Sofirn HS42 Headlamp Review

Sofirn HS42 Headlamp Review

The Sofirn HS42 headlamp features a throw emitter, three flood emitters, and red emitters, too! Bonus features include USB-C charging and an indicating switch.


Official Specs and Features

Here’s a link to the Sofirn HS42 headlamp product page.

Versions

There’s only one version of the Sofirn HS42 headlamp but you can buy with or without a 18650.

Price

Without the cell, the Sofirn HS42 headlamp sells for $33.99. The cell adds just $2 and is a great deal.


What’s Included

Sofirn HS42 Headlamp what's included

  • Sofirn HS42 headlamp
  • Sofirn 3000mAh 18650
  • Charging cable (USB to USB-C)
  • Spare o-rings (2)
  • Headband
  • Manual etc

Package and Manual

Sofirn HS42 Headlamp manual

Sofirn HS42 Headlamp manual

Build Quality and Disassembly

Sofirn HS42 Headlamp

The Sofirn HS42 headlamp is a great headlamp! It’s great as a right-angle light too! The build quality is great. That this light costs only $33 is a win, too!

These threads are very smooth and the tailcap has a nice big spring.

Sofirn HS42 Headlamp tailcap off showing threads

Unlike some other Sofirn headlamps, this HS42 has a spring in the head, too!

Sofirn HS42 Headlamp showing spring on head end

Size and Comps

Size: 26mm x 27.2mm x 112mm
Weight: 71g (only headlamp without battery)

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

Sofirn HS42 Headlamp in hand

Sofirn HS42 Headlamp in hand

Here’s the test light with the venerable Convoy S2+. The version below is a custom laser-engraved Convoy S2+ host by GadgetConnections.com. I did a full post on an engraved orange host right here! Or just go straight to GadgetConnections.com to buy your Convoy S2+ now!

Also above is the light beside a TorchLAB BOSS 35, an 18350 light. I reviewed the aluminum version of that light in both 35 and 70 formats. I also reviewed that specific edition, the “Oveready BOSS FT Collector Vintage Brass” 35. I love it!

Retention and Carry

One of the nice updates to headlamp carry lately is that the attachment no longer has silicone loops. Those were fine, but this clip system is better.

Sofirn HS42 Headlamp headband clips

Sofirn HS42 Headlamp headband clips

The Sofirn HS42 headlamp slips in with a firm click into the usual two grooves.

Sofirn HS42 Headlamp on headband

There’s no pocket clip, but if you did find one that fit, you couldn’t use it and the headband at the same time.

The headband has a loop over the top too. It could be permanently removed, but not really removed off and on on the fly.

 

Sofirn HS42 Headlamp headband

On the tailcap is a hole to attach a lanyard. A lanyard is not included, though.

Sofirn HS42 Headlamp lanyard hole

The tailcap magnet is strong enough to hold this light.

Sofirn HS42 Headlamp tailcap magnet in use

Power and Runtime

The Sofirn HS42 headlamp is powered by a single lithium-ion cell. Sofirn includes a Sofirn branded 3000mAh 18650, which was used for all testing of this light. Since the light has springs on both ends, any type 18650 should work just fine.

Sofirn HS42 Headlamp with included 18650

The cell goes into the light with the positive end (button) toward the head. If you forget that, you can view the little icon near the tailcap.

Sofirn HS42 Headlamp with included 18650 installed

Below you can see output for three levels with both emitters and one spot. Output is around 1500 lumens, below the claim of 2100 lumens.

Sofirn HS42 Headlamp runtime chart

Sofirn HS42 Headlamp runtime chart

Sofirn HS42 Headlamp runtime chart

Sofirn HS42 Headlamp runtime chart

Here’s one test of Medium output with the spot emitter.

Sofirn HS42 Headlamp runtime chart

When turning the light on, the switch indicates an approximate voltage for around 5 seconds, as follows:

Green: power level is 70-100%
Red: power level is 30-69%
Red flashing: power level is <30%

Charging

The Sofirn HS42 headlamp offers charging by way of a USB-C port in the head. The port has a press-in cover that’s easy to remove and replace.

Sofirn HS42 Headlamp charging port

Sofirn HS42 Headlamp charging port

A USB to USB-C cable is included.

Sofirn HS42 Headlamp charging cable

Charging looks nice and quick for both A to C and C to C charging.

Sofirn HS42 Headlamp charging graph

When charging, the switch is red. When charging is complete, the switch goes to green.

Modes and Currents

Mode Mode Claimed Output (lm) Claimed Runtime Measured Lumens Tailcap Amps
Turbo – Both 2100 2h20m 1578 (0s)
1458 (30s)
5.53
High – Both 900 3h30m 638 (0s)
626 (30s)
1.53
Medium – Both 350 5h30m 260 0.57
Low – Both 50 21h 40 0.08
Moonlight – Both 1 300h 0.27 [low]
Turbo – Spot 2000 2h30m 1251 4.85
High – Spot 1000 2h40m 725 1.74
Medium – Spot 400 5h16m 291 0.55
Low – Spot 100 17h50m 76 0.12
Moonlight- Spot 1 460h 0.15 [low]
Turbo – Flood 1000 2h50m 861 3.16
High – Flood 450 4h20m 353 0.88
Medium – Flood 150 9h30m 118 0.26
Low – Flood 30 40h 25 0.04
Moonlight- Flood 1 480h 0.24 [low]
Turbo – Red 65 5h 0.80
High – Red 35 10h30m 0.27
Medium – Red 15 25h30m 0.09
Low – Red 2 125h [low]
Moonlight- Red 1 270h [low]

Pulse Width Modulation

Only the red output (the second row) uses PWM. Any combination of the other emitters or modes doesn’t use PWM. Great!

