So I finally found some time to finish testing the lights djozz sent and crunch the numbers.
For the F3-L2 I tested throw at 5.867m with a protected LG18650MH1 and measured the output between 60-120 seconds. It came in at 74.5kcd initially, now I’m getting 68,116cd. I did notice some output fluctuation in the 60-120 time period on the recent test, with the final (highest of the recent run) measurement coming in at 2min 20sec. I let the battery and light rest and topped it off on the charger and tested it on my lumens measuring pipe “(see my pipe here)”:Lumens measuring contraption... (or just a pipe dream?) and got a reading of 952 lux in flood and 352 lux zoomed. My standard calibration has been .55, which would be 523.6 lumens and 193.6 lumens. The djozz measurements were 81kcd, 660 lumens (flood), and 210 lumens (zoomed).
The second light (Cofly) measured 24,746cd at 5.867m on a freshly charged Windyfire 14500 at the 8 minute mark. I let the battery and light rest and tested it on my lumens measuring pipe and got a reading of 264 lux in flood and 140 lux zoomed. My standard calibration has been .55, which would be 145.2 lumens and 77 lumens. The djozz measurements were 30.1kcd, 136 lumens (flood), and 66 lumens (zoomed).
Based on those findings vs djozz’s measurements, I’ll be using a calibrating factor of 1.20 for my candela measurements going forward which is closer to the calibration number suggested by the measurements off of the Cofly(1.2163) than the admittedly less reliable F3(1.0872-1.1891), and updating my conversion factor for my lumens pipe to 52. x Lux= lumens for floody lights (from averaging 2 lights at .6933 and .5151, weighted towards the Cofly), and .48 x Lux= Lumens for throwers (from averaging 2 lights at .5966 and .4714, weighted towards the Cofly), .5 if it’s somewhere in between (most fixed reflectors with larger than 40mm reflectors).
So all in all a mixed bag for me, I was a couple of percent high on my PVC pipe calibration, but I get to consider my throw measurements 20% higher than I always have thus far. Considering how much effort I’ve put into building throwers over high lumens lights I’m happy about the results.
I finished doing the measurements on both lights, the results are in the post above. I hope we get some more people signed up for this passaround, I can’t believe there isn’t more interest.
By the way, I put a collar on a Deerelight DBS V3 aspheric that I had a dedomed XP-G2 S4 2B in, running off a MTN17DD driver. Measured output 265kcd, after correction factor, 318kcd. It also means the 1405 I sold to Woodfiend wasn’t 490kcd, but 588kcd.
I’ll get a hold of MEM and n10sivern and see who’s ready for the lights.
Please do not take my 'djozz' lumen standard as the best one approaching the 'real' lumen. It might be more off than other people's lumen standards. It is calibrated agaunst less ANSI-rated flashlights than some other folks have done. My and Sma's suspicion is that it might be ~9% too high.
There is more reason to take my 'djozz' throw as the truth because it is directly measured with a (once) well calibrated very high quality luxmeter. So here there is no own guessing involved in the throw numbers.
Perhaps it is a good idea to explain where the second flashlight that KKW has measured suddenly came from. I was not happy with the constantness of the first one and sent him another one. This was the PM I sent him:
Hi Henry,
I could not help myself making another flashlight for you, a small zoomie that is also much (6 times) as cheap to send. Today I put it in the mail for you.
Output and throw are within 1% accurate if a freshly charged and rested (half an hour or longer) 14500 IMR is used (I used an Efest IMR14500 V2 750mAh) and measurements are taken between 8 and 10 minutes after switch-on without cooling.
Specifications:
*host=Cofly KX-H10
*led=dedomed XP-E2 R3 1D0 on 16mm Noctigon
*driver=2×7135 plain (no protections, no modes) linear driver, 710mA measured
*output flood=136 djozzlumen, measured between 8 and 10 minutes. (ftr, at 30 seconds, 143 lumen was measured)
*throw/flood ratio=0.478 , where the throw position of the lens is set at a sharply imaged die at 5 meters (a bit closer or further does not matter much)
*throw=30.1 kcd, 30.4 kcd resp. (two measurements on two different batteries of the same type), measured again between 8 and 10 minutes, at 5 meter distance, searching for the highest reading while moving the hotspot over the luxmeter detector.
