Originally Posted by
noglider
Headlights designed for dynamos have carefully engineered optics in the reflector and lens to create a sharp cutoff at the top of the beam.
This is pretty much only true of headlights from Germany, or maybe the EU, e.g. Supernova, Schmidt Edelux.
You can find less expensive LED headlights online from Asia (and maybe elsewhere) that just have a regular symmetrical lens for a lot less that would be illegal in Germany.
PS I can recommend the Supernova brand. I used one for over 10 years, constantly on, until my 1992 Trek Multitrack was stolen in Ventura, California, last month.