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  1. #1
    fc
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    Is a lumen a lumen?

    What is a lumen? Where do all these lumen figures come from?

    Did someone actually measure the light output of all these production lights? Or are manufacturers just estimating their lumen output from bulb ratings?

    How accurate are the manufacturer lumen ratings? Is there any way to verify them? Is a 500 lumen HID light the same brightness as a 500 lumen LED light?

    Enquiring minds want to know. I'm observing that 3 different '500' lumen lights seem to have noticeably different output levels.

    fc
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  2. #2
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    A lumen is a lumen. That being said, however, most of the ratings are best case scenarios and don't take into account losses in the lenses, reflectors, etc. The only company that I says how they measure the output is NiteRider on the TriNewt. They state in the paperwork that comes with the light that they used an integrating sphere -- the only method that I am aware of -- to measure the output in lumens.

    Princeton Tec might also... I remember having a discussion like this with them, but my memory is a wee bit foggy on the details at the moment.

    If any other company does this, I'd like to know.

  3. #3
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    As far as I know, yup, a lumen is a lumen is a lumen.

    Companies are out there to deliberately mislead consumers by tricking consumers into thinking that they are getting more utility than is the case. Look around and you'll see them... peak power on sound amplifiers, non-SAE horsepower ratings, contains real fruit, etc. I put turnkey lights with bulb lumen ratings into this general rubric.

    The use of an integrating sphere implies to me that the lumens made by the torch has been measured.

    Think of bulb lumens as the gross amount of light and torch lumens as the net amount of light after incidental losses due to design. Efficiency is a big deal when one doesn't have much light to play with.

    Flashlight wise, SureFire has been rating with torch lumens for a while now.

    Beam pattern, colour temperature, environmental factors, viewer night vision accomodation can all play a part in perceived light values. Integrating sphere output is not subject to interpretation but I suppose if it was not built properly then the results could be skewed?

  4. #4
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    Quote Originally Posted by mudmojo

    Beam pattern, colour temperature, environmental factors, viewer night vision accomodation can all play a part in perceived light values. Integrating sphere output is not subject to interpretation but I suppose if it was not built properly then the results could be skewed?
    You eluded to an important point, but didn't hit is head on. Color Rendering Index (CRI) plays a huge role in perceived brightness because it takes into account the distribution of light out put (the total color spectrum). Color rendering index is important because a large part of how we identify objects is by color. This is different than color temperature. Color temperature is a measure of the total sum of output of a white light source, while CRI takes into account the actual distribution of light colors.

    To give you an example the sun has a color temperature of 6500k, and a CRI of 100 during the middle of the day. An incandescent lamp has a color temp of about 3000k, while an HID has a temp of about 4200k. This causes most people to say, oh an HID is much better, its color temp is closer to natural sunlight. When they make this conclusion they are far from correct. When you look at a HID's CRI, you find it is a low mid 70s, while the incandescent bulb is in the high 90's. This is why even though HID's are bright, objects tend to look flat. LED's suffer from a low CRI index also, but they are getting better each generation.

    http://www.gelighting.com/na/busines..._rendering.htm
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  5. #5
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    Lumens is a measure of all the light from a source that is in the visible range by the human eye, weighted by how sensitive a "standard human eye" is to the different colours. It's not perfect, but it's a repeatable measurement.

    I doubt all light manufacturers measure their lights, but some certainly do. However, like all specs that get reported, they are often under ideal conditions, or quoted as a theoretical maximum. LED's an bulbs vary greatly from one to another, and lumens output decreases over their lifetime

    An integrating sphere is the best way to capture all the light from a source, but you still have to analyze the spectrum. A band pass filter can be used, but they are not that accurate for lumens determination. An HID puts out alot of energy in IR and UV, which we cannot see (but the sensors can), so that has to be removed from the measurement. White LEDs produce no IR or UV (they are essentially a blue LED and a Yellow phosphor). This is why digital cameras often show HID's or Halogens (lots of IR) as brighter than LEDs when they look the same in person. Also your eyes are probably not the same as the "standard eye" and depending on the colours that are emitted from a light, it may seem to have a different brightness than someone else.

    Objects can also visibly fluoresce when UV light hits them, so sometimes things look brighter with a HID because some of the UV is being converted to visible as it is reflected back.

    Our eyes are also logarithmic with intensity, so a change from 100lm to 200lm appears as a much larger change than one from 400lm to 500lm. (I should be using lux, but let's not confuse things more).

