I use the same camera that Mike Busch uses. Search eBay for UltraCam dental; several currently available for $100-300. These are US made professional dental cameras that originally cost approx. $7000 in the 1980s, and are no longer made. Make sure you get one that doesn't need repair; I don't believe the manufacturer still exists.
Excellent optics, internal adjustable lighting, easily fits through a plug hole, 8 ft. cable. Can be mated with either a laptop or TV for viewing.
I previously tried 3 of the cheapie Chinese cameras; one was DOA and the other 2 had terrible optics. Also have the HF camera; OK for looking inside your wings, but not much else.