Underwater Photography

Testing the Kraken KR-S02 Strobe

Kraken are well known for their excellent high quality video lights, that have become among the most popular in the industry. Last year, Kraken have released their first strobe, the KR-S02, competing with longtime brands such as Sea & Sea and Inon.

I got my hands on one of these strobes to test it out for myself and see how it holds up against the competition.

I was hoping to test it out in my home base of Cozumel, but unfortunately COVID-19 had other plans, so most of the tests here will be in a pool, until we can go diving again! (Update – Tested the strobe in the cenotes! See below)

Kraken KR-S02 Specifications

Guide Number (1m, 100 ISO) 24
Colour temperature 5000K
Beam Angle 90° Degrees
LED target light 200 lumen, 6000K white spot light and 2 Watt red light
Power Modes GN 1 / 1.4 / 2 / 2.8 / 4 / 5.6 / 8 / 11 / 16 / 22 / 24
Flashes per full charge 900+ (Wow!)
Recycle time ~1.5s at full power
Battery Lithium Ion (4 x 18650 / 3400mAh wrapped to single cell)
Depth Rating 330ft/100m
Weight 1050g / 2.3lb (on land w/ battery)
Buoyancy 240g / 0.5lb (underwater w/ battery)
Dimensions ~ 119mm (L) x 119mm (W) x 135.5mm (H)

Top Features

Power Output

The KR-S02 outputs a 24 GN beam, which is pretty strong. While not as strong as the S&S YS-D2J and Inon Z-330, it is stronger than the YS-01 and S-2000 which are rated at 20 GN.

Thanks to the circular beam, you can get nice and even 90° degree beam angle, without any diffusers attached. The optional diffused will increase that to 110° degrees. (Note – at the time of this review the diffusers haven’t been released yet, but are in the making).

This output is perfect for a mid-range strobe, strong enough to get good lighting even in clear day shallow water conditions, where the weaker strobes sometimes fall short. Especially when you’re limited by a slow max flash sync speed of 1/160s with the popular Sony a6XXX series.

Controls

The KR-S02’s controls and user interface are where it really shines!

The back side includes a small LCD screen that shows the mode and power output in a very intuive and well-lit format. The screen even flips to accommodate different strobe positions so that it’s always perfect clear and easy to read.

The two knobs are very sturdy, high quality metal dials. At the center of each dial is a push button. For those of you using gloves, Kraken includes an oversized knob extension that mounts right on the dial and allows adjustment even with thick gloves.

The silver flash power dial clicks between steps, allowing you to adjust strobe power. The center button is a Push-To-Test button to make sure your strobe is firing. Long pressing that button switches between S1 / S2 and Sync, which are used for pre-flash / no-preflash sync.

The blue dial controls the LED target light, rotating smoothly between 0 to 100% in 10% increments, both for the white light and for the red light. The center button switches between the two lights. Long pressing on that button turns the strobe on / off.

Target Light

Two focus / target lights are included – 2-Watt red and 200 lumen white.

Both lights produce a tight spot beam, increasing the intensity of the light at the center for ideal focusing.

A very useful auto-off feature is included, turning the focus light off for 1 sec when the flash fires, to prevent hotspots in the frame.

The blue control dial allows you to control each light independently, at 10% increments. The strobe has a memory feature that remembers the selected power output even when switching between modes.

Sync modes

The KR-S02 is a manual only strobe. There is no TTL available. Some users won’t mind that, since many underwater photographers prefer to set their strobes manually anyway.

However, those who rely on TTL and prefer a more automatic strobe setting, would be better off getting the YS-01 / YS-03 / S-2000 strobes.

Remote Ready

Kraken’s universal remote is compatible with the KR-S02 strobe as well! Using the remote you can control power output and light intensity of the LED lights using a fiber optic cable and positioned right at your finger tips, on the edge of the grip.

Two fiber optic holes are located at the bottom of the strobe – one for triggering the strobe and the other for connecting the remote.

Battery

One of the most annoying things for UW photographers is to change batteries between dives. The KR-S02’s battery is so powerful, you probably won’t have to switch!

The battery is a Lithium Ion type, containing 4 x 18650 cells wrapped into one. It’s actually the exact same battery as the Hydra 5000S+ light, so you can interchange between them and use the same charger.

This powerful battery allows over 900 flash cycles on full power! That’s the most we’ve even seen on an underwater strobe. For comparison, the YS-D2J is rated at 200 flashes on full power.

The battery charges via an external dedicated charger that connects with a cable to an input in the battery itself.

Even though the battery compartment is protected with 2 o-rings, in the unlikely case of a flood it is also water-sealed, so no harm will come to your light, just the battery will need to be replaced and the contacts cleaned.

Design

The general design of the strobe is great, as detailed in the controls section above. The light also includes a threaded bezel for optional accessories such as dome diffuser, snoot and more.

There are 3 standard 1/4″-20 threads on the bottom and both a YS mount and ball mount are included with the light. You can also easily mount it on a tripod, attach an optical sensor and use it as a slave in a pool, cenote or wreck photography.

The only downside here is that it is big, bulky and rather heavy. The big battery, nice screen and round bulb all come with a price and that price is size. It is bigger than the YS-D2J and the Z-330. Still smaller than the Ikelite DS160 / DS161’s though.

At about 1050g / 2.3lb with the battery, it’s about 40% heavier than the YS-D2J and about 20% lighter than the DS161.


PROS

  1. Strong power output
  2. Extraordinary battery life
  3. Beautiful and intuitive control interface
  4. 10-step control over LED
  5. Comes with a great padded case
  6. Easy to add accessories via threaded bezel

CONS

  1. Big, bulky and heavy
  2. Manual only, no TTL
  3. Fiber optic only, no sync cord

Sample Photos

In the samples below you can see the circular beam created by the KR-S02.

I compared it to the Sea & Sea YS-D2 with and without a diffuser, as well as the Inon Z-240, with and without a diffuser.

The KR-S02 probably has the most even beam without a diffuser compared to the other two. There is a small darker spot in the center due to the circular shape of the bulb, but it’s not a big issue. In many cases the closest point to the strobe on the subject is actually in the center of the frame, which makes it better for avoiding washed out highlights.

I also took the KR-S02 with me on a cenote dive, along with the YS-D2. I was using the YS-D2 as master and triggering the KR-S02 as slave.

The two strobes worked great together as you can see in the photos below. Both strobes were used on a fairly low setting for most of the dive, around 8-10 GN, since I had to use a high ISO for the sun rays.

The KR-S02 was on the left side of my camera (no diffuser) and the YS-D2 on the right (with diffuser).

Conclusion

The Kraken KR-S02 is an excellent strobe. While it does have several downsides compared to other options in the market, it compensates for them in phenomenal battery life, great interface and more cool features as we discussed here.

I highly recommend it for more advanced photographers, who don’t rely on TTL and can appreciate the advantages it offers.

Get your Kraken KR-S02 here

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Ran Mor

Sales and Marketing at Mozaik Underwater Cameras
Ran is a professional photographer for over 14 years. His passion for scuba diving and photography has pushed him to combine his profession and hobby and become a professional underwater photographer. Teaching is one of his greatest passions and over the years he has shared his experience with many divers and aspiring photographers. Along with his wife Danielle, an experienced Scuba Instructor, they have founded Dive and More, leading dive trips and UW photo workshops all over the world. Ran is also an electrical engineer and an avid internet marketing specialist.
Visit his personal portfolio at www.ranmorphoto.com.
Ran Mor
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