    Then there is the age thing, some of our older riders can't get by with as little light as some of the wippersnappers. Heck, there are a lot of young riders that can't stand riding with anything less than an HID (or 2!) when a lot of us ride happily with 100lm~200lm.

  6. #6
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    Ahh yes. I recall reading an article on automotive halogen versus HID headlamps.

    For what it was worth, the study showed that objects being illuminated by halogen light were more successfully identified. HID's did not lend to object recognition as well as everybody had thought. So one can look at objects better but not necessarily see objects better.

    However if one is jamming along singletrack at midnight, one might not care too much for identifying that slug... or wait, is that a snail?... by the side of the trail.

    I absolutely could not wrap my head around this until I started playing with coloured LED's and a ride in my friend's E46 M3 with what I reckon were badly colour shifted capsules.

  7. #7
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    From my time spent on the CandlePower Forums, this topic gets discussed in detail. The lumens figures are from the emitter maker, and is measured at the emitter surface. As stated by James above, loss from lens / reflector, etc. is not measured. Therefore real world figures are tough to obtain. On occasion, one of the geeks on CPF with a integrating sphere will test an MTB light, but they are often homemade. There are quite a few flashlight tests, and one can get a feel of mfg lumen best case figures vs real world lumens.

    That is why you do light shootout tests for the rest of us geeks.
    Plus James' invaluable reviews, and so on.
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    Speaking of colour, I have a question to complicate things.

    I was talking about lighting to a boatsman friend of mine. He indicated to me that on the boat at night he uses red lights exclusively. He said that the reason for this is red doesn't desensitize your eyes to ambient light. So, for instance, if you are reading a map to red light, you still retain your night vision for viewing areas which aren't illuminated. So I was wondering if red headlights would be better than white? I've never tried it. I was just wondering.

  9. #9
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    Quote Originally Posted by Cino
    Speaking of colour, I have a question to complicate things.

    I was talking about lighting to a boatsman friend of mine. He indicated to me that on the boat at night he uses red lights exclusively. He said that the reason for this is red doesn't desensitize your eyes to ambient light. So, for instance, if you are reading a map to red light, you still retain your night vision for viewing areas which aren't illuminated. So I was wondering if red headlights would be better than white? I've never tried it. I was just wondering.
    I think using red headlights would make it harder to distinguish between some objects as a limited range of colours would be represented. This might be okay for walking and is definitely fine for reading, but I wouldn't really want to try it when moving at speed.

  10. #10
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    Quote Originally Posted by Cino
    I was talking about lighting to a boatsman friend of mine. He indicated to me that on the boat at night he uses red lights exclusively. He said that the reason for this is red doesn't desensitize your eyes to ambient light. So, for instance, if you are reading a map to red light, you still retain your night vision for viewing areas which aren't illuminated. So I was wondering if red headlights would be better than white? I've never tried it. I was just wondering.
    Short answer is no.

    The use of red lights for night time navigation & astronomy is to preserve your night vision. Your eyes have 2 types of sensors, cones which are used for colour and detail, rods which are used for low light. In low light conditions, your rods will migrate to the front of the retina to serve duty, which take about 20 min. If you turn on a white light flash light, your retina will return to using the rods, and you loose your night vision - which take a while to return. Red light, as long as it is not too bright, will not cause your rods to activate, preserving your night vision.

    Night vision has no colour sensitivity (you see in B&W) and has poor resolution. As a result, bike lights (like automobile lights) are bright, and designed to work with your day vision.

    Under a bright moon, you can try riding with your night vision by turning off your lights, and waiting for your eyes to adjust. You cannot tell colour, and detail is hard to discern, so you learn to let the bike flow. It's different, some of us find it fun, but it's not for everyone.

  11. #11
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    And here I thought I was a light geek

  12. #12
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    Quote Originally Posted by Flyer
    And here I thought I was a light geek
    you've just got expensive tastes and most likely wear your dark tints during glow riding

  13. #13
    fc
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    Thank you, thank you for the responses so far. They are most helpful and will guide me when talking to the manufacturers. It does look like Lumens is a 'claimed output' spec with no measurements performed (except for Niterider).

    I'm playing with 19 lights right now. Here's a taste of some highlights.

    fc
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  14. #14
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    Quote Originally Posted by francois
    Thank you, thank you for the responses so far. They are most helpful and will guide me when talking to the manufacturers. It does look like Lumens is a 'claimed output' spec with no measurements performed (except for Niterider).

