# How many lumens do you need for a good led flashlight?



## emylieadam (Apr 29, 2018)

[h=1]How many lumens do you need for a good led flashlight?[/h]

Lumen is a measure of a LED light output. If you have ever purchased an LED flashlight. In a simple explanation, lumens equate to a the brightness of light, and while that’s not entirely true. But remember, the bigger the number of lumens, the brighter the light will be. So, how many lumens do we need for a specific task?


*10-20 Lumens *
Close up tasks: Searching for things up to 100 meters distance
*20-150 Lumens *
Basic household and outdoor activities: Searching for things up to 120 meters distance
*160-200 Lumens*
Activities like camping, hiking; Household use, Tactical tasks and Security: Cover distances up to 250 meters
*200-500 Lumens*
Sailing, Fishing, Climbing, Hiking, Hunting, Work Place, Tactical Tasks
*600-1000 Lumens*
Industrial Uses, Fishing, Caving, Hiking, Hunting, Camping, covers distance up to 300 meters.
*>1000 Lumens*
Best for recreational activities in large property, Outdoor lighting, Search & rescue, or Hunting


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## bykfixer (Apr 29, 2018)

Good first post.

Welcome aboard.

These days with the help of computers the manufacturers can tailor beams to provide a lot of WOW without having to place huge amounts of output. Or they can make big output become much easier on the eyes at intial output.

350-650 were my pinacle. Coupled with a low of 15-25.


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## parametrek (Apr 29, 2018)

Out of curiosity what do you do for a living? You don't happen to write for BrightBestLight perhaps?


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## FREI (Apr 29, 2018)

My EDC´s are in the range of 80-400lm max. My brightes lights ar in the range of 500-600lm.


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## Hugh Johnson (Apr 29, 2018)

Indoors: I almost never need more than 3 lumens at home. Lots of sublumen use. 

Hiking: 200-500 preferred. Less would usually be adequate. 

Camping: mostly under 50. 

And yet, I'm getting more powerful lights.


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## peter yetman (Apr 29, 2018)

emylieadam said:


> *>1000 Lumens*
> 
> 
> Best for recreational activities in large property, Outdoor lighting, Search & rescue, or Hunting


And Willy Waving.
P


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## bykfixer (Apr 29, 2018)

peter yetman said:


> And Willy Waving.
> P



Or saying "hello" to folks on the space station....


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## peter yetman (Apr 29, 2018)

Now I've got a very strange image in my head.
A bit like Robin Williams and Jeff Bridges cloudbusting at the end of The Fisher King.
Haha!
P


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## idleprocess (Apr 29, 2018)

Light distribution will play a big role in how many lumens a specific task demands.

Let's use two similar-ish modern flashlights - Emisar D4 and D1S; I happen to both own. The D4 has _four_ XP-L HI LEDs behind a quad optic rated at a maximum ~4300 initial lumens. The D1S has a single XP-L HI LED behind a wide/deep reflector rated at ~1300 initial lumens. The D4 is 'directional flood' that's great for task work - I use mine to walk the dogs all the time - and can reach out to ~100m or so through *sheer brute force*. The D1S puts out a pencil beam by comparison that's terrible for task work but will light up anything within ~1000m : street signs, water towers, airliners directly overhead on approach to the airport a few miles away.

No, the lumen - much like peak candlepower - is not terribly useful _of itself_ without context. If we had a standard set of optics with different-intensity light sources with otherwise-identical radiation patterns we could decide which lumen level is sufficient for a number of circumstances.

*Lux* is a useful unit, but a bit harder to determine since it's use case specific, although with a given system one can approximate lux at given range. I recall a few standard metrics that determine throw as the maximum distance that can achieve 1 lux.


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## spaceminions (Apr 29, 2018)

I know this comes directly from brightbestlight, but come on; does anyone here use 20 lumens when you're looking for something 300ft away? Because if so... why? Personally, I like to have a wide enough spot that A) the reflector isn't required to be as huge and B) I can actually cover some area instead of scanning a tiny circle across the entire open area. I've used a q8 on turbo at that distance, because it covers the area excellently, though I'd use an actual thrower if I was going to need it for more than a few minutes.


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## degarb (Apr 29, 2018)

First, you have permissible forms factor, which leads to maximum permissible battery. Then, there is minimum runtime/ideal runtime. LPW and optic matters, as well as understanding the cells in the eye, so that light is not wasted.

LEDs and battery technology is not truly advanced enough to match daylight outside with any practical runtime or circuit draw on household breaker. 

So, I feel very strongly-else, I would not bother posting - that we are about 1/8th, technologically, from getting enough light (flashlight or led work light) that is in a practical format factor, doesn't get hot, and is optimally bright enough.

