Convoy S21D w/ legendary Nichia 219b :) - Review & comparison w/ Nichia 519a, E21a & other lights with Nichia LEDs incl. Emisar D4V2, Convoy S21F. (Summary & measurements on P. 1)

1. 10 is the narrowest beam, 60 is the widest. Even with the 10, it’s not exactly a throwy flashlight, though.
2. 519A has great brightness, tint, and CRI. Most other emitters only have two of the three.
3. That depends on your taste. 4500K is what I like, although 5000K is all right indoors too. You might like something way different, but 4500K is probably a safe starting point for a lot of people.

Thanks for that nicodimus22

I’m not sure if you have look around, short list and choose a S21D-a light with TIR for a bike light.

Or at some point, you are confuse while reading this thread.

Imho, take a look at the S12 triple emitter with 519A-8A driver. It’s more appropriate then the S21D for a bike light.

I will, thank you

I was thinking the same thing. Bike light probably has specific requirements such as certain brightness and not shining on eyes of people in opposite direction, etc., and the S21D with Nichia (lowish brightness and throw, no easy control of direction) is probably not the best candidate, as nutty as I am about it :slight_smile: .

BTW the picture shows why I feel confident about Duv numbers from my Convoy AR Green Tint lens’s comparison. IMHO, the Opple’s number one “enemy” is change of position and angle between light and sensor. While there is nothing wrong with hand holding for quick reads, for me the only way to prevent fluctuation and improve repeatability is tripod use.

It turns out one weakness of my test, I couldn’t find the original “bad” Convoy AR Purple to buy and have to use the larger UCL Purple, is the same reason it is consistent, down to 4th significant figure of X,Y coordinates. I just hold the lens in front and record numbers. Moving it off shows instantaneous change, without touching the light. Where other testers may record one number, I could do 10 instant A:B comparisons (the best kind of comparison IMHO) without much effort.

To me the Opple is a garbage-in garbage-out type of device, if you want accurate comparison test, nothing beats repetition and nutty OCD. I have a nerdy notebook with pages of data to prove. :+1: :slight_smile:

For me photography is the final arbitrator - to answer the question “is there a difference.” I was happy that the beamshots support Opple measurements so closely.

We’ve seen Convoy AC Green vs UCL AC Purple and the rather remarkable effect of a 0.002 Duv change. I was also curious about Convoy AC Green vs NO LENS. Nearly identical Duv. No point to post BBL graph because they occupy basically the same spot.

But what about beamshot - as expected by the nearly identical Duv, the beamshot of Green vs No Lens are very, very close, but not quite the same to my eyes. But… I’ll let you decide for yourself. Is Convoy AC Green that magical, “better” than no lens? :slight_smile:

Repost of Convoy Green vs UCL AC Purple for comparison (much larger Duv change here)

Thank you so much for posting the comparison wallshots! The green coating really does make a difference over no coating, to my eyes at least. If you had shown me just the centers of the two beams, I probably won't be able to tell. But with the edges of the beams also in frame, the reduced tint shift from green coating is more obvious.

@QReciprocity42 thanks for the nice comment. The comparison test took a lot of time and effort so it’s good someone besides me is enjoying it :slight_smile: . The change in color of the beamshots is subtle yet still took me by surprise, especially Green versus NO LENS where Duv are so close I didn’t expect to see a difference. BTW I took 2 shots with each lens and did two rounds. The second round shows the same extremely subtle but noticeable change.

Another interesting note is UCL Purple was clearly worst wrt Duv, but best with light transmission. It consistently has highest brightness among the three TS30S lenses.

In earlier post above you were discussing change of Duv of a LED far from the BBL versus one close to the BBL. I happen to have a light that would be a good candidate to do that comparison with actual beamshots, my Wurkkos with Nichia 219c 5000k. This LED is much closer to the BBL than the very negative 219b.

I am not surprised that the purple AR has the greatest lumen count, since for the same radiometric amount of light, purple contributes a lot less to the lumen count than green, as the luminosity function on the visible spectrum peaks at green and decays quickly at the tails, which are blue and red.

I would be extremely interested to see the duv change comparison around or far from the BBL, and agree that your 219C sample is a good candidate. Though I do recognize how much work and effort it takes to make these comparison shots.

nice comparison :wink:

OT: I can’t help but wonder if optics is your field of expertise? You don’t have to answer - I’m just curious :+1: :slight_smile: . I am just glad that my observation is no BS & there’s an explanation.

