Despite being referred to as on-camera microphones, the array of such microphones from companies like Rode, Deity, Sennheiser and others are just as capable when used as an off-camera microphone, too. However, the one problem with using them off-camera is that the cables supplied with them are extremely short. After all, they’re only designed to go from your hotshoe to your microphone socket.
Even if you do pick up a long third-party cable, these microphones aren’t designed for long cable runs. The best option is to use them wirelessly. That, too, can be tricky on the end of a boom pole. However, Caleb Pike at DSLR Video Shooter has created a great-looking solution, called the MicBack, to solve this problem with several small on-camera shotgun microphones.