On Mon, 4 Dec 2017 20:19:24 -0800 (PST), Sir Ridesalot
wrote:
On Monday, December 4, 2017 at 10:47:49 PM UTC-5, Tim McNamara wrote:

snip

Not bright enough and you don't see well enough; too bright and you
don't see well either because near objects are too bright and
interfere with dark adaptation. Too narrow causes the same sort of
problem. The top of the beam should be brighter than the bottom.
Some scatter to the sides is helpful, scatter above the horizon is
not (I notice even my new Subaru has a sharp upper cutoff to the
headlight beams). It's easy to get into thinking that brighter is
always better, in which case one will ultimately ride only during the
day in full sun.

And even then there are those who believethat you MUST use
super-bright flashing lights in the daytime.

I'm not that overcautious, but I get the notion given the complete
obliviousness of about 1/4 of the car driving population. They're
looking at their phones, eating lunch, drunk, stoned, whatever.
Anything but responsible behind the wheel. What puzzles me are the
folks who only use a flashing light as a headlight in full darkness.
WTF is up with that?

What I like to see on a website is an image of the ACTUAL BEAM PATTERN
on the road not a wall.

Hence my reference of Peter White's page of beam photos. There are some
other collections of beam photos out there on the interwebs. The
challenge is setting the camera so that it sees approximately what the
human eye does, not making the beam falsely bright or falsely weak.