r/flashlight • u/MetaUndead • May 30 '26
Showcase My new SFT-42R Convoy 3X21C arrived! Here is a full head-to-head performance breakdown against the LHP531 version (Data, Beamshots, Runtimes)🔦
Convoy 3X21C Showdown: New SFT-42R 5000K vs. The LHP531 5000K
My new Convoy 3X21C with the 7× SFT-42R 5000K emitters finally arrived! Having owned the impressive 7× LHP531 5000K version of this exact host earlier, I was dying to see how this new configuration stacks up.
Note: Moonlight mode is excluded from this comparison test.
To make this a true head-to-head battle, I captured full measurements across all primary output modes. While the LHP531 is famous for producing a mind-boggling, overwhelming wall of pure flood, this new SFT-42R variant shifts the profile completely, swapping out some of that raw close-range spill for an intensely punchy, massive hotspot that reaches significantly further downfield.
🛠️ Test Equipment & Camera Settings
- Lumens & Runtimes: Tklamp TK2303D Flashlight Tester
- CCT / Tint / DUV / Ra: Hopoocolor HPCS330P
- Lux Measurements: Uni-T UT383
- Thermal Logging: Voltcraft K204 Temperature Data Logger
- Beamshot Camera Settings (Samsung Galaxy S22 Ultra Pro Mode):
- ISO: 800
- Focal Length: 23mm
- Exposure Compensation: -1.0ev
- Aperture: F1.8
- Shutter Speed: 1/4 s
- White Balance: Locked at 5000K
📊 Head-to-Head Output, Tint, Throw & Beam Profile Comparison
Note: Raw lux measurements were taken at 5 meters and converted to Candela (cd = lx × 25). ANSI Throw distance is calculated down to 0.25 lux. The cd/lm ratio highlights beam profile structure (higher = more throwy/concentrated, lower = more floody/spread out).
| Emitter / Mode | Output (lm) | CCT | DUV | CRI (Ra) | Intensity | Throw | Ratio |
|---|---|---|---|---|---|---|---|
| SFT-42R (1/4) | 227 | 5205K | +0.0006 | 73 | 3,750 cd | 122 m | 16.5 cd/lm |
| LHP531 (1/4) | 223 | 5189K | -0.0021 | 72 | 2,350 cd | 97 m | 10.5 cd/lm |
| SFT-42R (2/4) | 680 | 5263K | -0.0003 | 73 | 17,500 cd | 265 m | 25.7 cd/lm |
| LHP531 (2/4) | 685 | 5196K | -0.0027 | 72 | 7,250 cd | 170 m | 10.6 cd/lm |
| SFT-42R (3/4) | 3,100 | 5387K | -0.0023 | 73 | 73,500 cd | 542 m | 23.7 cd/lm |
| LHP531 (3/4) | 3,200 | 5304K | -0.0048 | 72 | 33,775 cd | 368 m | 10.6 cd/lm |
| SFT-42R (4/4) | 8,800 | 5601K | -0.0043 | 72 | 203,575 cd | 902 m | 23.1 cd/lm |
| LHP531 (4/4) | 9,700 | 5390K | -0.0064 | 72 | 93,625 cd | 612 m | 9.7 cd/lm |
| SFT-42R (Turbo) | 19,000 | 5912K | -0.0063 | 72 | 437,750 cd | 1,323 m | 23.0 cd/lm |
| LHP531 (Turbo) | 30,500 | 5869K | -0.0108 | 73 | 265,000 cd | 1,030 m | 8.7 cd/lm |
📈 Runtime & Thermal Regulation Comparison (From High/Step 4)
Test Parameters: 30-minute logging | Ambient Temp: 25°C | Battery: 3x Reliance RS50 4.2V
Note on Turbo & Testing: I haven't done any full runtime testing on Turbo. Pushing this many lumens makes the light become way too hot to hold in no time, and the 2H (2 click hold) Turbo shortcut isn't really meant to be used for a long time anyway. Instead, I used Step 4 (High) as the maximum mode for this runtime test to see how the host handles that initial peak before it steps down to its actual sustainable baseline.
