joeyduck

I was taught to look down and away from oncoming bright headlights. It seems only a few others here learned that.

Bikey Mikey

I see your point, but at the time I read it(admittedly quickly--as I was headed out the door), it seemed to me that you were talking about bikes riding against traffic--seems I was mistaken. But, at any rate, a cyclist is much further over than a car when approaching an oncoming vehicle. Of course, I don't ride with my light on bright; I ride with my MagicShine 808e on low at night.

sdwphoto

No argument when it comes to blinding someone with a bright light,however how many bike riders actually have fits due to a blinking light? Yes it is a real condition ,However finding data,statistics on how many folks are writhing on the ground is a bit hard to find even with the internet.Anybody got real facts and not just second hand stories?

dwmckee

Wow, that was really long-winded but I think we are getting to agreement. Shaped beams are better but more expensive than conventional lights.

tcs

Too expensive? Nah. The electrical and mechanical engineers just need to add an optical designer to their team, and Bob will be our uncle.

tcs

FWIW, sometimes the emitter is mounted facing to the rear and they bounce the light backwards off the reflector. If the observer is within the beam, then yeah, technically they 'see' the emitter, but the observer is not directly viewing the emitter. HTH, YMMV, yada yada.

LeeG

Thats a little like saying one doesn't wear a helmet because they're too expensive. There is no benefit to a cone shaped beam that sends light above the roadway in order for the center of the beam to illuminate far enough for riding speed. We're simply behind the times compared to countries like Germany where bike headlights are required to have beam cutoff.
Manufacturers are giving people what they want, max illumination intensity for the dollar, how that light is put on the road isn't a factor.
Emitters and power sources have become powerful enough that bikes used to illuminate roads should be required to have a defined beam if the output is above a particular minimum.

Athens80

I agree about putting most of the light on the road. But not 100%. I want persons whose eye level is above the road to clearly see my light. I want to put some light onto traffic signs, and on parked cars, etc. on the road. I want to light up the tree limbs and other vegetation hanging out into the road that will hit me in the head if I don't see them first.

cyccommute 

You make it sound like a large percentage of a cone shaped beam is above the roadway. That's hardly the case if the light is properly positioned. Even if the light is more flood than spot, there isn't a significant amount of light above horizontal. 80 to 90% of the beam is hitting the roadway if the light is aimed 2 to 3 carlengths in front of the bike.

Exactly. That's the argument that SAE makes for automobiles made in the US. The cutoff on those beams isn't as sharp nor as low as the cutoff for European headlamps. The way my lights are mounted and aimed, I get some reflection from street signs but it's not any more than I see when driving nor when someone in a car is passing me.

cyccommute 

That's just a diffuser and doesn't do much to "shape" the beam. If anything it spreads it out in all directions. Whether that is good or bad depends on your personal preference. I think that most of the LED lights on the market are already too floody and this diffuser makes them more so. I prefer a tighter beam which puts light where I need it most...right in front of me.

LeeG

Nope, pretty sure that's your interpretation. If a bright cone shaped beam is pointed two to three lengths ahead there is ENOUGH intensity above the road to cause discomfort to others if it is a bright light. Whether it's 10% or 50% is irrelevant, a low power blinky, old incandescent or 2 watt Dyno powered incandescent pointed straight ahead won't be a problem, it also won't light the road well even if pointed down but lights bright enough to illuminate the road for 20nph riding in the dark are bright enough for spill over to be a problem. I had a Dinotte X3 that was very bright but guaranteed to disturb others if I pointed it 2-3 car lengths ahead. Maybe I haven't tried enough cone shaped lights but the comparison I've seen between German shaped beam headlights and a couple LED cone beam is profound.

cyccommute 

Do some calculations. A car length is about 13 feet. Two car lengths is 26 feet and three is 39 feet. Using a handy beam calculator and assuming a 35 degree lens, you end up with a circle of light (it will be an ellipse but a circle is close enough) that is between 16 feet and 25 feet wide. Assuming a completely even distribution of 600 lumens of light across that circle, you have a lux between 3 lumens/sq meter and 1.2 lumens/sq meter. For comparison, that's about as bright as a full moon on a clear night (1 lux) and civil twilight (3 lux).