    I'm playing with 19 lights right now. Here's a taste of some highlights.

    fc
    you're a bit of a tease

    at least give us a list of the lights

  15. #15
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    Quote Originally Posted by All Mountain
    you're a bit of a tease

    at least give us a list of the lights


    Greetings - Saludos

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    Warning!!! my english is very very bad, sorry.

    Easy DIY led light1
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  16. #16
    Nightriding rules SuperModerator
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    Quote Originally Posted by All Mountain
    you're a bit of a tease

    at least give us a list of the lights
    totally.... Francois.... spill the beans

  17. #17
    fc
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    Quote Originally Posted by All Mountain
    you're a bit of a tease

    at least give us a list of the lights
    <table x:str="" style="border-collapse: collapse; width: 292pt;" border="0" cellpadding="0" cellspacing="0" width="390"><col style="width: 194pt;" width="259"> <col style="width: 98pt;" width="131"> <tbody><tr style="height: 18pt;" height="24"> <td class="xl23" style="height: 18pt; width: 194pt;" height="24" width="259">Light</td> <td class="xl23" style="width: 98pt;" width="131">Price</td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Ayup bar (regular kit)</td> <td class="xl25" x:num="380"> $ 380.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Ayup helmet</td> <td class="xl25">
    </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">BR Lights Jeni H</td> <td class="xl25" x:num="299"> $ 299.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">BR Lights C2.1H</td> <td class="xl25" x:num="330"> $ 330.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Cateye Tripleshot</td> <td class="xl25" x:num="330"> $ 330.00 </td> </tr> <tr style="height: 14.25pt;" height="19"> <td class="xl24" style="height: 14.25pt;" x:str="Dinotte 200L " height="19">Dinotte 200L </td> <td class="xl25" x:num="249"> $ 249.00 </td> </tr> <tr style="height: 14.25pt;" height="19"> <td class="xl24" style="height: 14.25pt;" height="19">Dinotte 200L Dual</td> <td class="xl25" x:num="349"> $ 349.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Dinotte 600-LI-4C</td> <td class="xl25" x:num="399"> $ 399.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Exposure Enduro Maxx</td> <td class="xl25" x:num="450"> $ 450.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Exposure Joystick Maxx</td> <td class="xl25" x:num="250"> $ 250.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Jet Lites Shadow Lithium</td> <td class="xl25" x:num="500"> $ 500.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Knog 605</td> <td class="xl25" x:num="399"> $ 399.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Light and Motion Vega</td> <td class="xl25" x:num="175"> $ 175.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Levin Brightstar</td> <td class="xl25" x:num="270"> $ 270.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Light and Motion Stella 180L</td> <td class="xl25" x:num="300"> $ 300.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Light On Expedition 1000</td> <td class="xl25" x:num="800"> $ 800.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Lupine Betty 12</td> <td class="xl25" x:num="1185"> $ 1,185.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Niterider Minewt.X2</td> <td class="xl25" x:num="190"> $ 190.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Niterider Trinewt</td> <td class="xl25" x:num="500"> $ 500.00 </td> </tr> </tbody></table>
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  18. #18
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    Quote Originally Posted by francois

