Today I did a similar thing as yesterday only now I used my 18mm Fujinon lens together with my new and cheap E-bay extension tube of 10mm. Using extension tubes on this kind of wide angel lenses is not something you normally do. Even the slightest raising of the distance between the lens and the sensor will shorten the focus distance dramatically. There was a bright sun so I had to wiggle around with the camera as to not cast a shade over my subject with the lens onto the tiny flowers. I had to remove the lens hood because I kept on bumping into them.
The focusing distance between closest and furthest is around 2 to 3 cm, really short so you have no choice to get close. The downside of this that if you bring this small and lightweight extension tube with you for the occasional macro shot you better make sure it’s only small flowers or other objects.
I still like the result of the pictures, the lens combination gives an other feel to the pictures than my other lenses do in macro mode and that’s worth something to. This time I choose the aperture and let the camera do the rest. The two out of focus pictures are also taken with this lens setup but might as well be taken without the extension tube. The pictures are sharpened and lightly edited in lightroom.