Electronics, Lighting, & Gadgets - How many Lumens is enough lumens for commuting.

I ride through the downtown area where there isn't as much light needed but half way through, I leave the city and it becomes pitch black on a two lane road.

Right now I have a 255 lumens on my Cygolight and it does brighten up the road but sometimes don't feel this is enough. I've been looking at some lights in the 800 lumens area. Is that to much/overkill? I don't want to blind the oncoming traffic but at the same time, I want the road to light up a bit.

Just asking. Might be a stupid question and right in front of my face but I don't know.

I have a newly-acquired MagicShine 900 lumen from GeoManGear.com and I love it. It's my 5th and favorite bike light. For $90 there's no way you can beat it, except maybe with a P7 flashlight but those aren't as convenient or as turnkey as this light.

My first light was a DIY 20W halogen. OK but heavy (SLA battery) and short run time (about 60 minutes).
Next was an HID - Great, but more expensive and also heavy (bottle NiMH battery) - not horribly expensive but about $250 all told.
Then I got a Dinotte 200L - A nice little light but just barely adequate, and not even really that for the gravel road I ride.
Then I got the MagicShine - I think this light should be all I need.

The rest of the lights were various little AA powered LED lights that were only acceptable as "be seen" lights in ideal conditions, or limp-home lights in case of main light failure.

Some people have expressed doubts about the quality of the MagicShine light, and it appears there was some basis for concern back in April when they first came out, but the manufacturer appears to have greatly improved the quality and the light I got seems great to me.

BTW here's the MagicShine thread:
http://www.bikeforums.net/showthread.php?t=576697

and here is my stuff on the light:
http://johnridley.livejournal.com/266955.html

I've got a Dinotte 600L on my handlebars and a Dinotte 200L on my helmet and I think it's a great combination.

Once you have tried something like the P7 LED based flashlights, you will never want to go back to something dim like the majority of bike lights.

i have the airbike everlight from geomangear.com

200 bucks. works very well.

Another vote for the Magicshine light. The best and cheapest light I've owned to date. And plenty bright. Ordered mine from geomangear.com as well.

Well the dentist's light they use to shine at your face when you're reclined is about 550 lumens.

Between 600 to 1200 suits me just fine.. I take 2 - p7's for my normal night rides.. Usually need just 1 for most of the ride.. A few dark spots where I have both on at the same time.. For longer rides carry a couple extra cells..

Once you have tried something like the P7 LED based flashlights, you will never want to go back to something dim like the majority of bike lights.

Planning on buying one myself. I've been searching for a good inexpensive light, and the best choice for a bike is a compact LED flashlight. There's a lot of info on the P7 LED flashlights, and I've been reading a lot the past few days. Here's a great thread about the P7:

http://www.bikeforums.net/showthread.php?t=464765

Unfortunately, the thread was closed because otherwise helpful members didn't agree with each other's opinions. I wish Tom had deleted the offending posts instead of closing such an informational thread. Would have taken a lot of his time though...

There's also a lot of info on candlepowerforums.com

edit: The P7 flashlights' 900 lumens claim is definitely theoretical, at best. But as I understood it, the output on high is around 500, which is a lot.

Planning on buying one myself. I've been searching for a good inexpensive light, and the best choice for a bike is a compact LED flashlight. There's a lot of info on the P7 LED flashlights, and I've been reading a lot the past few days. Here's a great thread about the P7:

http://www.bikeforums.net/showthread.php?t=464765

Unfortunately, the thread was closed because otherwise helpful members didn't agree with each other's opinions. I wish Tom had deleted the offending posts instead of closing such an informational thread. Would have taken a lot of his time though...

There's also a lot of info on candlepowerforums.com

edit: The P7 flashlights' 900 lumens claim is definitely theoretical, at best. But as I understood it, the output on high is around 500, which is a lot.
There is a light maker which gets good reviews on CPF that's having a 'scratch and dent' sale. They'll be better quality than a DX light for just a little bit more money, which is what I'd do if I had to do it again as after 9 months my DX light has started switching modes on it's own. Shining Beam also might have a decent MC-E or P7 in stock.

http://www.cpfmarketplace.com/mp/showthread.php?t=198779

http://www.shiningbeam.com/servlet/StoreFront

I don't think 800 lumens is overkill.

You gotta see, and you gotta be seen.

The only key to survival in the urban road jungle (at night time).

Planning on buying one myself. I've been searching for a good inexpensive light, and the best choice for a bike is a compact LED flashlight. There's a lot of info on the P7 LED flashlights, and I've been reading a lot the past few days.

Keeping it in the budget is good, but be sure you don't shoot yourself in the foot by being too cheap. I've got a box full of crappy bike lights including a DX flashlight that I got by deciding that they would "probably be good enough". In all they add up to about 3x what the Magicshine P7 cost me (I also have an HID which was fine (about as bright as the Magicshine) at $250. Admittedly, there was no such thing as a P7 for most of the time I was riding, but now that there is, IMHO there's no better choice in the < $200 range, unless you absolutely can't afford the $90.

