FF-light PL47G2 with 219*b*4000k produces a perfect beam with 30 deg lens and just 4 emitters. But my D4v2 219*c*4000k there is a similar problem (again, with 4 emitters).
I bet it worth trying then to sand off the legs of the lens to bring it a bit close to the emitter? (or does it already sit right on top of it?)
Also can anyone comment if they have similar problem with D4v2 and SST20 emitters?
OK, why not try another optic? What is the big loss since you don’t like what you see.
I do not have the 219B model but I do have a couple SST20 and they do not have that darker area, one default optic and one frosted optic, the frosted optic (10623) looks nicer for me personally as the hotspot is bigger.
Do you see that with the eyes or you take the camera and expose for the hotspot (thus underexposing the rest) and only see it in the photos?
These optics have a 2 step leg, so the legs rest on the MCPCB, with a narrower diameter smaller part of the tip of the leg fitting inside the MCPCB.
You can still shave the leg if you want but they will not grip into the MCPCB anymore after that.
I don’t want to shave the legs off fully, just some of it to bring the lens closer to the emitter. I guess I’ll order spare lens and try that 
Why my eyes of course. If these dark discolorations weren’t bugging my eyes I wouldn’t bother. But I see them and hence this thread. Just trying to get non-frosted D4v2 with a clean beam.
I’ll try my luck with SST20 as well then. I also heard Hank’s SST20 @4000k come from a nice rosy bin.
Thanks for the input!
I understand.
I have to say I do not have the dual channel SST20, but the older regular 4 LEDs SST20 single channel flashlights.
Does anyone else with a D4k have this problem, what optics are you guys using for your 219B d4k? My stock 10622 has this and looking for solutions. Is the 10621 any better? Hesitant to put the frosted 10623 because of the loss of throw
It’s a problem with phosphor distribution being uneven. The 10621 likely won’t improve it at all (it’s also a clear optic), I’m afraid the only way to get rid of the dark spot is to mix up the beam with frosted optic (10623).
Is that a LED quality control problem? If I order another of the same emitter will I potentially get better results?
It’s either a quality control problem on Nichia’s part, or that Nichia simply does not care about phosphor distribution, since it is not one of the parameters promised by the datasheet. It’s hard to say what will happen if you order the same emitter, whether it resolves the issue is entirely up to luck as even adjacent LEDs in the same reel can have completely different phosphor distribution.
I would just use the frosted optic and forget about it. If you want more throw you can even de-frost it a little by polishing it on soft clothing.
BTW here’s a discussion started by someone who is having the exact same issue: https://www.reddit.com/r/flashlight/comments/1bue93f/nld_disappointed_in_the_219b_beam/
Agreed that the 10621 will probably not be better.
First, I would try with frosting the 10622 optics. You can do this with some sandpaper. Start with some higher grit and if necessary, go lower to frost even more.
You could also replace the LEDs with some Convoy 219Bs. Every one I’ve gotten so far from Simon have been great.
I have quad 219Bs with 10621 and 10622 optics in other flashlights and the beams are great. The host shouldn’t matter that much in regards to the beam, but the optic, LEDs, and the MCPCB do. It appears the Hank board has very similar LED offsets as the MTN, which is what I have.
With triple Carclo optics, the position of them on the MCPCB will also make a difference with the beam. Just last night I changed the rotation of a 10511 on some sliced SST-20s in order to improve the beam. You could try the same with your quad.
Wanted to add that a convenient way to get sandpaper in a variety of grits is to visit the beauty section of your local supermarket and look for nail buffing blocks. Some of them have multiple faces each with a different grit and can be had around $1-2.
I had the same issue. Replaced them with FFL3501A emitters. No regrets.
Nice! I really wish these emitters were available in neutral tint and more CCTs. The smaller LES gives it a few advantages over the 519A:
It would’ve been a near-perfect use for the 719A, if Nichia hadn’t made it in that odd stacked-die configuration.
Maybe the domeless 219C-V2 would work? I’ve yet to see somewhere selling them though.
I’m not a particular fan of the 719A, as it somehow manages to have both lower output AND lower CRI compared to 519A at the same power. And the stacked-die thing that’s supposed to triple intensity was a total flop. Nichia could have just released a factory-domeless 519A which would be better in every way.
The 219C-V2 would be an interesting emitter, but from what I’ve seen it’s also R9050 and has a smaller die, so it won’t handle as much power as the 519A/FFL.
The 219C die is known to be pretty tough (goes to 5-6A just fine), and Nichia gets pretty good R9 even for R9050 emitters, usually an R9 of 70 or so. The die is smaller but not tiny, probably comparable in size to an XP-G4 HI but with better tint and CRI. I really want to get some but they’re not being sold anywhere.
The CRI is unfortunate, but the lower output is inherent to the domeless construction. It’s a similar lumen-watt curve to a dedomed 519a
The 219C can handle the current, but won’t produce as much output as a larger-die emitter like the 519A. The output of the blue die is limited by power density and heat, and so is the efficiency of the phosphor. But yes, it should certainly be an upgrade over the XP-G4 HI. It really does suck that nowhere seems to stock the 219C V2, it has potential to be the throwiest emitter in the R9050 CRI class.
The 719A has two advantages over the dedomed 519A when it comes to spectral efficacy: lower CRI (less power spent on deep red which contributes little to lumen count) and greener tint (more green which is the color that contributes the most to lumen count). Thus, to achieve the same efficacy as a dedomed 519A despite the more advantageous spectrum is truly a step backwards in efficiency.
You are forgetting the Cree XP-P, which has a 1mm² die, same as an Osram W1.
The XP-P in CCT≤5700k are available in Ra90 (in theory), which has a typical R9 of 50. The version in Ra90 3000k is known to have decent tint too.