Retra Flash Full Review

A full review for Retra's flashy new strobe
By Matthew Sullivan

A few months ago I had the chance to take one of the first production pair Retra Flashes underwater for just four dives. I did a very brief initial review on it. I was immediately impressed and confident that my decision to preorder my own pair was the correct one but four dives in bad conditions were not enough to put together a thorough review.

Fast forward to now and I've managed to have them out on around 35 dives so below is a more thorough overview of the flashes, my thoughts, and some images I've made with them underwater.

Nemo Brand Anemonefish- Anilao, Philippines. Nikon D500, Nauticam Housing, Dual Retra Flashes w/Wide Angle Diffusers, Nikonos 13mm


  • 100W/s 
  • GN30 in comparison with two strobes - see comparison here 
  • GN18 (absolute measurement on land) 
  • Recycle time @100%: 2s (4x eneloop pro), 1s (8x eneloop pro) 
  • Number of flash @100%, 0.5Hz: 450x (4x eneloop pro), 900x (8x eneloop pro) 
  • 300 lumen pilot light 
  • Pilot light burn time @100%: 3h (4x eneloop pro), 6h (8x eneloop pro) 
  • 5400K color temperature (4500K with wide angle diffuser) 
  • 110º beam angle 
  • 9 manual exposure levels 
  • S-TTL with +/- 2 F-stop adjustment 
  • Slave mode with smart pre-flash cancellation 
  • 4 level battery indicator for eneloop batteries 
  • Electrical connector options: S&S 5 pin, S6, N5 and Ikelite 5 pin 
  • Inon and Sea&Sea dual compatible optical connector 
  • Length = 120mm 
  • Diameter = 102,5mm
  • There are nine power settings on the the back of the strobes, all easily chooseable with the large, smooth dial. The flashes take electronic or fiber optic sync cables (both Inon style mount and S&S style mount), and have corresponding settings based on which you are using. The dial that activates the strobe has several different notations. OFF, ON (the setting to use with electrical sync cables), STTL, SL (the setting to use with fiber optic cables), and SOS. An easily pushable pilot light is centered in the back of the strobe, with multiple power settings. The battery compartment (sealed off from the rest of the strobe) is a screw in/screw off, with perfectly decipherable instructions inside the battery compartment as to how to load the batteries


On the left we can see the front of the Retra Flash showing the flash tube and the battery indicator lights which can be immensely helpful. The lack of a battery indicator was a gripe I always had with previous strobes I have used. On the right the back of the strobe showing the open battery compartment, the power modes, the power settings, the fiber optic port (the strobe comes able to handle both S&S and Inon style mounts), the electronic sync port, and the pilot light. The back light above the pilot light push button changes color depending on which setting you have the strobe on. 

  • Off=No light
  • On=White
  • TTL=Blue
  • SL (Slave Mode)= Green
  • SOS=Flashing White

Golden Gorgonion on the pilings of the Eureka Oil Rig off Southern California. Nikon D850, Nauticam Housing, Dual Retra Flash w/Wide Angle Diffusers, Nikonos 13mm



The Retra Flash is available now at Bluewater Photo!


At first glance it is apparent you are looking at a beautifully constructed tool. The sleek silver aluminum casing is not only nice to look at, but provides a tough exterior that should stand up to just about any wear and tear. The casing also prevents overheating that can sometimes plague the plastic bodied strobes. 

Two large, smooth dials control every function of the flash (aside from the pilot light push button) and are very easy to work, even while wearing the thickest coldwater gloves.

The back of the Retra Flash showing the battery compartment, the different power settings, the different modes, the pilot light, and the electronic sync port

Another image of the strobe back allowing us to see the large, very ergonomic controls of the Retra Flash that allow for easy adjustments while being nearly impossible to knock out of position.

