Lateral shading using barndoors or flags to cut the beam horizontally and prevent unwanted light spill or lens flares.
Technical Details
Standard side chops measure between 10-30 cm in length and are available in angles of 15°, 30°, 45°, and 60°. They are attached via standardized accessory mounts with 16mm or 28mm spigots. Modern versions are made of anodized aluminum with a matte black coating to prevent reflections. High-temperature variants for HMI lights can withstand operating temperatures up to 200°C. Some models feature adjustable hinges with detents in 5° increments for precise adjustment during shooting.
History & Development
Side chops evolved in the 1940s from the originally used improvised cardboard boxes and plywood boards. In 1952, Mole-Richardson introduced the first mass-produced metal side chops for their 2K Fresnel series. The breakthrough came in 1967 with Arri's modular barn door systems, where side chops were designed as separate components. Since the 1990s, computer-aided designs have enabled optimized light distribution curves with up to 40% less stray light compared to standard versions.
Practical Application in Film
In "Blade Runner 2049" (2017), DoP Roger Deakins used side chops on LED panels to create the characteristic vertical light streaks in interior scenes. For portrait shots, side chops limit specular highlights to cheekbones and the bridge of the nose without affecting the eye area. In dialogue scenes, they prevent spill between key and fill light, which is particularly critical in 2.39:1 formats. Their use reduces post-production time, as less digital masking is required.
Comparison & Alternatives
Unlike top/bottom chops, side chops work exclusively horizontally and do not affect vertical light distribution. Gobos offer more complex patterning but require greater distance from the light source. Modern LED panels with integrated honeycomb grids are increasingly replacing mechanical side chops but achieve only 75% of the sharpness of traditional metal versions. For moving camera shots, mechanical side chops remain indispensable due to their consistent characteristics, while programmable LED solutions offer advantages in static setups.