Keeping it in the budget is good, but be sure you don't shoot yourself in the foot by being too cheap. I've got a box full of crappy bike lights including a DX flashlight that I got by deciding that they would "probably be good enough". In all they add up to about 3x what the Magicshine P7 cost me (I also have an HID which was fine (about as bright as the Magicshine) at $250. Admittedly, there was no such thing as a P7 for most of the time I was riding, but now that there is, IMHO there's no better choice in the < $200 range, unless you absolutely can't afford the $90.

I rarely buy cheap because I can't afford it, but this MTE flashlight is worth the risk.

Please people, ignore me and answer SSfreak's original post.

SSfreak, I'll answer your question without recommending any specific light now. It's not the number of lumens that's important. You should buy the light that suits your riding habits. In general, if you ride mainly on the road, buy a light which has a good throw to be able to see the road a few (5-10?) seconds ahead. For mountain biking, a flooder is recommended. Maybe you'll find the ideal light that is able to do both at the same time. Some people buy the 2 kinds of lights, and direct the "thrower" some distance ahead, while the "flooder" is set to light the area directly in front of the bike.

800 lumens is somewhere around the output of a single automotive halogen headlight on low beam. Shouldn't blind oncoming drivers if properly aimed.

The answer to your question is as many lumens as it takes for you to feel comfortable. I believe that you can never have too many lumens.

800 lumens is somewhere around the output of a single automotive halogen headlight on low beam. Shouldn't blind oncoming drivers if properly aimed.

"If properly aimed" - it's not possible to aim a round beam the same as a low beam on a car. Car lights, by law, have a sharp cutoff and they're set up to be aimed to light up the street with little spill into the eyes of oncoming drivers.

Lots of bike headlights have an intense spot and a mild spill, and that's about as good as it gets for the stuff that's sold for US markets. If you aim those right, they're not too bad, but they're still not ideal.

If you look at what's sold for the German market, you'll see lights done right. They have swooped reflectors that put out an increasing amount of light farther away, until they reach cutoff. This makes the road appear to be uniformly lit from 5 feet to 50 feet in front of you, and only enough light in the driver's eyes so that they see you. Apparently manufacturers won't do it right unless forced to by law; the mass market doesn't know enough to demand this.

what is the relationship between lumens & candlepower? i am looking at the magicshine (900 lumens) & the cateye single shot plus (15000 candlepower)

Candlepower is a measure of brightness, but does not tell you how much total light is emitted.
The cateye is very bright, but only in a small spot. Its really a be seen light.
Lumens is a measure of the total light emitted. It doesn't really tell you how bright the light is because it could be emitted in 360 degrees.....however, it can be used to compare similar lights. And for purposes of a bike light, lumens are a better way to look at it.

what is the relationship between lumens & candlepower? i am looking at the magicshine (900 lumens) & the cateye single shot plus (15000 candlepower)

That's difficult. One is a measure of light flux at a specific spot, the other is a measure of total output. IOW, a 15000 candlepower bulb is 15000 candlepower whether it's in an excellent reflector with a tightly focused beam, or sitting bare letting the light go all over, but a lumen measurement means that they put a light meter at some point in the beam and measured a certain amount of light hitting a square centimeter per second. Lumens decrease as you get farther from the light. It's the SI equivalent of the foot-candle (how many candlepower at one foot) but even that isn't a straightforward conversion.

Basically I assume that if a light manufacturer is listing their specs in candlepower, the light sucks and they are trying to confuse the issue, because all the really good lights list output in lumens. Even manufacturers that list lumens are usually being extremely optimistic, but at least they're on the right page.

I did find this by googling:

http://www.theledlight.com/lumens.html

Candlepower is a rating of light output at the source, using English measurements.
Foot-candles are a measurement of light at an illuminated object.
Lumens are a metric equivalent to foot-candles in that they are measured at an object you want to illuminate.
Divide the number of lumens you have produced, or are capable of producing, by 12.57 and you get the candlepower equivalent
of that light source.

That would seem to indicate that a 900 lumen light is equivalent to a 11,300 candlepower light, but that's not really possible in a light that runs 3 hours on 2700 mAH at 4.8 volts.

I've seen some discussions online that put the Single Shot Plus at about 130 lumens.

Candlepower is a measure of brightness, but does not tell you how much total light is emitted.
The cateye is very bright, but only in a small spot. Its really a be seen light.
Lumens is a measure of the total light emitted. It doesn't really tell you how bright the light is because it could be emitted in 360 degrees.....however, it can be used to compare similar lights. And for purposes of a bike light, lumens are a better way to look at it.

Uh, the opposite of that, in fact. Lumens is measured light flux at a given point, candlepower is total light output. Foot candles (candlepower at one foot from source) is the english equivalent of lumens.

Uh, the opposite of that, in fact. Lumens is measured light flux at a given point, candlepower is total light output. Foot candles (candlepower at one foot from source) is the english equivalent of lumens.

http://www.pinnacleflashlights.com/blog/2009/04/30/lumens-vs-candlepower-sorting-through-advertising-gimmicks/


"To understand the advertising about lights which claim “80 lumens” or “1,000,000 candlepower,” you need to understand what those things are. To put it simply, lumens are a measurement of how much light a device produces, and candlepower is a measurement of concentration of the beam a device produces. These are not the same thing."

