Pentax-A 50mm with Helicoid Extension Tube K for a little more than 1:2 magnification.
The aperture was something silly like f/4I took many, many images and stacked them.
I could have used f/11 and stacked fewer images. The very narrow depth of field really allowed me to throw the surrounding buds and flowers out of focus. I could pick exactly where focus would end and f/4 gave a sharp fall off (relative to something like f/11)
A couple flashes. I forget exactly where I had them placed. The camera was on a manual focus rail. I moved the camera rather than adjust the focus ring. The software is Zerene Stacker.