DBCstm;
And overall performance of OMG? (Oh My God)!
Hand ANY modern high output flashlight to someone thirty years ago and that would be the reaction.
Ummm, nice try… but both reviewers use alkalines and L91 lithium primaries in their tests with the same peak results at both max and stepdown, obviously with different runtimes though.
many post during the last 3 months, building the sphere and buying the LX1330B, I find that the Sphere does integrate! And, this thread mirrors most of what I experienced, particularity the 1330B.
I’m happy, for now, that using sphere and meter helps me see smaller differences in lights that using my untrained eye was difficult and gave me better results than using my camera for ceiling bounce.
Yeah, I’m all for a cheap universal calibrator. Reading online had me taking readings from noon time sun; but had to see if meter was total junk or not. I read 12200 using foot candles. 10,000 is what is posted via Wiki. Wife wanted to know what I was up to on side of house…
Even taking a reading of the sun you have to take it at like times, varies daily…inclement weather notwithstanding.
During last couple of week, as I just got it. I only shot around noon, like today with cloudless light. Nothing online suggest long/lat or time of year so know this may be questionable.
I’m around New Orleans so wonder what reading I would get near equator?
Latitude can make a HUGE difference. Just try a noon reading in Point Barrow Alaska on June 21 and then repeat it on January 21. In January you will not even see the Sun. An extreme case but if sunlight intensity did not vary as you get away from the equator due to the Earth’s tilt we would not have summer and winter. In Reno I am at 40 degrees North so that the sun is never truly overhead even in mid summer. In fact the tropics is defined as the area of the Earth surface where the sun can be directly overhead during some day or days of the year, basically close to 23 degrees North to 23 degrees South if memory serves.
Thanks djozz… Yeah figured ah what was thinking 
Rich I found around 20 degrees here too, sounds about right, I’m in the valley- you can use a solar calculator online month by month. Fixed solar is tricky.
I have never taken our light meters/spheres to be an exact science. It is nice to be able to see gains/losses from different mods and the difference between different lights but I wouldn't get too upset if someone else's meter/sphere showed something different than mine!
I'm mostly trying to gauge the difference between my own lights with this setup; I don't expect it to jive completely with everyone else's. I know that a few of us have the same or very similar setups, which is nice, but this isn't an exact science so don't get too hung up if your meter reads different...there are so many variables that go into it: cell type, age, bin variance, contact cleanliness, lens type, lens cleanliness, just to name a few!
Carry on and keep having fun building lights.
hey guys!
I am afraid most of us are no scientists who need accurate to calculate the universe.
most of us can’t (or aren’t allowed ;)) to buy equipment for 1000s of Dollars
and most of us will/can not build a sphere
.
what about a “BLF normal light source”?
-> i am thinking of the board that came out when OL (afair) started asking how to test AMC 7135?
- how accurate Lumens comes out of a led (cheap one) with 2 7135 powered from 4,0 Volts (everyone has a dmm if he owns a Luxmeter)?
- how much could that cost?
maybe a member makes some / a lot and sells them?
so it would be possible he builds it, tests it and writes down the number.
we all can stick to this and “calibrate our meters” to China ANSI BLF Lumens!
I will take one!
Reppans - You had better check your interpretation of results again. Max measurements are taken 3 minutes after activation. SB is ~400 on Eneloops and TF is ~315 on Energizer & Duracell. When SB & TF do use the same batteries, they are graphing with different scales (Relative Overall Light Output vs OTF Lumens).
SB shows separate Runtime Graphs of Relative Overall Light Output (0 to 140) vs Time for Sanyo Eneloop (both Max & Med-Hi), Energizer 91 (Max), and Duracell Alkaline (Max). Each Graph shows Light Output relative to other lights compared using the same battery. The relationship between the separate graphs for the different batteries is not stated. The Lumen measurements for Energizer and Duracell are not stated by SB.
SB does give Lumen measurements, but only for Eneloop cells. He states “the QAA-2 X drops from ~400 estimated lumens to ~300 estimated lumens” in the note to the Lumens Table clearly identified as 2x Eneloop NiMH (2000 mAh, 1.5 V).
TF has Runtime Graphs of OTF Lumens vs Time for Energizer and Duracell but not for NiMH. He has no comparisons relative to other lights.
This is just another try to show the difficulty in reconciling the reported measurements of different people.
I’m sorry, but you seem to be missing the forest through the trees. But……
- My understanding is that max readings are taken between 30 sec and 3 mins, NOT AT 3 mins. In this light’s case, it would be at 30 sec.
- Yes, the Y-axis on SBs graph does not state lumens, but all three batt chems follow basically the same curve - starting at 140 and stepping down to 110 at the ~3 mins.
- Selfbuilt’s graphs are directly comparable across all his other graphs, you can read about this on his methodology page.
- Your argument that the three different chemistries will behave differently at the 30 secs Max might represent a few immaterial lumens, but no where near the 60-70 lumen differences I am highlighting between the two reviewers.
- You are ignoring the difference at stepdown between the reviewers (240 vs 300 lms). In this case it’s a proxy for a lower mode, where any of the three battery chemistries are easily able to hold regulation, and a better illustration of scale differences.
- You also ignore the other independent data point of the SC52/LD12/D25A graph - ZL specs 108 lumens while Selfbuilt believes 120, the reviewer thinks 98 (Fenix scale), and Eagletac thinks ~79 lms. Can the Selfbuilt scale really be ~50% (120/79) higher than Eagletacs?? Just take a look at his review of the rest of the D25 Clicky line.