800 lumens is somewhere around the output of a single automotive halogen headlight on low beam. Shouldn't blind oncoming drivers if properly aimed.

Sorry but you're about 700 lumens short. Most automotive halogen headlamps put out around 1500 lm.

Sorry but you're about 700 lumens short. Most automotive halogen headlamps put out around 1500 lm.

Serves me right for looking it up on Wikipedia.:o Numbers there for 9004 halogens are 1200 lumens on high and 700 on low. Of course, eyes are logarithmic detectors, so a factor of two isn't that big of a deal anyway. :D

The point remains that even an 800 lumen bicycle lamp is not overwhelmingly dazzling compared to a lot of automotive lighting.

Well... even though the OP hasn't been seen since the first post... LOL

I would recommend going to a bike shop and asking to try out the lights in the dark- at night behind the shop? That is how I chose mine. The only problem is that they don't always have batteries charged up.

I do ok with my trinewt at about 490 lumens

I ride at night all winter (weather permitting) but it is not commuting (I am just trying to slow the rate of getting out of shape) but I think you should go as bright as your budget allows.

I started with a $20 light that a car could see but really didn't throw any light out to a 15 watt halogen, to a 300 lumen to now a $250 Cygolite Trion which is 600 lumens (claimed). I don't think 1200 lumens is too much now!!!

The sweet spot seems to be that Magicshine P7 that a lot of people on this forum endorse. Mounting two of them would be a really sweet setup.

Dan

There is a light maker which gets good reviews on CPF that's having a 'scratch and dent' sale. They'll be better quality than a DX light for just a little bit more money, which is what I'd do if I had to do it again as after 9 months my DX light has started switching modes on it's own. Shining Beam also might have a decent MC-E or P7 in stock.

http://www.cpfmarketplace.com/mp/showthread.php?t=198779

http://www.shiningbeam.com/servlet/StoreFront

How do I actually order one of the cpf ones?????

How do I actually order one of the cpf ones?????

Here's how.


One year warranty is provided. Any inquiry, please send email to rita@epsilon-digital.com.

For ordering please send paypal to paypal@epsilon-digital.com.

Too many, too little or just enough, just depends.

If you are riding in city traffic or illuminated roads then most of the lights will become washed out at the lower lumens. In my opinion/experience that would be less than 200 lumens. I ride with a 180-200 light and use it in flashing/strobe mode to be seen. When I go into a darker street I switch it to high so that I can "try " to see the potholes and such. I have added another 200 for my helmet and expect this will improve my riding.

That said, it also depends on your speed. Faster riders, in the 17-19+ range need much stronger lights to see the problem faster further up the road. A slower 13-16mph rider will have a better chance to see the problem with a lower lumen light.

So as suggested do the following.
a) Keep your 200 light and if possible put it on your helmet
b) get a 400+ (budget dependent) light for the handlebars.

This is one of those things that more IS better, but light weight can cost $$$.

Good LUCK

Candlepower is a measure of brightness, but does not tell you how much total light is emitted.
The cateye is very bright, but only in a small spot. Its really a be seen light.
Lumens is a measure of the total light emitted. It doesn't really tell you how bright the light is because it could be emitted in 360 degrees.....however, it can be used to compare similar lights. And for purposes of a bike light, lumens are a better way to look at it.

It can only be used to compare lights with similar light distribution, i.e. beam properties.

"if properly aimed" - it's not possible to aim a round beam the same as a low beam on a car. Car lights, by law, have a sharp cutoff and they're set up to be aimed to light up the street with little spill into the eyes of oncoming drivers.

Lots of bike headlights have an intense spot and a mild spill, and that's about as good as it gets for the stuff that's sold for us markets. If you aim those right, they're not too bad, but they're still not ideal.

If you look at what's sold for the german market, you'll see lights done right. They have swooped reflectors that put out an increasing amount of light farther away, until they reach cutoff. This makes the road appear to be uniformly lit from 5 feet to 50 feet in front of you, and only enough light in the driver's eyes so that they see you. Apparently manufacturers won't do it right unless forced to by law; the mass market doesn't know enough to demand this.

+100!

Uh, the opposite of that, in fact. Lumens is measured light flux at a given point, candlepower is total light output. Foot candles (candlepower at one foot from source) is the english equivalent of lumens.

Not quite. Candle power is equivalent to lux or lumens/unit area. Lumens don't take area into account. One footcandle is approximately 10.7 lux.

Luminous flux, or lumens, is adjusted for the way our eye perceives the light. Radiant flux is a measure of the total light output of the light (what we can and can't see). The radiant flux is expressed in watts.

It's such a !@#!@ contentious issue. Personally, I find 200 lumens to be the "enough light to bike at an ok speed by" point, and 400 lumens to be about the "ride comfortably" point.

Thing is, this isn't really very helpful. I have to partially agree with the other poster who mentioned the shaped beam german lights. My best setup for night riding is a Lumotec Cyo - a german shaped beam light that puts out a beam pattern like this:
http://www.peterwhitecycles.com/images/products/Lights/B&MCYO1.jpg

It's a really great light for lighting up the road service - probably 200 to 300 lumens (it's rated at 60 lux, so I don't know how many lumens that is). It is absolutely the best light I've ever used for lighting up the road surface regardless of how much or how little ambient light there is, and for riding through the spots where there's either lots of ambient lighting (like streetlights) or where I'm riding through big flat areas (my MUP goes through some of these).

