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  1. #76
    Senior Member dynodonn's Avatar
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    Quote Originally Posted by cehowardGS View Post
    If you don't mind me asking, what do you do when Mother Sun shines her zillion lum/watt/volts light in your eyes, and really does blind you for a while (if you look at her)??

    Who you call to regulate?

    Who do you complain too?

    After all,that is the brightest light known to man, and she sets herself up right at the end of the highway too. Can't see nothing...

    Who ya gonna call? Who???
    Geezus, some things you cannot control, like the Sun's output, but the my headlight output and direction I can. Get a clue.

  2. #77
    Motorcycle RoadRacer cehowardGS's Avatar
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    Quote Originally Posted by dynodonn View Post
    Geezus, some things you cannot control, like the Sun's output, but the my headlight output and direction I can. Get a clue.
    One of us is worrying about shining bicycle lights in drivers eyes, the other one is worrying about being seen as to not get hit/banged/killed..

    To put it in plain talk, one of us is "out to lunch"...
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  3. #78
    Senior Member dynodonn's Avatar
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    Quote Originally Posted by cehowardGS View Post
    One of us is worrying about shining bicycle lights in drivers eyes, the other one is worrying about being seen as to not get hit/banged/killed..

    To put it in plain talk, one of us is "out to lunch"...
    Must not be me, since I've never been hit by a car or had head lights flashed at me.

  4. #79
    Motorcycle RoadRacer cehowardGS's Avatar
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    Quote Originally Posted by dynodonn View Post
    Must not be me, since I've never been hit by a car or had head lights flashed at me.
    Ha, then I am the one "out to lunch"...

    Safe riding to you..
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  5. #80
    Mad bike riding scientist cyccommute's Avatar
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    Quote Originally Posted by dynodonn View Post
    I currently use the beam on the left in your link, it's bright enough without being offensive to other road or sidewalk users. I tried the flatter beam on the right, but it was worthless in that I was practically ignored by other road users, and I could barely see the road way on rainy nights. I put in the center lens, but decided against it without any road testing.
    I'm having problems seeing you logic on lens choice. Most all of the arguments about the Magicshine and other high intensity lights is that they 'spray' so much light off the center axis of the beam that they are 'dangerous' to other road users. I'll agree that the Magicshine and most other LED lights I've seen are fairly wide angle flood lights rather than narrower angle spotlights. But the lenses you are using make the light wider and more floody. If the problem is spraying light into the other lanes where they can 'blind' other road users, isn't that going in the wrong direction?

    The whole point of this thread is that the Magicshine "lack a cutoff and are very bright". 'Cutoffs' mean that the beam is shaped and attenuated in certain directions.
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  6. #81
    Certified Bike Brat Burton's Avatar
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    Quote Originally Posted by cyccommute View Post
    Burton said to do a reality check, so I did. I took pictures on the way home from my truck to show what the light from other cars is really like. Here's a truck across a 2 lane intersection that was roughly 30 feet away. He's in a left turn lane as am I and he is slightly up hill from me. It was a Ford pickup and my truck is a later model Chevy Tahoe which sits higher than current models.



    So where's the reality. Your eyes use a logarithmic reference system and digital camera sensors use a linear one, so your eyes can register a much broader dynamic range than any digital camera or film. That's just a fact and it doesn't matter how much the camera cost. So you attempted to expose for the background and ended up overexposing all the highlights and want to pass that off as glare? You were there and you KNOW that photo isn't representative of what you were looking at. Those washed out traffic lights are a good visual reference point after the fact and if they're overexposed then so are the headlights. That's not glare you've captured - just blurred, overexposed photos.


    Not a lot of cutoff there and this is still not full dark. The light is a least as glary as Burton's picture but from further away.

    Maybe before you want to start making comparisons you should post your EXIF data. Your shots were all taken at high ISO values and with shutter times so long you couldn't even hold the camera steady. Mine weren't. Which means relative to anything I've posted your shots are so overexposed that making any sort of comparison is both pointless and misleading.