Obviously, the beam isn't evenly distributed with more intensity at the center of the cone than out the outer edges. From my own observations of cone type lights, I would estimate the central cone as about 20% of the total beam or a circle of about 3 to, perhaps, 10 feet with about 80% of the beam output. That increases the lux of the center beam to 60 to 80 lux but also greatly decreases lux at the outer edges of the beam...which is where the spill that you are so concerned about occurs.

If someone were to stand directly in front of the light and look into it, they are going to see spots (not be "blinded") but that doesn't occur all that often on the road. Bike paths are a different story but that's why I avoid riding bike paths at night.

cyccommute 

The light from the emitter gets out which means about the same thing. The lamp above would depend on why they are placing the emitter where they are placing it as well. I doubt that the point is to attenuate the light but to concentrate it better for a smoother beam. Putting the emitter where Cateye does puts the emitter closer to the focal point of the reflector. Beams like the Magicshine and the Clones (great band name) don't have the emitter in an optimum place for the reflector to work that well. They are a little nearsighted. That's the reason that most of them have a bit of a donut hole beam.

znomit

From the thread title I gather chicks with big high beams are OK?

Athens80

The thread title ignores women cyclists, or perhaps just assumes that the participants in this forum are male.

dwmckee

We are in agreement. No doubt shaped beams are better, I am just pointing out that it is unfortunate that the good shaped beams are not nearly as cheap as the 1000+ lumen cone reflector lights.

Team Sarcasm

You are suppose to dog them down dead in the center #neverbackdown !!

As if bike lights are the only "discomfort" out there for drivers.

Car vs. SUV/Truck = discomfort
City installed crosswalk blinkies in the road = discomfort
difference in elevation (aka on a hill) = discomfort
On coming cars w/brights or led head lights in a standard discomfort = discomfort

The list goes on and on at what discomforts a driver, and it is also subject to interpretation. Overall people need to learn to drive and as mentioned earlier, do not look into the lights. that is the first step in getting blinded.

And if you're blinded by a cyclist's light, from across the road, you probably did look directly into their light. Same applies to super bright tail lights, how ever, you DO kinda have to look at them in order to be able to pass safely but it is not like the light comes out of no where. Drivers see the light coming (or I should say they see it as drivers approach the cyclist).


High beams prevent drowning. So yes.

dwmckee

Wow, you sure can quite a lit of figures. Too bad most of it is tangential to the discussion. You are flat out wrong here. Even Kansas has bends in the road and dips and rises. Here in our syate you are liable to hit several dips and rises and several curves every quarter mile.. Many of those are going to throw your beam into oncoming traffic and the eyes of a motorist or another biker. Then there are the swerves around pothole here and dodging rocks and dead opossums too. That surely turns your handlebars back and forth several more times a minute. But you say "the beams on bicycle lights is either too narrow to shine all the way across the road or too wide to have caused you any discomfort." Common sense and all of 30 seconds of riding experience easily disproves your assertion. I guess if you just sit on the shoulder of the road and stand next to your bike holding the handlebars straight it might be true...

With low to moderate power lights under 500 lumen you can probably get away with out overly impacting oncoming traffic and riders, but these 1200 and 2400 lumen MagicShine or even brighter lights are a hazard to everyone else. Many of these high powered lights are sold with warnings about dangers related to shining the beam into a person's eyes. Many are sold as "tactical weapons." Reviewers quote using them to "blind trespassers" or "startle game" when hunting. These do not belong as headlights on public roads.

cyccommute 

You do realize that every one of those arguments apply to shaped beams as well don't you? Even automobiles with shaped beams are going to "throw [their] beam into oncoming traffic and the eyes of motorists". Cars without shaped beams...of which there are millions...do the same. When those cars are passing by each other within a few feet vs a bicycle passing an on-coming car by 4 to 5 times the distance, a bicycle isn't going to cause many problems for cars going the other way. Nor for bicyclists who are even further away.

Motorists may have to deal with hundreds of these kinds of encounters with other motorists on a daily basis but they seem to manage. There aren't that many bicyclist riding at night out there and most of them are in any kind of position to cause problems to other road users.

