Since so far no one has set images to here my first attempts out of the box with one cent. The 16mm extract resulted screwing together the retro ring and the protection ring (Protection Ring for lens in reverse position Canon).
In sum: Fantastic shots that would otherwise make only with unaffordable or unavailable magnifying lenses, and all of that extremely inexpensive.
A little thing that has not been mentioned: the distance to the object is extremely small at just 18mm focal length. The object then to light remains a challenge.
Depth of field is also scarce but it is quite well to be expected when the magnification.