Hi all

I have recently upgraded my Inon Z330s (the only strobes I've shot with) to a pair of Retra Pro Max IIs and am about to take it on my first trip. Banda Sea + Alor!

Hoping some Retra users can help me answer these basic questions:

For wide angle,

1) should I always just use the booster? In case I need faster burst? Does the battery last the whole day (4 dives) if I use the booster?

2) is HSS ever useful in wide angle? I mostly know of its application to create black backgrounds for macro. I heard it limits burst?

3) to use HSS, you enable wireless flash in the camera. Can I just leave this setting always on, even if not using HSS? Or should I adjust this every time I switch between Manual and HSS?

For macro,

1) is there ever any use cases for the booster?

2) same question for HSS and wireless flash settings - should I always shoot in HSS mode since you can still shoot slower than 1/250 i.e. with the same shutter speeds as in Manual?

Other:

1) it says there is a leak test, but when I turn the strobe on it only shows battery test. Where is the leak signal?

2) what accessories do I really need? In terms of diffusers, bumpers, etc? I'm a bit overwhelmed by the sheer amount of accessories available. I used to shoot my Inons with diffusers but none came with the Retras.

I also had to upgrade from my Nauticam flash trigger to the UWTechnic one for HSS.

1) How do I tell how much battery is left in the trigger, will it show a low battery warning?

Thank you!

59 minutes ago, jjmochi said:

Hi all

I have recently upgraded my Inon Z330s (the only strobes I've shot with) to a pair of Retra Pro Max IIs and am about to take it on my first trip. Banda Sea + Alor!

Hoping some Retra users can help me answer these basic questions:

For wide angle,

1) should I always just use the booster? In case I need faster burst? Does the battery last the whole day (4 dives) if I use the booster?

2) is HSS ever useful in wide angle? I mostly know of its application to create black backgrounds for macro. I heard it limits burst?

3) to use HSS, you enable wireless flash in the camera. Can I just leave this setting always on, even if not using HSS? Or should I adjust this every time I switch between Manual and HSS?

For macro,

1) is there ever any use cases for the booster?

2) same question for HSS and wireless flash settings - should I always shoot in HSS mode since you can still shoot slower than 1/250 i.e. with the same shutter speeds as in Manual?

Other:

1) it says there is a leak test, but when I turn the strobe on it only shows battery test. Where is the leak signal?

2) what accessories do I really need? In terms of diffusers, bumpers, etc? I'm a bit overwhelmed by the sheer amount of accessories available. I used to shoot my Inons with diffusers but none came with the Retras.

I also had to upgrade from my Nauticam flash trigger to the UWTechnic one for HSS.

1) How do I tell how much battery is left in the trigger, will it show a low battery warning?

Thank you!

Hi there, I upgraded to Retra a few months back. I got the reduction rings and the white diffusers. Previously using the Z240 strobes. I'm on m43 so I shoot at f10 mostly on macro. I recently did a trip to Lembeh with them. I can offer a few observations.

The reduction rings I would suggest are essential. Shooting in Sydney and then in Lembeh I immediately noticed a lot less backscatter using the retra with reduction rings used at a fairly standard 10 and 2 strobe position close to the port. You do need to adjust positioning some more when getting in really close to somewhat non standard positions at least compared to what I used prior. Simplest seemed to turn the strobes in a little. I work fairly close with the olympus 60mm macro , so longer lenses would be less prone until you venture into wet diopters as the working distance is greater. It wasn't backscatter proof as such, just a lot less compared to what I saw with the INON strobes. I also tried some inward lighting and that worked well.

The booster is quite useful. Shooting at f10 and one click past 25% power (this is a Retra pure) I got about 600 shots and the the battery test LED was hovering on turning yellow at the end. This was 3 dives a day over two days each dive about 1 hour 5 minutes. So I only pulled batteries and re-charged every other day. More powerful models may go through batteries faster if you use the power. Likewise is you are shooting at f11-16 on full frame you will need more power. This was all macro work.