    Here's a sedan across an intersection and, again slightly up hill.



    In Canada at least it's illegal to operate driving lights and / or high beams within city limits or on lit autoroutes and that's clearly what that that second vehicle back in that photo is doing. And all that does is illustrate the OP's concern about glare caused by a beam with no cut-off as is found in many models of MagicShine and other bike lights. So the point of posting this deliberately overexposed, blurry photo was what exactly? Are you saying that because some people feel free to cause issues by using their automotive high-beams illegally it should be OK to do the same thing with a bicycle?


    If you look at the lights they don't project as asymmetrical but as a round light source. The car was a late model Toyota. The car in the background's lights are even brighter and up close have more glare than the Toyota





    His lights are much brighter than mine as the light you see on the snow comes from his lights and not mine. The car was a Subaru Outback.

    Sorry, I'm not buying it. That nearest automobile is 40 to 50 ft away. Energy (light is a form of energy) is exponential in nature and to overpower YOUR headlights from that distance, HIS headlights would have to have been at least 4x as powerful as yours. Alternatively each of a set of four lights would have to have been at least twice as powerful as yours if you only had two. Its hard to tell because the photo is so overexposed and has so much blur from handshake that I can't even tell how many lights are actually on the car. But in any case no-one makes and markets any single lamp OEM replacements that fits either description. Moreover, the complete absence of any light, both in front of, and on the RHS of your car (where the low-beam cut-off directs light outwards and upwards to pick up street signs) makes it much easier for me to believe that you were simply parked with your lights off taking pictures.

    There has been no radical change in the lighting of a Chevy Tahoe in the last twelve years that would make your lighting so inferior to even another vehicle equipped with aftermarket lights that it would force you to make some of the claims you're making.
    photo(2).JPGphoto(3).JPG



    Overall, and I've experienced this before, sharp cutoff lights look great when projected against a garage door. Head on, a substantial portion of the light isn't cut-off but is projected upward. That is by design because you want some illumination of overhead signage.
    Nope - properly adjusted DOT approved low beams by design will NOT illuminate overhead road signage. And since overhead road signage is only found on autoroutes with highway lighting and where it's illegal to use a high-beam anyway - its a non-issue. However a DOT approved cut-off IS designed to extend a vertical wedge of light along the RHS of the road to illuminate the street level signage normally found on rural and urban streets. And the presence of that is conspicuously lacking beside YOUR vehicle in all your photos so you might want to either get your lights checked or simply turn them on.


    OK So I've stated that the highlights (and therefore the headlights) in your photographs are overexposed. That's not 'just my opinion' it's a fact that is reproducible.

    composite1 600x800.JPG

    This photograph was taken at 1/60 sec, ISO1600 and f3.5.

    Is it representative of what I was looking at overall? Naaawwwwww. The highlights are all overexposed and the shadow areas are still too dark because of the limited dynamic range of the camera sensor. 'Technology' sucks.

    But like your photos it does burn out the traffic signals and it did overexpose the car headlights so much that it looks like it could be a glare issue. Except that it isn't. The highlights have simply been overexposed by a factor of 20. And I'm thinking that's still low compared to yours.

    Glare is associated with bright light sources and can have a couple different effects. It normally produces a haze across part or all of the photo, reducing overall contrast and color saturation - even if that light source isn't actually visible in the photo. Alternatively, a bright light source within the image area will produce visible artifacts (lens flare) as well as reducing contrast and color saturation, either locally or in the overall photograph, depending on the size and intensity of the light source. I'm not seeing any of that - just exposure issues.

    Without resorting to an HDR process and combining a series of photographs with different exposure values, it's impossible to even approximate what your eyes can capture in a high dynamic range situation and IMO this post doesn't warrant that kind of effort. Not for your benefit anyway. An acceptable exposure of the headlights was all I'm interested in- NOT the background areas - so I'm going to simply expose for the highlights.

