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)

I’ve been looking to pick up the S21D in 3500k 519a but now I see this S21E with integral C charging… Sure its lower output but still brighter than my backpack zebralight. Anybody want to sway me one way or the other???

In the following picture note how hotspot becomes brighter (more throwy) at same time that tint shift appears and spill decreases (less floody) as we move from Carlo 10623 to 10622 and then 10621. Also the interesting difference between E21a and 219b: both has tint shift, but it appears “earlier” and more severe in E21a , resulting in Hank needing to use frosted 10623.

For 219b lights Hank uses 10622, a clear optic. For E21a however he switches to 10623, which is frosted and results in a beam that is for me, way too dim. D4V2 has more aggressive thermal stepdowns than Convoy in the first place, and starting that dim is not good for me. 10623 also drops overall brightness as well as throw using ceiling bounce method (down 16% from 10622). This is not something I see with the various Convoy optics wherein overall brightness stays the same between the 5 optics.

10622 versus 10621 for 219b 4500K: The little gain in throw from stock 10622 to 10621 is not worth it because now I see the appearance of a yellow tint shift. I also like the larger spill (more floody) of 10622, and the more gradual and pleasant transition from bright hotspot to spill to darkness. 10622 in this Emisar light creates a most beautiful beam.
10623 versus 10622 for E21a 4500K: This one is a little more difficult. 10623 decreases throw AND brightness so much that I am willing to trade to 10622 despite the appearance of tint shift with 10622.

The S21D has a big step up in max and sustained lumens over the S21E. The latter does have a better UI, a bit smaller, and charging.

Guys, are we picking up the Ti T3 or naw ;D

https://www.aliexpress.com/item/3256804460263119.html?spm=a2g0o.cart.0.0.6cdb38daqJ8xaW&mp=1

White wall hunting beamshots could only tell so much. How does it translate into real life scenes? Here are some actual pictures comparing the three 10 Degree optics:
Sofirn 10 Clear
Convoy 10 Clear
Convoy 10 Bead

The comparison between Sofirn 10° Clear vs Convoy 10° Clear optic is very interesting. They measure identical, the throws are identical, but photographically the Sofirn is just a touch brighter. But this could be shot to shot variation and it is so close I won’t argue if you see differently. Either of the two 10 Clears are winners for those wanting more distance.

I think it’s a matter of time until my neighbors complain about these beamshots into their yards. :person_facepalming: :confounded:

Great shots!

Thanks snfx. White wall beamshots have their role, but nothing could replace a real-life shot.

I added the same picture of the hill using Convoy 30° Bead optic to the collection above for comparison. In that series of 4 pictures, as the optics go from narrow to wide, it’s a very nice confirmation to see how the periphery, garage door on far left and olive tree’s branch on near right, becomes brighter (flood), at the same time that central brightness is decreasing (less throw/hotspot brightness). These series of pictures on this page are really the most fun flashlight “work” for me so far.

For me, this kind of floody view with 30 bead is useful if the light is used mostly close-up, such as inside house, at camp site’s dinner table, etc. It’s less blinding (less hotspot, more periphery). The 30 bead is a nice compromise between 10 Clear and 60 Bead. If anyone is ordering new S21D, I would ask for the gift pair Convoy 10 Clear and Convoy 30 Bead to start.

BTW I am aware some of these posts are for Emisar D4V2, but one, we have “cross” owners lol, and two, what’s interesting for D4V2 should be equally interesting for Convoy connoisseurs IMHO. Anyway, found something interesting while perusing the Carlo Optic web site
https://www.carclo-optics.com/products/optic-10621

It seems you could predict the nature of the optic by this ratio the arrow is pointing at. The higher candela (hotspot brightness representing throw) per lumen (“overall brightness” in simplified terms) means it’s a more throwy optic. By comparing this spec for the same LED by different optics, for example 10621 versus 10622 versus 10623, you could tell which optic has most throwy before testing. For example 7.6 for 10621, 7.2 for 10622, but only 3.2 for the frosted 10623.

This was how I could tell by spec the difference between 10621 and 10622. It wasn’t clear otherwise. It also confirms my observation why frosted 10623 is so dim for me. That is a big jump from 7.2 to 3.2, and I wonder if something in between the 2 would be a more moderate compromise.

The other way to tell visually is that little circle in the middle of each of the 4 small “lenses”. For the same optic series, that circle seems smaller with more throwy optic. But this “method” is more difficult and you have to be a little nutty to be curious about things like this :confounded: :smiley: .

Yet another thing I learned that makes this hobby more fun: AR coatings are not all the same, and they don’t reflect the same color using the light bulb reflection “test” (I just stand under a ceiling light bulb and look for reflection of the light bulb in the flashlight’s lens as if the lens is a mirror. AR coating changes the color of the light bulb reflection.).

I am curious how Duv would differ among the 4 lenses I have:
1. Convoy S21D lens, the latest per Simon with “green tint” - green reflection.
2. UCL Acrylic lens for Wurkkos TS30S - purple reflection
3. UCL Glass lens for Wurkkos TS30S - blue reflection.
4. Wurkkos non AR coated - no change in color.
The question is how to do the amateur level “test” in a reliable manner, not to screw up :slight_smile: as the other lenses are large and obviously don’t fit on S21D.

