Closed the sale - The Defiant "C" flashlight.

I think your distances or readings are in error.

Because your second set of readings (from 10m) is 5 times as far from the source as your first set (from 2m), the lux readings at 10M should be approximately 1/25th of the readings at 2m, with some leeway for measurement error and optics. This is the “one over r squared” rule (1 over 5 squared = 1 over 5 times 5 = 1/25).

Your readings are more like 1/9th for two different lights with totally different beams which implies a consistent error. Either the two distances were actually 3 times as far from the lights or there’s some issue with the readings. I’ve done this extensively with all kinds of lights at varying distances and see nothing about your lights, either from the beam shots or the optics, that would warrant such a huge discrepancy.

Defiant C looks like its doing 77K lux. Thats pretty sweet mine is only getting 55-56k with copper added to the pill and a xml U3 1C (thats the only mods that have been done).

So this pumping out some light! Someone needs to get this one atleast!

Since I have slept, I couldn’t tell you what might be wrong. I measured the distances and did the readings, but I probably won’t go back and do any more. I am returning the meter. I think it sucks and I realize that, like anything else, you need a good one to be accurate and then it still needs to be calibrated, none of which I am going to do. I’m just going to stick to the old way. It’s Damned Bright and lights up a long ways.

I doubt there is anything really wrong with that meter. Readings at 1m can be WAY off when it comes to throwers. Go by your 10m readings and disregard the 1m readings. Like I said in your thread about “bought lux meter, now what” you probably shouldn’t be using it at only 1m anyway.

77Kcd is pretty darn good. If I didn’t have another project coming in the mail right now I’d consider it!

I’ve done a ton of readings and have learned a lot through trial and error so if you want any help with this, just ask.
No need to use your wife by the way but you’re a lucky man that she’s so willing :slight_smile:

He didn’t take any readings at 1m and only one of the lights was a thrower. And both lights were off by the same factor.

Take a look at some quick and dirty readings I took of six different lights at 5, 10, 15 and 20 feet with a $15 lux meter and notice how all, including the TN31 and HD2010, consistently “obeyed” the 1/r^2 rule, even at 5 feet.

I’ve since taken many more readings from a wider variety of lights with a better lux meter (which I’ll post if/when I have time) and have never seen readings as inconsistent as what O-L posted. That’s not a slam, I love his work and am just trying to help.

The meter does not have a peak setting, so someone has to be reading the meter, while someone aims the light at it. That’s why I used my wife for the “meter reader”, LOL.

Dead reckoning! Now that’s a system I know and trust.

Well excuse me. Two meters is still too close for a serious thrower.

i would love to buy it… but too bad i don’t own a hobby charger…
now if only it run 26650 batteries :smiley:

How does that song by the Beatles go? Lovely Rita, meter maid…

I have to mount my light in a holder on a table, then go do the reading myself :frowning:

Here’s how Fenix does it:
“Use the luxmeter to identify the brightest point of the beam pattern and record the highest indicated value. Results are reported in candela. Measurements shall be taken 30s to 2 min of turning on the device.”

Not according to the readings I linked you to, or ANSI/NEMA FL 1 (unless you don’t consider the TN31 a serious thrower).

According to your numbers in the link there is a 10% + increase in lux from the 5’ mark to the 20’ mark in both the tn31 and the hd2010. Thats why you have to take the reading further back then one meter or even two meters. That is if my calculations are correct after correcting it back down to 1 meter. I think it allows the beam to focus better.
Tn31 at 5’ 110k at 20’ its 122k
Hd2010 at 5’ 37k at 20’ its 42k

Please correct me if I am not understanding somethin correctly.

Bump for the 3c defiant OL thrower.

Ok guys, here's the second set of lux measurements.

I did readings myself, at 1 meter, 2 meters, 10 meters and 20 meters.

The lux meter I am using has three possible ranges

  • lux at 1x
  • lux at 10x
  • lux at 100x

At 1 meter I had to use the lux at 100x setting to get and the reading was 905 I would think I would multiply that by 100, is that correct? If so, then the reading would be 90,500

At 2 meters I had to use the lux at 100x setting and the reading was 265. That would mean 26,500 and here I am again, right where it was last night. This does not seem correct.

At 10 meters I had to use the lux at 10x setting and the reading was 56, which would mean 560 This does not seem correct.

At 20 meters I had to use the lux at 1x setting and the reading was 127

I think the meter is totally inaccurate. Does anyone want to chime in here? I did all the distances twice and got almost the exact same readings both times.

I will let y'all go from here. I am done and I like the old way better. It's damned bright.

I took it to work tonight and put it up against the stock version. It beat the pants off the stock light.

Your are forgetting one step, I put the corrected lux readings above. :) So going off that it is a pretty awesome light that does maybe 65kcd. (Asuming the meter is accurateish)

DrJones is probably our leading expert in this area. According to him:

“Most of you already know that measuring the spot intensity at only 1m distance is not a good idea, as the beam often has not settled to it’s ‘final beam pattern’ in that short distance. Even ANSI/NEMA FL1 demands a minimum distance of 2m; for throwers that is still much too near (I suggest a distance where the spot size is at least 10 times as big as the reflector/lens diameter). ”

Old Lumens, I’ll quit side tracking your thread now.

Your calculations are correct but just because the 20’ readings show an increase in lux (they do for all six lights BTW), that doesn’t necessarily mean they’re more accurate, which is why I take readings at multiple distances and compare them. Also, those differences are within the margin of error for the lux meter, even though the 5ft = 1.5m. It’s not about allowing “the beam to focus better” it’s about measuring past the point where the expansion is spherical.

I calculated peak beam intensity in candela from your readings and got the same numbers as scaru (90500, 106000, 56000,50800). Not sure why there’s such a big difference… something ain’t right.

That’s fine but the actual ANSI/NEMA FL1 standard will allow the TN31 for example to be tested at 2m. And my readings confirm it’s viable. So we have the standard and measurements versus opinion. I’m not saying distances greater than 2m shouldn’t be used because I do test at multiple distances myself for confirmation, I’m just challenging the conventional wisdom here that only greater distances will give accurate readings.

Well, I think I have let this "sales thread" go to hell completely, so I will let this thread die and maybe try again.. or not.

I think the meter is a piece of crap. I am still fighting the seller over it. I opened a case with ebay, so at least I will get the auction money back.

I'm done, y'all fight it out if you want, but this thread is toast and I started the problem. Live and learn.