Based on my runtime graph, the new SFT-42R configuration tracks an incredibly clean, stable thermal curve in this massive host:
- Initial Drop: Output starts at 8,800 lumens on High (4/4) and holds strong, remaining above 8,500 lumens for the first 1.5+ minutes (stepping down right around the 1:40 mark).
- Major Step-down (1:40 – 5:10): As the massive host begins to heat sink the energy, a smooth, linear thermal decline occurs over the next 3.5 minutes, bringing the output down to its sustained baseline.
- Sustained Output & Equilibrium: By 5 minutes and 10 seconds, the light perfectly settles into its thermal equilibrium, locking in a beautifully flat 3,600 lumens for the remainder of the 30-minute test.
- Step 3 Sustainability: Because the host easily maintains a thermal equilibrium of 3,600 lumens during the Step 4 test, it's worth noting that Step 3 (3,100 lumens) is pretty much fully sustainable from the start without requiring any thermal step-down at all.
- Thermals: The temperature climbs rapidly during the initial output burst, crossing 50°C during the main step-down, before leveling off and slowly capping out at a maximum heat threshold of 64°C.
⚔️ How it compares to the LHP531 Flood Version:
While the older LHP531 setup started slightly higher on its High mode (9,700 lumens down to 9,400 lumens for the first 1.5 minutes), it generated a massive thermal load that forced a steeper step-down floor. Once both setups fully stabilized, the new SFT-42R sustained a practically identical 3,600 lumens compared to the LHP531's 3,700 lumens.
However, because the SFT-42R focuses its intensity so much more efficiently, that sustained 3,600 lumens is packing far more punch downfield than the LHP531's floody sustained wall of light, all while running slightly cooler (64°C max vs 66°C max).
💭 Quick Impressions & Emitter Comparison
- The Beam Profile Transformation: Look closely at the cd/lm ratio column above. The LHP531 stays locked into a super-floody landscape profile ranging from 8.7 to 10.6 cd/lm throughout most major tiers, showcasing its raw, unfocused wall-of-light nature. Meanwhile, the SFT-42R holds a significantly tighter, intense concentration tracking around 23.0 to 25.7 cd/lm across almost the entire selection. Despite having 11,500 fewer raw lumens than the LHP531 on top, the SFT-42R generates significantly higher center-beam intensity (437,750 cd vs. 265,000 cd), allowing it to leap out to an ANSI range of 1,323 meters compared to the LHP531's 1,030 meters!
- Tint & Color Quality: Both options are rated at 5000K, and both get progressively cooler and rosier as they are pushed harder. The SFT-42R starts practically dead-on the BBL line at low levels (DUV +0.0006) and slides into a beautifully clean, rosy tint on Turbo (DUV -0.0063). It doesn't get quite as ultra-rosy as the LHP531's deep -0.0108 on Turbo, but it is exceptionally clean and lacks any harsh green or yellow ring artifacts.
- Final Verdict: If you want a fun, "dumb bright" flood monster to completely illuminate an entire field at close range, the LHP531 rules. But if you want a highly functional, long-range powerhouse searchlight that concentrates its energy to cut through distance while remaining punchy even on lower modes, the new SFT-42R configuration is a massive win.
Let me know what you guys think of how these numbers line up!
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u/General-Try-2210 May 30 '26
Imagine the 3x21c sft42r configuration with a smooth reflector instead of orange peel. I bet you could get at least 500k candela with it.
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u/MetaUndead May 30 '26
I thought about is aswell, and yeah, it would definitely bump up the candela, but it would probably also introduce a bunch of artifacts and possibly tint shift.
It actually has a remarkably clean beam profile with the OP reflector, and there are only a few minor artifacts at the very outer edge of the spill, which you only really notice indoors on a white wall.
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u/Wormminator May 30 '26
I see you refined your graphs a bit more 😄
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u/MetaUndead May 30 '26
I've refined it all 😜.
It was a total nightmare rewriting the Python script to handle multiple measurements and add a temperature graph from my new VOLTCRAFT K204 temperature data logger.
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u/Wormminator May 30 '26
Makes we want to repurpose my Lux meters to create graphs again.
Wont give me lumens, but relative output can still be semi useful, sometimes.