    <table x:str="" style="border-collapse: collapse; width: 292pt;" border="0" cellpadding="0" cellspacing="0" width="390"><col style="width: 194pt;" width="259"> <col style="width: 98pt;" width="131"> <tbody><tr style="height: 18pt;" height="24"> <td class="xl23" style="height: 18pt; width: 194pt;" height="24" width="259">Light</td> <td class="xl23" style="width: 98pt;" width="131">Price</td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Ayup bar (regular kit)</td> <td class="xl25" x:num="380"> $ 380.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Ayup helmet</td> <td class="xl25">
    </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">BR Lights Jeni H</td> <td class="xl25" x:num="299"> $ 299.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">BR Lights C2.1H</td> <td class="xl25" x:num="330"> $ 330.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Cateye Tripleshot</td> <td class="xl25" x:num="330"> $ 330.00 </td> </tr> <tr style="height: 14.25pt;" height="19"> <td class="xl24" style="height: 14.25pt;" x:str="Dinotte 200L " height="19">Dinotte 200L </td> <td class="xl25" x:num="249"> $ 249.00 </td> </tr> <tr style="height: 14.25pt;" height="19"> <td class="xl24" style="height: 14.25pt;" height="19">Dinotte 200L Dual</td> <td class="xl25" x:num="349"> $ 349.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Dinotte 600-LI-4C</td> <td class="xl25" x:num="399"> $ 399.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Exposure Enduro Maxx</td> <td class="xl25" x:num="450"> $ 450.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Exposure Joystick Maxx</td> <td class="xl25" x:num="250"> $ 250.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Jet Lites Shadow Lithium</td> <td class="xl25" x:num="500"> $ 500.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Knog 605</td> <td class="xl25" x:num="399"> $ 399.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Light and Motion Vega</td> <td class="xl25" x:num="175"> $ 175.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Levin Brightstar</td> <td class="xl25" x:num="270"> $ 270.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Light and Motion Stella 180L</td> <td class="xl25" x:num="300"> $ 300.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Light On Expedition 1000</td> <td class="xl25" x:num="800"> $ 800.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Lupine Betty 12</td> <td class="xl25" x:num="1185"> $ 1,185.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Niterider Minewt.X2</td> <td class="xl25" x:num="190"> $ 190.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Niterider Trinewt</td> <td class="xl25" x:num="500"> $ 500.00 </td> </tr> </tbody></table>
    impressive shootout...

    can't wait for the results

  19. #19
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    Quote Originally Posted by francois

    <table x:str="" style="border-collapse: collapse; width: 292pt;" border="0" cellpadding="0" cellspacing="0" width="390"><col style="width: 194pt;" width="259"> <col style="width: 98pt;" width="131"> <tbody><tr style="height: 18pt;" height="24"> <td class="xl23" style="height: 18pt; width: 194pt;" height="24" width="259">Light</td> <td class="xl23" style="width: 98pt;" width="131">Price</td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Ayup bar (regular kit)</td> <td class="xl25" x:num="380"> $ 380.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Ayup helmet</td> <td class="xl25">
    </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">BR Lights Jeni H</td> <td class="xl25" x:num="299"> $ 299.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">BR Lights C2.1H</td> <td class="xl25" x:num="330"> $ 330.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Cateye Tripleshot</td> <td class="xl25" x:num="330"> $ 330.00 </td> </tr> <tr style="height: 14.25pt;" height="19"> <td class="xl24" style="height: 14.25pt;" x:str="Dinotte 200L " height="19">Dinotte 200L </td> <td class="xl25" x:num="249"> $ 249.00 </td> </tr> <tr style="height: 14.25pt;" height="19"> <td class="xl24" style="height: 14.25pt;" height="19">Dinotte 200L Dual</td> <td class="xl25" x:num="349"> $ 349.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Dinotte 600-LI-4C</td> <td class="xl25" x:num="399"> $ 399.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Exposure Enduro Maxx</td> <td class="xl25" x:num="450"> $ 450.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Exposure Joystick Maxx</td> <td class="xl25" x:num="250"> $ 250.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Jet Lites Shadow Lithium</td> <td class="xl25" x:num="500"> $ 500.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Knog 605</td> <td class="xl25" x:num="399"> $ 399.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Light and Motion Vega</td> <td class="xl25" x:num="175"> $ 175.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Levin Brightstar</td> <td class="xl25" x:num="270"> $ 270.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Light and Motion Stella 180L</td> <td class="xl25" x:num="300"> $ 300.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Light On Expedition 1000</td> <td class="xl25" x:num="800"> $ 800.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Lupine Betty 12</td> <td class="xl25" x:num="1185"> $ 1,185.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Niterider Minewt.X2</td> <td class="xl25" x:num="190"> $ 190.00 </td> </tr> <tr style="height: 15pt;" height="20"> <td class="xl24" style="height: 15pt;" height="20">Niterider Trinewt</td> <td class="xl25" x:num="500"> $ 500.00 </td> </tr> </tbody></table>
    Nice list.

  20. #20
    fc
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    Quote Originally Posted by James@GearReview
    Nice list.
    Hey James, talking to manufacturers, a couple of them mentioned you. They said you were awesome!

    fc
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  21. #21
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    Quote Originally Posted by francois
    Hey James, talking to manufacturers, a couple of them mentioned you. They said you were awesome!

    fc
    Thanks!

  22. #22
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    That ought to keep you busy.

