Also, someone else said before that the MK1 has softer glass than the MK2 so the image isn't as sharp. I personally don't really notice or mind how it looks but I've had people DM me saying the footage looks like shit. It's all preference.
If you keep your aperture narrow (F5.6 and higher), the footage looks way more consistent. I also sharpen my fisheye footage just a tiny bit in post.
Been using the MK1/HPX setup since this past fall and I'm really happy with how most of the footage has come out. I have an edit coming out fairly soon so I'll throw it up in this thread. I've been using a homemade (Shane Auckland -style) adapter but I have one of your bayo ring adapters on the way because I'd like to not have to fuck with threads anymore.