I recently bought a quark 123 (R5) and an ET T20C2 MKII (R5). While testing them both out on Max, I was expecting the ET to be much brighter for some reason, but in fact it is NOT that much brighter than the Quark. ET does have a tighter hot spot so it throws a little bit further, but the spill is about the same. I think I was just expecting the ET to blow away the quark since it has 100 more OTF lumens. I guess the human eye cant tell the difference in small jumps in lumen output.:candle:
Confused about the perception of lumens.
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kramer5150
Flashaholic
A ceiling bounce or integration sphere is the only way to evaluate Lumen output. Beam patterns in the field can be very misleading.
ACRbling
Newly Enlightened
I have both the T20C2 Mkii and Quark 123*2 R5. The T20C2 is noticably brighter and throws further than my 123*2.
The Quark does have a larger hotspot also with a wider spill range. But the ET's smaller hotspot and smaller spill range is much more intense.
Do a ceiling bounce and im pretty sure you'll see the difference in output.
The Quark does have a larger hotspot also with a wider spill range. But the ET's smaller hotspot and smaller spill range is much more intense.
Do a ceiling bounce and im pretty sure you'll see the difference in output.
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I think maybe I just hyped myself up too much about the T20C2 an was expecting it to be so much brighter than the quark. One good thing about the T20 is it can stay on Max for a while before it starts getting hot. The Quark starts getting hot prety quick.
ACRbling
Newly Enlightened
yeah, i read somewhere that it took almost twice the lumens for a light to be visibly brighter to the human eye.
lets pick up a couple of sr90's!
lets pick up a couple of sr90's!
Good points here.
In my case, i have a Flashlight which is ~60 Lumens (OTF) on Medium,
and ~160 Lumens on High.
The difference between the two is quite minimal, actually.
At least in my experience, and situations.
I hardly EVER use High, since Medium is "almost" as bright,
and yet has LOTS longer runtime.
Funny, indeed, how that has worked out for me.
If i hadn't tried this out for myself, i wouldn't have Believed It !
:candle:
_
In my case, i have a Flashlight which is ~60 Lumens (OTF) on Medium,
and ~160 Lumens on High.
The difference between the two is quite minimal, actually.
At least in my experience, and situations.
I hardly EVER use High, since Medium is "almost" as bright,
and yet has LOTS longer runtime.
Funny, indeed, how that has worked out for me.
If i hadn't tried this out for myself, i wouldn't have Believed It !
:candle:
_
Jash
Flashlight Enthusiast
I've read that several times too but I think it is just plain wrong.
Why? Because my Nitecore SR3 has eight different outputs: 5, 10, 20, 40, 60, 120, 160 and 220 lumens as stated by Nitecore.
Each level is noticably brighter than the last with the most notable being the jump from 160 to 220.
The least noticable is the 120-160 jump, but it is still obvious.
I think that it is the different beam profiles making things appear as they do.
WadeF
Flashlight Enthusiast
Isn't it 4 times the lumens to look twice as bright? 100 lumens, to 400 lumens. Or 200 lumens, to 800 lumens. This is why you don't see a big difference between 200 to 300, or even 200 to 400. Sure, you can tell it is brighter, but it doesn't look twice as bright.
ACRbling
Newly Enlightened
Yeah it is very noticeable when you're ramping up the output one after another.
But if i showed you 220, then turned off the light and showed you 160, you most likely wouldn't even notice the change in output.
Depends on the distance I'm comparing them. With these lights - short to medium distance with little ambient light I'd probably be able to tell.
Of course, if the lesser light has wider spill, that larger illuminated area can throw you off in wide open spaces.
Of course, if the lesser light has wider spill, that larger illuminated area can throw you off in wide open spaces.
i don't think you understand what "noticably brighter" means in that statement. it doesn't mean a perceptable difference as you describe (which is closer to a ~10% increase), but rather a "gee, that's quite a difference"
Jash
Flashlight Enthusiast
If you notice it's brighter, then you notice it's brighter. You percieve a change in output regardless of the increase.
As in, "Oh, I notice that 160 is brighter than 120. It is noticably brighter."
Only when I go from high to turbo on the TK40 do I go "Gee, that's quite a difference."
