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  • Stephen Knight

Flashlight Review: Sofirn SP31 V3.0

Updated: 1 hour ago

The Sofirn SP31 V2.0 was one of my favourite budget tactical flashlights / torches for light painting photography. This review is of its much brighter successor, the Sofirn SP31 V3.0.


Disclaimer


The Sofirn SP31 V3.0 was sent to me for an honest review by Sofirn. The product link is not an affiliate link.

Product Page at Sofirn code: SNDEAL (for 20% off).


Sofirn SP31 V3.0 Flashlight.
Sofirn SP31 V3.0 Flashlight.

Design and Construction


The Sofirn SP31 V3.0 is an 18650 battery tube light format flashlight, with side e-switch, tactical tail switch, USB-C charging, and cool white 6500K SST-40 LED for a claimed 2,000 lumen maximum output. At the time of writing, the cost was US$31.99 without battery and US$35.99 with battery. There are discount codes in this review.


The dimensions are slightly wider, but shorter than the SP31 V2.0 (which I reviewed back in 2020), with a head diameter of 25mm, and length of 122mm. The weight is 120g including the battery. The light arrived in a branded box, and the package included the flashlight, optional 3000mAh 18650 Li-ion battery, USB-A to USB-C charging cable, lanyard, side clip, spare O-rings, and instruction manual. The SP31 V3.0 feels higher quality than the 5 year old SP31 V2.0 (which is still working well for me). The light has a claimed IP rating of IP68, and impact resistance to 1m.


Unlike, the SP31 V2.0, the SP31 V3.0 has caught up with modern requirements by having internal USB-C charging. The charging port has a silicone cover to prevent water and dust ingress. The battery tube is only unscrewed at the head end, and there are springs at both ends of the battery tube. The light comes with an optional 3000mAh unprotected Li-ion 18650 battery. The charging is relatively slow at around 1A, and when the green "charge complete" illuminated, the voltage was at 4.19V. Whilst this is acceptable, my Vapcell S4+ charger was able to top up an additional 200mAh.



For light painting photographers, the SP31 V3.0 is compatible with multiple light painting systems including Light Painting Brushes (Universal Connector), Light Painting Paradise (Cone Adapters), and various T8 tube based systems (Luminosify, Light Painting Tubes, and Light Painting King). Due to the larger head diameter than the SP31 V2.0, it is not compatible with the Light Painting Paradise "All in One adapter". The light can be easily tripod mounted with a Small Rig Super Clamp. The light should also be compatible with 3rd party 25mm diameter diffusers.


Sofirn SP31 V3.0 packaging.
Sofirn SP31 V3.0 packaging.

Sofirn SP31 V3.0 and accessories.
Sofirn SP31 V3.0 and accessories.

Sofirn SP31 V3.0 USB-C charging port.
Sofirn SP31 V3.0 USB-C charging port.

Sofirn SP31 V3.0 and 18650 battery.
Sofirn SP31 V3.0 and 18650 battery.

The Sofirn SP31 V3.0 in a light painting connector.
The Sofirn SP31 V3.0 in a light painting connector.

User Interface


The user interface a "tactical" user interface, with two switches, a side e-switch for changing modes, and tactical forward clicky tail switch for on/off and momentary on. The user interface is as follows:

  • Click tail switch from off > on (last mode memory - Low/Med/High/Turbo).

  • Click tail switch from on > off.

  • Half press tail switch from off > momentary on (last mode memory - Low/Med/High/Turbo).

  • Click side switch from off > nothing.

  • Click side switch from on > cycles through Low>Medium>High>Turbo.

  • Long press side switch from on > Strobe (single click then cycles Strobe>SOS> Beacon).

  • Long press side switch from strobe group > on (last mode memory).

  • Hold side switch whilst pressing tail switch from off > Moonlight.


For accessing continuous brightness levels, I quite like this style of user interface as it allows for on/off or momentary on, with last mode memory with all of the normal brightness settings (Low, Med, High, Turbo). It is good that Turbo is in the main mode cycle. This is the similar to the older SP31 V2.0, plus the more expensive Acebeam T38, and Fenix PD36R (Pro). The tail switch is also easier to use than the switch on the SP31 V3.0, being harder to accidentally engage full on during a momentary press. This is useful for light painting and tactical use.


Accessing moonlight is a rather strange, requiring pressing both switches. I would prefer a hold for moonlight, and make strobe a double click, with last mode memory for both strobe and moonlight (so they are both hidden, but can be memorised once activated).


Unfortunately for light painting photographers, the strobe is alternating frequency, and not accessible via the tail switch. Constant frequency strobes are much better for light painters as it creates more even strobe patterns in light trails. Also, constant frequency strobes at approx. 13Hz are more annoying for tactical use than alternating frequency strobes which break up the "trance" effect. For the sample light painting photo near to the end of the review, the SP31 V3.0 was used for the continuous light trails, and the Light Painting Paradise LightPainter Ryu's Lightworks V2.0 used for the strobe light trails.


