Extreme macro photography is amazing to me and so fascinating to see a small world so close up.

I've only tried adapters and reversed lenses a couple of times and as you say focus is really fiddly to get just right. You also have to have really good lighting.

Canon make a macro lens that I would love to own, the Canon MP-E 65mm f/2.8 1-5x Macro Photo. This takes amazing macro images. Canon have some demo videos somewhere showing this lens in use. Quite amazing.

The one I use is this one. I wanted this lens for a long time and it didn't disappoint once I obtained it.