[JR1427]

You don't even need a macro lens. I used a kit zoom lens and some lens spacers, bought used for £60.

(I did my post-doc on slime mould decision-making)

[hermitcrab]

Yes, you can use spacers. That is probably a good way to get started. I believe you can even use kits to put a standard lens on 'back to font'. I prefer a dedicated macro lens personally. Lenses like the Laowa 100mm for Nikon are fairly decent and not _that_ expensive (note it is manual focus - in macro you generally move the camera rather than changing the lens focus).

[EvanAnderson]

Just to echo what you said:

The "reversing ring" trick does work, (mounting a lens backwards) but the ergonomics are shit. I bought one to play with and tossed it in a drawer after only using it once. A real macro lens is so much better.