^Reading that was a trip. At first I was like: who still uses an HV30? (worst of both worlds, 16:9 into tapes). Then I continued reading and the whole tapeless setup description surprised me. Love reading the technical nerdery.
On another note, I was checking this clip filmed by Kevin Perez and realized the vignetting on the fisheye isn't a circle.
This is a superimposed circle over a screencapture. As you can see the vignetting of the fisheye is more of a ellipsis.
So I assume that the footage is filmed on a more square-ish aspect ratio and stretched to fit a 16:9 aspect ratio.
Apparently it is a 3:2 crop stretched to 16:9.
There is a gain in vertical width without looking to stretched. I think a 4:3 crop to 16:9 would definitely be to noticeable.
I have mixed feelings about it though. Things get distorted horizontally and it reminds me of the era when people filmed VX and stretched it to 16:9 ie Solo Jazz.