Just ran across some beamshots of a couple Firefly E90’s with 909MX on reddit HERE, and I’m surprised by the nasty ring artifacts. I am no expert but my 4 lights with single large TIR (X1Lx2, Convoy M21H, IF22a) have the nicest and smoothest hotspot in comparison to my reflector lights.
And smooth hotspot is what I thought to be expected of single large TIR optic. Explanation anyone?