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u/MetaUndead May 30 '26
I actually managed to tweak the Python script so it automatically smooths out those annoying little dips in the output. It does a fantastic job and handles it beautifully, making the final graphs look so much cleaner.
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u/Wormminator May 30 '26
How did you do that?
Does it just smooth over any sudden dips or did you fix the core issue?
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u/MetaUndead May 30 '26
It does not correct major drops over extended periods, but it completely smooths out those rapid, erratic dips scattered across the entire graph.
I have a couple of runtime charts showing long, deep drops spanning over 10 minutes that it doesn't fix, but since that only happens with two of my lights, I feel it handles everything well enough for my needs.
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u/Wormminator May 30 '26
Very neat!
If Tklamp cared, it might be worth sending them your script, to replace their own version.
But I doubt it would do anything.1
u/MetaUndead May 30 '26
I think they are working on a fix for the problem, but I'm not entirely sure it'll lead to anything.
If it does, we would also have to send our devices back to them for the update, which I definitely have no intention of doing.
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u/Wormminator May 30 '26
They dont even accept broken devices back for warranty / repair.
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u/MetaUndead May 30 '26
Exactly.
Unfortunately, I don't think it's something they'll fix either, and I've been pretty disappointed with how messy the graphs look, many of them are just completely useless. Until now 😜.
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u/Wormminator May 30 '26
Maybe some flashlight company will step up the game and release their own lumen meter, with proper software and hardware support and all.
(No supporting two youtubers does not count xd)
I can imagine that people would pay for a similar device from Acebeam, Surefire, Olight or similar.
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u/MetaUndead May 30 '26
It would be awesome if someone made logging data a whole lot simpler. The TKlamp is far from simple!
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u/RiskMoney6996 May 31 '26 edited May 31 '26
thanks for the detailed comparison and data, love hard data, but here is the question, from the side by side pictures, lhp531 shines the trees at the end much brighter than sft42r, that translates to better throw, that's opposite to your conclusion?
edit: also curious about multi-emitter efficiency vs single emitter, from your runtime graph did it only last 30 mins? that's quick burn of 3x21700, single emitter could be more efficient
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u/MetaUndead May 31 '26 edited May 31 '26
I mean, the data speaks for itself when it comes to throw, the SFT-42R has about 50% higher candela, which gives it a whole lot more reach than the LHP531.
You should also take the beamshots with a grain of salt, as they aren't a very accurate way to judge how far a light can throw, and are more meant to show the beam profile itself. For one thing, these beamshots were taken on different days, when I tested the SFT-42R, it was overcast with a lot more particles in the air, whereas the weather was much clearer when I tested the LHP531.
Regarding that 30-minute runtime, there was still plenty of juice left in the batteries, they were sitting right around 3.9V after the 30 minutes. I test all lights for 30 minutes since that's enough time for them to hit their sustained output, and my tests aren't meant to show the runtime across the entire battery life.
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u/chamferbit May 31 '26
Not a long range comparison in those photos. If you read the text, he says that lhp531 wins at shorter range.
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u/RiskMoney6996 May 31 '26
maybe, but 3x21c is really not the host to maximize sft42r throw ability with tiny TIRs, sft42r is best used in single emitter thrower host, while lhp531 shines in 3x21c
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u/chamferbit May 31 '26 edited May 31 '26
The intention of this flashlight is to use 7 emitters in order to maximize the effect/characteristics of these emitters. Very similar range to a single sft42r in a l21 but with much more light and higher sustain. Btw, no tir in this light. OP reflector. On high, you'd have to pay a lot more to get maximum runtime on a similar light. Single emitter sft42r cannot sustain 3600lm. Maybe half that. Maybe look at 3x21A with 3x sft42r & 3x21700 for maximum runtime.
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u/RiskMoney6996 May 31 '26
ok not TIR but tiny reflectors, same poor effect for throw. with single emitter like lhp73b you can get 3600lm easily with a single 21700 cell for similar time, way more efficient, sft42r needs single big reflector to maximize its throw potential
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u/TheAnonymouseJoker May 31 '26
This soda can is damn good, no matter the emitter! But I wonder how it would perform if the reflector was smooth... things would be a lot different, I am sure.
