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  1. #26
    Seņior Member ItsJustMe's Avatar
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    Ooh, hologram on the wall. We still have some holograms around somewhere, I should put them back on the wall.
    Work: the 8 hours that separates bike rides.

  2. #27
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    Quote Originally Posted by ItsJustMe View Post
    Ooh, hologram on the wall. We still have some holograms around somewhere, I should put them back on the wall.
    Here's one I made in "84. It's a '72 Campy derailleur I'm using to this day. First one I sold was to one of the owners of Wheelsmiths bike Shop in Palo Alto, where my studio was at the time.


  3. #28
    Senior Member tarwheel's Avatar
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    I have both the Magicshine LED and a Fenix L2D. I've used the Fenix for 2+ years on my handlebar, and moved it to my helmet when I got the MS. The Magicshine puts out way more light than the Fenix, which served my needs just fine for the past two years.

    The lumen numbers are useful for comparing lights, but the main point to keep in mind is that there are few options that can compare with the MS in its price range. If you can spend $300-500 on a light system, I am sure there are better options. For less than $100, not many. The P7 flashlights are main competitors for MS in that price range, but they have a number of drawbacks (in my view) -- including size, weight, non-standard batteries, and the size and shape of the lightbeam.

  4. #29
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    In another forum there was a thread titled "lumen schoomen", and I gotta say I feel the same way at this point.
    All these numbers and all this talk and comparing, I'm over it.
    All I know is this, when I turn my MS on on the trail, it's BRIGHT. How many lumens? Don't know, don't care anymore. I just know that it's brighter, lights up a bigger area and throws further then just about every light on my group rides, and costs less, much less.

  5. #30
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    "Lumen schoomen" is the appropriate response to all the wildly inaccurate and often maliciously misleading numbers thrown out by manufacturers too lazy to measure their products, and advocates getting all their information from the boxes those products come in. I'm "in to" measuring light, and that's the motivation for my little project here.

    So what's your point? That I shouldn't post my results here? That now that YOU are happy with the light YOU have, that nobody should be concerned with the real output of these lights? Is that why you chose to come onto this thread and essentially say the topic of the thread is unnecessary?

  6. #31
    Senior Member tarwheel's Avatar
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    Testing

    Quote Originally Posted by RapidRobert View Post
    "Lumen schoomen" is the appropriate response to all the wildly inaccurate and often maliciously misleading numbers thrown out by manufacturers too lazy to measure their products, and advocates getting all their information from the boxes those products come in. I'm "in to" measuring light, and that's the motivation for my little project here.

    So what's your point? That I shouldn't post my results here? That now that YOU are happy with the light YOU have, that nobody should be concerned with the real output of these lights? Is that why you chose to come onto this thread and essentially say the topic of the thread is unnecessary?
    RR - Don't get me wrong. I appreciate the testing you've done. It's always good to see real data and facts to make comparisons. My post was mainly directed at some of the negative comments I've seen about the MS light by people who obviously have not actually seen or used the light.

  7. #32
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    I think this is one of the more useful threads out there: at least some real numbers to compare lights with versus the 'my light works great' thing.

    I was running a 10W halogen prior to getting my Airbike 900. The halogen cost me (2 years ago) almost what a MagicShine costs now, and puts out a mere fraction of the light of my Airbike.

    I ride mostly on really bumpy country roads with no streetlights, and at my age I don't think I'd want anything less than what I have now.
    I've ordered one of the '900 lumen' P7 Ultrafire flashlights from hkequipment, not because it is good value (the MS is a better deal with the batteries and bicycle mount) but I needed a light for hiking the trails around here at night, and will see how it compares to the Airbike as far as beam and brightness goes.

  8. #33
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    I also welcome some real numbers in the debate and discussion of lights. Many things might effect which light we like best for our own riding (beam shape, color, spill, etc) but some really comparable numbers on actual output with the optics in place is a very useful place to start. Thanks for your work and God bless those who love to collect useful data the rest of us have neither the tools nor time to collect! I loom forward to seeing some of your other data.
    God grant me the serenity to accept the hills and winds I cannot change;
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  9. #34
    vB4.0 for whiter whites OBXCycling.com's Avatar
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    Thanks for all the testing. Hopefully you can get a bunch more to compare it to so people can make a really informed purchase. I'd be interested in seeing some taillight figures too.

