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iTorch Symbiosis Strobe Review

iTorch Symbiosis Strobe Review

March 4th, 2017

iTorch Symbiosis Strobe Review

by Scott Gietler

Game-changing strobe combines video light with high-end strobe

Ultra-fast recycle times on certain power levels

Battery pack gives over 500 flashes

TTL training mode allows for accurate TTL

Remove the video light or change heads

We are in love with the new iTorch Symbiosis strobe. It allows us to take high-quality underwater video, and have a high-powered flash all in one unit. The video light has a red and white light mode, the flash recycles very quickly, and the unit is modular. For divers who sometimes take both video and photos underwater, the strobe may be just the right gear purchase for you.

Guide numbers of 24 and 32

There are two versions of the Symbiosis strobe, the SS-1 and the SS-2, with guide numbers of 24 and 32 on land, respectively. That rating puts the SS-1 strobe ahead of the Sea & Sea YS-01 and Inon D2000/S2000 in terms of strength, and puts the SS-2 strobe equal to the YS-D2 strobe and ahead of the Inon Z240 strobe.

2,000 and 4,000 lumen video lights

The SS-1 and the SS-2 Symbiosis strobes both include a 2,000 lumen video light, with white light and red light modes. While testing this light out, you could tell this was a serious video light, and it felt even brighter than its 2000 lumen rating.

Lithium-ion battery pack

Instead of using AA rechargeable batteries, the Symbiosis strobe uses a lithium ion battery pack that powers both the video light and the strobe flash.

Electronic dials

The rear of the Symbiosis strobe has 2 dials, and LCD screen and 2 buttons. Technology at its finest! The left button has 4 settings - Off, strobe mode, auto 1, auto 2, and video mode. Auto 1 and Auto 2 are the strobe's TTL modes which we'll explain further down. The video light can also be used in strobe mode, but with slightly reduced power. 

The right dial is a simple power dial - turn right for more power, turn left for less power. It is an electronic dial, which means when you turn the dial to the right, you will see the power level increase in the LCD screen.

The two buttons are simple enough, the "Test" button fires the strobe flash, and the right button cycles through the red & white colors of the video light when in "video mode", and cycles through the video light power levels when in "strobe mode".

Overall, the controls are very intuitive and easily mastered within a dive or two.

Fast recycle times

The recycle time of the SS-2 strobe on full power is 1.6 seconds, comparable to the YS-D2 and Z240 strobes. The SS-1 strobe has a blazing fast 0.8 second recycle time However, if you turn the SS-2 strobe power down just 2 notches (about 2/3rds of a stop), the strobe recycles very fast in about a half second, which is great for shooting behavior.

Long burn times, lots of flashes

You will get about 100 minutes of use with the video light on full power with a full charge on the battery, which is quite nice because most lights only give you 1 hour. Using the light on full power for 1 hour will give you 50% of the normal amount of flashes, which is still about 225 flashes.

Because this battery has so much capacity, you can actually get 550 full flashes from this strobe with the SS-2 strobe if you are not using the video light. No need to change batteries during the day! The SS-1 strobe will give you (drum roll please) 1000 full power flashes on a fully charged battery, wow.

Auto-TTL and TTL calibration

The iTorch Symbiosis strobe has a unique TTL implementation that allows you to calibrate the TTL functionality. This avoids alot of the inaccuracies that other strobe users have experienced.

Auto 1 mode is "wide angle" mode, meant for TTL when shooting from half a meter to 2 meters away. Auto 2 mode is "macro" TTL mode, meant for shooting 0.2 - 0.5 meters away.

In Auto mode, the right dial acts as a calibration tool. Do a test shot, and then adjust the right dial, repeat until your exposure looks good. After the calibration, you should not need to further adjust the calibration if your camera settings do not change. The downside of this method of TTL, is that the TTL will not work again when the aperture is changed while shooting macro, and you will have to recalibrate.

Training mode to detect pre-flash sequence

If you hold down the "test" button while turning the strobe on, the strobe will enter "training mode". This mode reads the pre-flash sequence of the camera you are using, and learns to ignore all pre-flashes.  Although it sounds like extra work, it actually it very easy to do, and only takes a second to put the strobe in training mode. All you have to do it take one shot, then you are good to go.

