A boom operator is an assistant of the production sound mixer. At Paramount, Dorothy Arzner directed Clara Bows first talkie, The Wild Party, to allow Bow to move freely on the set, Arzner had technicians rig a microphone onto a fishing rod, essentially creating the first boom mic. She did not, however, take out a patent, a patent was filed a year later for a very similar sound-recording device by Edmund H Hansen, a sound engineer at the Fox Film Corporation. They will also attach wireless microphones to persons whose voice requires recording, Boom poles are usually manufactured from several lengths of aluminum or carbon fibre tubing, allowing the boom to be extended and collapsed as the situation requires. The ideal boom pole is lightweight and strong, supporting the weight of the microphone on the end while adding as little weight as possible, frequently, a wind-attenuating cover, called a blimp or mic-blimp, is used to enclose the microphone. A blimp covered with sound-absorbing fuzzy fabric is usually nicknamed a windmuff or a dead cat, in film crew jargon, the gruesome-sounding phrase dead cat on a stick is simply a boom microphone fitted with a fuzzy wind-screen. The one-man unit is known simply as a sound recordist or sound man. Often the boom operator will need to be as familiar with the script as are the actors, in productions with a bigger budget, more than one boom operator may be used, with each operator focusing on a different actor. Having the boom mic or its shadow appear on the screen in a picture is considered a sign of poor film-making. The TV Tropes wiki has a list on its Visible Boom Mic trope page demonstrating more examples, pastiches of bad film-making may also use boom mic visibility to spoof their material
Combined boom operator/mixer holding in a rest position.
"Dead wombat" (L) and "dead kitten" (R) wind-attenuating microphone covers