It should be a well established truth that on-board camera microphones are bad to terrible, and on some cameras, for some applications, they are downright useless. A few months ago, I bought a Røde SmartLav+ to take more control over the sound quality of some of my videos. I record sound on my iPhone, and combine the footage with the audio in post production, an editing step that (given software that supports audio-based sync) takes very little time, and which helps solve the issue of poor audio quality.