# How Much Is Too Much? Lumens



## Pisgah (Feb 24, 2006)

Do "lumens" have a point of diminishing returns? In other words, does 1500 lumens offer twice as much seeing power than a 750?


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## Vancbiker (May 25, 2005)

Not a simple answer to this question. So much depends on the beam characteristics. As an example, I have 2 helmet lights that have exactly the same LEDs (dual XPGs), driver, and battery pack. The lumen output, ignoring optic efficiency, will be almost identical. One makes usable light out to about 60 feet. The other is good to about 100 feet.


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## Cat-man-do (May 16, 2004)

Pisgah said:


> Do "lumens" have a point of diminishing returns? * In other words, does 1500 lumens offer twice as much seeing power than a 750?*


In a nut shell, "Yes". However just what that max point is would depend on a lot of different factors. It needs to be pointed out though that when dealing with lower levels of light, doubling the output can make a big difference. Eventually you reach a point where it takes more and more output to make a noticeable difference. Then by that time you are limited by other factors such as lamp head weight, thermal issues, optics and battery size/weight.

To answer your example question ( high-lighted ), basically yes, 1500 lumen is about twice as useful as a single 750 lumen light source, particularly true when using two difference light sources using different optics and different mounting points ( such as helmet and bars ). Just remember that the relationship between what your eyes can see and what light is present is not a "True" linear relationship.


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## mattthemuppet (Jul 16, 2004)

as Vancbiker says, it's a tricky question, but there is a point I think where you get less increase in what you see with more lumens. Down at the 1-200lm end, doubling the output has a huge effect. However going from 1300lm to 2000lm isn't a huge jump. Noticeable, just, but not noteworthy. Also not worth the extra heat and power consumption. What you do gain with more lumens is more throw. That's for different output from the same light, however X lm from a thrower light won't be the same as X lm from a flood light. Add to that the egregious inflating of output figures from most light manufacturers and it becomes a complete mess. It seems better to pick a light with the beam pattern, price and customer support you like and completely ignore the lumen claims!

So, although you'll see a difference in going from 750 to 1500lm, it won't be as big as from 300 to 750lm and it won't be as useful as having two 750lm lights (one on the bar and the helmet).


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## MtbMacgyver (Jan 23, 2007)

Pisgah said:


> Do "lumens" have a point of diminishing returns? In other words, does 1500 lumens offer twice as much seeing power than a 750?


There are many different factors so it's hard to give a precise answer. Also, keep in mind that your eyes dilate once there is "enough" light to start limiting the amount of light your eyes take in. When that starts to happen, you'll be able see what's illuminated by the main beam well, but may start to lose some visibility to the periphery. So called tunnel vision effect.

I think it varies person to person, but personally I find that 700 lumens on the bar and helmet for a total of 1400 is about ideal. My lights are capable of double that, but after my eye's have adjusted I prefer the 700 lumen setting.


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## MtbMacgyver (Jan 23, 2007)

I should add that I'm talking about fairly accurate lumen outputs. If you're using lights with grossly inflated lumen ratings, you'll need to take that into account.


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## pethelman (Feb 26, 2011)

mattthemuppet said:


> as Vancbiker says, it's a tricky question, but there is a point I think where you get less increase in what you see with more lumens. Down at the 1-200lm end, doubling the output has a huge effect. However going from 1300lm to 2000lm isn't a huge jump. Noticeable, just, but not noteworthy. Also not worth the extra heat and power consumption. What you do gain with more lumens is more throw. That's for different output from the same light, however X lm from a thrower light won't be the same as X lm from a flood light. Add to that the egregious inflating of output figures from most light manufacturers and it becomes a complete mess. It seems better to pick a light with the beam pattern, price and customer support you like and completely ignore the lumen claims!
> 
> So, although you'll see a difference in going from 750 to 1500lm, it won't be as big as from 300 to 750lm and it won't be as useful as having two 750lm lights (one on the bar and the helmet).


Very well stated Matt. My experience has been the same.
Also, I would echo Macgyver's sentiment that blowing out huge amounts of lumens from a single light (a.k.a. the 3000 lumen crowd), although impressive in a "beamshot" photo can actually be detrimental to night riding. With the "round" beam patterns, to effectively get your maximum throw, the light will be angled down ever so slightly, and in doing so, a LOT of intensity can be put down on the ground in the near field (again very impressive in beam shots), but this has the effect of "blinding" your distance and peripheral vision. This is why a "compound" beam is so important.

You need to have a tighter beam that can project past the near field at the same time that a wider angle beam can illuminate the near field with less intensity. There are several lights in the shoot out that do this effectively, but mostly in the 1500 lumen or less range. In reality, if you have a light that is capable of putting out say 1000 lumens, but also boosting up to 1500, you may find that the 1000 lumen level is the best for 99% of your riding while the 1500 could be reserved for only very high speed. Sure, when you boost up to 1500, there is an immediate, "WOW, that's brighter" reaction. But if you were to ride for an hour with that 1000 lumens in a decent beam pattern in a setting with no ambient light, your brain would have a very hard time telling the difference between that level and what you "remembered" the 1500 lumens to look like when you bumped it up an hour ago.

Personally, I think one of the benefits of having the higher outputs (1200 to 1800) lumens from a single light is less about night time illumination and most helpful for the ability to flash at these levels in the daytime. Don't get me wrong... I REALLY like having 1200+ lumens available to me at night with the push of a button, I'm just saying, from a practical "How much is too much" standpoint, I think we've definitely already hit the sweet spot, and the uber powerful lights are becoming more about marketing and/or possibly targeting more than just the bicycling crowd (i.e. ATV's etc.) As usual, just my opinion.


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## Pisgah (Feb 24, 2006)

Thanks for the replies, and your advice is well received. I think I will defer to lesser lumens with greater run times. 3000 or 1500 seem a little over the top.


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## 40ncounting (Aug 5, 2005)

Pisgah said:


> Thanks for the replies, and your advice is well received. I think I will defer to lesser lumens with greater run times. 3000 or 1500 seem a little over the top.


 I think that depends on your needs.
I am realizing that even running 1500 lumens on the bar, I am wanting/needing more on my head for fast night time descents so as not to get ahead of what I can actually see.

At a slow pace, 400 lumens is sufficient for my eyes.


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## muzzanic (Apr 28, 2009)

I have ridden with so many types of lights & for me I feel that I would not bother with anything less than 900 lumens.

Yes there is much more to it than just lumens but keeping it simple, Under 900 lumen & you are slowing down because you can't see enough & above 900 lm you can pretty much ride as fast as you can in the day time.

In the rain or in the dust there is such a thing as to much light.

My good light is 3600 lumen & that is more than you need for sure if your eyes are good.


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