That’s a really interesting picture. First time I’ve seen the SC52’s L1 oscillations captured on film. I haven’t tried to get an image of it because it seemed like it’d be very difficult. You must be very quick!
I’m also going to have a hard time capturing the Qlite driver’s PWM in an image, since it runs at 19 kHz instead of the usual 4.5 kHz. It’s fast enough that I don’t notice it during use, and can barely even see it with the card-waving method.
However, I just today discovered that I can build a spectrometer from inexpensive parts, and I’m really excited about it. I’ve been wanting to map the spectral output of lights for a long time, and sometime soon maybe I can. (especially interested in comparing a N219 against my BST-wide and the sun… but it’ll also be neat to see how the D25A 219 compares against a N219 without the AR coating)
First, on a light with a similar blue halo (Olight S10, 2012 edition), removing the lens gets rid of the halo and makes the beam like 500K cooler and much whiter in color. This mostly confirms that I should be able to fix the tint and CRI issues by swapping the D25A’s lens for a plain piece of glass. That is, assuming I can get it apart.
Second, I got a slightly older aluminum D25A today (it was on a really good sale), and it has some major differences. Its moon mode is only a fraction as bright as my titanium model’s moon mode. Also, the lens is actually user-replaceable like the specs say. The front bezel comes off easily to expose the lens and reflector and LED. The head and body threads also swapped gender, and the head is narrower than on the titanium model. It seems the titanium version has a completely different head design than the aluminum model.
The aluminum model still has PWM on some levels though, and its moon mode has an initial pre-flash before it steps down to the correct level. But overall it’s much closer to spec.
I updated the OP with “Regular D25A Measurements”. I measured another D25A, a cool white XM-L2 model that I think is from 2013. It’s much closer to spec.
Tint: Not sure, blue-ish white with a primary blue halo around the outside of the spill. So, definitely cool white.
Lumen specs are listed as OTF lm / emitter lm, since EagleTac lists both on their site.
D25A-XML2 low / “moon-mode enabled” group:
Low (spec=0.5lm/1lm): 0.43 lm, current-controlled
Med (spec=9lm/11lm): 12.1 lm, with PWM
High (spec=85lm/121lm): 121.9 lm, current-controlled
D25A-XML2 high / “moon-mode disabled” group:
Low (spec=6lm): 5.86 lm, with PWM
Med (spec=20lm): 23.62 lm, with PWM
High (spec=85lm/121lm): 121.9 lm, current-controlled
This was, mostly, pretty close to the “emitter lumens” values specified on EagleTac’s site. Their “OTF lumens” specs seem low though, compared to the ZL scale my light box is calibrated to.
I was actually a bit surprised at how closely the measured output resembled the specs. Sure, it mostly matches the “emitter lumens” instead of “OTF lumens”, but at least it matches some part of the spec. And apparently ET’s “emitter lumens” are about the same as ZL’s lumen specs. Just FWIW. I mean, the numbers match up really closely, if you ever need to convert from one to the other.
I’d love a D25A Ti-219 with the lumen levels of the XM-L2 aluminum model (maybe a bit lower on high/turbo though), the titanium body, and a plain piece of glass instead of the AR-coated lens. Sigh.
Hello, Toykeeper… glad you found a decent sample to test. Your results appear consistent with my tests between the two lights and also with your statement in your OP that ZL and ET differ by ~40-50% in lumen scale. As you know I consider ET’s specs to be more ANSI accurate for reasons I mention in post 21 above, and because the ET/47s scale matches most of my light collection. The D25A has been one of my preferred lightbox calibration lights.
- I think with moonlight mode off, Low and Med spec should be 3 lms and 18 lms since the ET footnote say “6x and 2x, the L and M with MM-on.”
- Curious what voltage cell you used to test the ML mode since I find the relatively poorly regulated ML to be quite volatile depending on V. ie, I get half the ML output on <1.3v NiMh as >1.6v Alks or L91s.
