Sofirn LT1S Lantern Review

Sofirn LT1S Lantern Review

The Sofirn LT1S is a lantern that runs on a single 21700 (included) and has ramping from warm to cool white, and red! Also: USB-C charging!

Official Specs and Features

Here’s a link to the Sofirn LT1S lantern product page.


There’s really just one “version” of the Sofirn LT1S lantern, but many colors are available. Even orange…

Sofirn LT1S lantern colors


The going price for the Sofirn LT1S lantern is $45.59. You can add the 21700 cell seen in this review for another $5, and you should just go ahead and do that!

Short Review

I enjoy lanterns and I have a few, but I’m not a lantern collector. I will say that among the lanterns I have, this one is among my favorites – I love that it uses a single cell. I love that it can ramp from (very) warm to cool white and that there is a separate red option. All in all, I’d say this is a good lantern option.

Long Review

What’s Included

Sofirn LT1S lantern what's included

  • Sofirn LT1S lantern
  • Sofirn 5000mAh 21700
  • Charging cable (USB to USB-C)
  • Spare o-rings (2)
  • Manual

Package and Manual

Sofirn LT1S lantern box

Sofirn LT1S lantern box

Sofirn LT1S lantern manual

Build Quality and Disassembly

The build quality is here. Unlike a lantern by, say, Olight, the LT1S has more corners and is less rounded, but that also makes it a bit more “flashlight-like.”

The top has a switch, four charge indicators, and a USB-C charging port.

Sofirn LT1S lantern top and switch area

The bottom doesn’t have anything!

Sofirn LT1S lantern bottom

Sofirn LT1S lantern cell icon

Sofirn LT1S lantern top side view

Both head and tail have a nice big spring.

Sofirn LT1S lantern tailcap off showing spring

Sofirn LT1S lantern positive spring

Size and Comps

97mm x 68mm

257g (without cell)

If the flashlight will headstand, I’ll show it here (usually the third photo).  If the flashlight will tailstand, I’ll show that here, too (usually the fourth photo).

Sofirn LT1S lantern in hand

Here’s the test light with the venerable Convoy S2+.  Mine’s a custom “baked” edition Nichia 219b triple.  A very nice 18650 light.

Also seen is the light beside my custom engraved TorchLAB BOSS 35, an 18350 light.  I reviewed the aluminum version of that light in both 35 and 70 formats.

Retention and Carry

As a lantern, the LT1S smartly has a beefy hanging loop on the top. This loop folds down or up easily and can fold to either side.

Sofirn LT1S lantern hanging loop

That’s it!

Power and Runtime

The Sofirn LT1S lantern is powered by a single lithium-ion battery. If you go for the package deal, you’ll get the 5000mAh 21700 seen below.

Sofirn LT1S lantern included 21700 cell

The cell goes into the LT1S with the positive end toward the top of the light.

Sofirn LT1S lantern included 21700 cell installed

Because the output is 360°, I’ve just recorded these levels as percentages.  


The LT1S sports USB-C charging and the charging port is on the top. It’s covered with a press-in rubber cover.

An appropriate cable is included. It’s USB to USB-C.

Sofirn LT1S lantern charging cable

Charging looks very good at nearly 3A! For a 5000mAh cell like the one that’s included, 3A is perfectly fine.

C to C charging works great, too!

Sofirn LT1S lantern charge graph


The powerbank feature on the LT1S works great, too! I did a sort of “stress test” on the output – run at the highest level where it stays at around 5V until it shuts off, then repeat at the next lower level. The USB-C port can output over 3A at 5V, which is very good. After that shuts off, you can cycle the port and get 2A for a while, then 1A for a while. Just unplug/plug your device.  Here are a couple of graphs!

powerbank output

Here’s the same data, but a 2-minute window from the early heavy test at 3A, to the point where output shuts off because of high current.

powerbank output

The powerbank does eventually shut off. At that point (in the graph above at 52 minutes or so), the cell voltage was 3.2V – perfectly respectable for cell protection.

