Warning: spent $210 on a camera snake before I learned the mirror and flashlight trick
Bought one of those cheap borescope cameras online for $210 after a guy in Cincinnati told me it was the only way to check a flue liner right. Used it on three jobs and the picture was so grainy I could not tell soot from a crack. My old mentor Ray watched me mess with it for 20 minutes, then handed me a small mirror and a flashlight and told me to angle it up the flue. Saw more in 10 seconds than the camera showed me all week. What convinced me was a cracked tile I missed with the camera that Ray spotted right away with the mirror. So now the camera sits in a drawer and I want to know if anyone here actually gets good use out of theirs before I toss it.
Did you try wiping the lens and letting it warm up before using it? Mine fogged up on the first two jobs because I went straight from a cold truck into a warm house. Once I started doing that and holding it dead still, the picture got way better and I actually caught a bad joint last month. It is still slower than a mirror though, so I use both now.