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I want to hear how the light is. I normally use an 80-lux B&M headlight. What's 100 lumens in comparison? (I know, rhetorical question ... it's not as simple as converting inches to centimeters).
IIRC, lumens is a measure of how much light is produced by the source (in this case, a LED).
Lux is something I don't typically use, so I had to check wikipedia: "The
lux (symbol:
lx) is the
SI derived unit of
illuminance, measuring
luminous flux per unit area.
[1][2] It is equal to one
lumen per square metre."
As such, it depends a lot on the way that the light is shaped.
If the beam is very tight, then the lux will be greater than if the beam is wide, assuming the same light source is used.
Lumens is useful when comparing light sources such as LEDs, since there is no way to know what sort of optics will be used to shape the beam.
Lux is much more useful when comparing lights, assuming that the beams are roughly comparable.
I will say that modern white LEDs produce about 100 lumens per watt. A dynamo headlight should be able to produce around 300 lumens.
Overall, a light that produces 100 lumens is going to be noticeably dimmer than a standard LED dynamo headlight. Even so, it's also going to be brighter than if an incandescent bulb was used. I've compared an old Lumotec incandescent light with an early LED dynamo light. At the same power level, the incandescent Lumotec was just a feeble glow by comparison.
Steve in Peoria