Classic HSS usage for wide angle is a sunball, where you might want to use 1/320 - 1/500 range for shutter speeds. I have not done much wide angle work with mine as yet, only used with 60mm macro and now with the MFO-3 so far.

I traveled with the standard battery caps with the boosters separate, basically to improve my packing , with the booster the strobes were too tall for my backpack.

Hope that helps, let me know if you have questions.

Hi jjmochi

To add to Chris' comments:

I've been using Retras for about 5 years and now have the ProMax combined with a Nikon D500 - so an APS-C sensor. I switched from Inon Z240s.

I use the Boosters all the time perhaps because I'm often using a snoot for macro and I do find I need to boost the power with a snoot. That said, I usually find a 4-dive day shooting maybe 100-150 images a dive, the 8x batteries in the Retra with Booster will last the whole day. I can't think of any reason why you would NOT use the Booster on all dives. They take up little room and actually provide a useful handle for adjusting the strobe positioning. Their battery endurance is reassuring.

Accessories: I have White Diffusers but find I seldom use them. As Chris says, the Macro Reducer Rings are very useful for wider macro; I also like the Reflector for turbid/backscattery water. My all time favourite is the LSD which I find brilliant for macro. I very rarely photo macro without it.

HSS: As Chris explains, HSS is very good for sunballs: high shutter speed (say 1/2000), f11-ish, ISO100 and HSS to light the foreground. I don't use HSS when shooting below 1/250.

Leak Test: there is no "Test". Retra recommends you have the strobes switched on when entering the water so that if there is a leak the alarm will go off. I've managed to achieve this stupid feat once - and for sure, flashing lights! You can't miss it. Happily the way the strobes are designed, water only enters the battery compartment and I found it easy to clean out. No damage done. Well not to the strobes anyway: my self-respect took a hit.

Trigger: I use a UWT trigger. There is no way of checking battery life but UWT (Pavel) says it lasts 000s of dives. I change the 2x CR2032s maybe once every couple of years. Never had an issue.

Hope that helps. I think the Retras are terrific. I'm sure you'll like them once you get used to the new functionality.

Tim

Another Retra user experience FWIW... (I am using an older version : the Retra PRO which is notoriously battery consuming, hence everything would be improved with the PROMAX).

Wide angle :

• Superchargers (or boosters) are paramount whenever you need to shoot fast bursts, which will certainly happen in Alor.

• I have never used HSS even though it is enabled on this version, I am happy with my current 100 ISO-1/320s synch speed even in the shallows of Alor.

• I have the wide angle diffusers but won't use them anymore since it decreases the light and I am satisfied with the overall softness of the RETRA circular bulb. It also brings warmer temperature for a strobe that is already warm, since the diffusion was also improved with the PROMAX2, I feel it would be slightly overkill in such blue waters as Alor.

Macro :

• I am not using the superchargers, it saves me weight and charging time for 8 eneloops. I don't care for fast bursts at max level given in this case I'm always below 1/2 power and 200 ISO.

• HSS? really can't see when you should be faster than 1/250s, never happened to me in 25 years shooting macro... but YMMV

• LSD snoot is essential, perfectly fit and aligned with the Retra strobes (unlike the Inons with their offset light). Doing probably 1/2 my shots with it, just be careful not to fall into what I call the "black background snoot ditch" at the expense of your creativity. Background colors are nice too!

• Which brings us to the macro light reducer ring, critical piece of equipment when you're not using the snoot. So you shoudl already think how you're going to attach it to your BCD or housing when you screw your LSD on your strobe. On the other hand I am not in love with the supermacro reducer ring which I find either too narrow or not narrow enough to replace a snoot. Hence I'm usually equipped with 2 macro reducers (without the supermacro reducer ring) and a LSD attached to my BCD

Other :

• I don't think there is a leak "test" but a month ago I definitely had a leak alarm underwater flashing alternatively blue/red with the pilot light lit up. I stopped using it despite no apparent water in the battery compartment nor on the flash dome. Sent the strobe to Retra for an inspection, no water inside but they changed a few parts which were aging. For 130€ I have a serviced strobe now.

