Explanation of how secondary optic affects beam/throw (translated from TLF)

[Dc38 (The Glutton)]

Flashlight Optics - Dome, Dedoming and Throw

I wanted to write a longish text about flashlight optics for quite a while now, starting with all the optics and photometry basics, up to the details of what throw depends on and why, including how dedoming increases throw, all with a coherent line of argumentation and some experiments to try. I even started writing that document, but it seems I just don't find the time to finish it in reasonable time. I now decided to take a shortcut and just do a very short version of it, especially focusin…