We've seen numerous users have strobe problems because their camera flash more, or their strobe mode was not set correctly. We think this feature will go a long way in solving these kinds of issues.

No sync cord opening to flood

Because the Symbiosis strobe only works with fiber optics, there is one less seal on the strobe that can flood - not a bad thing.

Downsides of the Symbiosis strobe

Although we love the Symbiosis strobe, it does have its downsides which we should point out. Although the video light has a red mode, the light won't necessarily replace a focus light, since you rarely want your strobes to point directly at your subject. However, since the video light has a wide 100 degree beam, even when your strobe is angled out, your subject should be lit.

You will want a spare Li-ion battery pack, but they are not cheap and do cost more than AA rechargeable batteries. The TTL functionality is not as flexible as the TTL functionality of the YS-D2 or Inon Z240 strobes, but the training feature means it can be more accurate. Last, using the electronic dial to change the strobe power is fun and cool, but is sometimes not as quick as using a fixed position dial like the YS-D1 or YS-D2 strobes have.

Last but not least, this strobe is larger and weighs a little more than a standard strobe, which is to be expected since is has a video light attached to it. Still, the setup did not seem overly heavy underwater when compared to using my normal strobes.

iTorch Symbiosis Strobe - What's Included?

  • Strobe with video light head
  • Lithium Ion battery pack
  • Smart charger
  • 100 degree diffuser
  • YS-mount and 1-inch ball mount


The iTorch Symbiosis strobe has several exciting innovations that will excite still shooters and combination still shooters/videographers alike. The Li-ion battery pack, LED screen, Auto-TTL mode, and intuitive controls are all welcome features that we think will attract many people to this strobe. If you want to try video at some point, and you don't want to deal with a separate video light and a separate mounting system, this strobe is for you!

Links to Purchase

iTorch Symbiosis SS-1 Strobe
iTorch Symbiosis SS-2 Strobe

Full Specifications

  • Weight 970grams (SS-1), 1025 grams (SS-2)
  • Size 95mm x 120mm x 162mm
  • Depth Rating 60 meters / 200ft
  • Strobe Recycle time SS-1 0.8 seconds / SS-2 1.6 seconds
  • Strobe Angle of coverage 90 degrees (100 degrees with diffuser)
  • Guide Number 24 (SS-1), 32 (SS-2)
  • Strobe color temp 5700 K
  • # of full power flashes with LED off: 1000 (SS-1), 550 (SS-2)
  • Video Angle of Coverage: 100 degrees
  • Video Lumen Levels: 2000 lumens
  • Video color temp: 5675K
  • Burn time: 100 minutes at max intensity

Quick demonstration of the Symbiosis Strobe


iTorch Symbiosis Strobe Review
Photo taken with the iTorch video lights, no strobes. F6.3, 1/640th, ISO 1000


iTorch Symbiosis Strobe Review
iTorch video lights, no strobe. F8, 1/125th, ISO 1000


iTorch Symbiosis Strobe Review

Only video lights, no strobes. F11, 1/200th, ISO 1000

iTorch Symbiosis Strobe Review

This photo is with the Symbiosis strobes. F29, 1/250th, ISO 200. No surprise here, photos taken with the Symbiosis strobes look just like photos taken with other strobes.


Symbiosis SS-2R Sample Images (Strobe):


Pacific Northwest reef photographed with one Symbiosis SS-2R strobe

Pacific Northwest reef photographed with one Symbiosis SS-2R strobe


Pacific Northwest reef photographed with one Symbiosis SS-2R strobe

Pacific Northwest reef photographed with one Symbiosis SS-2R strobe


Pacific Northwest reef photographed with one Symbiosis SS-2R strobe

Pacific Northwest reef photographed with one Symbiosis SS-2R strobe


Symbiosis SS-2R Sample Images (with video light, no strobe):


Pacific Northwest anemone photographed just using the Symbiosis SS-2R video light

Pacific Northwest anemone photographed just using the Symbiosis SS-2R video light


Pacific Northwest anemone photographed just using the Symbiosis SS-2R video light

Pacific Northwest anemone photographed just using the Symbiosis SS-2R video light


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