Robert from JuicedLink illustrates why mounting a shotgun microphone to the DSLR’s hotshoe may lead to low-quality audio recordings. The solution? Get the microphone closer to your subject, position it high and point it downward toward the subject’s voice.
Doing so reduces the amount of ambient noise captured by the microphone’s tail end while simulatenously increasing the volume and quality of the audio recorded from the front.
B&H carries shotgun microphones.