  23. #23
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    ummm...lumen output is actually pretty easy to measure quite accurately.

    http://www.dasdistribution.com/produ...cal_models.htm

    light meters are cheap and measure in lux, which is lumens/square meter. measure output at the distance of interest. a decent quality meter is as accurate as the manufacturer specs for sure.
    what would rainbow unicorn do?

  24. #24
    fc
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    Another question: I understand a 10 watt HID is approximately 500 lumens.

    How many lumens is a 20 watt Halogen?

    fc
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  25. #25
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    Quote Originally Posted by francois
    Another question: I understand a 10 watt HID is approximately 500 lumens.

    How many lumens is a 20 watt Halogen?

    fc

    an "average" halogen should have around 16-20 lumens per watt.
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  26. #26
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    Quote Originally Posted by ferday
    ummm...lumen output is actually pretty easy to measure quite accurately...
    light meters are cheap and measure in lux, which is lumens/square meter. measure output at the distance of interest. a decent quality meter is as accurate as the manufacturer specs for sure.
    Can you elaborate on this? It seems actually pretty NOT easy to me. You would have to piece-wise integrate your lux measurement over the entire beam pattern, making sure you move spherically (or do a lot of trigonometry) to get something approximate.
    While there is a mathematical correlation between lumens and lux, collecting the data in a meaningful way to make that formula work is difficult. There is a specific machine for this called a goniometer which spherically integrates discrete points. The advantage to this method over an integrating sphere is that you get to see the beam distribution, rather than a single lumen rating.

    With a standardized test setup you can certainly get a RELATIVE difference between lights using a cheap light meter, but not the actual lumen rating. Unless of course, i am missing something (which i would love to find out because i've tried this very thing)...

    You do touch on a good point though, that we do not actually perceive lumens (essentially the number of photons leaving the light source). We perceive the light reflected back at us after that light bounces off an object. THAT is determined primarily by beam pattern and secondarily by the number of lumens. It is really easy to understand that a spot beam is perceived as brighter while a flood beam is perceived as dimmer, even though the number of lumens is the same. So to francois original question, one might argue that a lumen is NOT a lumen in the intent of the question.

    We really should have a lumens/lux measurement to give a better idea of the beam pattern. The lumen measurement would give the overall light output, while the lux measurement would be an indicator of how intense the center spot is.
    Actually, every light should have a beam distribution plot, but that is a lot to ask, and most people will find that confusing, anyway...

  27. #27
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    I'm not sure you could go on Lumens. If you say a 10 watt HID is about 500 lumens, then theoretically HID's should be similar to one and other. We just need to see pictures and hear what the claimed output is. I think it's all about the lenses and reflectors if the bulbs are all bout equal.

  28. #28
    fc
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    I think I'll buy a light meter and publish Lux readings.

    Also, I'll take photos of the beam on a blank wall, 10 feet away.

    Here is the lumens problem illustrated...
    The 830 lumen Lupine Wilma should be much brighter than the 486 lumen Niterider Trinewt right?
    http://bikemag.com/gear/accessories/LED_Light_Test_1/

    fc
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  29. #29
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    Quote Originally Posted by francois
    Another question: I understand a 10 watt HID is approximately 500 lumens.

    How many lumens is a 20 watt Halogen?

    fc
    I could be wrong, and I'm no expert, but... doesn't a MR16 Halogen produce some serious lumens ?~?

    I mean compared to a MR11 that is. I always thought the bigger reflector of the MR16 makes it more 'powerful'.

    I saw somewhere on the interweb that a 20w halogen will produce:
    • MR11 - 400 lumens @ 20 lumens per watt, 12v
    • MR16 - 850 lumens @ 42.5 lumens per watt, 12v
    • MR11 - 730 lumens @ 29.5 lumens per watt, 14.4v (overvolt)
    • MR16 - 1555 lumens @ 62.5 lumens per watt, 14.4v (overvolt)
    I suppose you would need 4.4 amp hour, 14.8v Lion battery to run a MR16 for just under 3 hours, which ain't all that bad.

    I guess what I am thinking now is the 'whiteness' of the halogen light at the same lumens would not appear as bright as a LED.... thinking the Lupine Betty versus a MR16 14.8v halogen ?~?

  30. #30
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    Quote Originally Posted by francois
    I think I'll buy a light meter and publish Lux readings.

    Also, I'll take photos of the beam on a blank wall, 10 feet away.