Retra flash used to illuminate the octopus while the bottle is backlit with a torch. Coconut Octopus- Anilao, Philippines. Nikon D500, Nauticam Housing, 1x Retra Flash w/Retra LSD Snoot, Sola 800, Nikonos 13mm


Specs are nice but if the gear can't perform in the real world, what's the point? I have been very pleased with my pair of Retra Flashes. They allow for far greater creativity than I was able to show in this article, they are built extremely well, they look nice, and the light they produce is beautiful. A soft, even beam at a color temperature of 4500K and a spread of 130 degrees with the standard wide angle diffuser in place. The real test will be long term reliability over years and years. The strobes I upgraded from (Inon z240s) are workhorses that have provided countless underwater photographers with years of solid use. The Retras need to at least match that reliability. So far they have.

If you're like me (forgetful) and dont remember to check the battery indicator lights once in a while and notice your strobe will only work in SOS mode, that is not cause for concern for anything other than your memory! It just means the battery levels are low and the strobe is requesting fresh ones. 

The Retra Flashes produce beautiful soft light, especially with the standard Wide Angle Diffusers in place. Inward lighting meant just the softest edge of the beam illuminated the Fish Eating Anemone. Monterey Bay, CA. Panasonic GH5, Nauticam Housing, Dual Retra Flash w/Wide Angle Diffusers, Olympus 14-42, Kraken Sports KRL-01 Wet Lens

Soft, even illumination throughout the frame, even on the smallest of subjects. I generally leave my wide angle diffusers on even for macro shooting. Pygmy Seahorse-Anilao, Philippines. Nikon D500, Nauticam Housing, Dual Retra Flash w/Wide Angle Diffusers, Nikon 105mm VR, Nauticam SMC


*All of the Retra accessories are easily attached and detached via the bayonet locking system on the strobe head. This means all tools are extremely secure on the front of the flash and you don't have to worry about knocking them off or losing them. Each accessory is marked with an open lock and closed lock symbol so you know exactly where to begin the bayonet attachment process.

-Wide Angle Diffuser- The diffuser recommended for most situations. Comes standard with each strobe so is not something that has to be purchased separately unless spares are wanted.

-White Diffuser- The white diffuser maintains the natural color temperature of the flash while spreading the light to 120 degrees. Can be good for greenwater diving so you aren't overwarming colors with the wide angle diffuser.

-Shark Diffuser- The shark diffuser is perfect for large animal photography to warm up the blue water (to 4400K) they're typicall found in. It maintains the 110 degree spread of the bare strobe head.

-Reduction Ring-The reduction ring does just what it sounds like. It reduces the light spread to prevent light spill and backscatter in macro or wide angle images. 

-External Battery Pack- The external battery life doubles the number of exposures you can make (up to around ~950) while also halving the normal recycle time at full power, from 2 seconds to 1 second. This means shooting at half power or lower, recycle time will be essentially instantaneous. The external pack threads into the back of the strobe and houses an additional 4 AA batteries for a total of 8.

-Retra LSD Optical Snoot- The Retra snoot has become the gold standard for snoots underwater. It is built in the same fashion as the strobe and uses optical glass elements to focus the beam instead of the fiber optic approach of most other snoots. It als has a number of inserts available for even more creative possibilities.

Hairy Frogfish-Anilao, Philippines. Nikon D500, Nauticam Housing, Nikon 105mm VR, 1x Retra Flash w/Retra LSD Snoot

The snoot isn't just for creating the spotlight effect. Here used to light just the face of the subject during a long exposure allowing the movement of the tentacles to show and the ambient light to illuminate the rest of the image. Flamboyant Cuttlefish- Anilao, Philippines. Nikon D500, Nauticam Housing, Nikon 105mm VR, 1x Retra Flash w/Retra LSD Snoot


The Retra Flash is available now at Bluewater Photo!


The Retra flash is fantastic tool for underwater photography. It allows for a seemingly unmatched amount of creativity between all the different accessories and is up to the task no matter what situation it is put in. I plan on using these strobes for a long time to come (I will keep my inons as back ups) and I expect them to serve me well. I would not hesitate to recommend these strobes to anybody especially if they are looking for an affordable, do it all option. 

Join me in Lembeh or Guadalupe this year.


Matthew Sullivan is an underwater and conservation photographer based out of Los Angeles, CA. For more of his pictures follow him on Instagram.


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