Lumens in the real world

[jabbaj]

Hi, I'm new to the flashlight world and have been browsing round and searching the forum for the past few days.

Have found a number of lights which sound interesting to me and have been comparing lights runtime/outputs etc so much and the wife called me sad!

Main applications of this light would just be general usage for power outages, outside repairs/searching and potentially as a bike light - nothing too specialist.

Thing is, its all pretty irrelevant as i dont know how much light in terms of lumens specified i need.
All i have managed to find here has been based on absolute figures but I am looking for some sort of baseline figure i can use to plan what sort of levels I actually DO need.

As far as I know 10 lumens could be enough to 'light up a room' or it just might be enough to keep myself from breaking my neck trying to traverse a room in the dark.

Can anyone give some rough ideas about real world levels of light?
eg
a single candle = x lumens with a diffuser
TV on in an otherwise darkened room
candle mode with diffuser - level to comfortably read from a metre or two away
Level of light from say 2-3m to light up the beam area to the the same degree as normal house lighting
good cycling visibility.
etc

Mainly this is from the point of view of a small EDC size torch but I have also seen the following of cheap torches such as the husky, wondered if there were any UK equivalents to these.
Obviously that one would not be an EDC but potential for very long runtimes at higher light levels is handy for the power outages etc

Thanks in advance for advice to yet another newbie.

 

[Sgt. LED]

15 will handle most general indoor illumination needs.

80 can tackle just about anything in real world use.


The rest of it is mainly for fun. I think you would be very pleased with an EX10 myself. 4sevens.com has free shipping too!

Find a different light for your bicycle though! For that I'd reccomend something with more throw.

 

[Marduke]

15 will handle most general indoor illumination needs.

80 can tackle just about anything in real world use.

+1
That's about it.

~5-10 is enough in darkness, and keep you from tripping over things.
~10-20 is plenty for most indoor tasks
>=60-80 is plenty for most real world outdoor use

 

[Stromberg]

a single candle = x lumens with a diffuser ?

I would like to know that too. Does anybody know actual measured lumen amount of typical candle?:candle:

Ps. Nitecore D20 is advertised to have 2 lumens on MIN, which is more than enough for indoor "navigation" when my eyes are adjusted to darkness. In fact, even the green display backlight in my old 3330 Nokia gives just the adequate amount of light for avoiding obstacles in perfectly dark room. And I have no idea of how little that is, but I'm guessing it's much less than what full moon casts in certain area.

 

[StarHalo]

Some comparisons:

A button-cell keychain LED light is ~5 lumens.
A MiniMag is ~10 lumens.
A candle is ~13 lumens.
A 3 D Cell Maglite is ~80 lumens.
A 60 watt household lightbulb is ~800 lumens.

The 15 indoor, 80 outdoor/general rule is very good, however for cycling you'll want something more; A good cycling light needs a wide spillbeam with a broad hotspot, high output with as much efficiency as possible. Most bike enthusiasts here prefer the Fenix L2D, as it has a nicely balanced beam profile, can output 180 lumens for two hours (or 15 lumens for three days), and uses standard AA batteries, which allows rechargeable use.

 

[Gunner12]

15 lumen or less is fine for indoor, 40 lumen or more is great for outdoor.

Your typical 2D light is 15 lumen.

Also remember that lumen is just how much output, not how well it is concentrated. A 1 lumen light can project further then a 100 lumen one if the 1 lumen light has a pencil beam and the 100 lumen light is pure flood.

 

[Jarl]

Some comparisons:

A button-cell keychain LED light is ~5 lumens.
A MiniMag is ~10 lumens.
A candle is ~13 lumens.
A 3 D Cell Maglite is ~80 lumens.
A 60 watt household lightbulb is ~800 lumens.

The 15 indoor, 80 outdoor/general rule is very good, however for cycling you'll want something more; A good cycling light needs a wide spillbeam with a broad hotspot, high output with as much efficiency as possible. Most bike enthusiasts here prefer the Fenix L2D, as it has a nicely balanced beam profile, can output 180 lumens for two hours (or 15 lumens for three days), and uses standard AA batteries, which allows rechargeable use.

Bear in mind that the minimag/3D cell is 10/80 lumens for the first couple of minutes runtime, quickly dropping down. (i.e, mag solitaire: 11 minutes to 50%... ouch).

An L2D is adequate for riding dark country lanes. If you're doing real MTBing, then you'll be needing 500 lumens at least. A P7 light with a helmet mounted thrower* is a good combination.

* I say thrower, something in the region of 10K lux (TK11) works well for me, not a DBS or spear! I did use an L2D as a helmet light, didn't quite have enough throw for me.

 

[jabbaj]

Thanks alot for the fast answers folks.
Good to see around 80 is most really needed apart from cycling as that keeps all the nice lights i looked at as options

The EX10 is indeed nice looking (and thats without switching on!) although I think I'd go for the D10 for easy batteries.
Think if going for cr123s I'd accept the greater bulk and 'bang per buck' although lesser looks of a p3d.
This is definitely the top end of my budget for a light though and probably over :naughty:

Just checking that i am getting this right about the candle and bulb...The perceived brightness at any point around the flashlight using diffuser is about the same as a candle if the flashlight is rated as 13 or so lumens? Which would mean that when taking the diffuser off for something specific indoors it would appear alot brighter? (making e01 a decent backup)

Any ideas of a rough figure for lumens with a diffuser to be able to read by? (this would be the min level of light I'd like in a power failure ideally)

 

[Sgt. LED]

8
For me anyway.

 

[Illum]

For general tasks it doesn't matter if your light is 30 lumens or 300 lumens, you can accomplish the task without too much hassle

real world applications aren't as consistently performed where a specific lumen rating would perform best. In pitch black conditions, you've got two options: light or no light.

