Reddit reviews Impact Mini Boom Arm - 5' 4"" [Camera]

The GH4 can record excellent audio from an external mic. I use mine with the [Shure VP83 microphone.] (https://www.bhphotovideo.com/c/product/966007-REG/shure_vp83_condenser_shotgun_microphone.html) I've done a lot of broadcast programming and commercials with this mic. Don't put the mic on the camera, put it on a boom and get it close to the person talking. This little boom is great for interviews.

Be sure to set the camera microphone gain to minimum and use the gain setting on the mic to get a good level. Also, be sure to get a shielded microphone cable (not a headphone cable) to minimize noise. As with any unbalanced mic connection, keep your mic cables away from power cables.

If the VP83 is too expensive, I've had great luck with the AT 829 which is built for Audio Technica's wireless system but works great with the GH4. Normally the mic is powered by the wireless transmitter, but the GH4's mic input also supplies the necessary power. Since this is a cardioid mic, it works great on a lightweight boom (I use a carbon-fiber fishing pole!) just above the talent's head. I've also used this mic on broadcast projects. The quality is very good.