Maxpedition - Knives and Tools
Results 1 to 17 of 17

Thread: How "bright" is a lumen?

  1. #1

    Default How "bright" is a lumen?

    Being a complete newbe, I've no idea how "bright" a given number of lumens translates to be in the real world. Hoping someone can give me some comparison insight to something I have actually seen and used. As a "fer instance" how bright (how many lumens) is the Garrity keychain light ( http://www.garritylites.com/page75.html ) ? Or a standard incandescent (I think they are?) 2AA Mini Maglight?
    Thanks for any help you can give to shed some light (sorry, couldn't help myself ) on the question.

  2. #2
    Flashaholic* mvyrmnd's Avatar
    Join Date
    Sep 2009
    Location
    Victoria, Australia
    Posts
    3,218

    Default

    It's actually more complicated than that...

    Brightness is all about perception. A 2000 lumen light can look less bright than a 500 lumen light, if the 500 lumen light is highly focused and the 2000 lumen light is a wide flood. This is assuming you're aiming them both at a wall at the same distance.

    You need to consider two values simultaneously when looking at brightness; the lumen output (a measure of the total amount of light being emitted, think of it as the number of liters of water coming from a hose) and candela (often spoken of as lux @ a given distance), which you can think of as the amount of water from your hose hitting a given spot on the wall at a given distance.

    Clear as mud?

  3. #3
    *Flashaholic* StarHalo's Avatar
    Join Date
    Dec 2007
    Location
    California Republic
    Posts
    7,384

    Default Re: How "bright" is a lumen?

    It would be difficult to use the MiniMag as a standard because its output dims continuously throughout its runtime; it averages around 12 lumens though, which is roughly the same output as a candle flame. As noted above, the candle distributes light 360 degrees, whereas the Mag puts it all in one direction, so the Mag seems brighter.

  4. #4
    Flashaholic*
    Join Date
    Oct 2010
    Location
    Hong Kong
    Posts
    1,164

    Default Re: How "bright" is a lumen?

    1lm was like, a burning candle at 1 meter away (was it? by definition we have 1lm=cd/sr)

  5. #5
    Flashaholic*
    Join Date
    Feb 2009
    Location
    Missouri
    Posts
    579

    Default

    Edit: nevermind.
    Last edited by Viper715; 01-22-2012 at 06:43 AM.
    My Lights: EDC; Nitecore EC1, ZLSC52, Quark Mini AAW, Preon P2
    Duty; Mag Recharger, Malkoff MD2 w/M60, C2 Bored w/LX2 clip Malkof M61 219

  6. #6
    Enlightened
    Join Date
    Aug 2011
    Location
    Winnipeg
    Posts
    73

    Default Re: How "bright" is a lumen?

    Quote Originally Posted by aephilli View Post
    Being a complete newbe, I've no idea how "bright" a given number of lumens translates to be in the real world.
    I'd like to find a table that shows what lumens you would expect for various tasks. I think it might go a little like this:
    *1-2 lumens: Finding a keyhole, close range work (within arm's reach), close reading, maybe a supplement to dark-adapted vision finding your way around a room. Some mini incandescent keychain lights admit to this level.
    * 5-10 lumens: Indoor use, close inspecitions, map reading, testing eyes; the 2 AAA penlight with a #222 prefocus bulb is in this range.
    * 15-30 lumens: General household indoor use, moderate range outdoor use ( a few yards); this is the light range that the 2 D cell plastic light with a prefocus bulb generates.
    * around 50 lumens: Walking a good trail at night, finding your way in unfamiliar surroundings.
    * 60-200: So-called "tactical" lights; identify a man-size target at firearms range. Power LEDs can give 100+lumens from an AA cell. In my experience, 100 lumens can light up a small suburban backyard (say, 60 feet x 30 feet) and verify the yard is free of the neighbor's cat.
    * 200 lumens and up - Outdoor, moderately long range, search and rescue - you can go up to several thousand lumens in a hand-carried light but I think anything much over 500 is a rather special purpose tool.
    * 500+ lumens- - I understand night-time orienteers use high-power lamps in this range for running unfamiliar trails in the dark.

    Don't take these numbers as anything other than the centers of pretty broad ranges.

