Diodes don't do the right job as discussed above. I have the knowledge but not the mechanical skills to fashion something so I bought an LED light source from this fellow:
Originally Posted by jp498
Seems to work great for black and white. I doubt its spectrum is good for color but I've enough 211s for when I start that again.
I may eventually get his complete VC head when I have the iPad to run it, or a revised iPhone, but that's a chunk of change right now. The light source works great on my D2.