- Might be interesting to run a side-by-side output/runtime test of the D25A 85 lm/2.5 hr mode vs SC52 116/3 hr mode.
- Interestingly, I have not read of any other owners of an N219 D25As having massive out of spec low modes… on the other forum that is. Perhaps you really have received a bad sample?
ToyKeeper, you said in the the review that your 219B in D25A ti is a little bit warmer or yellowish than your other 219Bs. I just read from the datasheet (if I understand it right) that they have cool and warm tints too. I just bought a 219B from IOS and it has been described as “D220” in the specs. It does have a little bit of yellow but I don’t mind that because I’m used to warmer tint now. If you can see from the table lum. flux of D220 is min = 220 and max =240. So, I guess the higher “ranks” (like D260, D280 and D280) will have cooler tint almost to white and that’s why the lum. flux is higher too.
The specs say: “With moon-mode setting disabled, lowest output will increase by about 6 times, to 4 lumen, and the second lowest output will double, to around 20 lumen”.
Even though the multiplication doesn’t work out very well, I used the numbers from ET’s specs.
Fresh-off-the-charger Eneloop. I don’t have alkalines on lithium primaries to use for testing.
It might be, but I’m not doing runtime tests. I enjoy selfbuilt’s runtime graphs, but unfortunately he didn’t test SC52 vs D25A… he only tested SC52 vs the 2xAA version (D25A2).
Something is clearly wrong about the ET specs. It’s a 219B but they claim it’s from the “B11” bin which doesn’t exist. That’s not even the correct naming scheme. It should say D220, which is the brightest bin available for the 92-CRI emitter they claim to be using. Then again, it should probably also say it’s a 4500K tint instead of 5000K tint, but this particular bin of 219Bs seems to be noticeably colder than the equivalent bin of 219As, so I can understand claiming it as 5000K instead of 4500K.
In any case, the yellowish tint isn’t normal. Anything with 90+ CRI at 4500K should look white, not yellow. I have ten lights with Nichia 219s in them, and the EagleTac looks rather different than any of the others. I have three lights with too-strong AR lens coating, and I can remove the lens from the other two. All three make the beam warmer and color-tinted, and all three look quite a bit better when I take the lens off.
So, I’m pretty sure the tint issue is the lens, not the emitter.
It occurred to me just now that I can actually test it; no need to guess. I took the removable lens from my regular D25A and held it over another Nichia 219B light, with a third 219 shining next to it for reference. When I shine the white 219B through the D25A lens, the beam turns warmer and yellow and colors no longer look nice in it.
I have seen similar results with another lights’s AR lens.
I had a Nichia 119 that looked slightly yellow with lens and less so with lens removed.
Also removing reflector got rid of all yellow.
I’ve noticed the coatings on the lens as well as reflectors can change tints.
The “around 20” statement seemed to me to be the averaging of 18 for the XML and 22 for XPG. OK, got the 4 lms, but then why do you use 6?
No big deal - it’s your call of course, but those two modes are the only ones that stand out as inconsistent to the rest of your measurements & lumen scale differences.
I’m glad you identified the problem. I just found the correct datasheet for high CRI 219B (min 85). Here. You’re right D220 is the brightest bin available for high CRI. Do you know why I see some yellow with my 219B D220 from IOS? The lens is without coating.
It’s hard to say. Individual emitters vary quite a bit, and the bins Nichia uses aren’t as narrow as the bins Cree uses.
I’ve seen at least 300K of color temperature variation between different 219B emitters in the same bin, maybe more like 400K. And next to a 6500K cool white emitter, if your eyes are calibrated so that 6500K looks white, anything in the 4500K to 5000K range will appear warm and sort of yellow. OTOH, if your eyes see 4500K as white, the 6500K tint will look rather blue.