Problem is that it only throws out a little light above the horizon and to the sides. It's just fine for a lot of my riding, but some of my riding goes through some areas where it's woody right next to the trail and I just feel better when I have a light that lights up those areas better (maybe I just feel like someone is going to jump out from behind a tree at me). To deal with that kind of stuff, I started using a Dinotte 200L helmet light which is a more traditional "flashlight" style beam that's fairly narrow, bright in the center but throws more light off to the sides, to. Together, it's pretty much the closest to perfect lighting setup I've ever used.

On my road bike I do not have a dynamo hub, so I use Dinotte battery powered lights. I have 2 Dinotte 400L's (so 800 lumens total) on the front, plus a 200L helmet light.

It works ok, and seems to be the best of the battery powered lights I've tried, but it's still not perfect. It just doesn't light up the road as evenly as the Cyo. I find that in order to light up the road surface enough, I have to turn on both lights on high and point them just above the horizon. I feel like I'm wasting a bunch of light that way, but it seems to work the best. One of the nice things about the 400L is that you can change the lense to get a wider beam, and I'm just starting to play around with that, so maybe that will make a big difference.

But one thing I've noticed when I had the 400L pointing it's hotspot directly and the road surface is that at a certain point, more light actually makes it hard to see. Like, stuff off to the sides actually gets darker when I change from the medium to the high setting. What seems to be happening is that my eyes can adjust to the dark (even when there's streetlights around) with the light on medium, but on high my eyes adjust to the brighter light in front of me, and can't see darker stuff off to the sides as well.

Like I said, I'm playing around with the different lenses for the 400L, and maybe that will help a lot. But my perfect light would be a combined Lumotec Cyo with a Dinotte 200L. If I was giving a recommendation to someone who doesn't have a dynamo hub, I'd probably recommend a Dinotte 400L on the handlebars and another on the helmet (or a 200L on the helmet).

To answer your question directly - is 800 lumens to much? Probably, though with the right shaping I can imagine it being ok. But is an 800 lumen "floodlight" style to much light for riding on the road and would result in blinding people? Definitely. The one caveat is that you probably aren't usually facing oncoming traffic (you're an entire lane over) - but I occasionally go by someone on the MUP with one of these things and just want to strangle them.

I have a 900 lumens DX special P7 on the bars. It is bright but floody. I also have a 230 lumen Q5 DX speci on the helmet. It's a spot light and IT IS SUPER BRIGHT! Two PBSF on the back. The wider light means I will be seen easier. The spot light is excellent for seeing what is on the road in front of me pr turning my head so that drivers on side streets can see me. I'm thinking of adding another Q5 to the bars. I go slower at night; generally try not to exceed 17 mph.

If you ride at night on a regular basis, you have to have good lights. Think of the cost if you crash because you couldn't see well.

The answer to your question is as many lumens as it takes for you to feel comfortable. I believe that you can never have too many lumens.

Exactly imo. I commute 3x a week in the dark hours, and I love my little Blackburn Flea. Its only 40 lumens, but it is bright enough for what I need. I was surprised at how bright it was. I'll upload pictures tonight. But my commute is around 15k long and it's all on a bike path separated from the car lane. It's tiny, basically weightless and I know people can see it from a good distance and I can see as far as I need to...But as you see in this thread, people are saying 400, 800, and more lumens...

Well, as I said (IME), even assuming you keep the additional light out of other peoples eyes, I think there is a point that modern lights can go past where additional lighting actually starts to become detrimental to your own ability to see. There's a certain point at which the amount of light you're putting out in front of you crosses a threshold and your eyes start adjusting upwards to the amount of light in front of you. As a result, when you cross that threshhold more light in front of you just causes your eyes to adjust (your pupils contract? I dunno) and as a result you're not seeing any more detail in front of you, but because your eyes have adjusted to a brighter light you can see less off to the sides that aren't as well lit up.

That point has been, IME, somewhere between 200-400 lumens, though it's highly dependent on a number of factors like where I mount the light, if I can secure my brake cables (light hitting them also has that "to much light" effect because they're so close to the light and my eyes), and of course would depend on what kind of shape your eyes are in, as well as the beam pattern of the light.

As for being seen, I've seen front lights that are to dim occasionally (some cheap $20 light I'm sure), but at a certain point (< 200 lumens) there's no benefit to adding more front light - they can see your light, they either see you or they don't. Short of blinding someone (and I just don't think blinding the 1.5 ton vehicle coming in your direction is a good idea) they either see you, or they don't - it doesn't seem like more light changes that. I think that at that point, if you want to be more visible there are other things you can do, it's just that "more lumens" isn't going to help. Things like reflective clothing, reflective or lit up ankle bands seem like they make bikers more visible. Though I hate a single front flashing light, I've found a non-blinding front flashing light right next to a solid front light has been extremely effective for me when I'm driving as identifying a bike as a bike and knowing where it is.

