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Why can't I see?_A theory on LED headlights.

5556 Views 9 Replies 6 Participants Last post by  Loboc
EDIT: This is a discussion about using the "high beams" or "brights" over a distance. This does not apply to "low beams" or "shuttered" projector bulbs.

You just sprang for a fancy new set of LED headlights, they looked great in the garage and you can't wait to try them out at night but the first time you hit the road you may feel a sense of disappointment and a disquieting sensation that the headlights aren't lighting up the actual road the way you feel they should.

This happened to me, my subjective human senses were insisting that there was this large black area down the road that simply wasn't being lit and that felt useless and unsafe.

However, when I resorted to some objective instrument based measurements of distance and light, I discovered to my immense surprise that in fact I could see test objects at much further distances with the LED vs the Halogen lights, even though my brain kept insisting that there was a huge dark hole in the lighting.

How could this be possible? I have a theory that it has everything to do with how the human brain and eyes interpret contrast.

This theory is my attempt to try and explain the effect.

Another example of the contrast illusion is demonstrated on this webpage.

This may also be why I'm so pleased with the "hexfire" light add on I just did, because I aimed the center spotlight parts of those lights down the center of the road, creating a "hot spot" much like the pattern of the traditional incandescent/halogen bulb.
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Bright headlights are over-rated anyway. Their main effect is to blind oncoming traffic. Eyes adjust to the light level, the pupils dilate, the retinal cells increase sensitivity, and you end up seeing more if there are fewer 'hotspots' around.

On a bright moonlit night (tonight would be ideal, brightest 'supermoon' in decades) if you are on a quiet moonlit road, turn your headlights off. You'll be amazed at how much MORE you can see!!

... I'll let you decide how fast you are going, or whether to stop, when you do that for the first time!!
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