Lichtdistanz

Lichtdistanz is a term used in lighting design, photography, cinema and related fields to describe the distance between a light source and the illuminated surface or subject. It is a fundamental parameter that influences illuminance, contrast, and the character of shadows, and it interacts with other factors such as light intensity, beam spread, and surface properties.

From a physical perspective, the light received per unit area, or illuminance, follows approximately the inverse-square law for a point source: E is proportional to I divided by the square of the distance d, where I is the luminous intensity. If the surface is not perpendicular to the light, the illuminance also includes a cosine factor. Real light sources have extended size, specific beam angles and falloff characteristics, so practical calculations use the source geometry, angular distribution and distance to predict illumination on a target.

In practice, a short Lichtdistanz results in higher brightness but stronger falloff with distance, while a longer distance reduces intensity and typically yields a harder light with sharper shadows. Conversely, moving a light closer increases softness if the source behaves as a larger apparent size relative to the subject, and using diffusers or modifiers can change the effective apparent size.

Terminology varies by context; Lichtdistanz is commonly understood as the distance to the light source or to the subject, but some sources may refer to related concepts as Beleuchtungsabstand or Abstandsgröße. It is routinely measured in meters and optimized during setup to achieve desired exposure, contrast, and texture.