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Kraken KR-S02 Strobe Underwater Review

Kraken KR-S02 Strobe Underwater Review

January 21st, 2020


Kraken KR-S02 Strobe Review

Kraken is one of the world’s top innovators in underwater imaging tools – especially when it comes to video lighting. Given Kraken’s success, it was only a matter of time that they would come out with their first underwater strobe, and now it’s here! The Kraken Sports KR-S02 is the first in Kraken’s new strobe line, and we at Bluewater Photo were sure to be some of the first to get our hands on it.
The highlight of this strobe is the battery life, with over 900 full cycles on a full charge! This is in part because the KR-S02 is more of a mid-range strobe when it comes to power. It has a guide number of 24 – which is powerful, but not at the highest end of the market (closer to 33 or even 64). It is certainly more than capable for macro photography and most types of wide-angle photography. The strobe features a 200 lumen white and red spot light which is great for focusing. The beam is 90 degrees with a color temperature of 5000K. Finally, the KR-S02 will be even more versatile in the future as Kraken is planning on developing diffuser and snoot accessories. So, on paper, the KR-S02 is a very promising piece of equipment. But paper isn’t why people by strobes - We took it diving in the cold waters of Catalina Island, California to put it to the test and see just what it could do. The KR-S02 strobe has proven to be a valuable tool for underwater imaging with a few features that has set it apart when compared to other strobes on the market.


Status: Available now

U.S. MSRP: $599.00



The relatively narrow beam angle on the Kraken KR-S02 can be used for creative lighting like in this photo of two California sheephead. Nikon Z6, Nikon 8-15mm fisheye lens, Isotta housing, dual Kraken KR-S02 strobes. f/8, 1/125, ISO 200


The Kraken KR-S02 is Available at Bluewater Photo!

Kraken KR-S02 Strobe



Kraken KR-S02 Key Specs


Guide Number: 24

Beam Angle: 90°

900+ full power cycles at full charge

Color Temp: 5000K

Recycle Time: ~1.5s on full power

LED Spot Light: 1 watt (200 lumen, 6000K) spot light, and 1 watt red light

Uses lithium ion batteries - the same as the Hydra 5000

Battery: 4X18650 (3400mAh) wrapped into a single cell

Depth Rate: 330ft/100m

Can be used only with fiber optic cables (universal Sea & Sea style plug), no sync cord connection. 1 multi core fiber optic cable with each strobe included

Weight: 1050g (on land including battery), 240g (underwater including battery)

Dimension: ~119mm (L) X 119mm (W) X 135.5mm (H)

Included in Box: Strobe, battery, YS mount, ball mount, charger, knob extensions, manual

Dimension: Diffusers and other accessories will be made in the future!



Build and Ergonomics

The Kraken KR-S02 is fairly unique in its build. The body of the strobe is “short and squat” but wide. Rather than a long cylinder with a short radius, it’s a short cylinder with a long radius. This provides a benefit to the beam because the KR-S02 is build with a large circular flash tube. The flash tube creates a nice, even beam that is great for getting even lighting in macro photography. When it comes to weight, the strobe weighs in at 1050 grams on land (240 grams underwater). On land, this is much more weight than some of its competitors. Part of the reason for this is the heavy lithium ion battery that results in the spectacular amount of battery life. And when we tested the strobe underwater, it was fairly easy to manipulate and move around. It didn’t make a noticeable difference in the weight of the rig underwater. Because the strobes are fairly wide, it does take some getting used to them when it comes to placement in the water. 
Despite the size and shape of the strobes, they’re pretty easy to pack up for a trip. Like all Kraken products – they come with a nice case that can store everything, including chargers, mounts, and a manual. 
As far as ergonomics are considered, this strobe is very easy to use – even in cold water with thick gloves. The power and mode selection knobs are easy to grip and turn. We didn’t have any problems with sand making them stick. The KR-S02 comes with knob extensions, to make gripping them even easier if you really are diving in a cold place. Both buttons are easy to press. The digital screen on the back is easy to read. It relays important information, like the battery level and how many shots you have left. No other strobes on the market will tell you how many shots you have left. We found the information to be extremely useful in planning our day of diving. Another nice feature is the ability to flip the display screen, in case you need to turn the strobe upside down while positioning it. We ended up using that function quite a bit while testing. 
A beautiful beam on this reef scene. Nikon Z6, Nikon 8-15mm fisheye lens, Isotta housing, dual Kraken KR-S02 strobes. f/11, 1/1160 ISO 200

Guide Number (Strobe Power)

