Just because a camera is MFT or a crop sensor doesn’t mean that the resolution of the video clip being recorded in terms of pixel dimensions will be smaller, they technically will still be 720p or 1080p in size.
There ARE going to be quality differences due to the fact the smaller sensor sizes on MFT and crop sensor can’t gather as much light as the larger pixels on the full frame sensors. For instance, how well the video looks in low light and how much noise is there can be a difference you will notice – but that isn’t a for sure thing.
There can very well be other differences too like in bit depth, color space, compression used etc….however all three sensors have the capability to mix very well together or not so much…it really all depends upon the image shot, how it was lit, the subject matter etc, but this is always the case. That’s where color correction and grading can come in to make the images “match” in look.
Steve Crow