Well, as I said (IME), even assuming you keep the additional light out of other peoples eyes, I think there is a point that modern lights can go past where additional lighting actually starts to become detrimental to your own ability to see. There's a certain point at which the amount of light you're putting out in front of you crosses a threshold and your eyes start adjusting upwards to the amount of light in front of you. As a result, when you cross that threshhold more light in front of you just causes your eyes to adjust (your pupils contract? I dunno) and as a result you're not seeing any more detail in front of you, but because your eyes have adjusted to a brighter light you can see less off to the sides that aren't as well lit up.

Unless your lights match the output of the sun...mine are close:rolleyes:...I'm not sure where your threshold would be. You use bright lights in your home, don't you? Most of us wouldn't want to try and function in a modern household under candle light. Bright light...and a lots of it...hurts nothing and greatly benefits your ability to see detail.

Lots of people think that a dim light will help you preserve your night vision but the light has to be very, very dim...a few lumens at most. Any light that gives enough illumination at 20 or so feet to see the ground has already ruined your night vision.

Finally, what do you really need to see on the side of the road? My bicycle lights illuminate enough of the side of the road for me to see anything coming from that quarter. I wish my automobile lights did as good a job:rolleyes:


As for being seen, I've seen front lights that are to dim occasionally (some cheap $20 light I'm sure), but at a certain point (< 200 lumens) there's no benefit to adding more front light - they can see your light, they either see you or they don't. Short of blinding someone (and I just don't think blinding the 1.5 ton vehicle coming in your direction is a good idea) they either see you, or they don't - it doesn't seem like more light changes that. I think that at that point, if you want to be more visible there are other things you can do, it's just that "more lumens" isn't going to help. Things like reflective clothing, reflective or lit up ankle bands seem like they make bikers more visible. Though I hate a single front flashing light, I've found a non-blinding front flashing light right next to a solid front light has been extremely effective for me when I'm driving as identifying a bike as a bike and knowing where it is.

If you ride like most people do, i.e. along the right side of the road in or near the right wheel track, you'd have to have extremely wide angle lamps to blind and oncoming vehicle. The driver of a vehicle approaching you is 13 to 16+ feet away from the center of you light. Even if your light is wide enough to spill light into the oncoming driver's eyes, that light is still going to be rather diffuse since it is a long ways away from the focus point of just about any light system.

Additionally, the right side light of automobiles are focused further down the road than the driver's side. While car lights may have cut-offs on the top of the lamp, they seldom have them to the sides...at least not the ones I've seen. That light is just about where bicycles are traveling. It's actually a little further towards the oncoming driver than a bicycle light would normally be...and it's aim further down the road than most bicycle lights are.

Finally, reflectors and reflective clothing require light to hit them before they can reflect. Depending on a light to hit the reflector is a crapshoot at best. Cars use active lighting for a reason.

Actually, your home vs outdoor lighting is somewhat illustrative of what I'm saying. After dark, go home and turn on all the lights. Sit there for a minute. Now look out the window. Unless you have your entire yard lit up, you can't see a darn thing outside, can you?

Now turn off all the lights. Go outside and sit in your yard for a couple of minutes. You can see your yard a lot better, can't you? Even without directly lighting it, unless it's a dark cloud night out in the country (away from ambient city lights) you can probably see your yard well enough to walk around in it.

Now I did *not* say "very bright lights are extremely bad", what I said was that "additional lighting actually starts to become detrimental to your own ability to see". I'm not saying it's a night and day issue, but I am saying it reaches a point of diminishing (and no) returns, then becomes *slightly* (but not majorly) detrimental. Having a really bright light is like sitting in a well lit house at night trying to look outside. It's simply harder to see anything outside of what you're lighting up with your light.

Now the next thing you might say is that your light is really bright and *does* light up everything in front of you. But I would say that you've now -
1 - Either spent a ton of money or spent a ton of time (diy) on your light setup
2 - Also need a really large (and expensive to replace) battery
3 - Are still really annoying/blinding to anyone who comes within range of your light
4 - Unless you suffer from eye problems, could have had the same effect with a much less powerful or expensive light

In regards to the other things, when I mention "night vision" I just mean your ability to see at night. I think you mean some specific thing that's turned off by bright lights. That's not what I'm talking about - I'm just talking about your eyes ability to see things when it's darker than daylight.

I need to see small animals on the side of the road (they may try to run through my wheel) and it's just plain more comfortable to be able to see of to the sides. I have no doubt your lights do the job - I was referring specifically to the light with the shaped beam that I mentioned when I was talking about a bike light not lighting up the side of the road.

As for the side of the road thing, I don't entirely disagree with you, I just already mentioned it 2 of my posts back "But is an 800 lumen "floodlight" style to much light for riding on the road and would result in blinding people? Definitely. The one caveat is that you probably aren't usually facing oncoming traffic (you're an entire lane over) - but I occasionally go by someone on the MUP with one of these things and just want to strangle them."

However where I live there's lots of bike trails (MUPs, dedicated bike trails, etc) and the wide angle high beam's are really really annoying to anyone else on the trail. You might not have bike paths where you are.

