My documentary group uses both the 6300 (with Vello adapter for Nikon lenses and Metabones IV adapter for Canon lenses) plus the A7RII and many other cameras.
We use many different mics but for hot shoe use the Sennheiser MKE 400 is pretty good if you want a physically small mic:
https://amzn.com/B0015CM64U
The Rode VideoMic Pro may have a little better sound than the MKE 400 but it's bigger and the 9v battery doesn't last as long:
https://amzn.com/B004K8WPUQ
We recently got a couple of Sennheiser MKE 440 mics which is the best hot shoe mic we've tested, but it is larger and more expensive:
https://amzn.com/B01EM70BE6
For most circumstances you don't want to rely on a camera-mounted mic (for main audio), whether in the studio or in the field. The sound just isn't that good, and audio is a crucial and often overlooked part of video production.
Even a Rode SmartLav going to an iPhone is better than any camera-mounted mic:
https://amzn.com/B00EO4A7L0. Probably even a $29 wired lapel mic is better:
https://amzn.com/B002HJ9PTO
The Sony ECM-W1M Blutooth wireless mic is one of the most convenient and is usually a much better choice than a hot shoe mic. It clips on the subject quickly and mounts directly on the camera hot shoe without requiring any battery on that end.
https://amzn.com/B00HPM086C
Where possible we use a boom-operated shotgun mic like the Rode NTG-3 or Sennheiser equivalent, but this is additional complexity and usually requires a trained boom operator for best results:
https://amzn.com/B001C0IFDQ
For field interviews where there is time to configure the mic, we use the Sennheiser G3 wireless lavs. They are really good and unobtrusive once positioned, but for quick walk-up interviews they take more time to configure than the Sony ECM-W1M:
https://amzn.com/B00BL87C42