Sofirn HS21 Headlamp Gesture Sensor Review
Sofirn HS21 Headlamp⌗
- Specifications
- Introduction
- Torch in use
- Build quality
- LED, bezel, lens, reflector and beam
- Size and comparison
- User interface
- Batteries and charging
- Performance
- Beamshots
- Conclusion
- Price
- Product page
Specifications⌗
| Brand/model | Sofirn HS21 |
|---|---|
| LED | Spotlight (1*Luminus SFT40 6000K-6500K), Floodlight (6*CSP1919 LEDs), Red (3*HFL1-R LEDs) |
| Maximum lumens | 2,300 lm |
| Maximum beam intensity | 13,250 cd |
| Maximum throw | 230 m |
| Battery | 1*18650 3.7V Li-ion |
| Onboard charging | Yes (USB-C) |
| Material | Aluminium |
| Modes | Spotlight (5), Floodlight (5), Spotlight + Floodlight (5), Red (5) |
| Blinkies | Red Flash |
| Reflector | TIR |
| Waterproof | IP65 |
| Review date | December 2024 |
Introduction⌗
The Sofirn HS21 is a T-shaped headlamp with a gesture sensor, one spotlight LED, six floodlight LEDs and three red LEDs. It features an infrared sensor on the right side so that the headlamp may operated by waving a hand.
Sofirn kindly sent this torch for review. I have not been paid for this review nor have I held back my opinions of this torch.
Packaging⌗
The Sofirn HS21 comes inside a white box with an outer sheath. The outer sheath has an image of the headlamp on the top and specifications on the back.
The following was included in the box:
- Sofirn HS21.
- Headband.
- USB-A to USB-C charging cable.
- Two spare o-rings.
- User manual.
Torch in use⌗
The headband is comfortable and it fits my large head.
The headlamp can be adjusted up and down by rotating the bracket.
I find it easier to adjust the headlamp by using two hands because there is a notch in the bracket that helps prevent the headlamp from rotating.
There are three ways of controlling the Sofirn HS21:
- A button to turn the headlamp on, off or to select the brightness.
- A rotary switch to select: Spotlight, Floodlight, Spotlight + Floodlight (S + F) and Red light.
- An infrared gesture sensor to select the brightness or turn the headlamp off (it can be activated with three clicks while the headlamp is turned on).
The Sofirn HS21 is a great for multiple situations:
- Spotlight: Looking at things far away with the Spotlight.
- Floodlight: Working on things nearby or when you need to light up a large area.
- Red light: Preserving night vision.
I personally think that the top strap is needed because the 18650-sized headlamp will wobble around when running. But you could remove the top strap if you want to attach it to something like a hard hat.
Build quality⌗
The Sofirn HS21 is made of aluminium and it has a matte black anodised finish. There are no sharp edges.
The headband is very comfortable. It can be removed from the bracket if you need to wash it.
It is worth noting that some people have complained about the bracket snapping. You may want to be careful when taking the headlamp out of the bracket.
The notch on the bracket is made of plastic so it might eventually wear down after a lot of use if the headlamp is constantly being rotated up and down.
The threads are anodised and they came well lubricated. You can mechanically lock out the headlamp by rotating the tailcap slightly.
There are springs at both ends of the headlamp that allow flat top or button top 18650 cells to be used.
LED, bezel, lens, reflector and beam⌗
The Sofirn HS21 has a Spotlight (1*Luminus SFT40 6000K-6500K), a Floodlight (6*CSP1919 LEDs) and a Red light (3*HFL1-R LEDs) behind a TIR optic.
There is no glass lens to protect the TIR optic.
CCT, CRI, and duv⌗
I have taken Correlated Colour Temperature (CCT) and Colour Rendering Index (CRI, RA of R1-R8) measurements with the torch positioned half a metre away from an Opple Light Master Pro III (G3).
The CCT is around 4750K, the CRI is around 99 and the Delta u, v is slightly negative (close to pure white) for the Floodlight. Despite the Opple LM3 measurement, the edge of the beam definitely has a hint of green.
The beam produced by the Floodlight is essentially a wall of light. It produces a very wide circle where the edges blend into darkness.
The CCT is around 6000K-6500K, the CRI is around 68 and the Delta u, v is positive (green) for the Spotlight.
The beam produced by the Spotlight has a narrow intense white hotspot surrounded by two small circles.
