This is the new method I am using to not only ensure the quality of solder joints, but also verifying vintage items that are not easily read or seen. Especially with vintage tubes. Transparent materials give this the ability to literally pierce down deeper.
This no-name brand standalone/portable microscope with a 6-8 hr battery comes in for under $60 shipped. It does 1080/60 video and 3.2 MP photos onto micro SD cards. Definitely going to come in handy down the road.