Just be aware that an LED ring light (I use the yongnuo) will leave distinctive reflections if you don't find a way to diffuse it:
Less obvious here, but quite annoying ( multiple reflections bouncing around inside the water drop):
Very handy to use for focusing, though. Just remember to turn it off if you don't need it. I didn't need the extra light for the photos in the series the second shot is from... just to focus (I was using a 50-135 mounted on a 2x macro focusing teleconverter, handheld. It was not easy.), but I didn't think to turn it off because I didn't see the reflections in the camera preview.