Those claims of 1200 and 2400 lumens aren't real. A Cree XM-L emitter running at it's optimal output puts out a maximum of 650 lumens under the very best conditions. The claimed output of a 1200 lumen Magicshine is not a realistic claim and is lower than the 650 lumens. The "2400" lumen lamps run 2 Cree emitters but even those aren't perceived by observers as bright as a single 1200 lumen source. The lumen output of the lamps is linear but our perception of light isn't.

I've run lamps that could put out 1500 lumens in the past. The Magicshines and the Clones don't even come close to the same light output.

Flashlights have been used tactically for a very long time. LEDs carry a similar punch in a smaller package than, for example, a 5 or 6 D-cell Maglite but Maglites have been used for decades. And using a flashlight tactically takes advantage of what I was describing above with rod and cone cells. Most people who are skulking around at night on nefarious missions are doing so in the dark to avoid drawing attention to themselves. Their eyes are dark adapted and they can see where they are going. When a cop shows up and shines a light in their face, they are blinded...temporarily...and probably start crashing into furniture or walls or other obstacles. The discomfort they would feel is the same as you feel when you flip on a light after having been asleep for hours. But that would happen with any flashlight from the time flashlights were invented to the present.

But motorists and other bicyclists aren't usually skulking around in the dark depending on dark adapted vision. They are operating under lights and with other light sources coming at them so the effect of some light in their eyes isn't as great.

Finally, if a 600 lumen light doens't belong on the road, what do your have to say about automobiles? They carry around two 1200 lumen light sources and many of them aren't shaped.

Team Sarcasm

How ever with all this being said, I do wish my light had a medium or low blinky mode. It only has a 1200 blinky

Any filters to take the edge off if I do run blinky mode?

wphamilton

Spreads it left and right, with less up and down. You'll see a fuzzy rectangle if you shine it at the wall. It's more "shaped" than unshaped beams, and I kind of like it. Not that one specifically but a similar Fresnel lens.

I suppose if you prefer more of the light in front you could always twist it 90°

dwmckee

Long winded again but you just made my point - Brighter shaped beams are okay to use on the road because they are in fact easier on the eyes than bright conical beams. They are used, and do not blind motorists BECAUSE THEY ARE DIFFERENT than conventional flashlight-style conical beamlights. That is EXACTLY the point of why they are used and why very bright conventional lights should not be used.

That is why the auto industry can use a 1200 lumen light in a shaped beam without major detriment to oncoming drivers and an 1000 lumen 'flashlight' is a hazard to oncoming motorists.

Thanks!

I hope others here will see and agree...

Gresp15C

What do you mean by shaped beams? Car headlights have controlled the shape of the beam since the dawn of the automobile age. The "sealed beam" headlamp that we grew up with shaped the beam with a combination of a reflector in the bowl and optical elements molded into the front lens.

Even the earliest LED bike lights controlled the shape of the beam, albeit crudely by using the optic molded into the LED package itself. Lower power high brightness LEDs were typically in lensed packages.
I suspect you're right about this.
Here, the problem is that lumens aren't a useful measure of the brightness of the light. Visible brightness at a given distance is determined by the luminous output of the lamp (lumens) per unit solid angle (steradian). The candela is a lumen per steradian.

Photometry (optics) - Wikipedia, the free encyclopedia

dwmckee

One note about those older auto headlights. If you pull out the bulb and inspect it you will see that the front of the bulb is opaque so the filament is not directly viewable. It can only be seen reflected off of the curved bowl behind it. That makes even older headlights more tolerable to oncoming motorists. Super bright LED lights where the emitter is directly viewable from the front are a hazard, even if the viewer is not directly in the main cone of light. Moderate brightness LEDs are okay but these high output ones should not be used for road riding on public roads.

krobinson103

On the MUP I run bright lights and loud music for a reason. If I don't the zombies on the path don't even know I'm there and since they are dressed in black its hard to spot them without at least 600 lumens up front. I can't count the number of close calls with cycle and ped ninjas. Even bright clothes or a passive reflector would show them up. Till people get a clue and dress to be seen I'll flood that path so I don't crash.