Edited October 7Oct 7 by Luko

1 hour ago, Luko said:

(I am using an older version : the Retra PRO which is notoriously battery consuming, hence everything would be improved with the PROMAX).

I changed recently from the old Pro to the Max II... the consumption are realy different. I didn't make for the moment a trip with the new one. But i'm sure that I will make 4 dive with the Max II Probably 300 or 400 photos with the booster.

I made 2 dives more or less 250 pictures batteries was 75% full

Like @TimG I found no reason to dive without the booster 8 is better than 4 batterie Faster and more .

1 hour ago, Luko said:

I have the wide angle diffusers but won't use them anymore since it decreases the light and I am satisfied with the overall softness of the RETRA circular bulb. It also brings warmer temperature for a strobe that is already warm, since the diffusion was also improved with the PROMAX2, I feel it would be slightly overkill in such blue waters as Alor.

I'm really happy the lght generate with the new MaxII the diffuser is in my opinion not necessary.

I didn't try the reflector with the Max II But with the old Pro I like using it in some situation wide angle situation to put the focus on a coral or on something else.

In one month I go for 2 weeks in Malapascua + South Leyte (Sogod Bay) It will be the first trip with the new retra strobe... I'm pretty sure that I'll enjoy the new model.

19 minutes ago, CaolIla said:

I found no reason to dive without the booster 8 is better than 4 batterie Faster and more

Here's a list :

• less batteries to charge at night time

• less negative weight underwater, easier to handle when detached with the snoot on

• less weight and protruding thingies bumping painfully into my body parts when carrying the camera for shore dives,

• I don't see any advantage with "faster and more", it doesn't mean better photos, esp for macro where precision of both composition and lighting is key. (TBH I wouldn't understand coming out of a macro dive with 150 shots, except that I probably wouldn't have any idea of what I'm doing, but that's me I prefer thinking my image over randomly clicking. )

8 minutes ago, Luko said:

less batteries to charge at night time

I have 2, 8x charger ;)

8 minutes ago, Luko said:

less negative weight underwater, easier to handle when detached with the snoot on

Humm can be a good argument... need to study this point, but a solution will be for me add some buioncy on the snoot to have exactly what is OK.

11 minutes ago, Luko said:

less weight and protruding thingies bumping painfully into my body parts when carrying the camera for shore dives,

Shore dive ??? what's that? ... seriously 4 AA more or less on my setup (+/- 10 Kg) will change nothing

13 minutes ago, Luko said:

I don't see any advantage with "faster and more", it doesn't mean better photos, esp for macro where precision of both composition and lighting is key. (TBH I wouldn't understand coming out of a macro dive with 150 shots, except that I probably wouldn't have any idea of what I'm doing, but that's me I prefer thinking my image over randomly clicking. )

Randomly clicking... hummm no no ... but when you found the good position why not shoot 2 3 or more time expectly when the subject is moving "fast"

I had problems with the batterie life with my retra pro... Diving without booster was not an option. Probably with the Max II it's possible.

I know a few people comment on the problem of having to charge 8x AA batteries if you use a Booster. I can't say though that this has ever been problem even charging 16x AA for 2x strobes - and I only use 2x chargers each of which holds 4 batteries.

I'd argue the extra weight is negligible.

I'd have agreed the older Super Charger was bulky but, for me anyway, the extra 2-3 centimetres of the Booster is neither here nor there.

But Luko offers an alternative view.

1 hour ago, TimG said:

But Luko offers an alternative view.

Yes and it is good to read somme other point of view..