It's a "no kidding" thing about the reflectors, but I certainly didn't say "you shouldn't use lights". I suppose it would be more visible if you used lights everywhere people use reflectors, but I don't have the kind of time to recharge and replace and turn on/off all those lights and batteries. I mentioned a front blinky light next to a solid front light - I can't think of a time you need to be more visible than that that you don't have a pair of car headlights lighting up your backside already.

Actually, your home vs outdoor lighting is somewhat illustrative of what I'm saying. After dark, go home and turn on all the lights. Sit there for a minute. Now look out the window. Unless you have your entire yard lit up, you can't see a darn thing outside, can you?

Now turn off all the lights. Go outside and sit in your yard for a couple of minutes. You can see your yard a lot better, can't you? Even without directly lighting it, unless it's a dark cloud night out in the country (away from ambient city lights) you can probably see your yard well enough to walk around in it.

Do the same with your bike lights. Turn them off and you'll not be able to see a thing for several minutes. That's what night vision is. Even small amounts of light saturate the rod cells in your eyes. The cone cells...the ones responsible for seeing detail...need tens to hundreds of times the light to activate. Too much light and the rods are saturated. Too little and the cones won't fire. The cones also rapidly respond when they have enough light. The rods take more time.

That's why everything is dark when you walk outside of the house or turn off your lights. There isn't enough light for the cones and the rods take time to overcome the saturation. For a while you are left without the ability to see much of anything. Typically it takes about 30 minutes for full night vision to return.


Now I did *not* say "very bright lights are extremely bad", what I said was that "additional lighting actually starts to become detrimental to your own ability to see". I'm not saying it's a night and day issue, but I am saying it reaches a point of diminishing (and no) returns, then becomes *slightly* (but not majorly) detrimental. Having a really bright light is like sitting in a well lit house at night trying to look outside. It's simply harder to see anything outside of what you're lighting up with your light.

But the issue is that even a small amount of light...enough to see a spot on the road...will ruin the night vision that you are seeking. Our eyes can't see well enough to function in the dark like many animals. We lack the tapetum lucidum which is responsible for the red glowing eyes of animals. The tapetum lucidum reflects the light in the eye and refocuses it so that they can function well in low light situations. While you can see well enough to walk around in your backyard after your night vision is established, you can't really run around nor ride a bike at 10 to 20 mph. Human night vision just isn't that good.

But seeing outside of the main beam of the light really isn't that big a deal. Most lamps have lots of spillage to the side (halogen and incandescent are better LED at this). No useful bicycle light should be so narrow that you can't see several feet width at 10 to 15 feet in front of you. Any narrower than that and it's not technically a light...it's a laser beam;)


Now the next thing you might say is that your light is really bright and *does* light up everything in front of you. But I would say that you've now -
1 - Either spent a ton of money or spent a ton of time (diy) on your light setup
2 - Also need a really large (and expensive to replace) battery
3 - Are still really annoying/blinding to anyone who comes within range of your light
4 - Unless you suffer from eye problems, could have had the same effect with a much less powerful or expensive light

I assure you that I can see quite well at night. I've also spent many years using lights that were weak. I've ridden with lights that put out 80, 100, 200, 500, 700 and 1500 lumens. I much prefer the 1500 lumens (I actually use 3 of them:eek: for a total of 4500 lumens). It's quite nice to ride without having to squint into a weak beam to see if that dark patch on the road is 1. a hole, 2. just a dark patch, 3. a live skunk or 4. (and far worse) a dead skunk:eek:

My light system is something that I have enjoyed tinkering with and while a little heavier than the current commercial systems, it's output is stunning. It's been worth the effort. NiMH batteries are fairly cheap, relatively light and very rugged. The response from other road users is more than worth the extra weight I have to carry.

I could go with a light that puts out less light. I could use one that is lighter. I could use one that is more understated. However, the point isn't to blend in with my surrounding. The point is to avoid getting squished. I want a light system that shouts my presence to the world. You do it with a flasher. I prefer to do it with massive amount of photons.



In regards to the other things, when I mention "night vision" I just mean your ability to see at night. I think you mean some specific thing that's turned off by bright lights. That's not what I'm talking about - I'm just talking about your eyes ability to see things when it's darker than daylight.

Night vision is the ability to see things when it's darker than daylight. Night vision is severely limited in the presence of any light source. It doesn't take a bright light to saturate the rod cells. You'd be amazed by how little light it takes to render them ineffective. They can detect a single photon. That's not much light at all.



I need to see small animals on the side of the road (they may try to run through my wheel) and it's just plain more comfortable to be able to see of to the sides. I have no doubt your lights do the job - I was referring specifically to the light with the shaped beam that I mentioned when I was talking about a bike light not lighting up the side of the road.

I can see animals from much further off with powerful lights. Their eyes glow in the dark for hundreds of feet. I also have a lamp mounted to my helmet so that I can target anything that "catches my eye" (another function of the rod cells). I find my helmet light to be the most useful of the lamps I use. If something happens to my lights, I'll salvage the helmet light before the others.

If you lights are so focused that you can't see the side of the road, they're too highly focused. You need more spillage to the side so that you won't have to worry about Ricky Raccoon running under your wheels;)

I've read many discussions over light and what is enough for several years. IMO, cyccommute and another person whose name escapes me (NW commuter) have had the best educated, most educated and even most nuanced discussions than any other. I would listen to cyccommute.