    I love my MS and it is one of the top 3 brightest lights in my group (20 or so) and WAY cheaper than most of them.

    I also know it's brighter than a scooters headlight and cars dim their high beams now.

  10. #35
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    I'll be happy if the magicshine is at least 2x brighter than my 200L. I paid $125 for the 200L (batteries extra), so the magicshine will actually be less.
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

  11. #36
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    Good job on the testing. It's really helpful to see that your test also pegs the Fenix L2d at a much lower lumen rating than the manufacturer - which suggests that your Magicshine results (tested similarly) will likely come in significantly (much signficantly, judging from the Fenix numbers) than the manufacturer claims.

    With your measurements, sounds like the Magicshine is at least 3x brighter than a Fenix L2D on turbo - that's hella bright, and I know you won't find any more inexpensive commercially non-DIY solutions with close to comparable brightness. Your helpful review further encourages that the Magicshine is the real deal with brightness as claimed by people and reviewers.
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  12. #37
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    RapidRobert;

    If possible try to test some Niterider lights. They CLAIM on their web site that the light outputs they list are based on the average of ten production units tested using an integrating sphere. If true this might allow you to calibrate your test procedure.
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  13. #38
    xtrajack xtrajack's Avatar
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    Quote Originally Posted by ItsJustMe View Post
    I do appreciate the measurements being made. Sorry if I gave the impression that I was blowing off the efforts here. I was just a little bugged by people (probably who just spent $300 on a 400 lumen light) saying in effect that the MS was obviously worthless crap since they said it was 900 lumens and it was actually 400. My response is, REAL numbers are good to have for comparison, but in the end the truth is that for $80 this is plenty of light for almost anyone's use.



    This is the truth.

  14. #39
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    Well I finally got the time to build up a more portable system to measure bike headlights. It's an 8" diameter Labsphere integrating sphere with my Luttron LX-101 luxmeter attached to the exit port and mounted on a tripod as shown below.



    I used a fan to cool the Magicshine headlight mounted on my handlebars, which was pointed into the entrance port of the sphere. The airflow (8 mph) and its temperature (51 degrees F) past the light are shown on the windmeter held next to it.



    I took the sphere over to the home of a local young laser enthusiast, LaserBen (who buys, repairs and sells surplus lasers), to calibrate it. He used a Spectra-Physics Millenium laser and a Coherent power meter, as seen below. According to the Photopic Spectral Luminous Efficiency Function, one Watt of laser light at 532nm equals 601 lumens. We put measured amounts of that wavelength into the sphere, between 0.1W and 1.9W, and noted the corresponding values displayed on the meter. I then converted Watts into lumens and graphed the results. The result was a straight line, as expected.



    Using this method, I measured my headlight to be 330 lm on high, 185 lm on medium, and 95 lm on low. Not bad! Despite wishing I verified the calibration laser's output power with more than one meter, these results agree quite well with those reported above. Certainly NOT 900 lm, or even the 450 lm reported elsewhere. So now i'm pretty confident with my measurements, and ready to start gathering data about other headlights and flashlights (for comparison), and modification of my light to increase its output.
    Last edited by RapidRobert; 12-08-09 at 01:22 AM.

  15. #40
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    Quote Originally Posted by RapidRobert View Post
    Well I finally got the time to build up a more portable system to measure bike headlights. It's an 8" diameter Labsphere integrating sphere with my Luttron LX-101 luxmeter attached to the exit port and mounted on a tripod as shown below.



    I used a fan to cool the Magicshine headlight mounted on my handlebars, which was pointed into the entrance port of the sphere. The airflow (8 mph) and its temperature (51 degrees F) past the light are shown on the windmeter held next to it.



    I took the sphere over to the home of a local young laser enthusiast, LaserBen (who buys, repairs and sells surplus lasers), to calibrate it. He used a Spectra-Physics Millenium laser and a Coherent power meter, as seen below. According to the Photopic Spectral Luminous Efficiency Function, one Watt of laser light at 532nm equals 601 lumens. We put measured amounts of that wavelength into the sphere, between 0.1W and 1.9W, and noted the corresponding values displayed on the meter. I then converted Watts into lumens and graphed the results. The result was a straight line, as expected.



