What gamma mode are you using?
I asked for best settings a couple of weeks ago and received great advice, I also made some tests, but with an HPX-170. The two Cinelike gamma modes were the noisiest, B.press was the one with the lowest amount of noise.
Detail level can change the way you see noise in your images. There are different controls for it: the detail level, vertical detail level and the core detail. Test lowering your detail and vertical detail a little. You can have a high detail level if you want a crispy image, but then you need a positive number in the detail core. The core is like a threshold value for the detail to show up.
My tests were not for green screen, but I liked a detail level of +3 with the detail core of +2. Vertical detail on +2. I use those settings now as a starting point, but you should do your own tests (my camera is different). The light on your footage looks fine to me, so check if you’re using a Cinelike gamma mode and change it to normal or b.press.
Keylight have an option for softening the edges of the mask, if I remember well it’s called “edge softness”. A value of 1 or 2 can improve the look of the key by softening the jags of a noisy image.
I hope this helps.
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