The light output measurement is performed by placing a Lux light meter beside the light. Both are pointed at the ceiling (five feet above) of a dark room. This measurement uses the ambient light produced by the bike light. We found this to be the most effective and repeatable measure of each light.
The room is 10×10 feet with white ceiling and white walls. It is completely dark and with only a desk and computer on one side. When it is completely dark, the light meter reads zero. The light is always pointed at the center of the room. And the light is measured 10 seconds after turning it on.
Pointing the light directly at the meter produced varying readings depending on exactly where the light beam was centered. Also, it was highly dependent on how focused the beam pattern was. Thus we chose the ambient light measurement test as the most effective for evaluating these lights.
One of our concerns was that wider beam patterns or hot spots would be inflated in our readings since they have more reflective surface (our ceiling) to bounce off from. But we found this to not be the case. Using two Dinotte 200Ls , we measured while they were pointed at the same spot, then measured with the them pointed apart for a wider beam pattern. Both cases measured in at 32 lux.
Another good indicator is the Lux measurements of two lights together was equal to the sum of each light measured separately. Example:
Dinotte 200L – 16 lux each
Dual Dinotte 200L – 32 Lux
It needs to be noted that the lux reading we publish is ONLY relevant to us for the basis of comparison. It has NO RELEVANCE to the lux readings of other people because their setup is different from our.
Our reading is also different from Lumens. Lumens is a standardized measure of total light output that should be consistent between lights. It is measured using a very specialized piece of equipment called an Integrating Sphere.
Most light manufacturers estimate their lumens ratings based on the LEDs they use. This leads to false claims and customer confusion. Some companies however like Dinotte, Light and Motion and Niterider get their light outputs measured in an Integrating Sphere and their Lumen claims are fair.