The CCT CRI and the Delta u, v (duv) of the Spotlight + Floodlight is somewhere between the two. I measured the center of the beam where the Spotlight is the most dominant. The Spotlight drags the CRI down from 99 to 77 and the duv is slightly greener.
The beam produced by the Spotlight + Floodlight is the best of both worlds. But it would be even better if Sofirn used a high CRI Luminus SFT40, or another LED, with a CCT closer to 4500K to match the Floodlight. The cool white Spotlight sticks out.
| LED | Mode | CCT (K) | CRI (Ra) | x | y | Duv |
|---|---|---|---|---|---|---|
| Floodlight | Low | 4644 | 99.2 | 0.3542 | 0.3464 | -0.0062 |
| Floodlight | Medium | 4692 | 99.8 | 0.3532 | 0.3495 | -0.0042 |
| Floodlight | High | 4761 | 100 | 0.3519 | 0.3539 | -0.0015 |
| Floodlight | Turbo | 4870 | 100 | 0.3491 | 0.3560 | 0.0006 |
| S + F | Low | 5520 | 82.5 | 0.3320 | 0.3446 | 0.0020 |
| S + F | Medium | 5766 | 77.9 | 0.3265 | 0.3416 | 0.0030 |
| S + F | High | 5957 | 77.2 | 0.3225 | 0.3390 | 0.0035 |
| S + F | Turbo | 6057 | 77.8 | 0.3208 | 0.3334 | 0.0015 |
| Spotlight | Low | 5921 | 66.5 | 0.3226 | 0.3499 | 0.0089 |
| Spotlight | Medium | 6152 | 67.7 | 0.3183 | 0.3406 | 0.0063 |
| Spotlight | High | 6413 | 68.8 | 0.3140 | 0.3322 | 0.0042 |
| Spotlight | Turbo | 6685 | 70.0 | 0.3101 | 0.3244 | 0.0022 |
Calculate Duv from CIE 1931 xy coordinates
Dimensions and size comparison⌗
Dimensions⌗
I took the following measurements using a digital caliper.
| Measurement | Unit (mm) |
|---|---|
| Head diameter | 32.92 |
| Length | 86.96 |
| Height | 35.32 |
| Tube diameter | 22.96 |
| Tailcap diameter | 25.56 |
Weight⌗
I took the following measurements using a digital scale.
| Weight | Unit (g) |
|---|---|
| Torch | 86.97 |
| Headband | 35.76 |
| Battery | 45.80 |
| Torch with headband and battery | 168.53 |
Size comparison with its competition⌗
The Sofirn HS21 is relatively compact with an infrared sensor built into the side when compared with a Wuben E7 where the gesture sensor is attached to the USB-C port as an additional accessory.
User interface⌗
The Sofirn HS21 has a button, a rotary switch and an infrared gesture sensor.
The button can be used to turn the headlamp on, off or to select the brightness.
The rotary switch can be used to select: Spotlight, Floodlight, Spotlight + Floodlight (S + F) or Red.
There are four modes in the main cycle group: Low, Medium, High and Turbo. There is a shortcut to Moonlight from off. And Red has a special Red Flash mode.
| Rotary switch | State | Button | Result |
|---|---|---|---|
| Any | Off | Press and hold | Moonlight |
| Any | Off | Click | On (memory) |
| Any | Off | Two clicks | Lock |
| Any | Lock | Two clicks | Unlock |
| Any | On | Press and hold | Cycle (Low, Medium, High, Turbo) |
| Any | On | Click | Off |
| Spotlight, Floodlight, S + F | On | Two clicks | Turbo |
| Red | On | Two clicks | Red Flash |
| Any | On | Three clicks | Activate infrared sensor |
Infrared gesture sensor⌗
The infrared gesture sensor on the right side of the headlamp is activated by performing three clicks while the headlamp is turned on.
The brightness level can be adjusted by waving your hand near the sensor.
The headlamp can be turned off by holding your hand near the sensor for more than three seconds.
Mode memory⌗
Moonlight, Low, Medium, High and Turbo are memorised individually for Spotlight, Floodlight, S + F and Red.
The brightness is not synchronised between Spotlight, Floodlight, S + F and Red.