    So what to use as a reference point? No magic involved - there are signal lights and street lamps at the intersection so I'll just take an EV reading and work out what it would take to correctly expose them, and set the white balance for the headlights.

    Subsequent shots of the street lights and signal lights confirm that those parts of the digital images are almost EXACTLY what I was looking at with my own eyes.
    composite2 600x800.JPG

    The numbers are very straight forward: 1/100 sec, ISO 400 and f5.6 Anyone can use them with any camera and expect similar results.

    Using those exposure values, the only headlights that showed any issues at all with flare were in the second car back in this photo, that sported a set of illegal aftermarket HID lights with no beam cut-off. The color and throw was a dead giveaway.
    Attachment 234543

    And letís be very clear. If the backgrounds are underexposed, that's incidental to the point of the discussion. This isn't about pretty pictures. Itís about capturing an accurate representation of the headlight illumination for the purpose of evaluating glare and THAT is EXACTLY representative of what I was looking at with my eyes.

    NONE of my photos showed the extent of the kind of 'glare' issues produced in YOUR photos. Because its an exposure issue - not a 'glare' issue.

    And one that can be reproduced even using low powered LED lights like Knog Frogs.

    DSC00026 600x800.JPG

    These things are really so dim any car driver could easily miss them from 10 feet away. Which is why they all NEED a flashing mode. Your eyes are particularly sensitive to change of any sort. Movement or light intensity.

    But gee, simply by holding open the shutter and making a ridiculously extended exposure like you did, they can be made to look like real flamethrowers. At least in an photograph that, like the initial street shot, has been overexposed by a factor of 20x.

    DSC00007 600x800.JPG

    I just wouldn't want to try to pass that off as 'representative' myself. Even if I was trying to sell them.


    And you seem have some paradoxical questions to boot. Exactly how do you expect anyone to accurately depict a 700 lumen light source on a monitor anyway? It's physically impossible since any monitor currently on the market has a screen with a maximum lumen output well below that.

    As for your statements that such lights shouldn't be a problem if cyclists rode where they're supposed to - personally I ride where I HAVE TO and some routes and road conditions FORCE ME to drive within a few feet of oncoming traffic.
    photo.jpgphoto(1).jpg
    Which is exactly why I CAN'T use those particular lights anywhere except off-road and personally don't recommend their use in the city. And actually I'm not too happy about that because it forces me to use multiple lights.

    But that's me. You can do whatever you want to yourself - just don't try to sell any of it to me. I don't consider your opinions objective in the least, and for someone trying to pass themselves off as some kind of scientist - thatís a major shortcoming.
    Last edited by Burton; 01-22-12 at 02:15 PM.

  7. #82
    Certified Bike Brat Burton's Avatar
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    The objective of this post was originally to address valid concerns about running high powered lights like MagicShines without a beam cutoff because of potential glare issues for oncoming traffic. My initial post contained photographs of lights manufactured by Vision X which have a rated output of about 700 lumens and a similar design to some MagicShine models so I thought they were very representative of the lights in question.

    I really assumed EVERYONE on this forum was familiar enough with high school mathematics that it wouldn't be all that difficult to grasp that something like a 500 lumen light source restricted to a 10, 15, 25 or 35 degree cone would be more intense than even a 1,000 lumen source spread over an 80 degree cone. Oops! My mistake!

    And apparently that photo I posted earlier of my bike beside a car wasn't conclusive enough for Mr Black so in the interests of providing a representative reference, here's a photo of ALL those combinations on one vehicle.

    photo(5).JPG

    High beam, low beam, 15/45 degree Vision X LED flood and 10 degree Vision X LED spot. These are EXACTLY the same lights I referenced myself, however the photo was sourced from an independent site. http://www.advrider.com/forums/showp...9&postcount=51
    If anyone had any problem grasping the comparison before - I hope this spells things out clearly enough. One difference between this photo and mine is that mine were color balanced to the output of the LED which made headlights look yellow. This one is color balanced to daylight and since the LED output is strong enough to overload the sensor array in that area - it shows as white anyway.

