Boom operators therefore need to have a high level of skill to perform their jobs to a high standard. Knowledge of various types of microphones and their applications is essential. A knowledge of camera lenses is also necessary as well a good overall technical understanding of all the varied equipment modern sound departments use. Because boom operators are required to liaise with actors and multiple departments they need to be diplomatic and have good people skills. They also need a good level of physical fitness, strength and stamina.