Appreciate the explanation of Lux, massively, as I was never quite sure of their relation to Lumens. But I have pulled two of TEEJ's quotes (and one twice) from separate comments because they contradict each other, but also something in the first post I disagree with and most know it not to be true. I'll start with that, then go back to what I'll call the hotspot conjecture.
but you can see more with more lumens
This is generally false. To illustrate why, some absurdity: imagine having
all the lumens, every single one. If TEEJ's statement was true, you'd see more than anyone else ever, but in practice you wouldn't be able to see anything at all, and I think you'd probably never see anything again. What I have learned from CPF is that you'll see a lot more with a dimmer and warmer HiCRI light than with a much brighter much cooler and lower CRI light. The irony is the popularity of bright, extremely cool color temperature lights, because the user actually sees less, and less and less as the blue in the cool white slowly permanently blinds them. This has been argued ad infinitum elsewhere in many CPF threads.
Humans suck at judging brightness in of itself...but you can see more with more lumens, but, most of the added vision is to the sides in a broad pool of light...and less is added to a central hotspot.
In real life, the beams tend to have three main parts though: A hot spot, the brightest part in the center, the corona, a donut shaped ring of somewhat dimmer light around the hot spot, and spill, the light that was sent out past the reflector bowl without being focused.
The second half of the quote from the first post and the quote from a subsequent post are contradictory. The second quote explains reflectors quite nicely, but the issue I have is the insinuation from the first quote that most of the light that comes out of a reflectored light is the spill even though the hot spot is brighter. But assuming the second quote is true, and I think it is, and we follow the logic and geometry, the spill couldn't have more light than the hotspot.
The light coming off a filament or emitter goes in all directions. But because the filament or emitter is surrounded on all sides laterally and most of it's bottom and the sides of above it, and all light bounced off the reflector contributes to the hotspot, and the spill is only the light that happens to miss the reflector
on one side, namely, in some direction not parallel (or else it may contribute to the hotspot or otherwise be negligible) but definitely out the front, then the hot spot contains most of the light that the filament or emitter produces because of the larger surface area of the 3D reflector compared to the 2D lens.
I'm terrible at explaining things, but I hope that makes sense, that the hot spot represents most of the light produced, except for the minority of light that misses the reflector and becomes spill.