Next to other emitters of a similar color temperature though, a high-CRI light should look pretty white. Do you have any other 219s or other high-CRI neutral/daylight lights to compare against?
A smooth reflector basically mirrors the emitter from the center outwards, so you are seeing the corners of the chip pointing towards the center of the beam, creating a dark X. It all averages itself out at distance, since ideally, your reflector will image to a point infinitely far. In my opinion, I almost think that seeing a dark X up close is a better sign than seeing a fully filled circle up close.
Perhaps the lens isn’t coated for a broad range of wavelengths, but maybe just coated for wavelengths centering around blue? AR is for increasing transmittance, and most typical high output LEDs are on the cool side, so if you had to pick one coating, you’d pick one for a blue wavelength.
Also, these may be truely current regulated, but thought I might posit the possibility that even though they are a smaller chip, perhaps they are more efficient at lower currents than the driver (or flashlight maker) is expecting, and perhaps this could somehow result in more light out for the same amount of power to the LED.
It certainly looks pretty white next to my T6-4C and T5-5B (of course it is much warmer) while the only other light with 219B I have right now is the L10. The L10 certainly a little colder (whiter) than my 219B from IOS. I guess not by much, maybe just my eyes. It could be the driver or reflector that caused that yellowish tint.
I don’t think a flat AR coated window will do much splitting of colors. A large focusing lens will. The way the colors get separated in reflector lights is that the light emitted sideways that hits the reflector has had a longer path through the phosphor, so it has less of the original royal blue or whatever left in it than is in the light emitted forward that forms the spill. That can be an advantage with a typical bluish LED because the spot is warmer and the spill is often too dim for the tint to matter much. But the bluish spill blinds other more than a warmer spill would.
On the other hand, I don’t see much advantage to anti-reflection coated lenses in flashlights, unless you want a very clean ringless beam.
I verified it on another D25A, and on an Olight S10. Stock AR lens equals nasty tint with a blue halo, no lens equals beautiful beam, plain piece of glass also equals beautiful beam. It’s not the reflector. I think this is also why so many ZebraLights have green tints, but I can’t remove the lens to test those.
Odd that they would use such bad coatings then. I don’t see green or yellow with my eyeglasses. Maybe a lot of people want coated lenses because that is like other optics but don’t notice the quality. Or maybe they don’t know what they are selling.
Just a quick note. You must have gotten a Friday afternoon sample. My late 2014 D25A (Nichia) has a similar low mode to my 2012 model (around 0.5 lumen or less).
The threading is nice and tight (a bit sloppy on the 2012 models I’ve seen), and I like how they redesigned the head to hide the brass threads. Overall, not a huge difference from the 2012 model (excluding 14500 use, I don’t use 14500 in these lights).
My knurling was clean, and I did note a blue tint to the edge of the spill but I don’t see it in use since it’s at the very edge.
Overall, I’m quite happy with my late 2014 model. I think you just got a bad sample. Unfortunately these mass market lights can have pretty big sample variation.
Ha! Great review and nice pun in the title.
The D25A was high on my list but, aside from ergonomics (mode switching), it seems that QC also prooves bothersome.
BTW, the driver came out of my D25A while I was trying to melt the glue holding the head together. It looks like the driver will be relatively easy to replace, and I can even keep the original contact plate.
So, the plan is to replace the driver, connect all three pins of the contact plate (batt plus, batt minus loose, batt minus tight), and write some firmware for it to take advantage of the tight/loose sensor. The down side is that I don’t have any boost drivers available so it’ll require 14500 cells after the mod.
And I still haven’t gotten the pill to unscrew from the head yet. Sigh. Stupid extra-strong glue.
Oh, and I also have a 2012 model of the same light now. It’s much better than the mid-2014 model. However, it still needs the lens replaced to get rid of ugly tint… but that’s a simple matter since the bezel unscrews easily.
Mostly, I’ve just been too busy to finish it, and the availability of other drivers is a fairly recent development.
