As ever, nice work Wal.

I bought one of those cameras sold for picking your ears - it has a 20mm focal length and illumination https://www.ebay.co.uk/itm/3-In-1-Ea...cAAOSwO0VeJ~E-
It produces reasonable images for £6 - This is inside a harmonica showing a faulty windsaver valve. The end of the valve is 2mm across.
Click image for larger version. 

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The biggest problem is holding it steady enough as the depth of field is very poor. I can't use my dad's loupe as he was an accountant.

Happy New Year FWIW.

Rob