The testing of these lenses itself is quick. It’s all the setting-up and little things I have to watch out for: battery full, light at warm temperature, pointing at exact same location, consistent camera setting, not mixing up the RAW files, etc., that’s tedious and a pain, if I don’t want any error.

I am running one more round of Duv testing of the 219c 5000k this evening then will post beamshots. Strange hobby, could only work at night.
Thanks Jon for the crop. Interesting isn’t it?

I recently replaced 9 of my purple AR lenses with the new Convoy green ones and noticed a slight, but noticeable improvement in the tints.

For my 219B flashlights, it restored them back to their notorious slightly rosy tint. I didn’t replace the purple lens in my 4500K sw45k flashlight since it was already very rosy.

The green lenses also made my 219C, SST-40, and LH351D flashlights just that much better.

Well worth the time and minimal cost to replace them. :beer:

In the past I always replaced the non-AR lenses in my mods with AR lenses to get the maximum lumens, but didn’t consider the impact on tint. Now with the green lenses, there doesn’t seem to be a compromise and may actually be a benefit.

I wish! I'm actually a fourth-year mathematics major in college, though I do enjoy reading about random stuff.

Here's an interesting thought: the low sensitivity of the human eye to blue/red is much like the low sensitivity of the human ear to low frequencies. Thus, perhaps a light with pink tint could be thought of as the visual analogue of bass-boosted headphones...

Your meticulous setup takes a lot of effort, and we really appreciate your doing these tests. Looking forward to your 219C 5000k comparisons!

A big weakness of my testing so far is the comparison is against another brand’s non-fitting large purple lens, not Convoy OEM purple. I actually have bought and am waiting for an Aliexpress small purple lens that fits my S21D, but that is still not Convoy OEM. If you don’t mind sending/”selling” one of those spare purple lenses to me, please PM. My Convoy’s are S21D, M21 B, E, F, but would really like the S21D purple. Thanks.

Oh one of those, Math major, now I understand the precise “language” (a compliment). Mine was Chemistry and I really think I would not have graduated had I chosen either Math or Physics. Also, I thought 1942 was the year of your birth; was thinking I was talking to some old fart, like me. :person_facepalming: :partying_face:

As well as an Opple, I also have a green AR glass Convoy S21E 519A 5700k in the post, that I can compare to a purple AR glass version. Will post the results and photos here.

Thank you! Studying math has definitely helped me with my communication skills. I have so much respect for chem and physics majors--I took both classes at the college level and found them much more difficult; the stuff they do makes math feel concrete in comparison. I actually really enjoy interacting with people from older generations, they always know so much random stuff I can't even imagine...42 is a reference to Douglas Adams's Hitchhiker's Guide to the Galaxy.

Looking forward to stephenk's comparison as well! And can't wait for my green lenses to arrive, the tint shift on my S2+ 519A 5700K triple is killing me.

Sorry, but 8 were the 20.5*1.6mm ar-coated glass lens ,suitable for Convoy S2/S2+/S3/S6/S9 BD03 flashlight and the other was for an S21A (23.2*1.4mm ar-coated glass lens ,suitable for Convoy S21A S21B).

Thanks for checking. I have this one on the way, 23.7 mm. Hopefully it’s the correct size and hopefully it’s a real bad AR purple so I could prove a point, that Convoy AR Green is magical :partying_face: : Page Not Found - Aliexpress.com

Please do! For me it’s important to compare with other people’s results. I am sure you’ll have a lot of fun with the Opple. I’ve gotten better at measuring, and results are more stable and consistent.

BTW a few things I do that have helped for Duv measurements, in case you find it helpful: I keep distance between sensor and light short (1-2 ft) so that it’s easier to keep center of beam on center of sensor and incident angle perpendicular (I’d better be careful with these math terms with QReciprocity42 around. :) ), use a lower brightness level so the light doesn’t step up and down too much (for me Convoy which settles at that 40% level seems easier to work with than Wurkkos & Anduril, which goes up and down a lot), let the light warm up Wurkkos TS21’s Duv for example keeps dropping slowly over the 20 minutes after turn on.

I added to the first page an index of the posts that I’ve wasted the most amount of time on :person_facepalming: :slight_smile: . Hope it helps for anyone looking to waste time reading about Convoy.