On Mon, 4 Dec 2017 20:19:24 -0800 (PST), Sir Ridesalot
wrote:

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

It's difficult to see variations in brightness on the roadway, where
everything on the road, trees, sidewalk, cars, dirt, concrete,
asphalt, street signs, and such, reflect light by varying amounts. For
example, if the road was made from a glass mirror, you would see
nothing because all the light would be reflected in the forward
direction and none would be reflected back towards the rider. Vertical
objects, like people and trees, appear brighter because more light is
reflected. So, if you want a "realistic" test, you end up measuring
reflectivity, not illumination.

Peter White's photos seem to be close to the way you are asking. The
problem is that it is difficult to see the variations in intensity. If
I accentuate the difference in light intensity using pseudo color
proportional to the (reflected) light intensity, I get a more
interesting picture. You can more easily see the hot spot(s),
pattern, beam width, and side lighting, like this:
http://802.11junk.com/jeffl/pics/bicycles/Front-Light-False-Color/index.html
Each (pseudo) color has a corresponding lux (brightness) value (which
I didn't bother trying to calculate). All the photos on the page are
of the same headlight and were derived from the color photo on Peter
White's web site. (Ignore pseudo-color-01.jpg, which is a duplicate
of one of the others).

Unfortunately, I've done nothing with this beyond the initial
tinkering. If any one is interested in how this was done, I'll dig
out the info and post it.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558