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  • Mid-range underwater strobes in test with the new Weefine WFS-05 strobe

    April 04, 2021 7 min read

    Mid-range underwater strobes in test with the new Weefine WFS-05 strobe

    Inon and Sea & Sea have dominated the consumer/enthusiast underwater strobe market for years now. There have not been many alternatives available if you wanted to get a compact, reasonably inexpensive strobe for your camera system. At the fringes, there have been makers like Ikelite with their monstrous old-school DS series of strobes, which were never really suitable for an up to date underwater camera system and then some real pro choices like Subtronic or OneUW, which are way over the budget for most underwater shooters.

    This review introduces the new Weefine WFS-05 strobe and pins it together with two well known mid-range underwater strobes, the Inon D200 and the Sea & Sea YS-01 Solis. The WFS-05 is Weefine’s first serious entry into the strobe market by the company and on paper comes with lots of great features. I dug out my old trusty Minolta Flash meter V (nowadays Sekonic) from my studio photography days and set out to see if any of the manufacturers specs are up to what they promise.

    Introducing the Weefine WFS-05 strobe

    Weefine WFS-05 Underwater Strobe

    Weefine’s strobe has been under development for a while now. I first saw a prototype model a few years back. For a short time, the light was already on the market with WFS-02 name. This early model was quickly discontinued and the new improved 05 model introduced. I’ve had the first 05s on hand for a few weeks now. From the outside, the 05 model is identical apart from the slightly different looking power dials. According to the manufacturer, the electronics are however been re-worked and the early issues are now ironed out.

    The most striking feature of the Weefine strobe is its large ring shape xenon flash tube and a two-colour LED spotting light in the middle. The white spotting light has decent power, maybe just under what you get with the Inon D200. The red LED is also very bright and I can see it being useful during night dives. The Red light is a feature I’ve not seen in any other strobe light yet. Another noticeable feature is that the light is built, if you wish, “upside-down”. Weefine seems to have followed the likes of Retra and designed the strobe with top mounting… sort of a hanging design, which is absolutely fine as this is how the light will mostly be positioned when in use. The little LCD screen can also be rotated to show power info and other settings upside down if needed.

    Weefine WFS-05 battery

    According to the manufacturer, the WFS-05 output is GN24. The main power dial allows the user to choose from 11 different levels. Both the white and red LED spotting lights have 10 different power levels. The unit is powered by a 42.92wh Li-ion battery pack. The same battery pack also works with various other Weefine video lights. According to the paperwork you can get up to 900 full flash discharges from one battery charge. This sounds like a very high number of flashes, and even if the real-life figure is somewhat less, it is still a very impressive number and easily double or triple what the other two AA-battery powered strobes in this review can achieve. Both non-pre-flash and pre-flash cameras are supported.

    The Weefine WFS-05 strobe also comes with an automatic sync TTL mode that adjusts the strobe output according to the camera’s onboard flash. Testing these slave TTL features is always hard as there are so many cameras out there and even the more established manufacturers have difficulties with certain camera models. In my tests I got the automatic sync mode to work well with Olympus TG-6. However, with the Canon G7X MKIII camera, I got more erratic results. Even Inon’s well trusted STTL mode struggles with Canon G range cameras, so more tests would be needed to really see how useful the WFS-05 automatic sync mode is. 

    Side by Side Comparisons

    Mid-range underwater strobes side by side


    No competition here. The Sea & Sea YS-01 Solis is by far the smallest and lightest of the three weighing only 480g (without batteries). The Inon D200 comes next with 580g and the Weefine WFS-05 is the heaviest at 870g

    Beam Angle:

    (Note that these tests are done out of water and in water results might be somewhat different.) The winner here is surprisingly the Sea & Sea YS-01. Even without the diffuser, the flash beam angle is very wide. Only annoying thing is that the sides of the YS-01s opaque front piece light up when the strobe fires and easily cause reflections on the camera lens or a housing dome port. You need to be very careful how to position this strobe.

    The Weefine WFS-05 also produces a wide and perfectly circular beam due to its round flash tube. However, there seems to be a slight shadow in the centre. It looks like this is due to how the flash reflector is constructed around the quite wide spotting light assembly. According to my light meter, this shadow area is about 1/4th stop less, so not really noticeable in real life but I can see it in my test pictures, which were taken against a white wall. There is no diffuser available for the WFS-05 at least yet but the light has a thread at the front so future accessories are very probable.