The UCL lenses are from https://flashlightlens.com/ and highly recommended - about 3-4% improvement in transmission vs non AR coated.

That’s a nice view!

The tested lenses are larger so what I did was taking off the S21D’s OEM lens, then placed the tested lens by holding it, recorded the number, then put back OEM, recorded another number. I did about 4-5 runs or so for each lens, sometimes more. The flashlight was set at 35% brightness and let sit for 15 minutes or so before measuring. I decided to use the middle-of-the-road 30° bead TIR optic this time.

With flashlight mounted on tripod (hence no shaking), I’ve found the Opple Lightmaster Pro (aka Series 3) to be incredibly consistent in its reading of Duv (and brightness & Ra etc.). It reads the same x,y coordinates down to the fourth significant figure between different runs. As such it is a great meter to do comparison work; just remarkable considering how cheap it is. I recommend it extremely highly for anyone into LED collecting.

Duv values for Convoy S21D with Nichia 219b 4500K
The color refers to a reflection of ceiling light bulb, NOT any tint I could see.
Home test for fun, please take result with a grain of salt. There might also be some correction as I double check data.

1. No lens: –0.0127
2. Convoy AR Green-reflection lens : –0.0124 CCT 4471
3. Wurkkos Non-AR: –0.0123
4. UCL AR Blue: –0.0123
5. UCL AR Purple: –0.0102 (Duv change: ~0.0020 more positive) CCT 4365

I find it interesting that the lens with the highest transmission rate, UCL Purple, is also the one that affects Duv the most. Next - beamshots to see if this difference matters in real life scenes.


Great info!

Green reflecting coating is supposed to prevent green tint from getting thru.

As we see from your test, Blue reflecting coating works Just as Well!

The Acrylic w Purple coating lets the most green get through, thereby raising the DUV by 0.0020 compared to the green and blue coated glass. It may not be the fault of the coating, since Acrylic transmits more light than glass, it may also be transmitting more of the Green tint, thereby raising the DUV.

What kind of clamp do you use on your tripod?

The tripod hold I use is this (a legit seller) HERE . It is much better than the small rubber without velcro. I’ve found keeping the light stable is the first step towards measuring reliably, especially for the throw where you have to keep hotspot centered on the sensor.

Thanks Jon. From what I have read (meaning I’m no expert), AR coating targets a wavelength that’s close to the center of the visible spectrum (which is yellow green as explained in article below) and as a result proportionally more green will go through with all AR coating, including Convoy’s. The difference is only how much green, as seen here obviously the Convoy is best, and UVL Purple an outlier worst. To be fair, outside of the UVL Purple, the difference among the lenses is small (it’s in the 4th digit) and within error limit of my amateur testing rig for example, even as I’m quite confident of the result.

A good article on this subject http://rick_oleson.tripod.com/index-166.html

So, if coated lenses are purple, won’t my photos have a purple tint?
No…. actually, they’ll have a slight yellow-green tint – the extra light that didn’t get reflected passes on through to the film, and there’s a little more of the 550nm yellow-green than there is of the other colors. But it’s not very much – glass only reflects about 4% of light from each surface to begin with, and the coating has some effect at all wavelengths – so there’s maybe a couple of percent of extra green light getting to the film. For most normal photography, this isn’t enough to be noticeable in the pictures.

Thanks Cannga!

Btw the Duv test between 1 and 2 (lens vs no lens) should be easy to do for any Convoy owner with Opple 3. I hope to see similar comparison from other owners, especially people who have the infamous lens w/ purple reflection. That way we could compare/correlate our findings.

I think either a. measuring Duv or b. comparison photography (as opposed to visual observation) are important to have some fun with this :-).

I would like to get a hold of Convoy’s lens with purple reflection but can’t find it on AliX. Would very much appreciate anyone who has spare putple lens for any of my Convoy to send it to me . I’ll pay shipping and lens cost of course.

In comparing Duv number, I’ve noted that if the change is in the fourth number after decimal point, for example
“No Lens”: –0.012 7 versus “Convoy Green-reflection”: –0.012 4
it is not easily noticeable on the Duv graph.

What this means is, at least per my test, unless I develop Superman’s vision, I am not sure that I could see a difference between for example No Lens versus Convoy Green Reflection versus UCL Blue. I plan to take beamshots against the wall of truth to confirm if this is true.

OTOH UCL Purple versus Convoy Green Reflection is a bigger difference (it’s on the third number after decimal point) and likely will be seen on Duv graph.

Visually if you compare some 519A lights with different lenses, the difference in DUV is visually noticeable. However if you then add other emitters into the mix such as SSTs and LH351D, then you realise that even the “worst” 519A/lens combination is very neutral and perfectly acceptable.

It's difficult to see a duv difference when both outputs are way into the magenta region--the percent difference between the two is tiny compared to their deviation from the BBL. (Imagine trying to discern between 1 and 10 lumens, and between 1001 and 1010 lumens. The absolute difference is the same, but the percentage difference is huge!)

I also suspect that the green AR lens would make a larger duv difference numerically with a light source that starts off as neutral or slightly green. If the emitter starts out magenta, there is little green to begin with, and not much removal can happen.

It would be lovely if the test could be re-done with emitters that are neutral or slightly green.

Djozz’s quick test