I've read many discussions over light and what is enough for several years. IMO, cyccommute and another person whose name escapes me (NW commuter) have had the best educated, most educated and even most nuanced discussions than any other. I would listen to cyccommute.

Ooh! A fan! Thanks:thumb:

Do the same with your bike lights. Turn them off and you'll not be able to see a thing for several minutes. That's what night vision is. Even small amounts of light saturate the rod cells in your eyes. The cone cells...the ones responsible for seeing detail...need tens to hundreds of times the light to activate. Too much light and the rods are saturated. Too little and the cones won't fire. The cones also rapidly respond when they have enough light. The rods take more time.

That's why everything is dark when you walk outside of the house or turn off your lights. There isn't enough light for the cones and the rods take time to overcome the saturation. For a while you are left without the ability to see much of anything. Typically it takes about 30 minutes for full night vision to return.

Look, I've tried to cover this twice already, but evidentally I was not blunt enough or did not cover the topic in enough detail.

Your definition of "night vision" doesn't have anything to do with what I'm talking about. When I turn off my really bright (but narrow) bike lights, I can immediately see things to the side of me better within a couple of seconds. Walking out of my house also results in better vision in seeing things in the yard immediately after leaving the highly lit house interior. It has absolutely, positively, nothing to do with rods, cones, or some specialized definition of "night vision". It doesn't take 30 minutes, or even several minutes. It's pretty much an immediate effect - maybe 15 seconds at most.

If you want to get technical, I am no expert, but I believe it has to do with the pupil dilating. When you're in dim light your pupil opens all the way to let all the light in. As it gets brighter, as some point your pupil starts contracting to control the amount of light that enters the eye. The point at which you put so much light out in front of you that your pupils start to contract more than they would from the ambient lighting is the point at which additional light from your bike light isn't actually helping you see, it's just causing your pupils contract more, letting less light into your eyes.

This is my theory of what happens based on my own personal experience with bike lights. I started with a Dinotte 200L with 200 lumens. It was "enough" to bike at night with, but not quite as full speed and I didn't quite feel safe. I then ordered a Dinotte 600L. Well, it lit up the ground in front of me pretty well but didn't have enough reach for me to feel safe biking at high speeds. Dinotte was kind enough to let me return it and exchange it for 2 400L's. That's 800 lumens. Well, I like these a lot better than the 600L, but I still felt like they just didn't give me that "riding in daylight" feeling.

Then I bought my winter bike which came with a dynamo hub and a really terrible front light. I figured since I had the hub, I might as well get a decent front light for it - the Lumotec Cyo. It had a shaped beam that focuses almost all it's light on the road surface, and evenly lights up the road by being brighter at the top (where the light goes farther) and dimmer at the bottom which results in evenly lighting the road near me and far away from me. The whole light puts out like 200 lumens.

I figured I would need another light to see by. I was *amazed* to find that I didn't need any more light to see the road surface clearly. I just couldn't believe it - it was completely unexpected. But as I mentioned several posts back, the problem was that it doesn't put enough light above the horizon or off to the sides to see stuff by when there's a medium amount of ambient light. So I started using my Dinotte 200L as a helmet light.

Imagine my surprise when I went from using just the Cyo to using both with my helmet light on high and found that I could see *less* of the road detail. I just couldn't believe it. I kept turning it on and off, and switching between high, medium, and low. Over several different trips, to. But it kept happening - with my headlamp on high, I could see (slightly, but noticeably) less road detail than with it on medium or off.

The only logical explanation that I've been able to think of is that when you reach a certain point, your eyes start adjusting to their being more light and putting out more light does little good. I don't doubt your insane amount of light output setup lets you see farther down the road, and part of me totally thinks it's awesome to have a bike light so bright it's like riding in daylight (as long as the light never hits anyones face, as it would undoubtedly be temporarily blinding).

But I don't think it's "necessary" - you could get the same effect with a lighting system that simply puts extra light farther down the road. The approach of simply spraying out more and more light will work eventually, as long as you have the time and battery power to power it and you can manage it output it fairly evenly.

I don't have any simple, practical solutions though, that are actually available - as I said I still haven't found the perfect solution. I just don't think that "more lumens is always better", for the reasons described above.

Simple...its enough lumens when you can safely ride at your desired speed and others can see you.

Look, I've tried to cover this twice already, but evidentally I was not blunt enough or did not cover the topic in enough detail.

There is no need for bluntness. However your detail and understanding of the physiology of vision is lacking. That's what I've been trying to explain to you.


Your definition of "night vision" doesn't have anything to do with what I'm talking about. When I turn off my really bright (but narrow) bike lights, I can immediately see things to the side of me better within a couple of seconds. Walking out of my house also results in better vision in seeing things in the yard immediately after leaving the highly lit house interior. It has absolutely, positively, nothing to do with rods, cones, or some specialized definition of "night vision". It doesn't take 30 minutes, or even several minutes. It's pretty much an immediate effect - maybe 15 seconds at most.