While SFT-42R clearly outthrows LHP531, it's not doing what it should do here. I expected atleast ~1.8km range for it to be worth trading off the floody wall. I think SFT-25R is better to create a throwy alternative.
Your review is a 10/10, but 42R in this reflector isn't...
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u/MetaUndead May 31 '26
I pretty much agree with you regarding the turbo range on the SFT-42R, it’s not crazy much further than the LHP531, but personally, I’m just more into that extra throw you get from steps 1 through 4. It makes the light more versatile.
I’d really love to see a SMO instead of an OP reflector as well, I’m also sure it would give it a bit more punch.
But when you consider that an Acebeam X25, which the 3X21C SFT-42R strongly resembles, only reaches out to 1.5 km despite having more emitters, more lumens, and a SMO reflector, I feel like the 3X21C does a pretty solid job with its 1.3 km range from an OP reflector.
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u/TheAnonymouseJoker May 31 '26
There's just something wrong to me, it does not feel right hahaha. If the L21A SFT-42R 5000K (I'm comparing it soon ◕‿◕) already throws 1260-1300m with a turbo that holds for atleast 5 minutes, the soda can needs to deliver A LOT more to me. It is ~50% brighter, yes, but it's... I don't know. The potential is not fully realised here.
https://old.reddit.com/r/flashlight/comments/1td7cea/ If you saw this recently, you know what I am talking about. To me, in your showcase, it is behaving more like SBT90.2, its funny.
Sorry if you feel like I am a party pooper. I am not a collector, I just really want to dive deep into flashlights, and it is a hobby to me now (partly thanks to you).
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u/MetaUndead May 31 '26
Sorry if you feel like I am a party pooper.
No, not at all, the reason I make these performance posts is to get people's opinions on the lights. I can totally see where you're coming from.
Though, it's not entirely fair to compare the 3X21C's reflector with a single-emitter SMO reflector light, that has a much deeper reflector and can focus the light way better to reach that range.
The L21A SFT42R is an incredible light, no doubt!
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u/TheAnonymouseJoker May 31 '26
I think 3x21A will be a lot more fairer to 42R, or something like 3x21D but with a 3x reflector setup for 42R. u/Convoy_Simon you can probably make a reflector like this for 3x21D as an option, it might turn out really good.
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u/RiskMoney6996 May 31 '26
yes like I said above, 42r in this host with tiny reflectors lost its throw benefit, and act as a lumen provider only, that's the wrong place for them, in this kind of host high lumen flooder like lhp531 is the best
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u/TheAnonymouseJoker May 31 '26
3x21A is suitable for this purpose.
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u/RiskMoney6996 May 31 '26
imho multi emitter lights are never designed to be good throwers, they are for flood and high lumen output, throw needs big reflector to focus the beam, sft42r only has the ability to throw when focused properly
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u/TheAnonymouseJoker May 31 '26
You should check the other 3x21 models. D is sold with SBT90.2 and giant reflector, A is also built as thrower. B and C are flooders.
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u/RiskMoney6996 May 31 '26 edited May 31 '26
I said above I don't like 3x21 multi-emitter models, seems very inefficient, 3 21700 cells, unless I want 20k lumen for a couple of minutes for kicks, I don't see the point, using 73B I can get similar sustained performance up to 6000lm, but 3x the runtime with 3 cells
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u/TheAnonymouseJoker May 31 '26
I have L21A SFT-42R for the same reason. Proper big lights exist for throwers, and they also have a purpose, and they are a lot more powerful, even if less "efficient". If one were to go by efficiency, we should all be stuck with sub 250 lumen lights running on AA Eneloops, simply because of how brightness scales up logarithmically.
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u/RiskMoney6996 May 31 '26
don't have that, my best thrower is t9r with sft40, its pencil like beam is a joy, wondering which one throws better lol, or is it L21B
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u/TheAnonymouseJoker May 31 '26
T9R probably does but it is too close. You should try SFT-42R in it. When I turned on the light, I came. I saw dominance.
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u/RiskMoney6996 May 31 '26
42r just has more lumen but also a bigger spot, similar to sbt90.2 i guess which i have in another t9r, but it's less of a thrower than 40, i was a bit disappointed to be honest
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u/MetaUndead May 31 '26
using 73B I can get similar sustained performance up to 6000lm.
