The boom microphone is very popular in film and television production. A directional mic is mounted on a boom arm and positioned just out of camera frame, as shown on the right. The cable is wrapped once or twice around the boom arm.
Booms have the advantage of freeing up subjects from having to worry about microphones. They can move freely without disturbing the sound, and concerns about microphone technique are eliminated.
You can make a simple boom from just about anything which is the right shape. A microphone stand with its legs removed is a good option, or even a broomstick or fishing pole.
A good boom will have some sort of isolating mechanism for the microphone to prevent vibrations being transferred to the mic. This may involve elastic suspensions, foam padding, etc.
The distance between the microphone and subject must be carefully controlled. The mic must be as close as possible without any chance of getting in frame (you might want to allow a safety margin in case the framing changes unexpectedly). It must also maintain a reasonably consistent distance to avoid fluctuating audio levels.
Make sure the boom doesn't cast a show on the scene.
In the example on the right, the sound operator is also acting as a guide for the camera operator as they walk backwards, keeping a constant distance from the walking subjects.
Next Page: The Hand Held Microphone