The KR-S02’s guide number is 24. We find this to be an ideal guide number for mid-range strobes. In general, we think this strobe is great for macro shooters that want a nice, even beam. It’s also great for wide angle shooters in most conditions except for the most extreme. During our tests we shot wide angle photos with two strobes in order to push them to the limits. Visibility was about 50-60 ft, and the sun was out and shining. We tried to get as much back lighting with the sun as possible to see if the strobes could properly light subjects while shooting sunballs – the ultimate test of a strobe’s power. In general, we found that they succeeded. However, when we shot wide-angle back-lit subjects in water shallower than 30 ft, we would have preferred a little more power. If you are going to be shooting wide angle images in shallow, clear, tropical water on sunny days, we would recommend another more powerful strobe like the Sea & Sea YS-D3 or the Isotta Red 64. But for any other conditions, the KR-S02 is a great tool.


The Kraken KR-S02 is powerful enough to produce nice reflections on the divers face, even in shallow water with a lot of light. Nikon Z6, Nikon 8-15mm fisheye lens, Isotta housing, dual Kraken KR-S02 strobes. f/11, 1/1160 ISO 200

Beam Properties

The ring flash tube is one of the most noticeable physical features on the KR-S02. Its shape creates an even beam underwater. However, it’s important to note that the beam is only 90 degrees. We found that this changed out shooting style underwater. We often had to point the strobe much more directly at subjects in order to light them properly in wide angle shots. At times, we missed shots, because the strobes needed to be pointed more directly. Although this doesn’t cause any issues in macro photography, more direct lighting did produce more backscatter at times. This problem will be eliminated in the future when Kraken comes out with a diffuser that will attach to the threaded bezel. 
We found the color temperature of 5000K to be an excellent temperature underwater – not too warm and not too cold. It really is the goldilocks temperature when it comes to underwater photography.

Battery Life

The battery life of the KR-S02 is the highlight of the strobe. No other strobe on the market is rated for more than 900 full power shots on one charge! The reason this is possible is the KR-S02’s lithium ion battery – the same one as can be found on the Kraken 5000S+. Because these batteries are interchangeable, the KR-S02 is an especially good choice of strobe if you have a Kraken 5000 series light for underwater video. During our tests we easily got three dives with the strobes. However, we sometimes found the shot count on the strobe to lower by more than one after a shot. That being said, it was extremely useful to know how many shots we had left with our strobes. And it was certainly more than others on the market. 


Recycle Time

The recycle time with the Kraken KR-S02 is fairly quick at ~1.5 seconds. In most circumstances we found it to be more than enough when shooting fast moving fish – like a pair of California sheephead that were fighting for territory. At lower powers, the strobe recycles even quicker.


Quick recycle times let us capture this quick fight between sheephead. Nikon Z6, Nikon 8-15mm fisheye lens, Isotta housing, dual Kraken KR-S02 strobes. f/8, 1/125, ISO 200


Sync Modes

The Kraken KR-S02 must be synced to your camera via fiber optic cable – it doesn’t have a sync chord connection. It has three sync modes – S1 single flash mode (for flash triggers), S2 double flash mode (for on-board camera flashes with preflash), and Synch mode (TTL). Manual adjustments are fairly easy in the S1 and S2 modes with the knobs. However, you have to make sure you are using the multi core fiber optic cable that comes with each strobe in order for some cameras to work properly. We used the sync mode (TTL) throughout most of our tests and found it worked fairly well. The strobe only missed a few exposures – most other exposures were quite accurate. 


Spot Light


The spot light on the strobe is great for focusing, but at 200 lumens it isn’t strong enough for video. We enjoyed using the red light to focus on subjects that would normally shy away from our white light. 



Easy to use knobs, and nice screen display on back

Amazing battery life

Fast recycle speeds

 Easy to pack



Strobe output could be a little brighter (guide number 24)

The beam angle could be a little wider 




More dramatic lighting with the Kraken KR-S02 strobe. Nikon Z6, Nikon 8-15mm fisheye lens, Isotta housing, dual Kraken KR-S02 strobes. f/8, 1/125, ISO 200




Overall the Kraken KR-S02 is a very capable strobe with a lot of potential. It currently offers some of the best battery life of any strobe on the market – this is a big deal when you’re diving multiple dives in a remote or difficult location. However, we do wish the strobe had a little bit more of a beam angle, in order to not point it so directly at wide angle subjects. This will be easily remedied when the diffuser comes out for this strobe. As far as macro photography, the KR-S02 will be a reliable option, especially when the snoot is released. Currently, the nice, even beam and beautiful color temperature makes it very compelling for macro and wide-angle photography photographers who are looking for quality light, unlimited battery, and quick recycle times. 




The Kraken KR-S02 is Available at Bluewater Photo!

Kraken KR-S02 Strobe



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Phone: 310-633-5052



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