Yo! Congrats on the wedding gig, honestly the GH6 is such a beast for video, you are gonna have a blast with it! For $200 you can definitely get something professional without breaking the bank. Don't stress too much about the technical stuff, it's simpler than it looks. Most of these mics slide right into that slot on top of your camera, which is called the hot shoe, and they just tighten down with a little wheel. For your budget, I'm totally obsessed with the Rode VideoMic GO II Lightweight Directional Microphone. It is super light and the best part is it doesnt even need a battery because it runs off the power from your GH6 mic jack! It sounds crisp and clear for those vows. If you want something with a bit more punch and dont mind spending every penny of that $200, the Sennheiser+MKE+400+On-Camera+Shotgun+Microphone&linkCode=osi&tag=7649-20" target="_blank" rel="nofollow sponsored">Sennheiser MKE 400 On-Camera Shotgun Microphone is absolutely fantastic too. It has a built-in wind shield which is a total lifesaver for outdoor weddings! I've used the MKE 400 on my own GH series setup and it's tiny but mighty. Just plug the coiled cable into the red mic port on the side of your GH6 and you're good to go. Just remember to do a quick sound check before the ceremony starts... trust me on that one. You got this, your sister is gonna love the footage!

I am just getting around to this but honestly weddings are a nightmare if you dont have gear you can trust. I have been disappointed by too many budget setups that picked up interference or just felt like cheap plastic. You really dont want to mess this up for your sister. To answer your questions directly:

• Most decent mics for the GH6 use a standard 3.5mm TRS cable.
• Yes they fit on the cold shoe mount on top of the camera.
• Batteries are a pain but usually necessary for a clean signal. I tried using some of those passive mics that dont need batteries but the audio was way too quiet and hissed like crazy on my GH6. It was a total letdown. If you want something that actually works for a long ceremony look at the Sennheiser+MKE+400+Shotgun+Microphone&linkCode=osi&tag=7649-20" target="_blank" rel="nofollow sponsored">Sennheiser MKE 400 Shotgun Microphone. Its right at your $200 limit and it is built way better than the generic alternatives. Here is why you need to be careful:
• Power management. This mic has an auto-power function. I have forgotten to turn mics on before and ended up with zero audio. It is devastating.
• Gain control. The GH6 preamps are decent but you want to set the mic to +20dB so the camera doesnt have to work as hard.
• Low-cut filters. You will need this to cut out the hum from air conditioners in the venue. I would also grab a Rycote Windjammer for MKE 400 if you are doing any outdoor shots. I made the mistake of trusting the built-in foam once and the wind ruined the vows. Never again.

I've been satisfied with the Rode VideoMic NTG Analog/USB Shotgun Microphone lately. It fits the shoe and works well because the auto-sensing 3.5mm output saves me from constantly checking battery levels.

ngl im in the exact same boat and it is so stressful. i have been looking for a reliable setup for my gh6 for like three weeks now and i still havent bought anything because im terrified of the audio cutting out or the battery dying during a big moment. it is seriously so overwhelming trying to find something that just works without failing... honestly i still dont have a clue what to buy.

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Saw this earlier but just now responding. Honestly, I'm in the exact same boat right now! My GH6 is an amazing piece of kit, but DIYing the audio for a high-stakes wedding is a huge challenge. I've been obsessing over my own rig and it's basically a massive headache trying to get pro results without a dedicated sound crew. To help me narrow down what we both might need for these DIY setups, I had a couple of methodical questions:

• Are you planning to be stationary on a tripod for the main ceremony, or will you be moving through the crowd for the reception?
• Is the venue an outdoor space where wind noise will be a factor, or is it strictly indoors? It's honestly so overwhelming but also kind of exciting to figure out!