear day.
Direct light produces dark, hard-edged shadows that crisply outline details. Here the light and shadows almost form an abstraction. Diffused light comes from a light source that is so large relative to the subject that it illuminates from several directions. On an hazy or overcast day, illumination comes from the entire dome of the sky, not from the brighter, but smaller, sun. Indoors, light bounced into an umbrella reflector or onto a wall or ceiling creates a broad source of light that wraps around the subject.