    Gee - half the power power output of an automobile headlight but concentrated within an area one quarter the size. Should have been a no-brainer. And since MagicShine markets lights with power ratings even higher than these and with similar tight focusing beams, it shouldn't be all that difficult to make the connection. But if anyone still has any further issues grasping a relative comparison and potential issues - you're on your own. I'm done with this thread.


  8. #83
    Senior Member mechBgon's Avatar
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    Which is exactly why I CAN'T use those particular lights anywhere except off-road and personally don't recommend their use in the city. And actually I'm not too happy about that because it forces me to use multiple lights.
    No one could get much closer to oncoming traffic than I do in my final left turn lane on the way home, since the turn lane is only about 7 feet wide (cyccommute posted a photo of it earlier). And my 1200-lumen flood-beam DiNotte is actually great for showing up against the backdrop I need to get seen against. This is a photo in the direction everyone will be looking when they're supposed to see me:



    In this scene, I have zero qualms about using as much light as possible, without a cutoff. And I have very little confidence in showing up with a cutoff-equipped headlight like my Supernova or Cyo, particularly on standlight mode... I routinely slap on a floody LED flashlight to actually get seen with in that environment.

    I realize cyclists are more attuned to being sensitive to other road users, since they're often on the other end of the stick. But get a grip... in the city, you will not blind anyone with a Magicshine, even by the BikeForums definition where "blinding" means the light is too intense to comfortably stare at. And the uncomfortable truth is that a cutoff is not very effective on a bike anyway... lift the front wheel an inch, such as going over a slightly-crowned intersection, and now your oh-so-leet cutoff is firing the most intense part of the beam up over the horizon ANYWAY. I can watch this effect in action any time I ride down my home street in the dark with one of my dyno lights. It's illustrated nicely by my left-turn-lane photo, so here that is again:


    Cutoffs aren't working so hot here, are they? All it takes is some non-level pavement to turn the plowshares back into swords

    If you're on the MUP, like I said, feel free to make a best effort for the sake of those with weak lights or no lights. If you're on a city street, up against people with anywhere from 2000 to 7000 lumens of their own light to see by, plus ambient lighting to maintain orientation, it's just a non-issue.

  9. #84
    Motorcycle RoadRacer cehowardGS's Avatar
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    Quote Originally Posted by mechBgon View Post
    No one could get much closer to oncoming traffic than I do in my final left turn lane on the way home, since the turn lane is only about 7 feet wide (cyccommute posted a photo of it earlier). And my 1200-lumen flood-beam DiNotte is actually great for showing up against the backdrop I need to get seen against. This is a photo in the direction everyone will be looking when they're supposed to see me:



    In this scene, I have zero qualms about using as much light as possible, without a cutoff. And I have very little confidence in showing up with a cutoff-equipped headlight like my Supernova or Cyo, particularly on standlight mode... I routinely slap on a floody LED flashlight to actually get seen with in that environment.

    I realize cyclists are more attuned to being sensitive to other road users, since they're often on the other end of the stick. But get a grip... in the city, you will not blind anyone with a Magicshine, even by the BikeForums definition where "blinding" means the light is too intense to comfortably stare at. And the uncomfortable truth is that a cutoff is not very effective on a bike anyway... lift the front wheel an inch, such as going over a slightly-crowned intersection, and now your oh-so-leet cutoff is firing the most intense part of the beam up over the horizon ANYWAY. I can watch this effect in action any time I ride down my home street in the dark with one of my dyno lights.

    If you're on the MUP, like I said, feel free to make a best effort for the sake of those with weak lights or no lights. If you're on a city street, up against people with anywhere from 2000 to 7000 lumens of their own light to see by, plus ambient lighting to maintain orientation, it's just a non-issue.
    Very good points..