    Bill

  7. #7
    Flashaholic*
    Join Date
    Oct 2010
    Location
    Hong Kong
    Posts
    1,164

    Default Re: How "bright" is a lumen?

    Something below 10lm is a 5mm nichia white led
    Raid of 5mm would give you 50lm something

  8. #8

    Default Re: How "bright" is a lumen?

    Quote Originally Posted by StarHalo View Post
    It would be difficult to use the MiniMag as a standard because its output dims continuously throughout its runtime; it averages around 12 lumens though, which is roughly the same output as a candle flame. As noted above, the candle distributes light 360 degrees, whereas the Mag puts it all in one direction, so the Mag seems brighter.
    Thanks, that helps. I've used a Minimag lots, so now I have a (rough idea of a) comparison.

  9. #9

    Default Re: How "bright" is a lumen?

    Quote Originally Posted by Kitchen Panda View Post
    I'd like to find a table that shows what lumens you would expect for various tasks. I think it might go a little like this:
    *1-2 lumens: Finding a keyhole, close range work (within arm's reach), close reading, maybe a supplement to dark-adapted vision finding your way around a room. Some mini incandescent keychain lights admit to this level.
    * 5-10 lumens: Indoor use, close inspecitions, map reading, testing eyes; the 2 AAA penlight with a #222 prefocus bulb is in this range.
    * 15-30 lumens: General household indoor use, moderate range outdoor use ( a few yards); this is the light range that the 2 D cell plastic light with a prefocus bulb generates.
    * around 50 lumens: Walking a good trail at night, finding your way in unfamiliar surroundings.
    * 60-200: So-called "tactical" lights; identify a man-size target at firearms range. Power LEDs can give 100+lumens from an AA cell. In my experience, 100 lumens can light up a small suburban backyard (say, 60 feet x 30 feet) and verify the yard is free of the neighbor's cat.
    * 200 lumens and up - Outdoor, moderately long range, search and rescue - you can go up to several thousand lumens in a hand-carried light but I think anything much over 500 is a rather special purpose tool.
    * 500+ lumens- - I understand night-time orienteers use high-power lamps in this range for running unfamiliar trails in the dark.

    Don't take these numbers as anything other than the centers of pretty broad ranges.

    Bill
    Just what I was looking for, thanks a heap.

  10. #10

    Default Re: How "bright" is a lumen?

    After a little research at the local china-mart, it looks like the Garrity folks rate theirs at 6 lumens and the Mini Maglight people say 14. This will really help me decide what I want.

    Thanks a bunch for the help, guys.

    Did I just miss the sticky that has the above numerical comparison info in it? (honest, I looked )

  11. #11
    Enlightened
    Join Date
    Mar 2006
    Location
    NE Oklahoma
    Posts
    52

    Default Re: How "bright" is a lumen?

    While I don't claim to know a lot about lights or about Lumens I know what I do to see the difference between lights is not shine them on a wall to see the pattern although I do that at times but to see Lumen accuracy for what the companies claim or try to see it is I walk into my bathroom which is about 80" x 80" and I close the door. Then I stand the light up on its end or make it stand up using something to support it if it doesn't stand up on its' own and turn it on high to see which flashlight is providing more light in the room. The way I can tell the JetBeam BA20 is actually putting out more light than the Nebo is by how much brighter the room is using the JetBeam over the Nebo 220 S.O.S Both of these come close to lighting up this small room like the light bulbs but the JetBeam is so much closer to this that it stands out in this test yet when shining them on the wall the Nebo appears brighter.

  12. #12
    Flashaholic* AnAppleSnail's Avatar
    Join Date
    Aug 2009
    Location
    South Hill, VA
    Posts
    3,979

    Default Re: How "bright" is a lumen?