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, comparing them to the test light will be easier. Unfortunately, the PWM on this light is so bad that it doesn’t even work with my normal scale, which is 50 microseconds (50us). 10ms. 5ms. 2ms. 1ms. 0.5ms. 0.2ms. 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 briefly explained PWM.

User Interface and Operation

The Sofirn HS42 headlamp uses an e-switch on the head. This switch has a knurled cover, as well as indicating LEDs underneath.

Sofirn HS42 Headlamp e-switch

 

Sofirn HS42 Headlamp e-switch actuation

Below, you can see the switch indicating in green. It can also indicate in red and flashing red.

Sofirn HS42 Headlamp e-switch lit in green

Here’s a UI table! This table is mainly for the stepped output options. The user interface also has a ramping option, which is pretty simple. Much of the information below also covers that group, too (like strobes and lockout).

State Action Result
Off (Unlocked) Click On (Mode Memory)
Off (Unlocked) Hold Moonlight
On Hold Mode advance (Low>Medium>High)
On Double click Turbo
Turbo Click Previous state
Turbo Double click Flashing mode ( White Strobe)
Strobe Double Click Red SOS (and switches memory to red (!!))
Either strobe Click Previous level (but not previous output)^
Off Click 3x White Strobe
On Click 3x Emitter advance (Spotlight > Floodlight > Both > Red)
Off Click 4x Lockout
Lockout Click 4x Unlock to on state
Lockout Click Blink twice to indicate lockout
Lockout Hold Momentary Moonlight of memorized emitter

^ There’s a weird corner case here where you can go from (for example) medium white output through (white) Strobe then red SOS and single click out of the red SOS to the “previous state” – the level is remembered but the emitters are not. You’ll end up in medium red in this case.

LED and Beam

The main emitter is a Luminus SST-40 at 6000K. It has a big TIR. You can just make out the two red emitters above that single Luminus. At the very top are three CSP2323 emitters. They’re warmer white, at around 5000K. More importantly, they’re higher CRI!

Sofirn HS42 Headlamp emitter detail

LED Color Report (CRI and CCT)

CRI for the warm white triple emitter output is a very pleasant neutral and high CRI. The Luminus higher output emitter is low CRI and a bit cooler. When they’re run together, the higher output emitter “wins” and so the overall profile is low CRI and cooler.

Beamshots

These beamshots are always with the following settings:  f8, ISO100, 0.3s shutter, and manual 5000K exposure. These photos are taken at floor level and the beam hits the ceiling around 9 feet away.

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

I keep the test flashlight on the left, and the BLF-348 reference flashlight on the right. These photos are taken around 18 inches from the door.

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

Summary and Conclusion

Sofirn is good at making headlamps, so it’s no surprise that this one is good. I really like the warm white emitters – 5000K and high CRI seems like a nice sweet spot. It’s nice that the red output gets the full host of (5) output levels. The user interface is simple and familiar and USB-C charging works great. All of that for around $35; this is a deal!

The Big Table

Sofirn HS42 headlamp
Emitter: Luminus SST-40 and CSP2323 x3 (both)
Price in USD at publication time: $35.99
Cell: 1×18650
Runtime Graphs
LVP? Yes
Switch Type: E-Switch
Quiescent Current (mA): ?
On-Board Charging? Yes
Charge Port Type: USB-C
Charge Graph
Power off Charge Port with cell: any output but just one (middle)
without cell or tailcap: no modes
Claimed Lumens (lm) 2100
Measured Lumens (at 30s) 1458 (69.4% of claim)^
Candela per Lumen 4.09
Claimed Throw (m) 176
Candela (Calculated) in cd (at 30s) 260lux @ 5.339m = 7411cd
Throw (Calculated) (m) 172.2 (97.8% of claim)^
Claimed CCT
Measured CCT Range (K) 5500-5900 Kelvin
Item provided for review by: Sofirn
All my Sofirn reviews!

 

Sofirn HS42 headlamp
Emitter: Luminus SST-40 (throw)
Claimed Lumens (lm) 2000
Measured Lumens (at 30s) 1251 (62.6% of claim)^
Candela per Lumen 9.48
Claimed Throw (m) 215
Candela (Calculated) in cd (at 30s) 479lux @ 4.71m = 10626cd
Throw (Calculated) (m) 206.2 (95.9% of claim)^
Claimed CCT 6000
Measured CCT Range (K) 5400-6000 Kelvin

 

Sofirn HS42 headlamp
Emitter: CSP2323 x3 (High CRI (Flood))
Claimed Lumens (lm) 1000
Measured Lumens (at 30s) 861 (86.1% of claim)^
Candela per Lumen 1.26
Claimed Throw (m) 63
Candela (Calculated) in cd (at 30s) 89lux @ 3.554m = 1124cd
Throw (Calculated) (m) 67.1 (106.5% of claim)^
Claimed CCT 5000
Measured CCT Range (K) 5500-5900 Kelvin

^ Measurement disclaimer:  Testing flashlights is my hobby. I use hobbyist-level equipment for testing, including some I made myself. Try not to get buried in the details of manufacturer specifications versus measurements recorded here; A certain amount of difference (say, 10 or 15%) is perfectly reasonable.

What I like

  • Good build quality
  • Low cost
  • Nice implementation of red emitters
  • Neutral emitters have all 5 modes
  • High CRI, neutral emitters

What I don’t like

  • Low CRI main emitter
  • Doesn’t hit output claims

Notes

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