L1D: 90 lumen no different than 80 lumen?

fredb · Feb 7, 2007

Yesterday I received my shiny new L1D and it's a pretty keen little light!

After playing around with it for a bit I noticed that the 90 lumen mode is not visually different than the 80 lumen mode. What I've been doing is setting the light to the 80 lumen mode and then twisting the head tight to switch it into turbo mode, but I don't see any change whatsoever.

Is anybody else's doing this?

Ty_Bower · Feb 7, 2007

I don't own one, but I'm not surprised by what you say. There is little to no visual difference between 80 lumens and 90 lumens. Our eyes perceive brightness in a logarithmic way. In order for one light source to appear noticeably brighter than another, it really needs to put out about 40% more lumens.

You would probably notice a difference between 80 lumens and ~110 lumens (80 * 140%), but the difference would be slight. You would definitely notice a difference between 80 lumens and 160 lumens (80 * 140% * 140%), but don't expect the 160 lumens to be twice as bright as the 80 lumens. It's like the difference between turning the volume knob on the stereo between 3 and 4.

hsjrev · Feb 7, 2007

I checked it with a luxmeter and there's very little difference on an alkaline battery. It's pretty significant with a fresh NiMH or a lithium AA though. I guess it takes more than 1.5v to get much out of the turbo mode.

Badbeams3 · Feb 7, 2007

I wonder if there is a diff in run time?

fredb · Feb 7, 2007

hsjrev said:
I checked it with a luxmeter and there's very little difference on an alkaline battery. It's pretty significant with a fresh NiMH or a lithium AA though. I guess it takes more than 1.5v to get much out of the turbo mode.

Well drat. I'm using a lithium AA and don't see a difference at all.

Ty_Bower · Feb 7, 2007

You need one of those AA sized 3 volt primary lithium cells.
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1617

edit: Oops! this cell is not suitable for high drain devices.

thiswayup · Feb 7, 2007

Ty_Bower said:
I don't own one, but I'm not surprised by what you say. There is little to no visual difference between 80 lumens and 90 lumens. Our eyes perceive brightness in a logarithmic way. In order for one light source to appear noticeably brighter than another, it really needs to put out about 40% more lumens.

You would probably notice a difference between 80 lumens and ~110 lumens (80 * 140%), but the difference would be slight. You would definitely notice a difference between 80 lumens and 160 lumens (80 * 140% * 140%), but don't expect the 160 lumens to be twice as bright as the 80 lumens. It's like the difference between turning the volume knob on the stereo between 3 and 4.

Arguably the situation is worse than that: you have to allow for a 4th root in the amount of light being returned to you from the object, unless the object is something like a mirror.

jhawkins1 · Feb 7, 2007

These appear to be for low drain devices, if you look at the specs. Not sure they would be good for a flashlight.

Pulse capability: Typically up to 200 mA
Max. Continuous current: 100mA Max

Ty_Bower said:
You need one of those AA sized 3 volt primary lithium cells.
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1617

Ty_Bower · Feb 7, 2007

Good point, jhawkins. Thanks for noticing that. There are 3v AA cells that are good, aren't there? Didn't people used to split some Duracell camera batteries in half to get two 3 volt lithium cells out of them? I can't remember the model number...

tebore · Feb 7, 2007

Battery won't make a huge difference you need a ~2x increase to notice something is brighter. A good way is using the HDS way take your current lumen level and multiply it by root 2 to get the next amount of lumens to seem brighter.

Ty_Bower · Feb 7, 2007

Ah, here it is:
http://candlepowerforums.com/vb/showpost.php?p=1836755&postcount=95

Break apart a CR-V3 cell to get two 3 volt AA sized lithiums. And yes, a 3 volt battery will make a noticable difference. Just look at the beam shots comparing the L1D-CE to the L2D-CE.

Hondo · Feb 7, 2007

Yes, when hooked up to the 2xAA tube, the turbo level is no doubt pouring out a lot more light than high. Unless you get a ~3v single cell, or 123 tube (not available yet), the only real advantage of this setting on the L1D is for those who want the light to come on directly in the brightest mode. So, still can be usefull for some. A 3.7v 14500 Li-Ion will get the turbo brightness, but when anywhere near full charge won't regulate down to the lower modes. I am anxiously awaiting both the 123 tubes and a 3.0v AA Li-Ion cell, those will give me L1D size with L2D performance, less the runtime, of course.

Hondo

Raptor# · Feb 7, 2007

I guessed we're going to see the first post going in this direction soon... (http://candlepowerforums.com/vb/showthread.php?t=149536)

fredb · Feb 7, 2007

OK, I improvised a rig for measuring brightness (photocell, multimeter, and a vice arranged in a horrifyingly non-scientific manner) and, yes, the 90 lumen mode (turbo) is indeed brighter, albeit not by much. I also noticed that the AA isn't able to maintain turbo very long and the additional brightness drops very quickly.

This leads my to believe that everything is working correctly. Now all I have to do is sit tight and wait for a CR123 body to appear...

Thanks to everyone for your input!

mchlwise · Feb 7, 2007

I can see a difference.

:shrug:

mchlwise · Feb 7, 2007

double post caused by server problems

:knight:

It's my first one, though! :buddies:

alvdll · Feb 7, 2007

Used Energizer e2 lithium battery on my L1D, I cannot see the difference btw the 80 & 90 lumens. I swapped out the battery with a Panasonic Oxyride battery, I could observed an increase in brightness from 80 to 90 lumens by twisting the bezel from general mode to turbo.

HarveyRich · Feb 8, 2007

Originally posted by Tebore: Battery won't make a huge difference you need a ~2x increase to notice something is brighter. A good way is using the HDS way take your current lumen level and multiply it by root 2 to get the next amount of lumens to seem brighter

Agreed and I agree with the 40% difference posted earlier. I have both a 2AA minmag led and 3AA minmag led. The posted lumens for each were 34 and 51 respectively ( 50% difference), by Flashlight Reviews, if memory serves. My eyes perceive a clear difference in brightness in a wall test and a definite difference in brightness in throw at a distance. The 3AA version is definitely brighter.

PB92 · Feb 8, 2007

Ty Bower, I received an email response from Batteryspace and they claim that as long as the voltage is correct, the 3v primary AA lithium cells you mentioned are ok for our applications, someone may need to verify that thoigh............

L1D: 90 lumen no different than 80 lumen?

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