What is the purpose of the fill light in video production?

The purpose of the fill light in video production is to soften deep shadows created by the key light. The key light is typically the primary light source, which casts strong and often harsh shadows on the subject. By adding a fill light, which is generally softer and less intense than the key light, you can reduce the contrast and create a more balanced and flattering illumination on the subject. This helps to reveal details in shadowed areas without overpowering the overall lighting setup.

In contrast, other functions mentioned, such as acting as the brightest light source, illuminating from a distance, or highlighting specific features, do not align with the primary role of fill lighting, which is specifically geared toward shadow management rather than creating dramatic effects or direct illumination.