Would you just look through an endoscope or do you use a tool to determine the quality?
Please share your opinion about testing endoscopes!
You need a really good trained eye. It sometimes is hard to see what's wrong with an endoscope and most of the time you are discovering this to late.
You have to check with Freeze spray to check for water vapor inside the endoscope.
If water vapor is present this can give a lot of problems.