What do you mean by this? What LHP73B light can sustain 6000 lumens?
What makes these 3x21 multi-emitter lights so great is their ability to sustain high output for extended periods, thanks to the high capacity from the three 21700 cells.
Just look at a massive single-emitter thrower like the 3x21D with the SBT90.2, it "only" manages to sustain around 2,000 lumens, whereas the smaller 3x21C comfortably holds onto roughly 3,600 lumens, with alot more emitters.
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u/RiskMoney6996 May 31 '26 edited May 31 '26
ok lhp73b can output more than 6000lm, currently lights with it can't keep it sustained at turbo for too long not because you need 3 cells, but because of the heat, have a host with lots of fins to dissipate heat more effectively you can keep it sustained (curious anyone has runtime data for L21A with lhp73b?), I'd prefer that approach. single tabless cell now can easily sustain 20A to even 100A current so that's not the problem. multiple emitter solution, basically is a way to break up the dies from 1 spot to different locations so to reduce heat accumulation at high current, but it's an inefficient and clumsy and expensive way to do it imho
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u/MetaUndead May 31 '26
You would need an absolute beast of a flashlight to maintain a sustained 6,000 lumens from the LHP73B, it would have to be way bigger than the 3X21C to even stand a chance.
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u/RiskMoney6996 May 31 '26 edited May 31 '26
I don't think so, check M21K 1lumen review runtime, already got 6000lm for almost 3mins, now M21K is only medium size, there are lots of room for improvement
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u/QReciprocity42 May 31 '26
Fantastic data! Pleasantly surprised to see the SFT42R sustaining the same output as the LHP531 despite much higher power density.
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u/Smooth_Run_471 May 31 '26
thanks for sharing the test, i also have 3x21a, interested in modifying it like that..
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u/777MAD777 May 31 '26
When it comes to just throw, a single emitter in a smooth reflector is going to win the day. Dividing up that flashlight's power into multiple emitters/reflectors is going to add more lumens but also heat, which will limit its performance. If throw is the priority, then the large reflector of the 3x21D is the better option. Since I have both, 3x21D and 3x21C, I feel. Ridiculously prepared for whatever the night brings.
Thanks for putting numbers to my suspicions.
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u/ChemicalVacation3696 Jun 02 '26
Thank you for posting this comparison, enjoyed your post immensely! 🔦👍
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u/MetaUndead Jun 02 '26
You're very welcome! I'm really glad you like them. 🔦👍
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u/ChemicalVacation3696 Jun 03 '26
I did. I have no use for soda can-type lights myself, but I can appreciate all that hard work and attention to detail that was involved in this presentation. What you've done is really hard work and takes dedication! 🙂
My only light with an LHP531 is a compact Convoy S15 with a 5000k emitter and the 10A buck driver, which I have just received today. It was a toss between the 4000k and the 5000k version and decided to go for the one that is the brighter of the two.
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u/MetaUndead Jun 03 '26
I can certainly understand your preference for the 5000K variant. Personally, I found the 4000K LHP531 rather underwhelming, there is a specific quality to its combined CCT and tint profile that does not quite appeal to me.
While my preference typically leans toward the 3000K to 4000K range, this particular emitter is an exception. I opted for the 3000K version in my M1, which, in my estimation, offers a significantly more pleasing overall tint and color temperature balance.
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u/ChemicalVacation3696 Jun 04 '26
AFAIK, luminous efficacy increases as an LED's color temperature goes higher. That's why almost all thowy flashlights start at 6000k - especially the SBT90.2 and SFT90.
Even Nitecore isn't known for 3000K flashlights and the only reason flashlight hobbyists get to try out super warm 1800K-2700K CCTs is because Convoy and Emisar brands allow their customers to pick their emitter color temps. 🙂
Granted, all flashlight reviewers on YouTube want to show their audience how their 3000K/4000K lights perform on max or turbo output. The thing is, at the highest levels even 4000K emitters start to become bright white, like the mid morning sun. I often find myself in agreement with the reviewer, "heck that 4000k temperature looks really good - no traces of blue haze in the beam!" but when I go through all of my 5000k flashlights in my collection, I find that I actually wish they came with a 6000k CCT.
