EOS 5D Mark IV
- Feb 25, 2015
interesting.. one of the customer reviews describes the adaptor affecting the noise floor in every video:
"... Reviewed in Canada on October 23, 2018
I bought this for my Canon 5d mkiii in order to power it during longer recording sessions of audio/video demonstrations I'm making. Since these are demonstrations focusing on sound character the audio quality is a priority. I find it most convenient to simply run the audio source to the camera input rather than try to align the audio later in post. After recording several sessions I noticed a ground hum significantly louder than the noise floor in every video. This led me on a very tedious troubleshooting journey that lasted the past two nights. Only after hours and hours today it dawned on me that I should check the power instead of the audio chain. As soon as I put the battery in I had clean audio again repeatedly. Next I tried making sure everything was powered using the same ground reference but it made no difference. Since this power supply renders the camera's audio input useless I must give it one star, but it seems it should work fine strictly for video..."
That's a ground loop, which is something you should always check for when you have something connected both to ground and mains power. It's sadly not so easy to solve, in a on-stage setting you can usually plug every mains power into the same group/phase, but if you're recording from the back of the room with an audio line snaking to the front, you're out of luck.