So, these numbers are meaningless because, 1. Runtime is far more important than lumens, as a dead light is rather dim, and changing cells cost money and safety. 2. Lux and optimal beam pattern mean I can get a equal or brighter, more useful beam from a 400 lumen 35 mm reflector, than a 900 lumen op 20 mm flashlight. But form factor means that the 20 mm light fits in pocket with little bulge, while I use the 35 mm for a 2s18650 rear pack buck, that can go 1 to 2 days between battery swaps. My emergency 20 mm convoy can only go 1h45 minutes before overheating, while I can get over 4 hours from my Imalent hr20... Had to make my own work head lamps, since manufactures like to overdrive, to appeal wow lumen specs. 4k lux at 1m for 10 hours is my minimal headlamp spec., working 90% 1 to 2 meter distant inspection. The xrc could do that on a paltry 2 aa battery tube, but Hotspot was too narrow to cover enough eye cone vision. 

Though, on a corded worklight to match the typical working lux of my headlamps, I desire 80k lumens, minimum, light necessary per 12 x14 room. A $130 metal halide can to it at 600 watts. Waiting for the led lights to catch up. And cost does matter... We cannot lose sight that halogen cost $8 per 10k lumens. So, once a 200lpw 300w led is released, along with a $20 driver (in lieu of the $300 500 watt driver), maybe the heat sink won't cost my left nut.

But, I assume this thread is more for entertainment, to get various opinions. 

So, for example, I learned a few years ago, that a jogging headlamp could not be a small ball of light, probably at least 1000 lumens and plastic, which is problem as anything over 560 ma creates exponentially more heat, even in an xpl v6, meaning more metal and more weight. So, occasionally, someone will list all the factors that come into relevance, and educate : weight, forming factor, runtime, heat, optic, lux, and thus, lumens.

So, for a work headlamp, you could squeek by at 200 lumen and an 8 degree Hotspot on one 18650 for a workday of 10 hours,with typical crews of several workers. 1 watt cc to led. But the eye cones, detail vision, cover 15 degrees. So, 12 degree Hotspot using a 35 mm smooth around a xpl v6 373 lumens at 700 ma to led is what I was able to achieve, using 2s18650 and a 90% efficient switching buck driver, with infinity variable down from the 350ma max draw per 3400 mah protected Panasonic cell. I could probably go many many times brighter before optically washing out, as on a bright outdoor day. Had I had more lumens I would widen the optic, until Hotspot as wide as my shoulders (light on top of my head), shining on the ground. And spill 120 degrees. But, everything is exponential in lighting. So, there are still practical limits....

On one hand, the nonflashaholic does not know what is possible. On the other hand, most flashaholics act like alcoholics, and throw the limits into the wind.

Color equals cri+gai+luminance. Not so simple. Additionally, Kelvin and cri really depends on which colors you are trying to see. Example, if you are looking for mold on tree bark, a cold color is better. Same with dry skin. ... I have rejected lights for objections to their color rendering, but still feel too cagey to declare any one light as the ultimate and perfect color, in all situations... And I have been searching for decades, still haven't found what I'm looking for.


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## richbuff (Apr 29, 2018)

Topic is copied/pasted from out there, brightbestlight.com/led-flashlight-bulb-selection-guide/, as already astutely noted, but here goes: >10,000 lumens in a power thrower, such as the inimitable X65.

5,000 lumens: thrower , CFT-90 in BLF GTvn is on my Next List. 

>20,000 lumens, in a flooder, such as the X45. For flooders, more power is better, so the X70 at 40,000 lumens is next for me. 

10-1,000 lumens, best for routine use. 


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Sometimes, bots open interesting topics.


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## e1000 (Apr 29, 2018)

How many lumens you got?!!!! I hike wearing a welding helmet, doesn't everyone around here?


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## StarHalo (Apr 29, 2018)

degarb said:


> I desire 80k lumens, minimum, light necessary per 12 x14 room.



Well that explains your insomnia problem..


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## LeanBurn (Apr 30, 2018)

Hugh Johnson said:


> Indoors: I almost never need more than 3 lumens at home. Lots of sublumen use.
> Hiking: 200-500 preferred. Less would usually be adequate.
> Camping: mostly under 50.
> And yet, I'm getting more powerful lights.



Ditto for me...except I won't be getting more powerful lights.


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## archimedes (Apr 30, 2018)

This thread has been shambling all over the place.

Text copied from elsewhere, started in the wrong subforum, duplicative of other (more relevant) threads, off-topic (and off-color) posts, but wait there's more .... :duh2:

No, actually there isn't. I've closed it


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