The side switch has a battery charge indicator. The light can be mechanically locked out by slightly unscrewing the head.


Sofirn SP31 V3.0 side e-switch.
Sofirn SP31 V3.0 side e-switch.

Sofirn SP31 V3.0 tail switch.
Sofirn SP31 V3.0 tail switch.


Beam, Output, and Runtime


The Sofirn SP31 V3.0 has a Luminus SST-40 cool white 6500K LED, placed in a TIR optic.

This created a general purpose beam profile, with a bright hotspot and wide spill beam.


The brightness modes and runtimes are:

  • Turbo - claimed 2000lm (2hr) - tested at 1670lm (step-down from 40secs to 665lm) (2hr 10min).

  • High - claimed 900lm (2hr 10min) - tested at 880lm.

  • Medium - claimed 300lm (5hr 50min) - tested at 240lm.

  • Low - claimed 15lm (120hr) - tested at 12lm.

  • Moonlight - claimed 1lm (550hr) - tested at 1.2lm.


The maximum brightness is below specification, at 1670lm, similar in output to the SST-40 equipped Wurkkos WK02 and Convoy S15. It is however 134% brighter than the SP31 V2.0 which I retested at 710lm There is a reasonably rapid step-down in brightness from 40 seconds, as opposed to 3mins 20 seconds in the SP31 V2.0. Light painters will need to be careful that the light is not on long enough to step-down mid-exposure. The light does however maintain 665 lumens after step-down which is good for the light's compact size. The FL1 runtime on Turbo was slightly longer than specification, and even after the light drops to Low mode, it keeps running for a while so that you don't end up stuck in the dark. The mode spacings are OK, but as there is a moonlight mode, I would prefer to see a higher low at around 50lm like on the SP31 V2.0.


Peak beam intensity on Turbo mode is claimed to be 18,100cd (269m), and was tested at 24,445cd (312m) (though my Opple Lightmaster 3 Pro tends to overestimate by 25%). This is a 65% increase over the older SP31 V2.0 which was re-tested at 14,754cd (242m).


Correlated colour temperature (CCT), colour rending index (CRI), and tint were tested as follows:

  • Turbo - CCT 5771K, CRI 66.5 Ra, Tint +0.0087 DUV.

  • High - CCT 5642K, CRI 65.4 Ra, Tint +0.0104 DUV.

  • Medium - CCT 5514K, CRI 64.4 Ra, Tint +0.0122 DUV.

  • Low - CCT 5422K, CRI 63.8 Ra, Tint +0.0131 DUV.

  • SP31 V2.0 Turbo - CCT 5983K, CRI 68.9 Ra, Tint +0.0065


As expected for a light with the SST-40 emitter, whilst efficiency is good, the CRI and tint are not great. There is a slight green tint, which is more pronounced at lower brightness levels. The hotspot CCT is slightly warmer than most other 6500K SST-40s I've tested, possibly due to the TIR optics increasing CCT shift between the hotspot and spill beam. A high CRI version may be in the works, using a Nichia 519A LED, which I would estimate would be around 1100lm. No visible Pulse Width Modulation was identified.



Sofirn SP31 V3.0 optics.
Sofirn SP31 V3.0 optics.

Sofirn SP31 V3.0 beam profile.
Sofirn SP31 V3.0 beam profile.

The Sofirn SP31 V3.0 was used for the fine green light trails in this light painting photo.
The Sofirn SP31 V3.0 was used for the fine green light trails in this light painting photo.


Conclusion


Positives:

  • Good value for money.

  • Decent build quality.

  • Last mode memory.

  • Momentary for all normal modes.

  • Turbo included in main mode cycle.

  • Internal USB-C charging.

  • Compatible with most light painting systems.

  • Considerably brighter than the older SP31 V2.0 (though below specification).

Negatives:

  • Rapid brightness step-down.

  • Strobe and moonlight modes are not memorised (and thus not directly accessible from tail switch only).

  • Alternating frequency strobe.

  • Access to moonlight mode is unusual.

  • Mode spacing is not quite as good as the SP31 V2.0.


For those looking for a budget tactical light, with momentary and last mode memory for all main brightness levels, then the SP31 V3.0 is a fantastic choice.


For light painting photography (creating light trails), the SP31 V3.0 is a good budget choice for continuous (non-strobe) light trails, if you require momentary on/off control. As the light has low CRI, I would recommend other lights for the illumination side of night photography (though a high CRI version may be in the works).


Product Page at Sofirn  code: SNDEAL (for 20% off).



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