ftw1952
Established
Back in the day, there was a a primer that we used to bite into hard-to-paint metal. Can't recall what it was called, but it had a greenish-yellow cast or color when dried. (Maybe Zinc-chromate?)
Something like this might work well on inexpensive cameras.
Emron was used in the 70's on semi trucks. It was scratch proof paint and deadly when applied without a respirator.