I like the point with the snoot

I use the standard 4 battery set up diving at home from the shore in Sydney, I average 70-80 shots over a 70-75 minute dive (I have to find my own critters) and I do a single dive. The 4 battery setup will last for 3 dives before needing charging. It's a 30 metre climb up from the waters edge as well, so I feel every gram, but seriously it's good enough, so I keep the boosters for dive trips where I have guides finding things for me and I do 100-110 frames per dive, 3 dives per day and it will need batteries charged every other day,

To answer another question from the TO. I'm using a Sony A7IV, and the camera is set to use HSS (no need to change it). Only the flash is set to whether HSS or normal mode is used. It's quite possible that this doesn't work with all cameras, but it does with my Sony.

I also use the neoprene covers and the bumpers. I like everything black, and it also provides excellent protection for the strobes :-)

Like jjmochi, I just switched from Inon Z330 to Retro Pro MaxII. Caollla was kind enough to share with me his 3d print file for reduction rings. They fit perfectly and I found them great for blackwater diving.

Thank you everyone! Very helpful. First day in the water with the new strobes and a few more questions in bold.

I made my first 3 dives today with the new strobes. All in Ambon so only muck, and didn't notice a difference in quality of light vs my old Inons. But I'm sure I will notice (I hope) tomorrow when we get to Banda and move to wide angle for the bulk of the trip.

I used the strobes without booster as my macro rig is perfectly neutral without booster (and wide angle is neutral with the booster). It lasted almost 3 dives, 70min each, 372 photos total. One strobe still showed one bar of battery and the other died towards the end of the 3rd dive. But when I switched it off and on again, managed to squeeze a few more in but it was not always consistently firing. So I guess must change after 2 dives if not using booster, and maybe / maybe not can last the whole day / 4 dives with the booster. My old Inons could last almost 4 dives but definitely at least 3 so this seems like it's worse. It did tell me CHG after the 2nd dive but I thought the battery must surely be better than the Inons and didn't listen lol.

I had HSS on for quite a while as was playing with it, does that chew up more battery? I didn't find HSS that helpful in muck as everything was sand background and not much open water. I just remembered reading the A1 review a few years ago where they said HSS can almost replace a snoot since you can shoot up to 1/400 for a black background, but almost everything we found today was not in the right position and I did wish I had my snoot. Still, would be nice to have for the sunballs.

How does the power markings on the Retras compare to the power markings on the Inons? I don't really understand Retra's power markings. Is half power 0 / 6, or is it 50 / +3?

Not looking for a precise answer but more a gut feel / rule of thumb. I mostly shoot wide angle with Inon Z330s set to 2-3, sometimes increase to 1 if really wide. 3 was half power on the Inons, should I start at half power on the Retra which would be the 0 marking? I know how much light I want if I had my Inons but feel a bit lost with the Retras, like I lost my gut feel for how much light I need.

I did notice SLOWER recycle compared to my Inons? This is without the booster. I was turning the dial to the same % as what I used to do on my Inons (so with the understanding that half = 0 / 6). Was I shooting way too high power for what I understood the same setting to be? I was at the same aperture and ISOs tho and the pictures weren't blown out.

I also notice the colour straight out of the camera is a lot more warm (yellow/orange-ish) compared to the Inons. I suppose I need to change my white balance settings. What do other Sony users set theirs at?

It sounds like lots of recommendation for the reduction ring and LSD snoot.

On 10/9/2025 at 3:34 PM, Hiloboy said:

Like jjmochi, I just switched from Inon Z330 to Retro Pro MaxII. Caollla was kind enough to share with me his 3d print file for reduction rings. They fit perfectly and I found them great for blackwater diving.

If you can share the 3D files that would be amazing!

For the snoot, I currently use a backscatter MF1 with optical snoot, which my guide carries and points it for me (the privilege of having affordable private guides in Asia) Is it a big difference for LSD snoot vs the mini flash? Would it be harder for a guide to point the LSD snoot for you since it's attached to the camera rig?

52 minutes ago, jjmochi said:

How does the power markings on the Retras compare to the power markings on the Inons? I don't really understand Retra's power markings. Is half power 0 / 6, or is it 50 / +3?