Rods and cones are the only way that we see. They are specialized nerve cells that are the light receptors in the eye. The physiology and chemistry of how they work are well studied and well established. Yes, when you turn the lights off or walk out of a darkened house you can still see things. You just can't see them in the detail that you can when illuminated. You don't really reach full 'night vision' for up to 30 minutes after you leave that illumination, however. And even then, your ability to move about without light is limited. That's why we little monkeys light up the night sky so much. We just can't function as well in the dark as we can in the light. That's why we have lights on our cars and our bikes and our planes and boats, etc. If you are going to operate something at higher speeds then walking, you'll find that light is necessary to do it safely...or at least comfortably.


If you want to get technical, I am no expert, but I believe it has to do with the pupil dilating. When you're in dim light your pupil opens all the way to let all the light in. As it gets brighter, as some point your pupil starts contracting to control the amount of light that enters the eye. The point at which you put so much light out in front of you that your pupils start to contract more than they would from the ambient lighting is the point at which additional light from your bike light isn't actually helping you see, it's just causing your pupils contract more, letting less light into your eyes.

I'm sorry but you couldn't be more incorrect. Your pupils work like the iris in a camera. They keep too much like from reaching the cones and rods in the retina. Too much light and the image is overexposed and pretty much useless. Too little light and the image is dark, underexposed and, again, useless. It's the eye's Goldilocks effect. The pupils make everything just right;) They also help with a little with image focus, which you've probably experienced if you've ever had your eyes dilated. If you've ever had your eyes dilated, you'll also understand the just rightedness of their job.

But your pupils only work to attenuate the light reaching the rods and cones. All of the heavy lifting of light detection is done by those cells. Without them, you can't see light at all. There would just be no connection between your brain and the eye. Blindness problems are cause by the lack of function of these cells.

If you get more light to the cones and rods, the chemicals that are used for signaling the brain are provided in the amount necessary for vision to be useful. However, the cells can get too much stimulation...too high of a concentration of the chemicals. It takes time for the cells to relax back to a lower light state. That's why it takes time for your night vision to reach full potential. They have to clear the chemicals. Exposure to even a fairly low intensity light, however, starts the process all over again. Exposure to a higher intensity light, like a 200 lumen light, takes even longer to clear the chemicals.



This is my theory of what happens based on my own personal experience with bike lights. I started with a Dinotte 200L with 200 lumens. It was "enough" to bike at night with, but not quite as full speed and I didn't quite feel safe. I then ordered a Dinotte 600L. Well, it lit up the ground in front of me pretty well but didn't have enough reach for me to feel safe biking at high speeds. Dinotte was kind enough to let me return it and exchange it for 2 400L's. That's 800 lumens. Well, I like these a lot better than the 600L, but I still felt like they just didn't give me that "riding in daylight" feeling.

Then I bought my winter bike which came with a dynamo hub and a really terrible front light. I figured since I had the hub, I might as well get a decent front light for it - the Lumotec Cyo. It had a shaped beam that focuses almost all it's light on the road surface, and evenly lights up the road by being brighter at the top (where the light goes farther) and dimmer at the bottom which results in evenly lighting the road near me and far away from me. The whole light puts out like 200 lumens.

I figured I would need another light to see by. I was *amazed* to find that I didn't need any more light to see the road surface clearly. I just couldn't believe it - it was completely unexpected. But as I mentioned several posts back, the problem was that it doesn't put enough light above the horizon or off to the sides to see stuff by when there's a medium amount of ambient light. So I started using my Dinotte 200L as a helmet light.

Imagine my surprise when I went from using just the Cyo to using both with my helmet light on high and found that I could see *less* of the road detail. I just couldn't believe it. I kept turning it on and off, and switching between high, medium, and low. Over several different trips, to. But it kept happening - with my headlamp on high, I could see (slightly, but noticeably) less road detail than with it on medium or off.

The only logical explanation that I've been able to think of is that when you reach a certain point, your eyes start adjusting to their being more light and putting out more light does little good. I don't doubt your insane amount of light output setup lets you see farther down the road, and part of me totally thinks it's awesome to have a bike light so bright it's like riding in daylight (as long as the light never hits anyones face, as it would undoubtedly be temporarily blinding).

I think your conclusion are wrong. Some people have issues with helmet mounted lights . They feel that the light from above can flatten road detail (I haven't had the same experience, however;)). LEDs may exacerbate this problem because of their color rendition and directionality. I've been using high power LEDs recently and the light is very different in quality vs halogen. Halogen's color rendition is closer to sunlight so the shadows seem more natural.


But I don't think it's "necessary" - you could get the same effect with a lighting system that simply puts extra light farther down the road. The approach of simply spraying out more and more light will work eventually, as long as you have the time and battery power to power it and you can manage it output it fairly evenly.

The necessity depends on the situation. In rural environment, less light is needed...contrary to most people's opinion...because the light is more effective. In an urban environment, more light is needed because your lights have to compete with many more light sources. A weak light...and 200 lumens is a pretty weak light, IMO...will just get lost in the background. More powerful lights...close to that of the cars around you...are far more noticeable and attention getting than even a flashing light. With what I throw out, cars think that I'm much, much, much larger than I am and will wait for extraordinary lengths of time for me at intersections.