LED test / review - Luminus SFT-25R (6500 K 70 CRI) - good thrower LED in 3535 standard footprint

LED test / review EN


Luminus SFT-25R (6500 K 70 CRI)


SFT-25R-WS65-A2-ENG(F6-VJ-AG)


2024-08-10


  • Type: round die, domeless
  • Bin: unknown
  • Color group: unknown (6500 K)
  • CRI: 70
  • Rated voltage: — V
  • Max. Forward current: — mA
  • Max. Peak current: — mA
  • Viewing angle: — °
  • Thermal resistance: — K/W
  • Max. Temperature Tj: max. —°C

Attention: An official data sheet and further information are not available for this emitter. Official details can therefore not be provided in the course of the test. Although excerpts of a data sheet are already circulating on Reddit, as this has not been published in full and the order code cannot be decrypted, it must still be assumed that there are no official specifications.

The emitter was regularly purchased from Convoylight at the beginning of August 2024.

The SFT-25R is 3.45 x 3.45 mm in size. It looks very similar to the previously introduced and tested SFT-12. The only differences are the round illuminated surface and the number of bonding wires. A silver metal frame is located on the substrate and is covered with white silicone. It can already be seen that the SFT-25R has an LED chip with a round illuminated surface, similar to other round-die LEDs. The factory-domed SFT variants from Luminus are often identical to the SST models, although in this case the illuminated surface of the SST-25 does not match the circular LES of the SFT-25R. This is possibly also the reason for the suffix “R”.

This LED uses the standard 3535, so all accessoires for this footprint will fit.

Bondings are attached to each corner of the LED chip with it’s circular LES. They do not affect the light pattern due to the round surface. The LED chip is 2.25 mm² in size.






  • Maximum reached at 8.2 A, at this point 2013 lm @ 3.84 V
  • Power at maximum 31.5 W
  • Efficiency at maximum 63.9 lm/W




Data for 25 °C Tsp (at 85 °C the luminance values are around 13 % lower).


There were already statements in advance that the forward voltage of the SFT-25R was very high and that the tint was often very green, as with Luminus.

Neither can be confirmed in the test. The Vf remains pleasingly low and also enables use with FET-based drivers. However, operation in direct drive is not recommended, as the maximum possible current could be exceeded depending on the voltage level. The SST-25 used as a comparison has a much higher Vf, which reduces its efficiency.

All in all, the SFT-25R is state of the art in terms of performance and is already quite efficient in this presumably pre-production specimen.

The luminance is in the range of other LEDs with a small luminous surface. As the SFT-25R has not yet been officially released and this sample presumably comes from a pre-production run, it is possible that flux binnings will be increased in later samples, thus significantly increasing the luminous area.



The beam is perfectly fine. Depending on the focus and reflector calculation, slight rings may appear. There are no color distortions in spot or spill.



The tint is pleasingly good. Although the SFT-25R has the extreme tint shift typical of Luminus with increasing current and at low currents it has a minimal green tint, from 1.5-2 A this slips into a clear and ultimately slightly reddish blue-white.

However, it should be noted here that the dispersion is likely to be significant and there will also be very green specimens in circulation.

There are no other surprises in the spectrum. The spectrum corresponds to that of a cool white LED with a CRI of 65-70.


  • Ra: 69
  • R9: -27
  • CCT: 7204 K
  • duv: 0.0010

In current state, the SFT-25R is not a game changer. The luminance is within the expected range of CSLPM1.TG, Black Flat and co. Nevertheless, its overall package provides a significant improvement for 3535 LEDs with high luminance. Until now, other emitters have had more or less significant disadvantages, such as poor beam, strange footprints, connected thermal pad or poor availability and a lack of information.

It can be assumed that the SFT-25R will soon appear at wholesalers such as Mouser, so that proper documentation is guaranteed.

It is also very likely that this LED will play an important role for (pocket) throwers in the future, especially in higher flux binnings, which are likely will released in the next years.


Thank you for reading this test. :slight_smile:

Greetings, Dominik


v1.0.2
23 Thanks

Thank you Dominik for this excellent test!

Given the Convoy samples are a F6 flux bin, I now have high hopes for the F9 bin 5700K that I just ordered from Kaidomain.

How did you arrive at this number? I have seen elsewhere 2.5mm2 or even 2.67mm2.

Thanks Dominik. There is actually an official datasheet for these emitters, Luminus calls it an “Preliminary Product Datasheet”. I remember Simon posted it on BLF, here is the link. Actually people can try asking the dealer for it.

There were already statements in advance that the forward voltage of the SFT-25R was very high and that the tint was often very green, as with Luminus.

