Thrunite TN 42 ,a new record in Throw

HI

I,ve done a (non profesional) review- comparative k70-TN42. Its in spanish Flashlight Forum ForoLinternas. (In spanish).

K70-TN42

If there’s no PWM, the image should be a long streak of continuous light, not a single point. If not, you’re not moving the light/camera fast enough.

If you have a BLF D80, drop the shutter speed to 1/10 and try that.

Hi Maiden666, great looking review with plenty of pics. Sorry I can’t read spanish.
I would say you review looks very profesional. Do you feel the TN42 has made much of a step forward over the K70?

Nice review and comparison, love the graphing charts. :slight_smile:

It might be very important to note the K70 uses 4 series cells and as such, a Buck driver. The TN42 uses 2P2S and as such, a Boost driver. So the type of cell can probably matter more to the boost circuit than the Buck circuit, in other words, it would probably benefit the TN42 more to use better cells, the K70 wouldn’t show any marked increase for the top or premium cell.

This is me reasoning it out, I really don’t know 100%. What I do know is that my lightbox showed 2463 lumens from the TN42 using Samsung 30Q cells, and 702.5 Kcd throw on my lux meter. I have since proven that Kcd reading out by getting at-target photo’s of the light illuminating a target at one mile, so it’s not just numbers, it’s proven.

Also, for very fast PWM it might be hard to move the light fast enough to see the separate blinks. I just tried with a mtnelectronics FET driver light on low mode and saw a continuous streak.

For PWM over 10kHz it is probably very difficult to capture with a camera, but that’s when it usually doesn’t even bother anyone. I prefer moving the camera rather than the light.

At 1/10th of a second, as fast as I could shake the big flashlight (in firefly mode) side to side…

Now you need to make sure the led is not overexposed. Stop down the camera to f11 or so and adjust ISO down if needed.

You seriously make me laugh!

I take it that the PWM isn’t that bad then :slight_smile:

I could set up my 1DsMkII on a tripod and darken the room and go to great lengths, use a shutter release, swing the light on a string from the ceiling, but I’m willing to concede that the little G1X got it right and there’s simply no visible PWM, even at 1/10th of a second shutter.

MakeCanon
ModelCanon PowerShot G1 X
Aperturef/4.5
Date & Time2016-09-30 10:26:27
Exposure Time1/10
Focal Length29.3 mm (35 mm equivalent: 104.5 mm)
ISO100
Dimensions2345 x 1565
Size0.8KB

I read thru the Maiden666 review on ForoLinternas as well. Comparing a CW to a NW is difficult - they will not match up well. I'm sure the bins of the XHP70 are different, lower for the NW. The TN32 product page here clearly says the NW is 10% lower, but that's probably just in lumens, - kcd is usually about double the loss of lumens, bringing the kcd spec down to 480 kcd.

So if Dale's TN32 is CW (think so), both Dale's and Maiden666 measured #'s are probably about dead-on matching.

I did choose the CW for absolute power and throw. :slight_smile:

Edit: So yes, if you add 10% to the NW output numbers it would come within about 60 lumens of my measurements. And I did use the premium Samsung 30Q cells, which might account for the rest of the difference. Providing we can assume the testing methods fall pretty close even if quite different by application. I find my P-Trap box to be very close to ANSI numbers of quality lights, this has proven out repeatedly over the past several years. So I trust it. FWIW, I had Chris at flashlightlens.com make me up an UCLp lens to put in my light box, after removing the silicone seal around the heavy plate glass that the brother’s R used when building it. It tested out virtually the same with the high grade UCLp lens. A testimony to the already well thought out build. :wink: I am back to using the glass plate for it’s durability. The big UCLp lens? Retrofitted to my 15,000 lumen TR-J20. :slight_smile:

I agree the numbers make sense: the NW TN42 has about 80-84% of the lumen output and Kcd of the CW version.

But I’m not sure I understand this. If the reflector and LED type are the same, the beam intensity should scale directly with the lumen output.

Pushing light downrange is an exponential factor, it takes 4 times the amount of light to reach twice as far. This is something photographer’s deal with all the time. :wink:

That’s really a big head for a single emitter light like this!

So no surprise that it throws better than the K70 although with lower lumens output.

Yes, but I wasn’t talking about the distance. I meant that if you dim a light to half its lumen output, its beam intensity (in cd) will also be half.

Boost or Buck is irrelevant if the output is constant current and the drive circuity is competently designed. As long as the inductor is sized to switch enough current without going into saturation after the battery voltage sags, you’re pretty much set.

IMO, none of these lights should use cells in series if they need unprotected cells. Unprotected cells and series use is a dangerous recipe without a proper battery monitoring system. Of course all of these lights all lack such a system.

I dunno, I just see it empirically (measured) more often than not. Are you sure that's what you measured in lumens vs kcd for a thrower?

Actually it's probably wayyy more complicated than what I said. All sorts of variables - our meters (cheap ones, like under $1000) I believe are calibrated better with CW tints than NW tints, so they tend to read NW's lower and probably in the high range of CW read higher on the meters. There's other factors. Just checked some of my numbers, and sometimes yes, kcd scales well with lumens, but other times I've gotten higher differences on kcd than lumens, percent wise, and I thought as much as 2X.

This is all part of the issues comparing two lights with different tints. Specs from the manufacturers that offer multiple tints are typically not providing the data points per tint, some do, most don't. Chances are they'll quote CW because of the better results.