Sofirn IF25 USB-C 2500lm Variable Temempeture 2700K-6500K quad led

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SKV89
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Sofirn IF25 USB-C 2500lm Variable Temempeture 2700K-6500K quad led

I just discovered this new Sofirn light quad emitter light on Aliexpress. It has some amazing features.

USB-C recharge
Variable CCT 2700K to 6500K (SST-20 emitters)
21700

This will be sweet. I’m hoping they release another version with the same LH351D 2700k and 5000K 90CRI used in the BLF LT1.

maukka
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This is an interesting light but it would have to be high CRI. Since SST-20 isn’t even available in CRI90+ at CCTs over 4000K, I’m assuming it’s CRI70 all the way. No thanks. They should’ve used LH351D like the LT1 lantern.

Lux-Perpetua
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Please find the English manual of Sofirn's IF25 on my sharepoint:

https://drive.google.com/drive/folders/1De_MmcMGuhuxvfccCWKHTcWVXCfZFRAk

 

It uses 2x SST-20 2.700K 95CRI and 2x SST-20 6.500K 70CRI (apparently L4-bin code AFAIK). The driver is stated as a constant current driver that can also work in 2S configuration with 2x CR123A (6V), i.e. it seems to be using a buck converter. Like Sofirn's LT1 this flashlight has tint ramping but uses a proprietary user interface. Tint ramping can be accessed by click + hold ("2H" in terms of the Andúril UI explanation), i.e. press, release, press and hold. Like Sofirn's SP33 V3 the IF25 uses an updated thermal management (ATR) without any timed stepdowns.

maukka
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It’s a strange design choice to make the stepless and stepped ramp modes change output modes in different ways. Hold for output ramping but click for output mode selection. I assume the light turns off with a single click in ramping mode even though the manual doesn’t say how to turn it off. This is weird since you need to hold the switch for off in stepped mode.

Also, I would like to be able to switch the light off immediately after tint ramping (click + hold), but you can’t do that in the stepped mode, since the tint ramping just changes direction if you press the switch within 1.5 seconds. Does a single click still turn off the light in ramping mode?

Lux-Perpetua
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maukka wrote:
It's a strange design choice to make the stepless and stepped ramp modes change output modes in different ways. Hold for output ramping but click for output mode selection. I assume the light turns off with a single click in ramping mode even though the manual doesn't say how to turn it off. This is weird since you need to hold the switch for off in stepped mode. Also, I would like to be able to switch the light off immediately after tint ramping (click + hold), but you can't do that in the stepped mode, since the tint ramping just changes direction if you press the switch within 1.5 seconds. Does a single click still turn off the light in ramping mode?

 

Thank you maukka. I just updated the manual. The light will be turned off by a single click in ramping mode. In stepped mode you need to keep holding the button for 0.5s to turn the light off.

About your concerns of a conflict between tint ramping and stepped modes:

To turn off the light: Press and hold 0.5s (=1H)

To change the tint: Press, release, then press and hold (=2H)

So, if you use tint ramping in stepped mode and want to turn off the light immediately, just release the button after tint ramping and then press and hold to turn off. The tint ramping will only start again if you click (= press, release) and then press and hold.

 

The IF25's UI was Sofirn's decision but they did it differently on the SP33 V3 (consistently between ramping and stepped modes). I will soon get a sample of the IF25 and will report if there is any conflict between turning the light off in stepped mode and using tint ramping before.

SKV89
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Oh man the UI is confusing as heck. I wish they stuck to the SP33 UI with click for off instead of click and hold for off. Also the UI could have been so much simpler if it had a tail switch also. The UI could be simple like this.

1) Click tail-switch for on-off

2) Click side switch to change brightness modes

3) Hold side switch to change color temperature

Well at least they updated their ATR to get rid of the timed step down, which I really hated.

middle age man
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The website shows it is no longer available. Two pairs of high CRI emitters and a separate button to ramp the tint would be nice; maybe use the 8CF as host with the tail button reconfigured to adjust the tint.

Lux-Perpetua
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Sofirn was so kind to send me a late prototype of their IF25 for testing and for reporting any recommendations what to improve in later batches. Many thanks for that to Sofirn. The IF25 prototype arrived here on 10/25/2019 and I would like to share my initial impressions with you. Further tests like a thermographical analysis of heat transfer and regulation as well as measuring tailcap currents are still pending for I did not have the time to do that yet.

All in all, I'm quite satisfied with the IF25 and can recommend this flashlight to anyone who is interested in a handy and versatile 21700 EDC light with tint ramping. The points of criticism and suggestions for improvement that I have noted below relate mainly to details that could further enhance the user experience and appeal to an even larger group of buyers. As always, I have tried to express my feedback as objectively and unbiasedly as possible.

@ maukka: I tested following scenario for possible conflicts in the UI:

