Is 65 lumens brighter than 80?

tirod

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Just got a new light off the Brown truck. What do you do? Load it up and compare it to the others. The ceilings, trees, and neighbors houses get lit up, and you stand back amazed at progress.

I fired up my new Maratac AAA with a new Energizer lithium, and dragged out the previous hot dog in my cheap collection, the Energizer Lithium AA, with the push adjusting clicky. Out on the deck, let's hope dry leaves don't catch fire!

Not so much. The Energizer, in this corner with a 65 lumen rating and donut beam, clearly washes out the 80 lumen Maratac.

Aannnnd, I already set up a showdown with a coworker against his old Rock River projector. Looks like crow is coming up on the lunch menu. At least it's all in fun.

Am I disappointed in Maratac, no. It's a great light, and clearly out performs the Microstream I've carried for two years.

The real issue: is 65 lumens brighter than 80? If you have both, check yours and see. Maybe not? I'd like to know, it's NOT a QC issue a far as I care. More like, an intro into marketing and the industry.
 

enomosiki

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You are comparing the total output of a light (lumens) versus spot intensity (candela).

With the smaller Maratac, even if it has higher lumen figures, the fact that its smaller reflector cannot focus the beam into a tighter pattern than the Energizer with its larger and deeper reflector means that the beam of the former will be more "floody", meaning that the total output from the light will be spread out more evenly and have brighter spill, whereas the Energizer will have a tighter spot.

If you still doubt the Maratac, give the ceiling bounce test a try. Go into a room with white ceiling, turn off the room light, take your light and point it up at the ceiling and activate it. Do this for each of the lights and you will notice that the background will be dimmer or brighter depending on how much total lumens your light can produce.

To put it bluntly, think of comparing a .357 to a buckshot. A buckshot might produce more total energy, but the .357 is still going to go farther down the range.
 

Jash

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Hehe... You want to be amazed at progress? Get a TK41 and compare it to a 2D maglite with an Incan bulb. Both about the same size, but the output....
 

MikeAusC

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Lumens is a measure of the TOTAL light that a source puts out - whether concentrated in a narrow spot or spread widely.

Lux is the measure of brightness at one point.
 

Lynx_Arc

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Some of it also depends on how the lumens are rated/calculated. Newer lights are rated ansi lumens which tends to use lower numbers than previously rated lights that did not adhere to this standard so a 65 lumen ansi could be brighter than an 80 lumen non ansi which could be just emitter estimated lumens also not taking into account reflector and lens losses.
 

the.Mtn.Man

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There's more light coming out the front at 80 lumens than at 65, but whether or not it appears brighter depends on a number of factors. However, even if all other things are equal, it won't appear significantly brighter since you need a 4x increase in output for a perceived doubling in brightness, so even under ideal circumstances, 80 lumens will appear only slightly brighter than 65.
 
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carrot

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I like to compare the lumens/lux to sand. If you have a bucket of sand, let's say each grain representing a single lumen, you can spread it out really thin and cover a wide area, or make a big pile. You can have a smaller bucket of sand and make a tall pile, whereas you might have a bigger bucket of sand and spread it out to a wider area. The height of the sand would translate to lux, which is represents the brightness at the brightest point (or the height of the sand you have poured out) rather than the total amount of sand you have.

In this case, you should note that 80 lumens is only 25% brighter than 65, and not likely to make a huge visible impact anyway.
 

tirod

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All good intelligent answers. I thought as much. Rather like my 170 hp Cherokee being out accelerated by a 135hp Honda Civic, it's not the numbers, it's about how they are used. And the form factor.

The Maratac is more floody, the Energizer much more a spot. The coworkers Rock River with projector lens even more so. What can be a lesson learned is just like cars, too. HP is hypemarketed, the reality is living with it's actual performance and gas mileage.

You don't drive your Wisconsin summer car in January. Not for long.
 

Kitchen Panda

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I like to compare the lumens/lux to sand. If you have a bucket of sand, let's say each grain representing a single lumen, you can spread it out really thin and cover a wide area, or make a big pile. You can have a smaller bucket of sand and make a tall pile, whereas you might have a bigger bucket of sand and spread it out to a wider area. The height of the sand would translate to lux, which is represents the brightness at the brightest point (or the height of the sand you have poured out) rather than the total amount of sand you have.

In this case, you should note that 80 lumens is only 25% brighter than 65, and not likely to make a huge visible impact anyway.

Or as I like to think of it, if someone asks "How deep is the pool?" and you say "Seven thousand gallons", you really haven't answered the question.

Playing around with multi-level lights, I was surprised that there isn't even more difference between the 0.2 lumen setting and the 90 lumen setting of an AA light - that's a 1:450 range, you'd think the 0.2 lumens would be invisible , and yet it's quite useful. Then I recall that the human eye can cope with a range of moonlight to desert sunlight and I suppose it's not that surprising; a lot of the variability in light gets cancelled out by the adaptability of the visual system.

