Re: For those who believe in electricity

On 4/11/2025 3:24 PM, Roger Merriman wrote:

Frank Krygowski <frkrygow@sbcglobal.net> wrote:

 [about headlight beam optics, generating "specially shaped beams":]
I don't think that's true at all. Take a look at some of the beam shots
at this site: https://bikelightdatabase.com/beamshots
>
Or go to
https://road.cc/content/feature/roadcc-front-bike-lights-beam-test-310999
  and look at the beam shapes of the Ravemen and the Knog.

 Both of which have shaped beams, Raveman and Knog both claim road specific
beams and reviews tend in Road.cc and others mention this, Raveman make lot
out of their High and low beams, though they are far from the first to do
that sort of thing!
 I get why they do this, but a camera isn’t an eye and it’s rather false if
not misleading to use beam shots.

I think you and I have different definitions of beam shapes, and different standards. (Andrew will be thinking "Of course!")
But the beams shown for the Raveman and Knog are rotationally symmetric. That can be called "specially shaped" only in comparison to totally random shapes, or to a light source with no focus at all.
Here's a good article on beam design that highlights the shortcoming of a round beam for road use. https://www.renehersecycles.com/myth-14-more-lumens-make-a-better-light/
Essentially, the illumination of the road surface can't be uniform. It's closest to uniform if you're wasting half the light above the road surface. Otherwise it generates hot spots that are detrimental to your night vision. A properly designed beam will do a much better job of giving uniform illumination and will better show road contours, obstacles, potholes, rocks etc. The information is much the same as the Peter White article below, but with graphics that may make the ideas more clear.

In the past few years, there's been more attention to optics, but I
think there are still plenty of small manufacturers who use rotationally
symmetrical optics. Peter White has an explanation of why those are far
from optimum, at https://www.peterwhitecycles.com/plight.php

--
- Frank Krygowski