The shape!!! Like a little nest of eggs. I'm blown away by the resoltuion you can get. I know that there is a way to get even stronger magnifications by mounting microscope lenses. Have you, or anyone reading this tried before. I would love to see results of that.
No, I've just used my 60mm macro with my MSN-505 lens. That's all. I've read a lot at Traumflieger.de about such microscope lenses (which you alos can buy there) but I haven't ever tried it.