My F7-BB-VJ and F9-BB-VJ bins have a noticeable “blue-green” tint to the naked eye at low mode (80mA), but I don’t have a spectrometer to confirm it. Also, when I or others mention “high Vf,” it might be based on the datasheet, where the VJ bin shows a voltage of around 3.7-3.9V at 8A. I’m not sure if that’s considered “high”, but it’s definitely higher than the SFT40.

Another thing is that I think it’s a slight improvement over the CULPM1 and could potentially replace the CULPM1 in the flashlight market, offering more lumens and greater intensity. It might be hard to understand just by looking at the datasheet, but that’s the feeling I and others have. Actually there have always been doubts about the actual lumens of CULPM1, even Acebeam only rated their L19 2.0 CULPM1 version for 1650 lm. There is no rigorous and detailed third-party test of CULPM1 so far, but if there is, I believe it will not be a rival to SFT25(R).

6 Thanks

I have the same question. According to the datasheet, its diameter is 1.7, which should be 2.269800mm^2 in theory.

1 Thank

I measured the size with counting pixels. The area given in the datasheet is right.

Thanks @yoelpez for the link to the datasheet. Hopefully we will see an official one directly from Luminus/Sanan.

4 Thanks

The die looks surprisingly similar to the Yinding 5050, same arrangement of the chip vias, also very similar emitting area. I wouldn’t be surprised if the die end up being the same. If yes, this would be the confirmation that we needed, that the round dies were actually made by Sanan.

Edit: Early sample of the glass Yinding 5050 lit up, looks slightly different from the FFL505A and W5050SQ3 but very similar to the SFT25R.

7 Thanks

Not only similar, they are identical.

Both the chips are 1.8 x 1.8 mm in size, the vias pattern and design is identical. The surface finish of these chips is also identical.

Very interesting: the LMP W5050SQ3 (and FFL505A which is the same as for W5050SQ3) uses a different LED chip, despite from being of similar production date (2023). This chip is also identical in size and surface finish, but the vias pattern and bonding pads are different. I cannot say for now what that means…

8 Thanks

One inconvenient thing about this emitter at present is that at least you can’t buy a matched centering ring from Convoy, cause Convoy’s 3535 centering ring is really compatible with the 3.50*3.50 size of 519A, which is too big for SFT25 3.45*3.45, and these small LES emitter have very high centering requirements. Grinding a 3030 CSLNM1 centering ring may be a option.

You mean this?
I don’t think so. Quite a huge gap, this centering ring used in my S2+ only fits for 3.75 mm LED, not 3.5 mm.

(S2+ red w/ OP reflector and 519A 3000 K, bought August 2024 from Simon/convoylight)

I think I will tell Simon about it. I’ve noticed the same thing with an S2+ with SST-20, except that the light image doesn’t look quite as good because of the SMO reflector used.

3 Thanks

Oh, I get it, so the reason is that Convoy’s 7mm 3535 centering ring is not 3535 at all.

1 Thank

I posted this flaw in Convoy thread already.

I also worry about damaging the LED substrate by pushing with this ring sideways against it. You can see on my pic that one corner of the LED is already pressed into the ring.

Off-topic question - Which part can be moved in the flashlight to accurately centre the LED with the help of the centering ring? I thought both the dtp board and the reflector is fixed in place by the diameter of the host body.

The board has a little bit of play inside the pill. The ring holds the LED which is held by the reflector, and therefore the board can center itself properly (and press it against the thermal paste on the pill) while screwing the pill in.

2 Thanks

oh ok i understand now, thanks

Could I ask how the luminance(cd/mm2) data in the test results is obtained and calculated?

The brightness of the LED is measured with a optic. The LES in mm^2 is then used to calculate the luminance. Advantage of this method is that the effects of sideways emitted light from the LED chip are properly included in the measurement.

1 Thank

Thanks for the test!, This LED looks interesting hopefully its sold a reasonable price.

The Boost HX LED in the L19 (actually the v1…the v2 has the SFT40-W) underperformed in my testing also. It was being driven prety hard also, but struggled to crack 1400 Lumens. My test equipment has been updated since that review (2021) so my Lumen figures have increased in accuracy by 10%. The optic shaves off 2% of that or so so even then you’re still under 1700 Lumens at start. The 4040 footprint helps, but it can’t beat the SFT40-W for output (but does throw lots better), and can’t compete with the newest crop pf domeless LEDs (like SFT25R). I’d like to swap one of those into the L19 to see how it does!

1 Thank

Yes, a 5050 version of the SFT25T with lower Vf would be amazing and be perfect for flashliggts like the Acebeam L19v2.