    Here is the lumens problem illustrated...
    The 830 lumen Lupine Wilma should be much brighter than the 486 lumen Niterider Trinewt right?
    http://bikemag.com/gear/accessories/LED_Light_Test_1/

    fc
    Good observation, but the Wilma beam penetrates much farther down the trail in the static photos. The big difference would be riding when you would clearly pick the Wilam over the Trinewt. Trinewt just spews light out next to the bike which is good at slow speeds but not so good at medium to high speeds, where the Wilma seems to excel.

  31. #31
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    Cool, looking forward to this writeup! Wow, I didn't know production lights had breached the... gulp... 1K dollar mark!!

  32. #32
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    Quote Originally Posted by francois
    I think I'll buy a light meter and publish Lux readings.

    Also, I'll take photos of the beam on a blank wall, 10 feet away.

    Here is the lumens problem illustrated...
    The 830 lumen Lupine Wilma should be much brighter than the 486 lumen Niterider Trinewt right?
    http://bikemag.com/gear/accessories/LED_Light_Test_1/

    fc
    If you put both lights (TriNewt & Wilma) on an integrating sphere, the Wilma would probably measure more. The Wilma looks like it is pointed slightly higher than the TriNewt, plus the Wilma has a narrower beam, so more of the light is traveling farther down the trail. Light behaves with an inverse-square law, if the light has to travel twice as far, it returns 4x dimmer.

    A light meter is a good way to get repeatable measurements, I use one when I did some reviews here (DiNotte Ultra-5 / 200L review. I used a standard photographic hand held meter (because I had one) but those reading can be converted to lux. Integrating the profile spherically can give you lumens, but it would be easier for me to bring them into the optics lab and stick them on an integrating sphere, I just can't be bothered (...yet). With the profiles, you can compare one light to another measured at different times, and you also get a reasonable idea of the beam pattern. If you measure profiles with a lux meter, and record the specifics (distance, angle, etc...) the profiles can be compared with these.

    Oh - sorry with all the geek talk, but everyone gets a better review in the end!

  33. #33
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    Quote Originally Posted by francois
    I think I'll buy a light meter and publish Lux readings.

    Also, I'll take photos of the beam on a blank wall, 10 feet away.

    Here is the lumens problem illustrated...
    The 830 lumen Lupine Wilma should be much brighter than the 486 lumen Niterider Trinewt right?
    http://bikemag.com/gear/accessories/LED_Light_Test_1/

    fc
    I have a question for your tests. How did you know where to aim the lights so they all come out even? If you aim one light higher and the next type lower the one that points lower is going to appear to be brighter. I am not saying that this is what you did in your shots but just curious on how you tried to position each light so they are on a level playing field. Did you try and point the hot spot of each light at the same object, or maybe put each light so they are level on the bars or just kinda pointed them the way you would have mounted them if you were going to ride with them?

    I adjust my lights while i am riding and sometimes I have them pointed pretty far out if I am going fast or pointed closer to me if its a technical trail or thier is alot of dust. And I notice that people will come next to me and say my light isn't that bright until i point it at the same spot they are pointing thiers and it makes a big difference. Maybe that is where the pefect beam pattern comes in.

  34. #34
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    Framcois, can I make a suggestion. Why not take it to a "real" world measurement, that's pretty easy to replicate and not expensive - use a photographers light meter and either measure in normal exposure readings 1/60 @ f 8 or in EV (exposure value) . I did this with my NR ENduro HID and Cateye TS and found that they're about a 1/2 stop difference between them - the Enduro is brighter(don't know what the claimed lumens ratings are for both lights) Also colour plays an important roll in depth perception with lights. I plan on going for a night ride sometime within the next week using the HID on my helmet and the TS on the bars and see how they compare.
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  35. #35
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    Quote Originally Posted by francois
    I think I'll buy a light meter and publish Lux readings.

    Also, I'll take photos of the beam on a blank wall, 10 feet away.

    Here is the lumens problem illustrated...
    The 830 lumen Lupine Wilma should be much brighter than the 486 lumen Niterider Trinewt right?
    http://bikemag.com/gear/accessories/LED_Light_Test_1/

    fc
    Zowie, there photo handling on their site where you roll over the light for a beam shot is great for comparing the beams. Can you do that FC, when the shootout is posted?
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  36. #36
    fc
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    Great question. Aiming the lights is critical. I have selected a nice trail with a tree canopy all around. I will have four orange cones at 10 yard intervals. I will have a Jumbo beach ball at the 50 yard mark.