Perhaps you wouldn't notice, but don't go telling me what my eyes do and don't percieve.
It's all about your personal perspective I guess. Obviously being a vegetarian does make your eyes better.
Moka
Enlightened
Henry of Ra Lights is who explained this to me...
As was mentioned before, it is approximately 4 times the output to appear as what we perceive as 'twice as bright'
COPIED FROM THE RALIGHTS WEBSITE... Under the FAQ, this refers to the difference in Maximum output on Ra Clicky Flashlights... But I believe it is relevant in this case...
As was mentioned before, it is approximately 4 times the output to appear as what we perceive as 'twice as bright'
COPIED FROM THE RALIGHTS WEBSITE... Under the FAQ, this refers to the difference in Maximum output on Ra Clicky Flashlights... But I believe it is relevant in this case...
No, you're not only confused, but being disingenuous.
Jash used "noticably brighter" as synonymous with "visibly brighter." You threw in the non-sequitur "perceptable" as part of your failed attempt at being pedantic.
A just noticeable difference (jnd - yes, that's a real term) for light intensity is widely accepted to be 8%. Note that this accepted scientific terminology uses "noticeable," not "perceptable."
In regard to this thread, it's widely accepted that human perception of brightness is a logarithmic function. In short, a doubling of perceived brightness would require a quadrupling of lux. There are other factors, a recent paper can be found here.
So, assuming the beam is unchanged so that lux is proportional to lumens, Jash's assertion that a change from 120-160 is noticeable fits with accepted facts. 160/120 is a 33% increase, considerably more than the accepted 8% jnd.
Swedpat
Flashlight Enthusiast
According to my personal experience it will make the demand of at least 30-50% or more brightness decrease before you suspect a brightness drop when it happens gradually. Differences of 10% or less you may not notice even with a side-by-side comparison. I find that the eyes ability to estimate brightness often is logaritmic, though not always that it needs 4 times brighter to be perceived as two times, rather usually 3 times for a perceived doubling.
Regards, Patric
Regards, Patric
Personal experience will certainly vary, but there have been many studies, done over many years, which support a logarithmic relationship and a jnd of ~8%.
For more info, google the terms "weber-fechner law," "weber fraction Teghtsoonian," and "psychophysics."
Oh, there's also the Stevens Power Law, although in the case of brightness the results are similar to Weber-Fechner.
Contrary to my earlier post, Fechner's Law actually says you need ~7.4x lux for a perceived 2x brightness. Steven's would say you need ~8.1x. My earlier post was based on assuming base 2 logs, Fechner actually stated natural logs.
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I am kind of in the same boat. I have bought a few lights over the last few weeks:
Quark Mini AA
Eagletac T20C2
Surefire LX2
JetBeam M2S
Olight SR90 - haven't had a chance to use yet
anyways, kind of always seems I am on the verge of dissapointment with my lights compared to what I was expecting when they first arrive. Started with my m2s.... it's bright, but compared to other lights, in the sub $50 price range putting out 200 lumens, it doesn't seem 'that' bright. Then today I was comparing my T20C2, rated at 300 lumens, to my LX2, rated at 200 lumens. The surefire not only has a nicer beam, but is noticeably brighter, with less lumens.
I find I need to use the lights for a few days and then go back and reevaluate my thoughts, both in brightness (lumens) and usability (beam and UI). I find the beam of the lights impacts greatly my perceived lumens.
long post short... use the T20C2 for a while and then see how you feel about it
When ramping up lights with different levels, I notice the difference too (and I love the taste of red meat Jash).
However I think we're all a little disappointed when he get a new light with 50-100% more lumens and we turn it on and find it doesn't blow away our previous light.
However one time I really notice almost any increase in output is when trying to read small writing in poorly lit areas. As you get older you have more and more reason for an EDC
However I think we're all a little disappointed when he get a new light with 50-100% more lumens and we turn it on and find it doesn't blow away our previous light.
However one time I really notice almost any increase in output is when trying to read small writing in poorly lit areas. As you get older you have more and more reason for an EDC
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gcbryan
Flashlight Enthusiast
I don't think anyone is implying that you don't notice the change when you are ramping up a light.
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