Available Light

Ambient, or available light refers to the light that already is present in the location where you plan to shoot. This light could be sunlight or indoor overhead lighting. Typically, when using studio flash units, the ambient light will be overpowered by the direct flash. However, it is important to factor in any ambient light in your flash meter readings to insure a proper exposure.

StudioLighting.net

About StudioLighting.net

A Free Online Resource for Studio Lighting and Photography Information: Tips, Tutorials, DIY Instructions, Reviews, and Much More.