Camera microphones have a relatively short but interesting history. The demand for high-quality audio to accompany video content has been high since the 1950s. This has helped to precipitate a number of innovations including the Neumann SM2, the world's first stereo mic, released in 1957.
Similarly, the booming film and television industry of this era required the ability to capture live audio from a respectable distance 'out of frame'. The shotgun mic, developed by Harry F. Olson, solved this problem by using slots on the side of an 'interference tube' to cancel unwanted, 'off-axis' frequencies. With the advent of virtual reality, 3D camera microphones are becoming increasingly popular to capture highly-detailed positional audio.