Preliminary brightness testing only, no accuracy testing.
With old LED timing light circuit :-
1 - 4 off 5mm LEDs
2 - 8 off 5mm LEDs - resistor value wasn’t reduced for larger current draw, so light intensity could be improved
3 - 8 off 10mm LEDs - resistor value wasn’t reduced for larger current draw, so light intensity could be improved
4 - Peter’s(Vanepp) new improved LED timing light circuit using 8 off 5mm LEDs . The circuit filters stray after-triggers and increases light by delaying LED switch off. and that produces a longer “block shape” mark. To use this circuit accurately you must only use the leading edge of the timing mark.
I stuffed up with the COB because it was 30V, and that made it barely turn on even without a resistor.