    Inon is known for having dual flash tubes on their strobes, which are positioned on top of each other into the shape of T. The D200 is not an exception. This means that without the diffuser the beam is quite uneven and by far the narrowest of the strobes here. For the Inon strobe, the diffuser is definitely needed. (Worth remembering that the whole front of the D200 is essentially a dome port. It's difficult to say how exactly this works in water without careful tests but in theory, it should help to keep the angle of the beam wider than if the front would be flat).

    Flash Output:

    Most flash manufactures, both underwater and topside, use metric guide number (GN) as a measure of how powerful their products are. The GN is simply calculated by multiplying the distance (in m or ft) by the f-stop number. To measure this properly a flash meter is required. For example, if the meter says f8.0 at 4 meters at ISO100 the metric GN is 32. However, these are by no means absolute measures as there are lots of other variables like ISO sensitivity and angle coverage. Remember also that flash meters measure only the incident light that hits the sensor whereas all contemporary cameras measure the reflected light, which is highly dependent on the scene. Hence when measured with a camera the results will vary wildly.

    According to the manufacturer figures the Sea & Sea YS-01 Solis and Inon D200 are rated as GN20 and the Weefine WFS-05 as GN24. Weefine also gives another figure for their strobe; 80Ws or Watt-seconds. This number is to do with the amount of energy the strobe's capacitor can store. This number does not directly equate to how much light comes out of the flash. The final output is affected by the efficiency of the flash tube and things like how good the reflector is.

    My measurements were done at the centre, at 45 degrees and 90-degree beam angle at 2m. ( Note that my Minolta light meter measures as accurately as 1/10th of an f-stop. For example, it might give f5.6 and 9/10th… so almost f8.0. Most today's photographers are more familiar with the 1/3rd f-stop numbers most cameras now show in their exposure meters. For measuring the GN it could be said with reasonable accuracy that the meter reading of f5.6 and 3/10th would be f6.3 and f.5.6 and ½ would be f6.7 etc…

    Phew… that got a bit sciency there. Let's get back to the results.

    The Sea & Sea YS-01 Solis is the most powerful strobe of my test. It measured f8.0 and 1/10th at the centre, f5.6 and 7/10th at 45-degree angle and f4.0 and 8/10th at 90-degree angle, without the diffuser. The inon D200 measured f5.6 and 9/10th (centre), f5.6 (45), f2.8 and 3/10th (90) without a diffuser. The Weefine WFS-05 measured f5.6 and 6/10th (centre), f5.6 and 8/10th (45), f4.0 and 8/10th (no diffuser available)

    Note that at least for wide-angle work with the Inon D200 the supplied diffuser is needed to get an even spread of light. The diffuser cuts the power of the light for about half a stop in the centre areas but slightly improve the situation at the edges. (f5.6 and 3/10th (C), f4.0 and 6/10th (45), f2.8 and 6/10th (90) with diffuser). But with the diffuser, the Inon D200 has the weakest flash output of the strobes in this test.

    What about the guide number then? According to my measurements all of the manufacturers GN promises are quite far from reality. Taken from the highest reading (note that the WFS-05 had slightly better output at the 45-degree beam angle) and rounded to the nearest 1/3rd f-stop numbers I get the following. YS-01: GN16-17. D200: GN15-16. WFS-05: GN14-15.

    Spotting light:

    Inon D200 has the most powerful white spotting light of the bunch… but as you are “forced” to use the diffuser that covers the LED assembly only a dim glow comes through it. The Weefine WFS-05 has both good white and red spotting light; Useful even for longer distances. The YS-01 has the weakest light of the bunch, although still powerful enough for close-up work.

    Final Words

    The Weefine WFS-05 is an interesting entry to the market and although far from its promised output still offers divers something no other strobe can. Due to its powerful Li-ion battery, it will last far longer than any AA-powered strobe. You could easily go through the whole day without a need to open the light. The red LED light is also a very nice extra that keen night divers (like me) will appreciate. The ring shape flash tube provides a round beam and flat soft shadows for macro photography. At £480.00 it is an affordable mid-range choice.

    But if you want a compact strobe that packs a punch then go for the Sea & Sea YS-01 Solis. I didn't rate this strobe very high before but this test has changed my mind. Costing only just above £400 it's a solid choice for an underwater photographer on a tight budget.


    Check out the full range of Mike's Dive Cameras underwater strobes HERE