    Not only that, how come it is so easy for you and others to see that fact (bike lights are a non-issue as far as hazard), and others are way on the other side of the opinion???

    I guess I am just "out to lunch"...
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  10. #85
    Motorcycle RoadRacer cehowardGS's Avatar
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    Quote Originally Posted by Burton View Post
    But if anyone still has any further issues grasping a relative comparison and potential issues - you're on your own. I'm done with this thread.
    Don't go!!

    This is an INFORMATIVE and ENTERTAINING thread!!!

    Even though my view/opinion often run contrary to yours, I still value and respect your opinons. There is something for all of us to learn here from both sides of this discussion.

    Example, I haven't progressed up to the high end lights yet. However, when I do get some, because of this thread, I will be more knowlegable and responsible in the use of the high powered lights.
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  11. #86
    Senior Member mechBgon's Avatar
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    Quote Originally Posted by cehowardGS View Post
    Very good points..

    Not only that, how come it is so easy for you and others to see that fact (bike lights are a non-issue as far as hazard), and others are way on the other side of the opinion???
    My best guess is what environments we've gotten accustomed to. I avoid MUPs like the plague, so my normal environments are 1) lighted arterials in a city full of US-spec cars, 2) divided highways where I'm literally 50-100 feet away from oncoming vehicles at their closest approach, and 3) dark 2-lane country roads.

    The last of these is the one where I play the game of "let's both dim our high beams" and concern myself with my own impact on the other person, since we actually do get a fair way into our night-adapted vision and do have actual hazards to look for (deer especially). And even a modest headlight shows up in complete darkness. The problem with a cutoff-equipped light in that scenario, is that you have no bargaining chip to play in the "let's both dim our high beams" game, unless you happen to be packing a secondary light to remind them with. The nitwit who was trying to get me to dim my Supernova finally got treated to a quick blast from my S-Mini, which of course "blinded" them and sent them careening off the road... wait, no, that didn't actually happen

    Anyhow, a useful suggestion: based on some video tests with my Seca 700, the best way to mitigate impact on a dark 2-lane road appeared to be switching to 25% power AND aiming the light down by lifting the rear of it with my thumb (it had a rubber strap mount). Since the MagicShine mounts with an O-ring, altering the aim is simple. But cycling through the modes to reduce power and bring it back up... not something I'd look forward to doing 30 times a night.

  12. #87
    Motorcycle RoadRacer cehowardGS's Avatar
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    Quote Originally Posted by mechBgon View Post
    My best guess is what environments we've gotten accustomed to. I avoid MUPs like the plague, so my normal environments are 1) lighted arterials in a city full of US-spec cars, 2) divided highways where I'm literally 50-100 feet away from oncoming vehicles at their closest approach, and 3) dark 2-lane country roads.

    The last of these is the one where I play the game of "let's both dim our high beams" and concern myself with my own impact on the other person, since we actually do get a fair way into our night-adapted vision and do have actual hazards to look for (deer especially). And even a modest headlight shows up in complete darkness. The problem with a cutoff-equipped light in that scenario, is that you have no bargaining chip to play in the "let's both dim our high beams" game, unless you happen to be packing a secondary light to remind them with. The nitwit who was trying to get me to dim my Supernova finally got treated to a quick blast from my S-Mini, which of course "blinded" them and sent them careening off the road... wait, no, that didn't actually happen

    Anyhow, a useful suggestion: based on some video tests with my Seca 700, the best way to mitigate impact on a dark 2-lane road appeared to be switching to 25% power AND aiming the light down by lifting the rear of it with my thumb (it had a rubber strap mount). Since the MagicShine mounts with an O-ring, altering the aim is simple. But cycling through the modes to reduce power and bring it back up... not something I'd look forward to doing 30 times a night.
    IMO, what I have in bold would be more of a hazard putting your attention on dimming our lights and not on the road. Like you, very seldom I am on the MUP and trail, and if I am, it is not at night. However, I am starting my commute in the dark in rush hour speeding traffic. I must be seen to have any chance of survival.