If you want to use Moonlight for Spotlight, Floodlight, S + F and Red while using the rotary switch then you will need to turn the light off, hold the button to enter Moonlight, turn the light off again, rotate to the next light, and repeat until Moonlight has been memorised four times.
Red Flash⌗
The Red Flash mode appears to have a constant frequency.
I measured the Red Flash mode with a Zoyi ZT-703S oscilloscope using High Speed mode.
Battery level indicator⌗
The indicator LED in the main button will display the power status for 5 seconds after turning the torch on.
| Colour | Battery level |
|---|---|
| Green | 60% - 100% |
| Red | 20% - 60% |
| Red flashing | 0% - 20% |
Low voltage protection⌗
The headlamp appears to have low voltage protection.
The output drops around 2.90V and the light turns off around 2.70V.
What I like about the UI⌗
- The button and rotary switch make the headlamp easy to control.
- The infrared gesture sensor is hidden away on the side.
- Shortcut to Moonlight from off.
- Shortcut to Turbo from on.
What could be improved⌗
- It would be even better if the headlamp used the same brightness level when using the rotary switch to change between Spotlight, Floodlight, S + F and Red. Currently the brightness level for each light is memorised. This is a personal preference. Some people may prefer individual mode memories.
- The shortcut for Lock is two clicks from off. It would be even better if Sofirn used a shortcut like four clicks from off instead. Usually two clicks from off is reserved for Turbo.
Batteries and charging⌗
Battery⌗
A button top Sofirn 18650 3.7V Li-ion 3000mAh cell was included inside the torch. The cell arrived with a voltage of 3.79V.
The cell was isolated with a piece of paper to prevent accidentally turning the torch on.
I tried the following cells:
| Cell | Top | Compatible? | Comment |
|---|---|---|---|
| Sofirn 18650 3.7V Li-ion 3000mAh | Button | Yes | |
| Sony Murata VTC6 18650 3.7V Li-ion 3000mAh | Flat | Yes |
Charging⌗
The Sofirn HS21 has built-in USB-C charging.
Power supply: PinePower Desktop USB-C
USB Meter: ChargerLAB Power-Z KM003C
Room temperature: 18 C
I charged the included battery from 3.00V to 4.11V with the built-in USB-C charger.
It took about 2 hours to charge the torch at a rate of 5V/2A.
The charging status indicator is red while charging and it turns green when charging is complete.
Power supply compatibility⌗
I tried the following power supplies with the built-in USB-C charger:
| Power supply | USB Type | Protocol | Does it charge? |
|---|---|---|---|
| Apple 61W Power Adapter | USB-C | PD | Yes |
| Google Pixel Power Adapter | USB-C | PD | Yes |
| PinePower Desktop | USB-C | PD | Yes |
| PinePower Desktop | USB-A | QC | Yes |
| PinePower Desktop | USB-A | Yes |
USB-C to USB-C charging works.
The headlamp can be powered off of a USB-C power supply without a battery. Moonlight, Low and Medium modes work.
Performance⌗
Specifications from the user manual:
Floodlight
| Modes | Moonlight | Low | Medium | High | Turbo |
|---|---|---|---|---|---|
| Output (lumens) | 2 | 30 | 150 | 500 | 1,200 + 500 |
| Runtime | 250h | 45h | 10h | 2h 25min | 2min + 2h 20min |
| Beam Distance (metres) | 3 | 11 | 22 | 40 | 60 |
| Beam Intensity (cd) | 2.5 | 30 | 140 | 403 | 975 |
Spotlight
| Modes | Moonlight | Low | Medium | High | Turbo |
|---|---|---|---|---|---|
| Output (lumens) | 2 | 50 | 400 | 1,000 + 800 | 2,000 + 1,000 |
| Runtime | 350h | 37h | 6h | 10min + 1h 30min | 2min + 1h 30min |
| Beam Distance (metres) | 8 | 39 | 112 | 180 | 230 |
| Beam Intensity (cd) | 17.5 | 375 | 3,125 | 8,075 | 13,250 |
Spotlight + Floodlight
| Modes | Moonlight | Low | Medium | High | Turbo |
|---|---|---|---|---|---|
| Output (lumens) | 2 | 100 | 400 | 1,000 + 650 | 2,300 + 1,000 |
| Runtime | 250h | 12h 30min | 3h 30min | 8min + 2h 30min | 2min + 1h 30min |
| Beam Distance (metres) | 8 | 33 | 77 | 120 | 226 |
| Beam Intensity (cd) | 15 | 265 | 1,500 | 3,575 | 12,775 |
Red
| Modes | Moonlight | Low | Medium | High | Turbo | Strobe |
|---|---|---|---|---|---|---|
| Output (lumens) | 0.5 | 2 | 20 | 50 | 100 | 50 |
| Runtime | 425h | 250h | 29h | 29h | 5h | |
| Beam Distance (metres) | 3 | 10 | 10 | 25 | ||
| Beam Intensity (cd) | 2.5 | 30 | 30 | 157 |
The beam distance in metres appears to have been rounded up and down to the nearest integer.