  • IF25 set to stepped mode
  • IF25 being used for tint ramping (click + hold)
  • Immediately, after tint ramping I tested to shut down the IF25. Holding the button was successful and the light went off. Click + hold reversed the tint ramping direction or (after 1.5s) changed the tint in the same direction as before.
  • Bottom line: No conflicts in the UI. Still, I would prefer to "click" for ON/OFF and "hold" for mode cycling.
Component Pros Cons Suggestion
Overall appearance The workmanship and material quality is as far as possible at a high level. The threads are cleanly manufactured, the optic is free of dust and dirt inclusions and the battery tube is concentrically drilled out. The 21700 format is future-proof and offers high capacities for long runtimes. The IF25 also looks extremely compact and handy. The switch has a good pressure point. The dust protection cap of the USB-C port holds it securely in place. The cooling fins are sharp-edged and the anodization has small imperfections. This will be fixed in series production. The battery tube of the prototype is firmly glued to the head (probably to protect it against reverse engineering) - it remains to be hoped that the production model does not have a glued battery tube. The sharp-edged cooling fins should be better deburred. I also recommend to grease the threads slightly (they are dust-dry from factory). A knurling on the battery tube and tailcap would fit the IF25 well to improve tactile handling.
Beam quality Due to the small die area of the SST-20, the beam is not too floody. The beam profile is nevertheless quite balanced in throw and flood due to the optics Sofirn used to get a nice hotspot for effective ranges up to approx. 50m while still having plenty of light in front of your feet. Despite "shifted-running" LEDs (in the pure WW/CW settings) the beam on a whitewall is mostly homogeneous and free of deformations or artefacts. The color mixing of 2x CW and 2x WW results in a rather reddish drift from the BBL, instead of going into the yellow-greenish (above the BBL). This effect is usually preferred. Due to a proprietary optic, no alternative optics with a different beam angle or degree of diffusion can be used. Cold white light (> 5.000K) has a strong tendency to blue - a typical disadvantage of the SST-20 6.500K. The use of 95CRI leads to a disproportion of the power compared to 70CRI LEDs. Warm white light is therefore measurably less bright than cold white light. No immediate need for action, but standardised optics such as those from Carclo or Ledil offer more flexibility for customizing the beam profile. For a less bluish light I recommend to use SST-20 5.000K 70CRI with which a relatively clean neutral white can be realized.

Alternatively, it would be better to use Samsung LH351D of consistent CRI values to balance the performance gap of the LEDs. However, the beam profile will then become more floody, which could only be influenced by changing the optics.
Driver and thermal control A constant current driver with buck converter is used. This allows a stable power level without the typical FET brightness drop in the voltage curve. Thanks to the buck converter, widely used 2x CR123A primary batteries can also be used for emergencies.

Sofirn finally got rid of a timed stepdown. The thermal regulation has also been revised and automatically intervenes in 3 stages (45°C, 55°C, 65°C) to regulate heat generation.
Unfortunately, a configurable stepdown behavior has been omitted. It would be nice, if Sofirn were to give the user the possibility to change the light's thermal control according to his own wishes, like HaikeLite, Tom E's NarsilM or Toykeepers Andúril offer for quite some time.

The regulation seems a little too "aggressive" to me personally, i.e. the IF25 steps down quite far, subsequently cools down more than necessary and thus gives away some potential.
A configuration menu for changing the stepdown behaviour, which can be reached via e.g. 10x clicks, would be useful. Power users might want to accept a significantly warmer lamp for a longer runtime at higher light levels. Other users may prefer a very moderate heat output and would like the IF25 to remain cooler even more than the factory default.

Sofirn's ATR could be somewhat less conservative and allow a warmer, regulated continuous temperature.
Charging With USB-C, Sofirn has chosen a format that is future-proof and significantly more failsafe. Gone are the days when you wanted to plug the fiddly microUSB plug into the socket the wrong way round. With an effective 1.7A at 5V there is a reasonable charging current for the 21700 format. The prototype has charged a Samsung 50E battery up to 4.165V, which isn't 100% but on the other hand it will ensure a better battery life expectancy.    
User Interface Sofirn uses a sophisticated but simple user interface. A short glimpse into the user manual is therefore sufficient. In addition to stepped modes there is also stepless ramping. The light can also be operated at a low light level during charging.

Tint Ramping for changing the colour temperature works extremely well and intuitively.
Unfortunately, Sofirn is not always consistent in defining the UI for stepped modes. While some of their flashlights require the switch to be held in order to cycle through the light levels, the IF25 requires single clicks to be made and the switch to be held down to turn it off. This leads to confusion for the customer, who may has bought several Sofirn lights. Most customers prefer "hold to cycle throgh modes" and "click for on/off", as in ramping mode. This is also implemented in the UI of the new SP33 V3. It would be nice if an IF25 V2 also gets this.

Unfortunately, the IF25 has no mode memory for Moonlight in ramping mode, i.e. it starts at least at a low mode above moonlight. It would be desirable that the mode memory works to the lowest setting.

 

TexasToasted
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I’m getting one of these lights, but I will be replacing those ugly, cold, blue LEDs.

LightObsession
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Thanks for the review.

I definitely prefer the IF25 beam profile over that of the optic in that Convoy S2.

SKV89
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Thanks for the review. I hope they can “fix” the UI so it is always “click” for on/off and even better if they can implement tail switch so it will be muggle friendly. I wonder why they didn’t use the LH351D like in the BLF LT1. The SST-20 2700K is great but the 5000K and 6500K is very green and the difference is forward voltage makes them not a good combination.

If they can make these improvements before Christmas, I would buy a bunch as this would be the ultimate gift light.

Th558
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Been waiting for some more lights with adjustable colour temp. I’ll get one if they can fix the UI and increase the throw a bit.

Edit: oh yh and also use only 90+ cri emmiters

Lux-Perpetua
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Sofirn told me they tested another prototype with LH351D but the beam quality was dissatisfying.

djozz
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The solution is LH351C, available in 90 CRI at all CCT’s, but that led has never taken off very well.

SKV89
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I heard the LH351C is very positive in DUV (greenish tint). At least we know the SST-20 2700K and LH351D is not far from the BBL. Per Maukka’s recent review of the TO50R, the LH351D 5000K used in the latest version is actually not too far above the BBL. The older version of the LH351D 5000K is very far above the BBL.

Jackie
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thank you for the thread and update of sofirn New model IF25

beggindog
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t ouellette

Kindle
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Lux thanks for putting in the work on the mini-review. It helps a lot.