A few years ago I purchased one of those crappy $50 macro ring flashes. It broke. The unit came with a series of adapter rings to attach to various lens sizes from it's standard 52mm size. I had an old F-mount that I had removed from a really cheap manual focus lens that I've used on everything from a Diana and Holga lens to failing at attaching a Fisher Price telescope to some old 1960s Mamiya 35mm lenses. So I unglued it from the 2x Mamiya teleconverter I had and attached the F-Mount to the 62mm ring adapter then took the 52mm screw from the junk ring light and super glued it all together. The result is being able to reverse mount and 52mm lens onto any F-Mount Nikon. Of course there's no autofocus and it needs to be on a tripod. The results are quite stunning. I used a 24mm prime ƒ2.8 set to ƒ5.6 (it has a manual aperture ring) and captured a regular printout sheet of paper using a SP-600 at 1/2 power at ISO 50 and 1/200th shutter speed. Here's the results and the build. Examples are from iPhone 6+ capture of the Nikon D610 LCD.