    Using this method, I measured my headlight to be 330 lm on high, 185 lm on medium, and 95 lm on low. Not bad! Despite wishing I verified the calibration laser's output power with more than one meter, these results agree quite well with those reported above. Certainly NOT 900 lm, or even the 450 lm reported elsewhere. So now i'm pretty confident with my measurements, and ready to start gathering data about other headlights and flashlights (for comparison), and modification of my light to increase its output.
    I'd like to see what a Dinotte 200L rates with the same test.
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

  16. #41
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    excellent thread. lumens are not very interesting without knowing what methods the manufacturers used to arrive at that number. unless every manufacturer measures their light output using the same, standardized method, it's not exactly an apples-apples comparison. not sure it is feasible for RapidRobert to do this, but it would be a great service to the community if more lights can be tested using the same setup (or at least some of the more popular/recommended setups). at least that way we can know the relative performance of the different lights.
    i won't deny it i'm a straight ridah

  17. #42
    Senior Member mechBgon's Avatar
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    Beam pattern is also quite important. I was doing my highway commute route the other day with my DiNotte 600L and my Dereelight DBS, and while the DBS is "only" a ~250-lumen light, it completely dominates the 600L for actually seeing forward down the highway, because the light goes where I need it. I'd compare it to driving with one's parking lights, then switching on the low-beams. Lumens are one factor to look at, beam pattern's another.

  18. #43
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    Quote Originally Posted by mechBgon View Post
    Beam pattern is also quite important. I was doing my highway commute route the other day with my DiNotte 600L and my Dereelight DBS, and while the DBS is "only" a ~250-lumen light, it completely dominates the 600L for actually seeing forward down the highway, because the light goes where I need it. I'd compare it to driving with one's parking lights, then switching on the low-beams. Lumens are one factor to look at, beam pattern's another.
    Absolutely right! That's why I advocate describing headlight performance by the following four numbers:
    1) Total Lumens
    2) Hot Spot Lumens
    3) Total Divergence
    4) Hot Spot Divergence

    All four numbers are easier to measure with my first system above, which is why I started with that one instead of the sphere. The sphere is easier to take to bike shops for comparisons, but the benchtop system gives a better picture more accurately. Perhaps with the addition to a camera looking down on the target to see beam shape as well.

  19. #44
    Senior Member dougmc's Avatar
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    Quote Originally Posted by barturtle View Post
    I believe there are some other losses: some of these high-power lights have been known to cause interference with wireless cyclocomputers, so either magnetic or RF fields are created, causing some of the lost power. I'd also guess that the lumen/power input ratio is not a linear ratio.
    The RF noise power loss is real, but miniscule. As for the lumens/power ratio not being linear -- you're right, it's not.

  20. #45
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    RapidRobert;

    Personally I believe that beam shots taken on a surface perpendicular to the light beam are also definitely worthwhile. The majority of LED lights seem to have what is basically a round beam like a flashlight while those that are road legal in Germany have a sharp cutoff, like a auto low beam headlight., to prevent blinding oncoming traffic and pedestrians. For most American LED bike headlights the differences in beam pattern are primarily divergence amount and spill divergence. Amount of light in the main beam and the spill beam also vary.

    Lux figures are not much help as they are normally given for the brightest part of the beam and are totally distance related. Busch & Muller of Germany give their Lux figures for a distance of 10 meters while a British dynamo headlight maker lists 4000 Lux but this is at a distance of 1 meter. At 10 meters this should equate to 40 Lux if my calculations are correct.
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  21. #46
    Senior Member Garfield Cat's Avatar
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    Now I have more to talk about at the coffee shop.

  22. #47
    Senior Member mechBgon's Avatar
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    Quote Originally Posted by RapidRobert View Post
    Absolutely right! That's why I advocate describing headlight performance by the following four numbers:
    1) Total Lumens
    2) Hot Spot Lumens
    3) Total Divergence
    4) Hot Spot Divergence

    All four numbers are easier to measure with my first system above, which is why I started with that one instead of the sphere. The sphere is easier to take to bike shops for comparisons, but the benchtop system gives a better picture more accurately. Perhaps with the addition to a camera looking down on the target to see beam shape as well.

    Huh. I just slap 'em on the bike and ride. This is the DBS alone on a pitch-dark 600-foot straightaway in an area infested with deer, which is its showcase environment. Light metering was adjusted to match how it looks to my dark-adapted vision... might be a tad overcooked, but pretty close actually:



    Nice flashlight. I give it a 7

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