Excellent question! I was being hypothetical, but I had at one time a 500mm.... maybe it was f/4. Dunno, maybe it was built from a telescope, but it was a light cannon for sure!
That appears to be an AI answer.
My experience with Mylar and Kapton is that it is generally RF-transparent.
A sputtered metal coating can be added to it.
The balloon issue isn't so much the conductiveness of the material, it is that it is...
Mylar may have a metallic film applied to it, but not all Mylar does. Metal is not necessary for the material to be reflective. Mylar is also used as an electrical insulator.
There are highly reflective polyester materials, such as mylar, that are non-metallic. They're used on truck and trailer reflectors, road markers, and traffic signs. My offshore PFDs have strips of it on the shoulders.
But there's little real...
This might be silly, you guys probably know, but there is a FPV mode on the camera. I tried it, kind of felt like I was flying, but was terrible for videography. (shrugs)