Paralleling a 510 Ω resistor with each of the 180 Ω resistors on the LED ring light around the macro lens holder boosted the LED string current from 15 to 20 mA:
The complete botch job in the lower right is what you get when you don’t wipe the soldering iron tip first.
LED brightness being pretty nearly linearly proportional to current, the exposure gets another 0.4 EV that probably doesn’t matter in the least.
A hand-held picture of the pile of SMD resistors (which willingly produced four of the five resistors and required enhanced interrogation to extract the last one):
That’s pretty much overhead at f/8, so the depth of field is as good as it gets.
The Smell of Molten Projects in the Morning 