Oddbean new post about login | logout To work under a microscope by eye or with cheap(ish) cameras, you need a lot of light since the image's brightness gets divided by the same multiplier that it gets magnified by.
That in mind, I set out to get a decent but not too expensive microscope ring light. I scrolled through a few listings, and I was disappointed to see that most cheap ring lights use bent 5mm THT LEDs to avoid the need for a custom lens or reflector.