Modes and Currents

Mode Mode Claimed Output (lm) Claimed Runtime Measured Lumens Tailcap Amps
Turbo 500 2h20m Warm White: 2.24
Cool White: 2.19
High 150 6h Warm White: 0.60
Cool White: 0.60
Medium 50 18h Warm White: 0.21
Cool White: 0.21
Low 10 90h30m Warm White: 0.06
Cool White: 0.06
Moon 1 555h Warm White: 0.03
Cool White: 0.03

Pulse Width Modulation

It doesn’t seem like the LT1S uses PWM, but on the highest mode we can see just the tiniest bit of peaks showing. In any case, it’s nothing to worry about.

As seen below, the mode order is

Warm white: 5 (top row)
Cool white: 5 (middle row)
Red: 3 (bottom row)

This mode order will be followed throughout the rest of the review.

For reference, here’s a baseline shot, with all the room lights off and almost nothing hitting the sensor.  Also, here’s the light with the worst PWM I could find.  I’m adding multiple timescales, so it’ll be easier to compare to the test light.  Unfortunately, the PWM on this light is so bad that it doesn’t even work with my normal scale, with is 50 microseconds (50us).  10ms5ms2ms1ms0.5ms0.2ms.  In a display faster than 0.2ms or so, the on/off cycle is more than one screen, so it’d just (very incorrectly) look like a flat line.  I wrote more about this Ultrafire WF-602C flashlight and explained a little about PWM too.

User Interface and Operation

A single switch controls the Sofirn LT1S lantern. That e-switch is on the top of the lantern and is covered by a knurled rubber boot.

Sofirn LT1S lantern e-switch

The action is fine and the sound is moderately clicky.

Sofirn LT1S lantern e-switch actuation

Here’s Sofirn’s graphic of the user interface.

user interface graphic

Here’s a UI table!

State Action Result
Off Hold Moonlight (of memorized side and CCT)
On Click+Hold Tint Ramp
Off Click Memorized brightness (of memorized side and CCT)
Off Click 2x Turbo (of memorized side and CCT)
Any Click 3x Red output (Memorized level)
Red on Hold Red advance (LMH)
Red on Click Previous state
Red on Click 2x Red Strobe or Red SOS (Memory)
Red Strobe group Click 2x Iterate between Red Strobe and Red SOS
Red Strobe group Click Previous Red state
Red on Click 3x On in white (of memorized side and CCT)
On Click Off
On Hold Mode advance
Stepped output: LMHT and cycles back to low
Ramping output: Ramps in one direction and stops at that extreme (does not cycle back to the lower output and ramp more)
On Click 2x Cycle emitter sides: (One side (half) > the other half > both halves)
On Click 4x Iterate between Ramping and Stepped output

LED and Beam

Sofirn uses “36 CSP1919 LED and 4 Red LED” emitters in the Sofirn LT1S lantern. 

Sofirn LT1S lantern warm white emitters

Sofirn LT1S lantern red output

Sofirn LT1S lantern half lit

Sofirn LT1S lantern top view warm white

Sofirn LT1S lantern top view cool white

The tint ramp feature of this light is pretty neat, I’d say. You might not think you’d find it all that useful, but there are times when a bright white (cooler) CCT is welcome and distinct times I find that a very warm white CCT is welcome, too. Your mileage may vary, as they say!

LED Color Report (CRI and CCT)

I’ve tested the CCT for the extremes. First (top row) is the warm white, which comes in at around 2500K. Then (second row) the cool white, which reads around 5900K.  Both are great for their purposes and have nice and high CRI!

I don’t think I grabbed CCT for the red, but I can if anyone needs to see just how red they are. 😀


These beamshots are always with the following settings:  f8, ISO100, 0.3s shutter, and manual 5000K exposure. As above: warm white in the top row. Cool white in the middle row. Red in the bottom row.

Tint vs BLF-348 ( 219b version) (affiliate link)

I keep the test flashlight on the left, and the BLF-348 reference flashlight on the right. As above: warm white in the top row. Cool white in the middle row. Red in the bottom row.

I compare everything to the 219b BLF-348 because it’s inexpensive and has the best tint!


What I like

  • Uses just one cell!
  • Good user interface  
  • Has red
  • Red has modes (and one of them is pleasantly low)
  • Tint ramping is a very neat feature
  • Tint ramping doesn’t really get in the way
  • C to C charging works

What I don’t like

  • No magnet in base


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