Key grip

In US American and Canadian film-making, the key grip is the chief grip on the set. Like a foreman, the key grip directs a crew of grips, some with specialized skills such as dolly grips, crane operators, camera car operators, etc.In Australia and New Zealand the key grip generally owns the grip equipment including, dollies, track, cranes, camera cars and insert trailers.Additionally, the key grip is often the safety monitor of the film set, responsible for safety of all personnel in the presence of theatrical ballistics, pyrotechnics, stunts, and any other potentially dangerous situations and devices operated by other departments.
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