    BTW, I am not even running Magicshine or anything close.. However, even my cheapos are aimed at a spot about 20feet in front. No were need aimed at drivers eyes. However, just like somebody mentioned, when you are on a upgrade, your lights do shine upward. But, as you have stated, and I concur, bike lights are a non-issue in this world of super car lights, along with the way greater number of cars compared to bicycles..
    Last edited by cehowardGS; 01-22-12 at 05:21 PM.
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  13. #88
    Mad bike riding scientist cyccommute's Avatar
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    First, it would be proper to place your responses in your own post rather than embed them in a quote of my post. It makes it easier for the reader to follow your arguments. For convenience, here are Burton's quotes:

    So where's the reality. Your eyes use a logarithmic reference system and digital camera sensors use a linear one, so your eyes can register a much broader dynamic range than any digital camera or film. That's just a fact and it doesn't matter how much the camera cost. So you attempted to expose for the background and ended up overexposing all the highlights and want to pass that off as glare? You were there and you KNOW that photo isn't representative of what you were looking at. Those washed out traffic lights are a good visual reference point after the fact and if they're overexposed then so are the headlights. That's not glare you've captured - just blurred, overexposed photos.

    Maybe before you want to start making comparisons you should post your EXIF data. Your shots were all taken at high ISO values and with shutter times so long you couldn't even hold the camera steady. Mine weren't. Which means relative to anything I've posted your shots are so overexposed that making any sort of comparison is both pointless and misleading.
    Yes, I was there and I know that the pictures are very representative of what I saw from the seat of my truck.

    You seem to have conveniently ignored my post #64 in which I gave you all the data on the pictures. All three pictures were taken at an ISO200 which isn't all that high. Shutter times were 0.3 and 0.2 sec at an f2.8. Considering that the time of the pictures and the light conditions, that's not that long of an exposure and certainly not over exposed. You tell me that I have to post data on the photo...which I did...and you haven't posted anything on your exposures. Where's your data?

    No, I can't really compare my pictures to yours because you haven't posted anything for comparison.


    In Canada at least it's illegal to operate driving lights and / or high beams within city limits or on lit autoroutes and that's clearly what that that second vehicle back in that photo is doing. And all that does is illustrate the OP's concern about glare caused by a beam with no cut-off as is found in many models of MagicShine and other bike lights. So the point of posting this deliberately overexposed, blurry photo was what exactly? Are you saying that because some people feel free to cause issues by using their automotive high-beams illegally it should be OK to do the same thing with a bicycle?
    The Subaru wasn't running his brights. He was uphill from me so even his low beams would have been shining down on me. His lights did have a lot of spillage upward but they weren't being run on highbeam.

    orry, I'm not buying it. That nearest automobile is 40 to 50 ft away. Energy (light is a form of energy) is exponential in nature and to overpower YOUR headlights from that distance, HIS headlights would have to have been at least 4x as powerful as yours. Alternatively each of a set of four lights would have to have been at least twice as powerful as yours if you only had two. Its hard to tell because the photo is so overexposed and has so much blur from handshake that I can't even tell how many lights are actually on the car. But in any case no-one makes and markets any single lamp OEM replacements that fits either description. Moreover, the complete absence of any light, both in front of, and on the RHS of your car (where the low-beam cut-off directs light outwards and upwards to pick up street signs) makes it much easier for me to believe that you were simply parked with your lights off taking pictures.