Handling of the flashlight:
*if not needed, do not open the head of the light
*do not place the flashlight vertically on the lens, it will scratch because it sticks out a bit ( there is already a tiny scratchmark in the middle)
*avoid smudging the lens, it is plastic and will scratch easily, also when cleaned, a scratched lens will influence the throw number.
*this flashlight should be waterproof but to avoid having to clean the lens (introducing extra scratchmarks), do not use in wet conditions.
Perhaps you can put this flashlight in the same box with the other one, with the above specs, for the pass-around?
Yes I can, both lights fit in the box. I did my testing with an LG MH1 and a Windyfire 14500. Should I go ahead and leave them in the lights and include the XTAR charger in the pass-around, or do you think they’ll be unlikely to make a difference in measurement consistency?
I forgot to mention, I also put together a spreadsheet in excel that I’ll print out a couple pages of and send along to make the data easy to organize and reference in the future.
I think the Windyfire IMR14500 is comparable with the Efest IMR14500 I did my testing with so that may be a nice addition. For the Supfire light I would not advice a high drain cell, the (non high drain) NCR18650B cell gave such a nice flat bit in the output between 1 and 2 minutes.
I don’t have a spare NCR18650B, perhaps someone down the line will have one they can send along when they pass them along. I’ll include the Windyfire and the MC1+ charger.
As with most of us,calibration is based on ANSI based lights,and the collection is growing.Nitecore MH20 and HC50 not yet tested,but at my 25 lux/lumen calibration factor,my 2 BLF EE X6’s tested at just over 1000 lumens(25000 lux) on HE2’s and a tiny bit more on LG 4.35v,3Ah cells.But I still seem to have over 10% variation compared to ANSI.
One interesting thing I notice about the outcome of my testing is that compared to a well built homebrew integrating sphere, my PVC pipe contraption for measuring lumens with a sanded interior does not massively favor a thrower over a floody light. It is about 8.5% more sensitive to throwers, which isn’t completely insignificant, but it’s still reasonable. I think the suggestion some have made about these being more sensitive to throwers could be valid if they don’t have a sanded interior to reduce direct reflections. I hope some more guys with PVC pipes take up the call to join in this group effort at understanding our measurements relative to each other better.
I don’t want to get on the list yet, because I’m not quite done- but I am interested. I’ve been putting off doing it for over a year and in the past two weeks I have been constructing it- when I get free time. I’ll pop back in when I get a bit closer… but I did some initial testing today… and I have a .035 and .042 factor. I found I need the .042 for small lights like my Fenix LD15… and I have a Fenix HL50 headlamp that I got the .035 for stuff that pumps out more. I calibrated the .035 against 285 lumens and the .042 against 117 lumens. Then I went and looked at some Subwoofer and Johnny Mac reviews and I was kind of close to what they measured. I dunno. That thread I posted in earlier had a lot of good info in it and that’s where I learned how to do the math. Thanks everyone for that.
Gday Billy X, i am charging my ncr18650b protected cell as i type and i will post the lumens i get from my nitecore hc 50 shortly , it would be interesting to compare. I am using the hs1010 light meter in a 4 bend pipe box.
Candela at 1 metre = 2150cd [measured at 4m]
All measurements taken at 30 secs.
I use my lux meter at the 20 000 lux range which 1 lux = 5.75 lumen in the pipe.
It would be interesting to see other comparisons- i can test any of the following if some one wants to compare, all stock tn32 sc600 bc40 tk75 i3s ec25 and others.
I'm interested in being on the list. Just heard bout this now... I got a PVC lightbox made by manxbuggy1, same exact setup as Dale and Richard (RMM) have.
, Jos