importance of beam pattern
this was originally my post in another thread but it got so long i knew it deserved its own thread because it was turning into a hijack:
i think it is oversimplification to say a light is flood or spot or has a certain angle. that angle may mean something for Lupine-type pattern, which they do specify in terms of angles.
Originally Posted by Vancbiker
but for reflector lights you have two separate angle - that of the spill, that of the hot spot, and then you have the transition from the hot spot to the spill. IMO all 3 are equally important.
i think the problem with most reflector lights on the market is that the transition from hotspot to spill is too abrupt. it needs to feather out more, otherwise you're looking not at the road but at the pattern itself. we need that hotspot for good throw, but the edges of the hot spot must be feathered out so that it isn't distracting.
ideally the edge of the spill cone should also be feathered out but that's harder to do, and i think only Light & Motion actually does that, and only on the bottom side of the beam.
with L&M Seca at the bottom side of the spill first the top row of the LEDs cuts out, then the bottom row, and finally the light from the frosted part of the lens gradually feathers out. so just for the spill it's a 3 step transition with 2 abrupt steps and a third gradual step. when i aim the light at the wall i can see the first 2 steps clearly, and the third is feathered out. when i aim the light at the road i can't see any of the steps - it all looks even.
the hot spot on Seca 1700 also is feathered out - you can sort of tell where it is, but it doesn't have any sharp edges - rather it is sort of out of focus - which is good. once again i can see the hot spot when aimed at a wall, or when the light is aimed down on the road, but when it is aimed forward you can't see it - all looks even.
as i said, feathering the edge of the spill may not be possible with a usual style of light, however feathering out the hotspot - making an "out of focus" type hot spot is definitely possible, and frankly any light that doesn't do this is not a bike light - it's a tactical light in a bike form factor.
tactical lights can actually be mounted on your weapon and used to aim your shot
in which case you don't want the hot spot "out of focus" ...
home-made-style lights tend to use off-the-shelf optics which tend to be of the tactical flashlight variety with a very hard hotspot. IMO these aren't suitable for bike use. and talking about floody or spotty doesn't make a lot of sense to describe them because both a floody tactical pattern or a spotty tactical pattern are both equally wrong for the bike.
even Lupine pattern IMO is wrong for road use IMO.
now the non-Seca lights which have a tolerable beam pattern i think definitely include NiteRider Pro 3600 because it has in effect 4 different beam patterns that overlap to produce a more even light. the problem with that light is that it is so heavy and floody that its use is really limited to off-road bar use, but in that application it should excel.
there are other lights that i suspect might be OK but there are not enough beam shots to judge them.
i think the tunnel beam pattern used by L&M and now also MTBR is the most useful, but it's hard to find a tunnel that is unlit. a straight road / trail surrounded by trees, thus creating a sort of a tunnel is also useful.
from my understanding of physics and geometry it should be possible for a single reflector light to produce a decent beam pattern if that reflector is actually DESIGNED to produce it, rather than just grabbed off the shelf. i am surprised however by HOW FEW lights actually bother to do it right. even some of the Light & Motion lights i would consider unacceptable in this regard. Light & Motion Stella is a rare example of a single LED light with a tolerable beam pattern.
i really don't understand why there is so little interest in a useable beam pattern from either the manufacturers or buyers of lights. focusing on lumens alone ( even when they are real lumens, as opposed to chinese lumens ) is like buying / selling cars based only on top speed without caring if the car can stop or turn.
i suspect the reason for this situation is that designing a good beam pattern like designing a car that handles well is something that requires THINKING while most people are either not able to think, or cannot be bothered to do it because they just want to get rich quick.
the tactical pattern is automatically generated by a parabolic reflector - you don't need to have a brain to draw a parabola - a computer will do it for you - or you just grab one off the shelf. but if you want a custom geometry then you need to use the brain.
i do not fault Chinese lights for having the atrocious beam patterns that they do - you can't expect custom reflectors on a $30 light - having off the shelf tactical beam pattern reflectors is sort of part of the deal here - but the shocking part to me is that many of the relatively expensive lights from relatively big name companies are not much better in this regard.
the lights that do deliver the goods such as L&M Seca ( best pattern for road and helmet use ) NiteRider Pro 3600 ( best pattern for bar / off road use ) and Philips SafeRide ( best pattern for MUP use ) are the exceptions.