Lumen measurements⌗
Note: Lumen measurements may be off by 10% with my DIY lumen tube. Output measured from TIR optics may be lower than normal with my lumen tube.
I measured the current at turn on for: Moonlight with a UNI-T UT139C digital multimeter; Low to High with a bench power supply; Turbo with a UNI-T UT210E clamp meter.
| LED | Mode | Amps at start | Specs | Lumens @turn on | Lumens @30 sec | Lumens @10 min |
|---|---|---|---|---|---|---|
| Red | Turbo | 0.601 A | 100 | 96 | 92 | 91 |
| Spotlight | Moonlight | 7.88 mA | 2 | 3 | 3 | 3 |
| Spotlight | Low | 0.073 A | 50 | 122 | 122 | 120 |
| Spotlight | Medium | 0.672 A | 400 | 466 | 359 | 355 |
| Spotlight | High | 2.023 A | 1,000 + 800 | 877 | 849 | 805 |
| Spotlight | Turbo | 5.720 A | 2,000 + 1,000 | 1,670 | 1,480 | 703 |
| Floodlight | Moonlight | 11.4 mA | 2 | 3 | 3 | 3 |
| Floodlight | Low | 0.064 A | 30 | 31 | 31 | 31 |
| Floodlight | Medium | 0.325 A | 150 | 157 | 155 | 153 |
| Floodlight | High | 1.245 A | 500 | 522 | 507 | 496 |
| Floodlight | Turbo | 4.110 A | 1,200 + 500 | 1,233 | 1,125 | 491 |
| S + F | Moonlight | 11.48 mA | 2 | 1.7 | 1.7 | 1.7 |
| S + F | Low | 0.217 A | 100 | 119 | 117 | 117 |
| S + F | Medium | 0.861 A | 400 | 452 | 445 | 436 |
| S + F | High | 2.436 A | 1,000 + 650 | 1,075 | 1,040 | 914 |
| S + F | Turbo | 7.400 A | 2,300 + 1,000 | 2,122 | 1,867 | 716 |
The lumen output is slightly lower than expected for Turbo at 30 seconds.
Standby drain⌗
42 µA
A fellow enthusiast pointed out that the standby current may increase when the infrared sensor is exposed to direct sunlight. They blocked out the sensor to reduce the standby current.
Runtime graphs⌗
I used my own DIY lumen tube with a TSL2591 sensor and forked bmengineer’s project RuTiTe to record runtimes.
The room temperature was approximately 18 C.
Red graph⌗
Runtime⌗
Here is a summary of the runtime results:
| LED | Mode | User manual | Runtime | Turn off | Final voltage |
|---|---|---|---|---|---|
| Spotlight | Turbo | 2min + 1h 30min | 1h 39min 13s | 2h 11min 53s | 2.79 |
| Spotlight | High | 10min + 1h 30min | 1h 40min 51s | 2h 18min 15s | 2.82 |
| Spotlight | Medium | 6h | 4h 46min 29s | 4h 46min 29s | 2.93 |
| Spotlight | Low | 37h | 10min+ | 10min+ | |
| Spotlight | Moonlight | 350h | 10min+ | 10min+ | |
| Floodlight | Turbo | 2min + 2h 20min | 2h 13min 58s | 2h 42min 36s | 2.87 |
| Floodlight | High | 2h 25min | 2h 20min 59s | 2h 52min 48s | 2.85 |
| Floodlight | Medium | 10h | 8h 56min 15s | 8h 56min 15s | 2.87 |
| Floodlight | Low | 45h | 10min+ | 10min+ | |
| Floodlight | Moonlight | 250h | 10min+ | 10min+ | |
| S + F | Turbo | 2min + 1h 30min | 1h 38min 51s | 1h 52min 51s | 3.00 |
| S + F | High | 8min + 2h 30min | 1h 55min 25s | 1h 55min 26s | 2.90 |
| S + F | Medium | 3h 30min | 3h 25min 59s | 3h 25min 59s | 2.98 |
| S + F | Low | 12h 30min | 11h 59min 51s | 11h 59min 51s | 3.08 |
| S + F | Moonlight | 250h | 10min+ | 10min+ | |
| Red | Turbo | 5h | 4h 42min 25s | 8h 51min 11s | 2.76 |
“Runtime” is the time until the output reduces to 10% of the output at 30 seconds (as per the ANSI/PLATO FL1 2019 Standard).
