I Guess Lumen Specs Don't Tell the Whole Story

I am a flashlight novice, but I am confused when comparing 2 single AA flashlights I recently purchased:

1) 4Sevens Quark AA XP-G R5 edition - max lumens = 109
2) Eagle Tac D25A Clicky XM-L U2 Neutral White - max lumens = 160

With alkaline batteries, the Quark appears noticeably brighter than the D25A even though it should be the opposite based on the max lumens specs.
I see 2 differences that could account for this:

1) Cool white vs. Neutral white tint
2) Quark has a larger head diameter than the D25A

As a newbie, can someone explain the technical reasons for what I am seeing? Thanks.

It's easy.
Eagletac over promises and under delivers.
FourSevens under promises and over delivers.
I know which one I'd buy...

Colour has an effect on our eyes and may seem as though one colour is brighter than another but also keep in mind some companies out there say their light is 850 lumens when it's actually 400. They also use candella or what not which is crap in my eyes.. Certain brands are correct with the lumen value and others are not. Although I won't speak for the two lights you mentioned only from my experience on others.

Good points made above, I would also like to add:

Maybe you are comparing which light has a brighter spot?
This would be comparing lux (intesity) not brightness (overall lumens).
A simple way to compare overall brightness would be to do a ceiling bounce test.
Shine each light at the ceiling one at a time, preferably in a small room.
Then examine the surroundings not the spot on the ceiling.
How much the surroundings are illuminated will give you clearer picture of which light is brighter.

Try TD's trick.

You said the Quark has the larger head - it also has an XP-G, whereas the smaller-head D25A has an XM-L. Since the XM-L has a larger die, it needs a larger reflector to achieve the same throw (Lux.) Basically, you have a mini thrower in the Quark and a flooder in the D25. When I was just starting out, all my more throwy lights seemed brighter because of that tight, bright hotspot - but, as stated above, lumens is a measure of total light output in all directions.
Once you understand the difference between the two and where/when each works best, I think you'll be very pleased with both and worry a lot less about the lumens output.
As counterpoint to some comments above, though I haven't measured them, comparatively I have found both EagleTac and FourSevens to be pretty accurate in their output estimates and able to deliver quality lights at reasonable prices - and I really love my lights from both companies.

GPeaslee said:

I am a flashlight novice, but I am confused when comparing 2 single AA flashlights I recently purchased:

1) 4Sevens Quark AA XP-G R5 edition - max lumens = 109
2) Eagle Tac D25A Clicky XM-L U2 Neutral White - max lumens = 160

With alkaline batteries, the Quark appears noticeably brighter than the D25A even though it should be the opposite based on the max lumens specs.
I see 2 differences that could account for this:

1) Cool white vs. Neutral white tint
2) Quark has a larger head diameter than the D25A

As a newbie, can someone explain the technical reasons for what I am seeing? Thanks.

Click to expand...

+1 to what RWD13, THE_dAY and tjswarbrick posted above...
but GPeaslee, I believe you are looking at Quark's OTF lumens vs EagleTac's LED lumens, try taking a look at EagleTac's quoted OTF lumens (~100-120 lumens), combine with the reasons provided by the three members mentioned above, and you have your explanations.

Read up on the 4sevens website... They tell you the reason why their lumens are larger than (some) other companies lumens . Its like promising 100 BHP and delivering 120 WHP. That definitely sold me to their brand.

GPeaslee said:

2) Eagle Tac D25A Clicky XM-L U2 Neutral White - max lumens = 160

Click to expand...

The declared OTF lumens for Eagletac D25A Clicky XM-L neutral are 110lm not 160. Eagletac is more floody than the Quark so it will have dimmer hotspot.

Eagletac does not under deliver - if anything it over delivers on their brightness - check selfbuilt review of D25 Clicky series for numbers but in his testing the actual brightness was always higher than the manufacturer declared.

Also, there is the big "what if" of using an alcaline battery. 160lm would require at least 1.5V at the input side, meaning drawing 1A from the AA battery.

Different boost circuit designs could very well mean that for the eagletac, the battery voltage under load is not sufficient for maximum output.

To add another perspective...

When comparing flashlight beams, lumens and brightness have no direct relationship, unless everything else in the equation is identical (eg. reflector, emitter size, etc)

The beam (spot) of a 200 lumen light can appear far brighter than the beam (spot) of a 500 lumen light.

Many new enthusiasts assume high lumens = brightest because lumens is the measure that is most talked about on cpf.
Give the same two lights to a non-flashaholic and ask them which is brighter and 9 times out ouf 10, the non-flashaholic will choose the one with the brighter hotspot (and might I add that they are correct when you are asking about brightness).

If you want the brightest light, look for something with high LUX (as has been mentioned).
If you want the most volume of light, look for maximum lumens.

and then there are many lights that are in between flood/spot....

If you compare 2 lights with the same lumen output but where one is floody and one is a tight spot, the one with a tight spot will always appear to be the brightest. This misconception can sometimes be the cause of initial disappointment when buying a new light.

tgwnn

Beam hotspots are very deceptive. Point the light at the ceiling in a large room and look around the room to get a feel for the actual brightness.

In either light.. try to get "TITANIUM INNOVATIONS CR14505 CRAA 3V LITHIUM AA BATTERY" to get maximum brightness..

mossyoak said:

It's easy.
Eagletac over promises and under delivers.
FourSevens under promises and over delivers.
I know which one I'd buy...

Click to expand...

Exactly what Eagletacs that you've bought have under performed according to their specs? I've found mine to live up to their billing when comparing to other lights.

My personal testing on several eagletacs resulted with all measuring slightly higher lumens than the manufactures official numbers.

Both these flashlights are 180 lumens.


Reason the El Cheapo plastic Dorcy's hotspot is so much brighter is because it has a much bigger reflector than the Quark MiNi AA2.
The bigger reflector concentrates light better.

Right, which is why ceiling-bounce is the only way to test overall brightness without an integrating sphere or similar equipment.

Thanks to all for the explanations! Looking at the specs again, I was mixing up max lumens vs. OTF lumens. The Quark AA is 109 OTF lumens, and the Eagle Tac is 122 OTF lumens which is not a big difference. However I tried the ceiling bounce test, and the Quark still seems brighter when looking around the room. But not as much as when I had the bright spot in my field of view. If I understand correctly, the perceived difference I see is due to the beam tint and the degree of throw vs. flood. Both lights are excellent but different not in a bad way.

GPeaslee said:

Eagle Tac is 122 OTF lumens

Click to expand...

122lm is for the Cool White emitter - you have Neutral White one and according to Eagletac spec it should be 10% dimmer (Neutral White LED are always dimmer than their Cool White equivalents) than Cool White equivalent. So it's around 110lm for your Neutral White version.

And yes, color makes a difference.

Cool white also usually seems brighter than neutral or warm white, even with the exact same lumens.