What is a crab dolly commonly used for in filming?

A crab dolly is primarily used to capture movement shots smoothly, which is crucial in film and video production. This type of dolly allows the camera to move along tracks or on wheels in various directions, helping to create fluid, dynamic shots that enhance the visual storytelling. The ability to move smoothly is essential in achieving cinematic quality, especially when capturing action or following characters.

The other options do involve important aspects of production equipment but don't accurately represent the primary function of a crab dolly. For instance, stabilizing audio equipment is generally done with other types of gear designed specifically for sound, and supporting lighting rigs requires different equipment that is built to hold and position lights effectively. Similarly, while certain setups may involve holding the camera stable for still shots, this is typically performed with a tripod rather than a dolly, which is not designed for static positioning. Overall, the crab dolly's emphasis on mobility and smooth transitions is what distinguishes it within the context of filming practices.