    I will aim all lights at 20 yards (I think). The center of the light should be on the 20 yard cone.

    I will also do some combo bar/helmet shots from the same manufacturer. I will aim the bar light at 20 yards and the helmet at 40 yards.

    Suggestions?

    fc

    Quote Originally Posted by brent878
    I have a question for your tests. How did you know where to aim the lights so they all come out even? If you aim one light higher and the next type lower the one that points lower is going to appear to be brighter. I am not saying that this is what you did in your shots but just curious on how you tried to position each light so they are on a level playing field. Did you try and point the hot spot of each light at the same object, or maybe put each light so they are level on the bars or just kinda pointed them the way you would have mounted them if you were going to ride with them?

    I adjust my lights while i am riding and sometimes I have them pointed pretty far out if I am going fast or pointed closer to me if its a technical trail or thier is alot of dust. And I notice that people will come next to me and say my light isn't that bright until i point it at the same spot they are pointing thiers and it makes a big difference. Maybe that is where the pefect beam pattern comes in.
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  37. #37
    fc
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    Quote Originally Posted by All Mountain
    Good observation, but the Wilma beam penetrates much farther down the trail in the static photos. The big difference would be riding when you would clearly pick the Wilam over the Trinewt. Trinewt just spews light out next to the bike which is good at slow speeds but not so good at medium to high speeds, where the Wilma seems to excel.
    It seems like the Trinewt was aimed lower than the Wilma.

    fc
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  38. #38
    fc
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    Quote Originally Posted by slocaus
    Zowie, there photo handling on their site where you roll over the light for a beam shot is great for comparing the beams. Can you do that FC, when the shootout is posted?
    Sure, I can borrow their idea.

    Slocaus, yes I will buy a light meter and measure Lux.

    fc
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  39. #39
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    Quote Originally Posted by francois
    Great question. Aiming the lights is critical. I have selected a nice trail with a tree canopy all around. I will have four orange cones at 10 yard intervals. I will have a Jumbo beach ball at the 50 yard mark.

    I will aim all lights at 20 yards (I think). The center of the light should be on the 20 yard cone.

    I will also do some combo bar/helmet shots from the same manufacturer. I will aim the bar light at 20 yards and the helmet at 40 yards.

    Suggestions?

    fc
    I think that is a good way of doing it. I would do it the same way and just put a note that you tried to aim at the 20 yard cone, and then people can see if the lights aimed at 20 yard produce enough lights close to the wheel as well as farther down the road. Or maybe draw an X on the picture when you are done showing the aiming point so people can really see where the center of the light is as with sometihng like a flood its hard to tell where it was initally aimed. Atleast those are my thoughts.

  40. #40
    GMF
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    You could use a little laser light held on the end of the glass/optic/reflector/whatever to accurately aim it at a specific target. Those are cheap and seems like it would be easy to do...

  41. #41
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    Photos are misleading. The Trinewt looks megabright in the photo, but all of the light is close to the bike. The last target (the mask in the tree) is only 165 ft from the lights and the trinewt barely hits it. To ride safely at speeds approaching 30 mph you need about 230 ft of sight distance - more if you are going downhill. The Wilma is the only light of that bunch that shoots that far - (you can see the trees lighted by the Wilma well beyond the 165 ft target). ((man, the Betty must be something else)).

    I don't care much about what is going on under my front wheel - by the time I see something there it is usually too late do do anything about it. I don't aim my lights at the ground - that only produces a distracting and blinding white spot that reduces my ability to see stuff at the fringes of the lights. I aim them high to the point where adjusting them any higher doesn't increase the length of illuminated ground in front of me. That way I end up with a lower brightness of beam that reaches far, has good spread, but is very even. I find I can see a whole lot more that way than having a bright spot on the ground in front of me.

    I guess that is what works well for me anyway.