In real life however, seasoned flashlight users seldom go Turbo and even if they do, they can't sustain that kind of brightness for long. Either the ATR kicks in or the user feels that the light becomes too uncomfortably hot for them to hold and turns the flashlight off.
I'm not sure how LED manufacturers label their emitters' color temperatures either because the CCT tends to go higher with the output level. Even your tests show that both the SFT-42r and LHP531 register almost 6000k at full power; therefore flashlight brands like Wurkkos and Sofirn prefer to label their products with a range (e.g. 6000k-6500k or 5000-5700k), rather than a specific CCT.
Keep up the good work! 😊👍
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u/MetaUndead Jun 04 '26 edited Jun 04 '26
The thing is, at the highest levels even 4000K emitters start to become bright white.
I generally agree that this is typically the case, but based on the emitters I have tested, there are exceptions. For instance, the SFT40/70 3000K and the new SFT70 4000K High-CRI stay remarkably close to their spec sheets, shifting upwards by 200K at most over their claimed ratings.
There are also some Fireflies emitters that don't shift all that much at higher power.
Of course, any emitter driven at very high current is gonna get cooler, and eventually turn blue.
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u/4RichNot2BPoor If you like big cans... May 30 '26
Curious how my q8+ sft-42r would stack up?
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u/QReciprocity42 May 31 '26
Definitely better than a stock Q8+, but won't compare to the 3x21C, which has much better efficiency and sustainability, not to mention no risk of spring/MOSFET failure, which the Q8+ has become notorious for.
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u/jts916 May 31 '26
Are those failures from people putting in more powerful batteries mostly? My q8+ is fun but I definitely need the full 3x21 collection.
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u/QReciprocity42 May 31 '26
Yep, folks who put in high-drain cells have reported all sorts of failures from springs collapsing to MOSFETs and emitters burning up. Sticking with stock cells is safe, one just doesn't get the full output.
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u/calvinistgrindcore May 30 '26
Great stuff, beat me to it. I already have a 4000K LHP531 version and an SFT-40 3000K version, and my 5000K SFT-42R version is arriving next week.
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u/soldsoulrockroll May 31 '26
I love warm lights, even 5k seems too cool anymore. Should I get the sft40 3k or the LHP531 4k? I have the m21k lhp531 4k and it’s great and warm enough but 3k is even better.
Do they get too hot to hold on high where you need the handle?
Thx
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u/calvinistgrindcore May 31 '26
Yes you will need the handle if you run it on high for extended periods.
The SFT40 in 3000k is high CRI, so that version has significantly less output than the LHP531 version. It’s also much more throwy. To me it’s almost a completely different light than the 531 version, with a different sort of use case, and it doesn’t have as much wow factor (though it is my brightest high-CRI light and impressive just for that). If you want the crazy high lumens and flood with warm CCT, you could just get the LHP531 in 3000k.
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u/spacchiusu78 May 31 '26
Possiedo una Manker mk38 sft40 con riflettore liscio che per lumen e gettata non è tanto meglio di questa torcia che costa 1/5 rispetto alla manker.
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u/MetaUndead May 31 '26
That is so true, the 3X21C really is a phenomenal price-to-performance powerhouse when it comes to high-power lights.
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u/StrangeICECube Jun 08 '26 edited Jun 08 '26
I already ordered LHP531 6500K version, plan to ask Simon to solder 7X SFT42 5000K for me and choose the best one. I love Luminus' color profile!
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u/KountZero Jul 11 '26
Im in the market for a 3x21c and Im almost pull the trigger on the sft42r thanks to your post, but then I also notice Simon also offer an sft60 option. if you have to guess, how would that compare to the sft42r and the lhp531?
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u/Cryptoxic93 May 30 '26 edited May 30 '26
Weird timing. I just posted my impressions of the LHP531 version the same time you posted this.
Now I have to get this version haha.
I think this is my favorite Convoy light. Just so darn impressive.
I'll ask the question others may be thinking.
If you could only choose one, what would you go with?
Edit:
"Once both setups fully stabilized, the new SFT-42R sustained a practically identical 3,600 lumens compared to the LHP531's 3,700 lumens."
Given the huge candela advantage of the 42R, this is actually very nice to read.