You can even shoot in the field using a microscope! I designed a 3D-printed mount to attach a $25 4x microscope objective to a DSLR or mirrorless camera:
https://www.printables.com/model/143754-microscope-adapter-f...
A shorter version of the adapter "underclocks" the objective to 2x magnification, which is much easier to hand-hold:
https://www.printables.com/model/397489-microscope-adapter-f...
If you already have a 3D printer then this is a very cheap way to get started.