    There has been no radical change in the lighting of a Chevy Tahoe in the last twelve years that would make your lighting so inferior to even another vehicle equipped with aftermarket lights that it would force you to make some of the claims you're making.
    I took the picture from about the distance of the width of an intersection, 25 to 30 feet. My vehicle was moving too, so it is hard not to shake the camera especially with a 0.3 sec exposure.
    Stuart Black
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  14. #89
    Mad bike riding scientist cyccommute's Avatar
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    Quote Originally Posted by Burton View Post
    The objective of this post was originally to address valid concerns about running high powered lights like MagicShines without a beam cutoff because of potential glare issues for oncoming traffic. My initial post contained photographs of lights manufactured by Vision X which have a rated output of about 700 lumens and a similar design to some MagicShine models so I thought they were very representative of the lights in question.

    I really assumed EVERYONE on this forum was familiar enough with high school mathematics that it wouldn't be all that difficult to grasp that something like a 500 lumen light source restricted to a 10, 15, 25 or 35 degree cone would be more intense than even a 1,000 lumen source spread over an 80 degree cone. Oops! My mistake!

    And apparently that photo I posted earlier of my bike beside a car wasn't conclusive enough for Mr Black so in the interests of providing a representative reference, here's a photo of ALL those combinations on one vehicle.

    photo(5).JPG

    High beam, low beam, 15/45 degree Vision X LED flood and 10 degree Vision X LED spot. These are EXACTLY the same lights I referenced myself, however the photo was sourced from an independent site. http://www.advrider.com/forums/showp...9&postcount=51
    If anyone had any problem grasping the comparison before - I hope this spells things out clearly enough. One difference between this photo and mine is that mine were color balanced to the output of the LED which made headlights look yellow. This one is color balanced to daylight and since the LED output is strong enough to overload the sensor array in that area - it shows as white anyway.

    Gee - half the power power output of an automobile headlight but concentrated within an area one quarter the size. Should have been a no-brainer. And since MagicShine markets lights with power ratings even higher than these and with similar tight focusing beams, it shouldn't be all that difficult to make the connection. But if anyone still has any further issues grasping a relative comparison and potential issues - you're on your own. I'm done with this thread.

    I notice you conveniently ignore the other set of photos I posted and you have conveniently ignored my questions about why you are running such powerful lights if they are a problem. Nor have you addressed the issue of the location of your bicycle in your photos. The lights are damnably bright from head-on. Seldom are they used in that manner. If, like you say, you have to ride so close to on-coming traffic, why are you using them? Why aren't you using something more motorist friendly?

    Too bad you won't be around to answer those questions.
    Stuart Black
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  15. #90
    Dept. store bike bandit
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    I have a MagicShine clone (Gemini Titan) which came with a set of optics that spreads and flattens the beam and actually provides it with a cutoff of sorts. I aim it exactly like a car headlight and thus it illuminates the road much like a car. It's not particularly blinding to oncoming traffic, no more so than other cars which put out the same or higher lumens.

    But as we know, the MagicShines and similar are easy to adjust on the fly. I've used it to flash drivers (by tilting the light up) who leave their high beams on, almost always they turn their highs off. Also do the same to simulate a high beam on empty paths or dark roads.

    I think the MagicShines are not particularly dangerous as long as they are aimed properly, even on high. I do feel like a lot of light on standard optics is being wasted though. A simple lens switch to provide flatter light distribution makes a huge difference. I've had many different fellow riders comment on this. Often times I'm confused for a car when I come upon another rider, because the light distribution is much better than just the standard flashlight optics. It's even, flat, and wide...though not so wide as to send light off where it's not needed. It's hard for me to guess, but I'd say the standard light spread (concentrated center beam) is fairly narrow...probably 10 degrees...the flatter optics spreads it to 20 degrees and limits the light spread to the top and bottom. Like so:



    Bike is about 10 feet from the wall, light is tilted level or slightly up as it would be in "high beam". As you can see the center hotspot is flattened which minimizes upward light spill where it's not needed and provides a sort of a cutoff. Drivers don't get blinded, you see better, everyone wins.

    So in essence, no I don't think they are particularly dangerous, but they could benefit from better optics to distribute the light better. Fortunately it seems these optics are readily available, and some lights come with them already installed.
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