I can measure a lower mode and extrapolate, but if you have half the lumens then no, you wouldn’t have half the candela. It’s that exponential issue again.
I’ll measure and see what shakes loose.
But, in photography terms… I’m standing on the sidelines at a football game, the punter is directly in front of me in the middle of the field… he’s 25 yards away. Easy flash shot. He punts 50 yds downfield to the sideline I’m standing on, I want to capture the opponent catching the punt, he’s exactly 50 yds from my position. Twice as far away. It’s going to take 4 times the amount of light to reach him for that shot. 4 times at twice the distance.
Candela is a measure of intensity in the center of the beam, so if you cut output in half…. I’ll measure it.
Ok, today for sure this is not my cup of tea. So I’m gonna just tell you guys a few test results and I’m sure some one of you can figure the percentages easily enough…
The TN42, on level 3 of 4 (High) makes 1003.95 lumens and 46750 Candela
The TN42, on level 4 of 4 (Turbo) makes 2459.85 lumens and 702500 Candela
So what does this tell us?
(I have to say here, I’ve tested the candela on this light at least 4 separate times, with the cells at different charge levels two of those times and fresh or almost fresh the other two… every stinking time the meter tells me 2810 with a x100 setting. 28100 at 5M, for 702.5Kcd. Reliable, the most reliable I’ve seen to date)
Maukka, did you see my test results directly above your post? That doubling concept is obviously not true. I’m pretty sure that double 46.75 isn’t anywhere close to 702.5, even with the differential there.
Dale, I can’t explain your result, but in Maiden666’s review the measured Kcd scales very well with measured lumens and this is generally what I have observed with my lights.
Testing the light’s output with cells at various states of charge would give you how good the circuitry is. Like fully charged, 75, 50, 25%. If they’re all the same the circuitry is very good at running constant current through the LED even as the cell voltage drops and the current draw from the batteries increases.
Think of it this way:
If the intensity of the hotspot doubles when changing modes, the intensity in every part of the beam has to double too since the reflector and emitter are the same. Thus the total output doubles = the lumens double.
Led-Rise’s calculator is misleading. You cannot directly convert lumens to lux. Lumens is a measure of total output, lux is the measure of intensity in the center of the hot spot. A floody 1500 lumen light creates very little lux, whereas a pencil beam thrower making 1500 lumens puts virtually all it’s lumens down the middle, into the hot spot, for far greater Lux.
Candela, downrange illuminance, isn’t all about the emitter and driver and reflector. It’s about the avaialable light spreading out in a cone as it travels downrange, very quickly losing it’s power.
Science is wonderful when in the lab or sitting at the desk, going out in the field and proving the science is an entirely different matter.
Y’all might be the scientists, I’m the guy out in the field taking pictures of real world results. And the results don’t agree with the science.
Build a light, measure it’s lumens and candela. Then de-dome it. Measure lumens and lux again. You’d find that that the lumens dropped while the candela nearly doubled. Less lumens, more candela. Fact. There are more variables at play here than it would seem.
But, taking a lumens reading immediately after taking a lux reading on the same light, same cells, IS maintaining constants. And those number disagree with the representation of physics here.
I can’t argue with physics, unless the chapter and verse being quoted are wrong.
By the way, who said we couldn’t send a man to the moon? And who is now planning to send men to Mars? Physics and it’s laws change as we learn, there are very few hard cold facts.
I’m not trying to convince anyone of anything. I’m the guy with the light in hand, the results from testing in front of me. It’s everyone else that’s scrambling trying to figure it all out. Fact is, at 42% of the output, the light is making less than 7% of the throw.
That does not support the theory that halving lumens also halves candela. So when the facts from testing don’t support the theory, it’s time to put new chalk on the board.
The meter read 1830 on High, 28100 on Turbo. My meter has 3 places, it actually showed 183 to the power of 10 in High, errored in Turbo and I had to switch to the power of 100, where it showed 281.
I argue to understand, not necessarily to prove anyone wrong. I forget a lot. Widely known fact. So if I can argue myself to an understandable truth it is well worth all the verbage expended in the acquirement.
Yes, it is entirely possible that I made a mistake taking the readings, so I will do it again. (I have been known to make the same mistake over and over, so bear with me. ) I will go slower, double checking mode levels along the way, for extra care and authenticity.
So there ya go, y’all are pretty much spot on. Within a couple percent. lol
I forget little things, like all of how the UI works. I forgot that when you press and hold from off the TN42 comes on in moon, then will cycle through 3 more levels LMH. BUT if you cycle it through again, there are only the 3 levels LMH, moon is only accessible from off. So I must have cycled it back through checking that I had the right mode after setting up the meter and was actually in Medium instead of High.
The numbers, carefully obtained…
High (Level 3 in the main UI) is making 1003.95 lumens (I got that correct in the light box) and 272Kcd for 1043.07M throw
Turbo (Double click in any mode when on) is making 2477.1 lumens and 702.5Kcd for 1676.31M throw.
Thank ya’ll for pushing me into finding where I went wrong. 41% of the lumens is making 39% of the lux, so it’s fairly linear if not quite exactly. The actual throw numbers are not linear, the candela reading pretty much is.
Why is it that by the numbers, with the lumens at 41% and the lux at 39, the throw is actually at 62?
I’m gonna have to give up. When the time comes that you know you don’t know half of what you think you know but you really only know a quarter of what you thought you knew you know then it’s time to have a drink. Seriously though, you hear about the football players that retire dang near a vegetable after so many concussions in their career? Or a boxer? Well, I’ve had more concussions and micro concussions in the past 16 years than a great many professional athlete and it’s catching up to me. Gonna be drooling and staring off into space before long, I can see it coming. (I’ll have a light to shine the way though, in case anything’s really out there.)
Thanks for clearing that up that measurement, Dale.
You know, I find that I don’t really understand a concept until I’ve been utterly confused about it a few different times; it’s all part of the process.
(listening to some tunes on new dual driver headphones from XiaoMi, GearBest. $17, these things sounds like Bose or something!)
Well, almost 17 years ago I started having issues with severe spasms, eventually diagnosed as a Conversion Disorder. Stress, both physical and emotional, causes me to have spasms that might just affect my arms, or my whole body, sometimes causing my head to shake side to side violently. It’s these last episodes that crash me, sometimes leaving me walking crooked for several days. Early years, it was daily or every other day. Nowaday’s it’s more sporadic but damage has been done and each time causes more. I once had a pec muscle torn for 2 years! And once I went to shake a bottle of ketchup at the table and it caused a partial vision loss for several minutes in my left eye.
I mod for relaxation, got into it because I needed a portable light to use to take macro ring shots at weddings. Couldn’t find a light that fit the bill and started trying to create one. Found that I liked the modding part of it and before you know it I’ve got more flashlights than most stores. lol
Gettting harder to wrap my mind around things, to remember details, names, virtually anything really. Sometimes what I DO remember may be way off base, leaving me arguing a false point but convicted in the knowledge I’m right. Hard to believe, I know, but it’s true. And then I see that little detail I was missing, and the rest comes together and shows me I was on the wrong page. Whatareyagonnado? And such is life in the basement of Dr. Frankendale, discombobulated and non-incorporated.
) I will go slower, double checking mode levels along the way, for extra care and authenticity.