  42. #42
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    My photoshoot went pretty well this evening. The cones are 10 yards apart and the beachball is 50 yards away.

    fc
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    Quote Originally Posted by francois
    My photoshoot went pretty well this evening. The cones are 10 yards apart and the beachball is 50 yards away.

    fc
    What camera did you use, and what were the settings?
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  44. #44
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    Quote Originally Posted by Sasquatch
    What camera did you use, and what were the settings?
    Exif IFD0

    * Camera Make = Canon
    * Camera Model = Canon PowerShot G9
    * Picture Orientation = undefined (0)
    * Last Modified Date/Time = 2007:12:17 21:13:28

    Exif Sub IFD

    * Exposure Time (1 / Shutter Speed) = 50/10 second = 5.00000 second
    * Lens F-Number/F-Stop = 40/10 = F4.00
    * ISO Speed Ratings = 80
    * Original Date/Time = 2007:12:17 07:50:28
    * Shutter Speed Value (APEX) = -74/32
    Shutter Speed (Exposure Time) = 1/0.20 second
    * Aperture Value (APEX) = 128/32
    Aperture = F4.00
    * Flash = Flash did not fire, compulsory flash mode
    * Focal Length = 7400/1000 mm = 7.40 mm
    Need optics for DIY bike lights?

  45. #45
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    Partly right...

    Quote Originally Posted by Cino
    Photos are misleading. The Trinewt looks megabright in the photo, but all of the light is close to the bike. The last target (the mask in the tree) is only 165 ft from the lights and the trinewt barely hits it. To ride safely at speeds approaching 30 mph you need about 230 ft of sight distance - more if you are going downhill. The Wilma is the only light of that bunch that shoots that far - (you can see the trees lighted by the Wilma well beyond the 165 ft target). ((man, the Betty must be something else)).
    The comparison photos do show that the Wilma lights the final target better than the Trinewt. And that the TriNewt is very bright close to the bike.

    But the Wilma also has a lot more side spill. The photo only shows it in the bottom left side. My guess is that the Wilma is using a combination of different optics that give it a strong center spot along with wide angle dispersion. Since most of the area in the photos is in the mid-range, the TriNewt looks very bright: that's where most of it's light is going.

    I think that taking the comparison photos from farther back behind the light would give a more balanced view of how the lights are performing. Personally I find it hard to ride with only a narrow beam. My sense of balance is fairly poor and I depend on my peripheral vision to do most of the work.

    Walt

  46. #46
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    It would be very helpful if during the Light Shootout, you provided wide angle photos in addition to the standard lens used in the previous shootouts.

    Many lights, such as L&M, provide an extremely wide output that does not get reflected in the standard shootout. I know that in the light shootout, the L&M looked dimmer than the comparable Niterider, but in actual use, the L&M's wide even pattern is more useful, imo.

    Just a suggestion.

  47. #47
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    Quote Originally Posted by Blue Shorts
    It would be very helpful if during the Light Shootout, you provided wide angle photos in addition to the standard lens used in the previous shootouts.
    I think that is a good idea, and you could take it one easy step further. Finding the beam angle is super simple - you just hold the light some distance away from a wall, and measure the widest point. A little simple math (tangent of half the beam width divided by the distance from the wall) will give you the half angle.

    Beam shots really are the best illustrator, though.

  48. #48
    fc
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    Quote Originally Posted by brum
    Exif IFD0

    * Camera Make = Canon
    * Camera Model = Canon PowerShot G9
    * Picture Orientation = undefined (0)
    * Last Modified Date/Time = 2007:12:17 21:13:28

    Exif Sub IFD

    * Exposure Time (1 / Shutter Speed) = 50/10 second = 5.00000 second
    * Lens F-Number/F-Stop = 40/10 = F4.00
    * ISO Speed Ratings = 80
    * Original Date/Time = 2007:12:17 07:50:28
    * Shutter Speed Value (APEX) = -74/32
    Shutter Speed (Exposure Time) = 1/0.20 second
    * Aperture Value (APEX) = 128/32
    Aperture = F4.00
    * Flash = Flash did not fire, compulsory flash mode
    * Focal Length = 7400/1000 mm = 7.40 mm
    Man, that is good espionage!! I didn't know about half that data.

    One really interesting observation is the camera reveals more than the naked eye sometimes. In the dark, looking at all these lights, it is very hard to tell the differences between some of these lights. Too much infortion for my eye or my brain, maybe. But in the computer, with hi-res photos, it is very obvious.

    fc
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  49. #49
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    Nice- this review along with James' review will be some fun reading.

    James- I hope you have had a chance to get started as well. No night riding for almost two weeks here so this is the closest I'll get. Once the snow packs down or melts, I'll start again.

  50. #50
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    Quote Originally Posted by francois
    Man, that is good espionage!! I didn't know about half that data.

    fc

    fc,

    just install FxIF on Firefox and you will be "spying" on everybody's pics

    (when the leave the exif on the pic at least)
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