Bill
 

carrot

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Playing around with multi-level lights, I was surprised that there isn't even more difference between the 0.2 lumen setting and the 90 lumen setting of an AA light - that's a 1:450 range, you'd think the 0.2 lumens would be invisible , and yet it's quite useful. Then I recall that the human eye can cope with a range of moonlight to desert sunlight and I suppose it's not that surprising; a lot of the variability in light gets cancelled out by the adaptability of the visual system.
Which is why I think people who make a big fuss about "fully regulated" lights are making a big deal out of nothing. Can you really tell that the output is sagging? Maybe a bit, but only when it sags a ton and the batteries are almost dead.
 

xul

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You just need a 10 vs 9 degree beam angle

80 >enter lumens
Divide by 4Pi to get candlepower in all directions, CPALL.
6.4 =CPALL
If you have lamp cp in all directions CPALL and you know beam angle BA
then the multiplier to find beam cp BECP is
MULT
so CPALL x MULT = BECP
a = sin(BA/2), b = sqrt(4-4(a^2)),
then MULT = 4/(2-b)
then CPALL x MULT = BECP
6.4 >enter CPALL
10 >enter BA in degrees
0.087155743 =calc'd a
1.992389396 =calc'd b
525.5824763 =calc'd MULT
3346 =calc'd BECP

for 65 at 9 degrees it's
3356 =calc'd BECP
 
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speedsix

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You don't really believe this nonsense, do you? Clearly Cpat=432 +\- a factor of .06 yet you seem to claim with your calculations a bias to positive live figures. That is impossible and it makes me very agitated.


You just need a 10 vs 9 degree beam angle

80 >enter lumens
Divide by 4Pi to get candlepower in all directions, CPALL.
6.4 =CPALL
If you have lamp cp in all directions CPALL and you know beam angle BA
then the multiplier to find beam cp BECP is
MULT
so CPALL x MULT = BECP
a = sin(BA/2), b = sqrt(4-4(a^2)),
then MULT = 4/(2-b)
then CPALL x MULT = BECP
6.4 >enter CPALL
10 >enter BA in degrees
0.087155743 =calc'd a
1.992389396 =calc'd b
525.5824763 =calc'd MULT
3346 =calc'd BECP

for 65 at 9 degrees it's
3356 =calc'd BECP
 

xul

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You don't really believe this nonsense, do you? Clearly Cpat=432 +\- a factor of .06 yet you seem to claim with your calculations a bias to positive live figures. That is impossible and it makes me very agitated.
I'll need a tutorial on Cpat.

My spreadsheet is based only on geometry; the surface area of sphere vs. that of a spherical cap. It corresponds very closely with two examples from the Web but gives me 9 MCP vs. Maxabeam's spec'd 12 MCP. This last one is puzzling because if there are losses my spreadsheet should overstate, not understate, the CP.
 
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Swedpat

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Which is why I think people who make a big fuss about "fully regulated" lights are making a big deal out of nothing. Can you really tell that the output is sagging? Maybe a bit, but only when it sags a ton and the batteries are almost dead.

You have a point here! While a 10% drop can be noticed by the eye if it occurs instantly(though it's very subtle), a 30% drop often will not be noticed if it occurs slowly during half a minute or so. In some cases I think it demands a 50% drop before we suspect: "hmmm...isn't it dimmer now?". Therefore I use to use the expression "practically stable output".
Before the output has dropped to ~75% of the initial I consider it as stable output.

Also a declining brightness is harder to notice with LEDs because the color temperature doesn't drop with the brightness in the same degree it does with incans.
 
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xul

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For incands a 10% drop in V to 90% [.9] gives you a drop in brightness down to 100 x (0.9^3.5)= 70%, a 30% drop.
 

bob4apple

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My understanding of this thread is inversely proportional to the volume of mathematic
formulas used to determine an understandable answer- understand? :confused:
 

Bullzeyebill

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bobforapple, don't be too confused. The simple answer is with the same flashlight, same emitter or bulb, battery, electrics, reflector, etc, one putting out 65 lumens and the other 80, you will not really notice the difference.

Bill
 

bob4apple

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Now, sure, Bill, that I understand, but I think the original poster of the question
may now regret having asked it. :banghead:
 

TyJo

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nickdolin

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This thread points to the same thing I noticed in a couple of my lights....

M1X= 700 (emitter lumens) with a thrower head
P-Rocket (810 emitter lumens) with an Xm-L and a much smaller head....

The M1X's beam looks brighter and throws farther but like has been said before... it is a more condensed beam that doesn't offer as much total light. Up close...say wall hunting... the M1X looks brighter.... taken outside the total light in a dark night the light difference isn't nearly as great as the XM-L not only has decent throw but a very bright spill and a huge hotspot while the M1X has a tighter/dimmer beam with a more intense smaller hotspot. Overall the P-Rocket is putting out more light but over a wider area. AN extreme example is when I take off the head of the P-Rocket outside and put it on high.... an amazing wall of light the size of the complete 120 degree viewing angle...it's quite amazing actually... but again there is no throw at all as the beam has no focus but it will light up a complete 50ft radius around you...almost like a streetlight kind of thing but the beam won't go far....but it's still 800 lumens.
 
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