Put down the surefire hat, step away from the fenix banner...my opinion would be to disregard all lumen ratings and stick with the ergonomics like user interface, etc.

 

[Sgt. LED]

But I like my Surefire hat!

I actually have one................

 

[StarHalo]

The perceived brightness at any point around the flashlight using diffuser is about the same as a candle if the flashlight is rated as 13 or so lumens?

No, anytime you shine your flashlight through a medium (this includes the lens of the flashlight itself) there is loss. There's probably a specific percentage of light loss through your diffuser, and you'll have to up the output of the flashlight that same percentage to maintain the same lumen number with the diffuser on. But this is all nitpicking - when you're in the dark, you won't care much if you're looking at a diffuse 10 lumens or a lensed 15 lumens.

Which would mean that when taking the diffuser off for something specific indoors it would appear alot brighter?

Correct.

Any ideas of a rough figure for lumens with a diffuser to be able to read by? (this would be the min level of light I'd like in a power failure ideally)

If you're going for max runtime, skip the diffuser and just read with the light as-is (it's difficult to read with a diffuser anyway, because it's shining in your eyes more than it's illuminating the page). If you really want a good light to read with that will give you huge runtime, look for a model that has a removable head/reflector assembly for bare emitter lighting. These are ideal for reading in the dark because the light is very smooth and even, shines only in a 180 degree radius (not in your face), and since there's nothing blocking the emitter, you can have the output set extremely low. My personal favorite the JetBeam Jet II IBS can do this, as can the Lumapower Incendio.

 

[metawaffle]

I had a power failure a few days ago (and I didn't cause it just to bring out all the lights, like a friend implied). By far the nicest light to actually do anything by, including read, was my ZebraLight H50, with it's ultra-smooth, ultra-diffuse light.

Granted it was fun to walk around the dark neighbourhood with JetBeams and such, but from a practical point of view, there was no going past the Zebra.

 

[Jarl]

No, anytime you shine your flashlight through a medium (this includes the lens of the flashlight itself) there is loss. There's probably a specific percentage of light loss through your diffuser, and you'll have to up the output of the flashlight that same percentage to maintain the same lumen number with the diffuser on. But this is all nitpicking - when you're in the dark, you won't care much if you're looking at a diffuse 10 lumens or a lensed 15 lumens.



Correct.



If you're going for max runtime, skip the diffuser and just read with the light as-is (it's difficult to read with a diffuser anyway, because it's shining in your eyes more than it's illuminating the page). If you really want a good light to read with that will give you huge runtime, look for a model that has a removable head/reflector assembly for bare emitter lighting. These are ideal for reading in the dark because the light is very smooth and even, shines only in a 180 degree radius (not in your face), and since there's nothing blocking the emitter, you can have the output set extremely low. My personal favorite the JetBeam Jet II IBS can do this, as can the Lumapower Incendio.

Or there are the H30/H50 zebralights, which are also headlights so much easier to read with, and will be perfectly adequate for reading with.

 

[brighterisbetter]

This is definitely the top end of my budget for a light though and probably over :naughty:

You say that now, but give it a few weeks and you'll be hopelessly addicted

 

[bullfrog]

Amazingly informative thread - thanks guys!

 

[Double_A]

Since Maglite seem to be a reference non-flashaholics use,,, here is some info from Maglite themselves....

Incandescent Mini-Mag is 15 lumens http://www.maglite.com/lampspecs_aa.asp

C/D Maglite lamp specs are here http://www.maglite.com/lampspecs_dcell.asp

Careful though! These C/D lamp specs are not for the standard factory included lamp. These are replacement hi-intensity lamps advertised as "twice" as bright.

Also the run-time is deceptive. If you contact Maglite as I did a few years ago and ask about brightness and runtime Maglite admits with fresh quality batteries light output will drop to HALF-50% in approx 30mins.

 

[Patriot]

Put down the surefire hat, step away from the fenix banner...my opinion would be to disregard all lumen ratings and stick with the ergonomics like user interface, etc.

...sounds funny at first but that's actually some really good advice. In practical terms it really doesn't matter what the output is as long as it allows you to accomplish your task. Ergonomics and user interface are great places to begin a selection process.

 

[Double_A]

Also remember that lumen is just how much output, not how well it is concentrated. A 1 lumen light can project further then a 100 lumen one if the 1 lumen light has a pencil beam and the 100 lumen light is pure flood.

VERY true!

If you want a light that has an excellent runtime and will throw a 300 yards, get a laser pointer. It has super Candelpower and minimal lumens.

One more thing...... THERE IS NO MATH FORMULA TO CONVERT CANDLEPOWER TO LUMENS......

 

[Woods Walker]

In the dark, dank and spooky woods all lumens seem more.