    A lumen is not brightness, a lumen is output. Let's go with output per area (Photons per area, so to speak, accounting for human sensitivity). Given that 1 lux is 1 lumen per square meter, use this table:

    Source from Wiki

    120,000 lux Brightest sunlight
    110,000 lux Bright sunlight
    20,000 lux Shade illuminated by entire clear blue sky, midday
    10,000 - 25,000 lux Typical overcast day, midday
    <200 lux Extreme of darkest storm clouds, midday
    400 lux Sunrise or sunset on a clear day (ambient illumination).
    40 lux Fully overcast, sunset/sunrise
    <1 lux Extreme of darkest storm clouds, sunset/rise

    For comparison, nighttime illuminance levels are:
    <1 lux Moonlight[3]
    0.25 lux Full Moon on a clear night[4][5]
    0.01 lux Quarter Moon
    0.002 lux Starlight clear moonless night sky including airglow[4]
    0.0002 lux Starlight clear moonless night sky excluding airglow[4]
    0.00014 lux Venus at brightest[4]
    0.0001 lux Starlight overcast moonless night sky[4]



    So if you have a 1 lumen light shining evenly on 1 square meter, then it's about like bright full-moon light. That same lumen spread over a 1cm square will look as bright as an overcast day.
    My biggest light-hog is my camera.

  13. #13
    Flashaholic*
    Join Date
    Oct 2009
    Location
    Seattle,WA
    Posts
    2,470

    Default Re: How "bright" is a lumen?

    I think (but am not sure) that one lumen is approximately the output of a birthday candle if you place a piece of white cardboard 1 foot 1 away and only consider the light hitting that cardboard. You would size the cardboard so that it covered 15 degrees. I think 1 lumen produces 1 lux under those circumstances.

    This is off the top of my head so someone correct me if I'm wrong. It's close anyway.

  14. #14

    Shrug How bright are Lumens?!?!?!?

    I would really like to know before I buy I light how bright 0.2, 5, 6, 10, 30, 60 etc. Lumes are, like could you use real life examples like how bright it would be to walk around a house or outside etc. I think you get it, thanks a ton!!

    Merged
    Last edited by Norm; 01-30-2012 at 07:06 PM.

  15. #15
    *Flashaholic* StarHalo's Avatar
    Join Date
    Dec 2007
    Location
    California Republic
    Posts
    7,384

    Default Re: How bright are Lumens?!?!?!?

    Quote Originally Posted by luketheduke8 View Post
    I would really like to know before I buy I light how bright 0.2, 5, 6, 10, 30, 60 etc. Lumes are, like could you use real life examples like how bright it would be to walk around a house or outside etc
    The problem is that your real world perception of how bright something is depends on how much light your eyes are currently acclimated to. You can't see 2 lumens at all outdoors during the day, yet with dark-adjusted eyes, 2 lumens looks as bright as you'd expect a regular, general-purpose flashlight to look.

  16. #16
    Flashaholic*
    Join Date
    Oct 2009
    Location
    Seattle,WA
    Posts
    2,470

    Default Re: How bright are Lumens?!?!?!?

    To me the spacing is as important and the lumen figures. The modes are unique enough if the spacing isn't at least x3 as in 3-10-30-90 or something like that. Having something like .2 is nice as well.

    There is no difference between 5 and 6 and little between those and 10.

  17. #17
    Flashaholic
    Join Date
    Feb 2008
    Location
    Oregon
    Posts
    402

    Default Re: How bright are Lumens?!?!?!?

    There are lots of considerations in picking a light. The three major considerations for flashlight performance are: total output, run time and how that output is distributed, the beam pattern. The post #12 by AnAppleSnail gives an example of a fixed output distributed over two different areas. For the same output, a beam focused one square inch will be very bright and spread on one square yard very dim. A laser like beam will be very bright on a small spot at a great distance, great for spotting but useless for reading a map or lighting an area. This is the "flood" versus "throw" discussion. Beam patterns range across the spectrum. Use up close favors flood, use at distance favors throw. Beam pattern can be modified using a diffuser to move from throw towards flood.

    For a given emitter, batteries and circuit, more lumens means less runtime. Two hunderd lumens with throw is great for searching at a distance, 10 lumens of flood is good for reading or looking for your shoes in a tent at night. A light that puts out two hunderd lumens might run a couple hours. The same light at 10 lumens will run a day and a half. Multiple output levels give you efficiency and usability options.

    When you select a light consider how you will use the light and what performance is most important to you. The new ANSI label gives lumens and runtime. Some manufacturers give a "throw" distance, but this doesn't adequately characterize the beam pattern.
    Last edited by mbw_151; 01-31-2012 at 03:56 PM.
    Looking for something, use a handheld. Actually doing something, you need a headlamp.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •