FL's higher & higher Lumens, throw further & further, how far can you actually SEE?

[RWeis]

FL's higher & higher Lumens, throw further & further, how far can you actually SEE?

Just bought my first FL (TN31 XM-L2 U2).

Lots of throw, love it. I think it throws further than I can reasonably see clearly. I see FL's throwing further and further, more and more lumens, but isn't there a point that generates diminishing practical visual returns?

Where do you think that point is?

Of course there are flooders and throwers and combinations of the two, but there must be a point that additional lumens really will be of little use (other than bragging rights).

I see more and more multiple emitter bigger lights, other than weight what are we gaining?

I can see more modes maybe, simplier UI's, better run time efficiency, better design, better price point (talk about subjective), but higher and higher Lumens seem to be counter productive to me, but I qualify that in that I am a NG (new guy).

Is really what we are after is the ideal FL (modes, design, UI, efficiency, price) for you specifically?

Bob Weis

 

[reppans]

FL's higher & higher Lumens, throw further & further, how far can you actually

Light, lumens, and brightness perception seem to be generally subject the common physics square/square root laws, and economic laws of diminishing returns. I'm not an expert, but from my understanding, doubling distance means one fourth the lux, and quadrupling lumens will only appear about twice as bright to our eyes. However, the battery power required is closer to a linear equation - it's similar the sq/sq rt laws for wind force which where many cars can hit 100 mph, yet it takes about 4x the horsepower, and fuel, to hit 200 mph.

I like the laws of increasing gains and pursue dimmer lights with long runtimes for a given battery. The fact that our pupils dilate and eyes gain rhodopsin (for night vision) just seems to be another freebee on top of the sq/sq rt physics thing above.

Having said all that, the perpetual lumens/throw arms race is will always be a good thing and insure constant improvement in efficiency and effectiveness for everyone.

 

[AnAppleSnail]

Re: FL's higher & higher Lumens, throw further & further, how far can you actually SE

I see a future of near-heatsinkless LEDs powered by a AA-sized cell, mounted in baseball caps for use by workers. A living hinge in the brim allows precise pointing, and a smart-brightness system like the Nite-something and Petzl SENS system that can be overridden when needed. There are definite ends to the throw race. Fog, backscatter, and other things limit the practical reach of a light as much as human vision does.

 

[Swede74]

Re: FL's higher & higher Lumens, throw further & further, how far can you actually SE

I could be wrong, but I think that due to the curvature of the earth, the furthest you can see if your eyes are 1.7 m above the ground is 5 km. You don't want to accidentally blind yourself with a light capable of throwing that far:duck:

 

[AnAppleSnail]

Re: FL's higher & higher Lumens, throw further & further, how far can you actually SE

I could be wrong, but I think that due to the curvature of the earth, the furthest you can see if your eyes are 1.7 m above the ground is 5 km. You don't want to accidentally blind yourself with a light capable of throwing that far:duck:

It depends on what you're looking at. I can see mountains from 80 km away if they are quite high and it's a clear day.

 

[Swede74]

It depends on what you're looking at. I can see mountains from 80 km away if they are quite high and it's a clear day.

True, I should have said the horizon is 5 km away if your eyes are 1.7 m above sea level.

 

[Rexlion]

Re: FL's higher & higher Lumens, throw further & further, how far can you actually SE

I am heading to Yosemite this summer and plan to be at Glacier Point at night. I was thinking how fun it would be to have a thrower that could reach the valley floor, 3000 feet below. But then like you, I thought: even if I bought a DEFT-X, would I even be able to see what the beam was shining on at that distance? I doubt it! Even if I could make out the bright spot way down there, I could not see any details anyway.

So I'll take my TK70 just because I have it already, but I have no expectations for it and I'm not buying anything with more throw.

 

[ledmitter_nli]

Re: FL's higher & higher Lumens, throw further & further, how far can you actually SE

I've touched on this in a previous debate regarding the Polarion HID.

"A high output LED light that can achieve say 3/4 the luminous output of a Polarion HID and throw to 550 yards (as far as the naked eye can see) will accomplish 90% of the illumination ground work that a Polarion can. Cleaner beam, multiple output levels, better heat management, and cost about $1,800.00 less -- to-boot..."

Anything more and you're wasting lumens washing everything out.

 

[TEEJ]

Re: FL's higher & higher Lumens, throw further & further, how far can you actually SE

One thing I see again and again is that people seem to think a light that throws to a given MAXIMUM range as per ANSI's 0.25 lux standard is only for seeing AT that range.

Think of it this way instead: A VERY dark day, overcast and raining leaves the ground illuminated at ~ 90 - 100 lux. No one I know would argue that THAT is when they see best at a distance. Most people see best at a distance in broad daylight, which means closer to 5,000 - 10,000 lux on the ground.


So, lets say with our relatively adjusted night vision, that a really dark day would be an acceptable target for equivalent illumination by flashlight. IE: Use 100 lux on target as the objective.

If you want to see something 300 meters away with 100 lux on target, you'd need a light with ~ 9,000,000 cd (9 Million cd).


Right now, we don't have ANY "flashlights" that are rated at 9 MILLION cd, its just way beyond the current technology.


The DEFT-X for example, is rated at 900,000 cd, almost 1 million cd, but, not quite there (yet).

That will get us ~ 10 lux on target at 300 meters, a very respectable figure, albeit no one would say 10 lux is sending steaming melted eyeball lava running down cheeks 300 meters away, etc.


If you use the ANSI standard of 0.25 lux, we get closer to a range of 1.9k meters (~1.9 kilometers, or ~ 1.18 MILES)


The point is that a light that can REACH a given range will be BRIGHTER at any given range between that, and the light.



So, don't focus on the maximum range quoted for any given light, focus on what you will see at YOUR OWN ranges of concern.

 

[AnAppleSnail]

Re: FL's higher & higher Lumens, throw further & further, how far can you actually SE

I actually cut the ANSI quoted 'range' spec by 3 or 4 to get the 'glimpse things at night' distance for many situations. So the "388m" MagLED 2D is useful to 130m or so... On a clear night, with few obstructions, no fog, and non-dark-adapted eyes. A 'general' sort of setting. I could probably spot a white T-shirt in a field at greater distance, but wouldn't see downed power lines until more like 30m. Cut these values further for fog, smoke, or rain of course.

 

[2xTrinity]

Re: FL's higher & higher Lumens, throw further & further, how far can you actually

Light, lumens, and brightness perception seem to be generally subject the common physics square/square root laws, and economic laws of diminishing returns. I'm not an expert, but from my understanding, doubling distance means one fourth the lux, and quadrupling lumens will only appear about twice as bright to our eyes. However, the battery power required is closer to a linear equation - it's similar the sq/sq rt laws for wind force which where many cars can hit 100 mph, yet it takes about 4x the horsepower, and fuel, to hit 200 mph.

It's actually proprtional to the cube. It takes 8x the power to go double the speed (assuming air resistance dominates, which it does at 100mph+)

Drag force is proportional to the square of the velocity. Power to overcome drag is drag force (work per unit length) times velocity (length traveled / time) again.

 

[eksiray]

Re: FL's higher & higher Lumens, throw further & further, how far can you actually

One thing you can do with lots of lumens is light up a room with indirect light. I have a few "really bright" lights, and I can point one up to the ceiling to flood the whole room. Also useful in theater, where you may need to spot something on a truss that is above the theatrical lights, so lights in your eyes and a very dark target beyond them, can be solved with a punchy light.