I'm still working on the lighting. Maybe I'll get something that I can rely on. Latest "other" coin (try #4 or 5 of the 1954 Jefferson) I placed a second light and reduced the exposure a bunch. (technical photo term of course) But honest, I was shooting at a 30th and went to 1/125th.
Problem with the extension tube on the macro lens, it's manual, so no F/Stops just adjust the lighting and the shutter speed.
As for the diffuser I've used things like old Rubbing Alcohol Bottles, cut up. Gallon milk bottles, paper napkins, and layers of shelf tape. I'm working on this coin thing as a project and learning.
I want something to diffuse the light, that can clip on and off easily. The ring light clips on the lens, LEDs, cheap from eBay. I think it's a bit to harsh.
Time to spend this nickel, it doesn't go through the counting machines.