Last edited by androgen; 08-22-2013 at 08:34 PM.
I'll stand by my statement in another thread that the best pattern is the one that works best for the individual and what type of night riding they do. My night rides are 99.9% off road. Mostly singletrack but a little fire road in the mix. I've not yet made nor tried a light that was too tight for my preference. I'm not sure of the "tactical" beam pattern, I've never seen one. The best beams I have used so far are from reflectors, the narrowest available from the manufacturer at the time. A "floody" or wide beam just lights up stuff I have no interest in seeing.
I am intrigued by shaped beams like the Saferide. I would sure like to find a source for that reflector to do a build around as an experiment.
I've often thought about the Saferide beam pattern, usually after I avoid getting thwacked in the face by a low hanging branch on my commute home. A small hood and judiciously aimed light is enough to avoid bugging other road users but still have a bit of light thrown upwards to see obstacles or signs in the distance.
i use the SafeRide and love it. but i only use it by itself on MUPs. after hurricane Sandy for example, we still haven't had all of the street lighting restored in coastal areas, and bike MUPs tend to run along the coast a lot of the time. in pitch black darkness on MUP like that the SafeRide is perfect - it provides enough light to see where you're going without aggravating others.
Originally Posted by mattthemuppet
but in other scenarios i use it in combination with a helmet light. compared to helmet light alone ( assuming your helmet light is aimed forward, not down ) it provides significant additional amount of light directly in front of the bike.
right now i have 1 x Seca 1700 on helmet and SafeRide on bar. i would estimate that when i aim the Seca forward, and just about 10 degrees down from horizontal ( which i usually do ) about 70-80% of all light hitting the fist 25 feet of pavement in front of me comes from the Saferide, while about 95% of all the light hitting tree branches, cars, buildings etc comes from the Seca.
the SafeRide beam is very efficient, but not nearly as even as that of the Seca. the SafeRide beam puts the light exactly where it should be, but the beam itself has jagged edges which aren't very pleasant to look at.
the Seca beam isn't as efficient as SafeRide ( for road use ) but it it is decently efficient, and makes up for the difference by producing 4X the lumens. the benefit of Seca versus the SafeRide is that the edges of the beam are less pronounced and much further out from the center of your field of view so they are an order of mangnitude less conspicuous and annoying.
if i have a SafeRide on and then i turn on the Seca as well it doesn't really make the patch illuminated by SafeRide any brighter, but instead what it does is it removes the jagged edges of that patch by filling out the shadows left, right and top.
when both lights are properly aimed their combined effect is spectacular - the road is lit extremely evenly and efficiently. much better than either of the lights by itself. that is not to say that these lights are bad on their own, but combined they take it to another level because they compliment each other - covering each other's weaknesses up.
when i was ordering the Philips i thought it would be under-powered because it runs on AA batteries, but i underestimated the difference beam pattern makes. in actuality the 1700 Lumen Seca can't quite keep up with 400 Lumen SafeRide, so i ordered a second 1700 Lumen Seca, and will try to fit both of them on the helmet. at the time of this writing the order status for my 2nd Seca is " Packaged " ...
when you test both lights in the room the Seca 1700 looks very bright - brighter than the lighting you have in your room. the SafeRide in the room doesn't look bright - it looks like an average LED flashlight. but when you're on the road with both lights properly aimed the results are unexpected: the Seca looks much more even than you could imagine by looking at its beam pattern indoors, and the SafeRide looks much brighter than you expected. the first time i turned on SafeRide on the street i couldn't believe what i saw - i didn't understand how an AA battery powered light lit up basically the entire bike path.
my biggest gripe with SafeRide is the size and weight. the weight makes it sag so you need to readjust it often, and the size prevents me from being able to put a second one on the bar. oh well ...
if you have money to burn you can try Ixon IQ Speed - it is 3 times the price of SafeRide and not much brighter, but it comes with two lightweight light heads and a large frame mounted battery pack whereas Philips has an extremely heavy light head with limited battery capacity built in.
the Ixon IQ Speed system compared to SafeRide should hopefully offer a more secure mounting that doesn't sag, double the battery life and SYMMETRICAL light due to having two identical light heads instead of one mounted on the side of your bar.
even though you can aim the SafeRide sideways the adjustment is not continuous - it is in steps - and more importantly you cannot rotate the light around its axis, which is important because the beam is not round at all - it is flat - and unless your bar is flat you will easily be able to tell which side of the bar its installed on just by looking at the beam.
so in my estimate the Ixon IQ speed, when used with a secondary light ( you can order it with eithe 1 light head or 2 ) is probably a 50% better light than Philips for 3X the price of Philips. if you're loaded with cash i would suggest you go with the Ixon IQ speed, otherwise with SafeRide.
the SafeRide build however is extremely sturdy - all metal - even the battery compartment door is cast metal. the Ixon IQ Speed probably isn't as sturdy - but then, neither of these lights are off-road lights.
the SafeRide will probably be 100% uselss off-road both due to beam pattern and due to its mount not being able to keep the heavy light in place under high vibration.
An Orange peal reflector takes care of the smooth transition from spot to spill.
A cheaper, higher performance setup that may work for you would be the MJ-808 with one of our wide angle lenses installed. If you want more throw with that add a second with the stock lens. Your still under the cost of the saferide and have 3+ hours of run time and over 1700 real lumens (MJ-808-L2).
Here is the light distribution with and without the lens. Understand that this "with the lens" pattern is in the horizontal direction only. Vertically it would resemble the "without the lens" pattern, only with the maximum brightness of the "with the lens" line.
Similar distribution graphs for all the lights we sell are available HERE
Last edited by Action LED Lights; 08-23-2013 at 08:03 AM.
Philips SafeRide aside ( it was developed in Germany to meet German regulations, so is not representative of lights designed for American market ) i would estimate maybe 20% of high-end lights even TRY to shape the beam pattern, maybe 5% of mid-range lights like TAZ and none of the lower-end ones.
what this tells me is that economically it is more profitable for light makers to spend extra $20 on components which will add 700 Lumens than to pay some engineer $100,000 a year to fiddle with beam patterns.
the only time a company will resort to doing the right thing and optimizing the beam is when their back is against the wall of physics and they can't obtain any more output from a light without making it excessively large or heavy.
for example most people would say NiteRider PRO 3600 is ALREADY too large and heavy - if it was any larger or heavier nobody would buy one no matter how manly Lumens it put out. so it was only after NiteRider knew there is no way to get any more Lumens out of the light when they decided fine, if we can't get MORE light then we will give it BETTER light and they created a nice even beam pattern than NR 3600 has.
the other lights with good beam patterns appear to have been following the same logic - they are all bordering on the "too big" line.
I just ordered a 800 Seca because of the beam pattern....how is it on the Bar?
well as i have said in other threads i don't recommend any Seca older than 1700 which you can get for $319 shipped from Tree Fort Bikes. the older ones are too inefficient and their beam patterns are too narrow with a hotspot that is too hard.
Originally Posted by canuck_tacoma
in fact i specifically talked somebody out of getting the Seca 800 in another thread ...
the only ones i would get are the 1700 ( 2013 model ), the 1500 ( 2014 model ) and the 2000 ( 2014 model ). the 1500 is more expensive than 1700 and the benefit with the 1500 is higher efficiency which results in much longer run times.
i wouldn't pay more than about $250 for Seca 800. if you paid more i suggest you cancel it and / or return for refund. on the other hand if you got it for $199 on Ebay:
Light Motion Seca 800 Lumen Sport Bike Headlight KIT | eBay
it might be worth it, but i personally still only recommend 1500, 1700 and 2000.
haven't tried Seca on the bar. on a straight poorly lit road it will probably be good, even the 800. on a more brightly lit road the 800 probably won't work. and on the curvy stuff neither one will work most likely unless mounted on the helmet.
I got it for $248 shipped...fairly happy with the price. I use it for MTBiking so there's no other lightening around. I should be able to test it out in the next couple of weeks.
Couldn't find a 1700 for a good price.
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