I agree that it can be difficult reconciling different reviewer’s numbers, but not at this magnitude of difference.
Let’s see then if the math itself is being handled properly…
Divide 30 by half and add 10, what is the answer?
Rich,
What you, and I do, is tilt your meter slightly to the south. The dome on the meter integrates slightly but you can see the little numbers climb on the meter when you line up better for direct sunlight. Yea, people in Barrow are SOL, no?
The readings you get sort of reflects (pun) everything mentioned in yours and many other posts. The only people that would really take the numbers seriously are horticulturist; and others that grow illegal herbs. Curiosity gets me doing dumb stuff now and then:)
Ill use a rating from 1-5 just to give a view on how I sometimes adjust numbers. (let those 1-5 numbers represent the metaphorical pages if you want). Ill put in some user names as well.
All numbers from a stock K50
1 (165kcd and lower): 140kcd, Supbeam`s official number
2 (165 to 180 kcd): My lowest reading meter would probably be close to 160, certainly in the 2 category.
3 (180-193 kcd): Selfbuilt 188kcd,
4: (193-203 kcd): ImA4Wheelr 198kcd
5: 203+ kcd): DBCstm 218kcd
As can be seen. DBCstm`s kcd number is 55,7% higher compared to the supposedly ANSI rated number from Supbeam when it comes to kcd on the K50.
My viewpoint of Supbeams K50 numbers are that they are on a 1 when it comes to kcd(basically as low as it gets), and their lumen number is a 5 (basically as high as it gets) Why 5? They are considerably higher than selfbuilt who is quite consistently a 3. Can I do a double check of this? DBCstm usually have the highest numbers. In the 5 camp. His K50 lumen number is 1642. Only a little bit higher than Supbeam. Its a little verification that Supbeams K50 lumen are indeed a 5.
If I want supbeams K50 numbers to be closer to the "baseline" of 3. I have to increase their lux numbers and decrease their lumen number. When it comes to many BLF users a approach like this often works. That makes it easier to compare numbers from different people who often post numbers.
Some manufacturers are quite consistent if we look at these things. Supbeam is not. If we look at the X60, Id say Supbeam are on a 3 when it comes to lumen, and on a 3 when it comes to lux simply because they are close to selfbuilt.
It does not always work this way. But surprisingly it often does work quite well. Well enough, that I often see who rates in the middle, who are always high, and if some numbers are really low.
The above is just a simple example of how I personally and occasionally corrects numbers in order to make them more comparable. I don't know if Ima4wheelr numbers usually are a "4" or what they are. Sometimes people with who usually have fairly different numbers, can have similar results. So sometimes 1 and 3 get look similar. Sometimes 3 and 5 can look similar.
To me, it seems that DBCstm, Tom E, RMM, rdrfronty or pretty much on the same page when it comes to both lumen and lux. Lets call it page 5. Based on their responses I think they can agree that their results are comparable with each other too. I don't think Tom E`s numbers are generally comparable with selfbuilt (despite that it may happen). Neither does he, simply because they are generally higher.
Id say JMpaul320 is on that same page (5) when it comes to lux. But not lumen. So if he measures a vinh lights lux, I expect it to be quite comparable with the lux from say DBCstm. Not when it comes to lumen.
Several members can basically get on the same page and consistently stay there. The way I see it, I can fairly easily join whoever I want (fine tuning would take some time though) I also think that DBCstm, Tom E, etc could also try and match selfbuilt numbers better if they wanted their numbers to be more comparable with his and others with that calibration.
Im thinking Ill join Tom E, DBCstm, etc in both lumen and lux, maybe lean towards "4" if I can. It makes more sense to me to match other modders who does "similar stuff" that I do. That is, unless pretty much everyone could agree to say use Fenix numbers, and selfbuilt reviews as reference for calibration. These numbers are quite consistent as far as I can see. Selfbuilts reviews/numbers are easily available. And with lots of regulated lights being tested and reviewed, the difference from flashlight to flashlight is not that large. Many people are already in that area when it comes to numbers.
Do you know, for instance, that rdrfronty himself built my lightbox, Tom E’s lightbox as well as RMM’s lightbox? All of ours are FROM rdrfronty. So, if we are all on the same page, then we have set a standard that other single instances are trying to replicate. We are showing 4 separate yet duplicatable systems, that are being done from Texas to Oregon to Mass. covering virtually the entire United States and getting the same results. So these 4 systems are the standard. As nobody elses single system is so reliably duplicatable.
I still haven’t heard anyone state the answer to a basic elementary school question…. Divide 30 by half and add 10, what is the answer?
How people look at this simple equation might tell us quite a lot about why we all have different viewpoints when a single formula is involved.
70
Amazes me how many get this one wrong, I mean really! I’ve had math teachers get it wrong!
Not even because of this thread, but in a weak and blind moment last night I bought secondhand a class A luxmeter (Mobilux A). I had a good deal on it, but even so I do not dare to confess what I payed. It was officially calibrated a few years ago, but it is hardly used (belonged to an old lady, had always been in the garage ;-) ) and I think the calibration can be trusted. Even though it is a high end luxmeter, it only claims an overall accuracy of 5%, that tells something of how tricky luxmeasurements are.
When it is in, I will do some comparisons with my present Tondaj LX-1010B meter (which I always thought was pretty good).
DIVIDE THIRTY BY HALF AND ADD TEN
(30 /.5) + 10 = 70
I took the statement literally as it said divide BY half (.5) rather than divide 30 IN HALF. If the instructions said that then the total would be 25.
Edited: Posted BEFORE I read post 56!
At least we're on the same page. ;)