“Turn off” is the time until my DIY lumen tube no longer detects more than one lumen.
“+” indicates that the light remained on after recording had stopped.
The runtimes for Turbo and High were close to what Sofirn claimed.
Medium and High modes fell slightly short.
The output is well regulated. I am impressed!
Throw⌗
I took lux measurements with a UNI-T UT383BT at 30 seconds. Turbo was measured at five metres.
| LED | Mode | Specs (cd) | Specs (m) | Candela measured (cd) | Distance (m) |
|---|---|---|---|---|---|
| Spotlight | Turbo | 13,250 | 230 | 17,450 | 264 |
| S + F | Turbo | 12,775 | 226 | 16,650 | 258 |
Pulse Width Modulation⌗
I did not notice any visible PWM (flickering).
I measured the PWM of the light with a Zoyi ZT-703S oscilloscope.
Spotlight (Moonlight, Low, Medium, High, Turbo)
Floodlight (Moonlight, Low, Medium, High, Turbo)
S + F (Moonlight, Low, Medium, High, Turbo)
Beamshots⌗
I went to a local park and I aimed the torch at a tree 70 metres away.
Beamshots were taken using a Sony RX100M2 using 3.2", f3.2, ISO 100, 5000K WB.
Sofirn HS21 Spotlight (Turbo)⌗
Sofirn HS21 Floodlight (Turbo)⌗
Sofirn HS21 S + F (Turbo)⌗
Wuben E7 (Turbo)⌗
Cyansky HS6R Spot (Turbo)⌗
Cyansky HS6R Flood (Turbo)⌗
Armytek Wizard C2 WR (Turbo)⌗
Nitecore NU27 (Turbo) Neutral⌗
Nitecore NU27 (Turbo) Warm⌗
Nitecore NU27 (Turbo) Cool⌗
I later visited a playground and aimed the headlamp at a big apple approximately 2 meters away while using the red emitter.
Red beamshots were taken using a Sony RX100M2 using 0.25 second shutter, f3.2, ISO 800, 5000K WB.
Sofirn HS21 (Red) Turbo⌗
Nitecore NU27 (Red) High⌗
SPERAS B7 (Red)⌗
The following red beamshots were taken using a Sony RX100M2 using 1/2.5", f3.2, ISO 800, 5000K WB. They might appear to be slightly brighter due to the slower shutter speed.
Cyansky HS6R⌗
Armytek Wizard C2 WR (Red) Turbo⌗
Conclusion⌗
The Sofirn HS21 is a great all-rounder headlamp!
The rotary switch makes it easy to switch between Spotlight, Floodlight, S + F and Red.
It is cool to see an infrared gesture sensor hidden away on the side. It might be useful in situations where you need to go handsfree.
I was pleasantly surprised at how comfortable the headband is.
Sofirn have lifted their game when it comes to drivers. The output is well regulated.
I highly recommend the Sofirn HS21.
Pros:⌗
- Good build quality.
- The output is well regulated.
- Beam distance is better than expected.
- Headband is comfortable and fits my large head.
- Runtimes are close to what Sofirn claimed on Turbo and High.
- Simple user interface.
Cons:⌗
- Lumen output is slightly lower than expected for Turbo.
Price⌗
The Sofirn HS21 is about US$35.74 on amazon.com (affiliate link with promo code) at the time of writing if you stack the 15% promo code with a 20% coupon code on the product page.
Product page⌗
Sofirn HS21 at amazon.com (affiliate link with promo code)
I may earn a commission if you use an affiliate link or a promo code. This will help fund future torch reviews and tutorials.