Not looking for a precise answer but more a gut feel / rule of thumb. I mostly shoot wide angle with Inon Z330s set to 2-3, sometimes increase to 1 if really wide. 3 was half power on the Inons, should I start at half power on the Retra which would be the 0 marking? I know how much light I want if I had my Inons but feel a bit lost with the Retras, like I lost my gut feel for how much light I need.

I did notice SLOWER recycle compared to my Inons? This is without the booster. I was turning the dial to the same % as what I used to do on my Inons (so with the understanding that half = 0 / 6). Was I shooting way too high power for what I understood the same setting to be? I was at the same aperture and ISOs them and the pictures weren't blown out.

When I got my Retras, set them up with the housing etc on the bench with the normal strobe position and did some test shots increasing the output till the exposure was corrrect using my usual shutter speed, aperture ISO. The basis was using the camera settings I usually do and getting the strobe output right. Distance was for an "average" subject. That was my starting power on the first dive and the exposures came out correct. Flash output only needs to change if you change distance at the same camera setting. In close shooting similar size subjects, the required exposure doesn't change much. I figure that changing camera settings to get the right exposure would be the tail wagging the dog.

I have the Retra Pure which is lower power and basic starting point was 25 on the dial or 1/4 power or two stops off full. On the INON Z240 I was about 1.5 stops off full. The Retra PRO Max II is something like 1.5 stops more powerful than my strobes. I think if your photos are blowing you are certainly using more battery and the response should be to turn them down. Likewise HSS if it activates will use more strobe power - this should only happen if you are above the cameras max sync speed.

I hope the first day was fun!

Would it be harder for a guide to point the LSD snoot for you since it's attached to the camera rig?

The LSD does not NEED to be attached to the rest of your system. Just make/use a longer fibre optical cable. The LSD/Retra is no harder to point than any other snoot/strobe. Its advantage is that the pilot lines up perfectly. So what you light with the pilot is what you shoot with the strobe.

I did notice SLOWER recycle compared to my Inons

It's never been noticeably slower than my Z240s. It is faster with the Booster.

I don't really understand Retra's power markings. Is half power 0 / 6, or is it 50 / +3?

0/6 is half power. I found comparing with Inon was not very helpful - God knows the Inon numbering was confusing. Figure that 100 is full power, 0/6 is half and go from there.

I also notice the colour straight out of the camera is a lot more warm (yellow/orange-ish) compared to the Inons

Yep, I found the Retras warmer than the Inons - which I prefer. Can't help on a Sony, but on a Nikon I use AUTO and that for 95% of the time works out fine.

2 hours ago, jjmochi said:

It sounds like lots of recommendation for the reduction ring and LSD snoot.

  On 10/9/2025 at 10:34 AM, Hiloboy said:

Like jjmochi, I just switched from Inon Z330 to Retro Pro MaxII. Caollla was kind enough to share with me his 3d print file for reduction rings. They fit perfectly and I found them great for blackwater diving.

If you can share the 3D files that would be amazing!

I have this part

It is a protection and with this I can put the Retra on a table without that the glas is touching. It's also large that's mean I can make wide angle without losing light on the side.



@Hiloboy ask me for a simple "snoot" I build one without testing it.
I'm right know make some test with an adaptation of this one..

That's a picture from @Hiloboy

and the model

and here the protection on my old retra pro


You see it's realy wide the beam is not restricted

the model I made and printed for testing is this one

Th e idea is putting some reduction in the tube and why not some extension with lens in it.
BUT there is a BUT with a lens when the distance is the focus length the light is like a donut because the tube of the retra a circular.
I need to but a diffusor on the retra side...

3 hours ago, jjmochi said:

I had HSS on for quite a while as was playing with it, does that chew up more battery? I didn't find HSS that helpful in muck as everything was sand background and not much open water. I just remembered reading the A1 review a few years ago where they said HSS can almost replace a snoot since you can shoot up to 1/400 for a black background,

Most probably, since the HSS is used to generate a longer than usual flash of light, hence using more power. This possibly explains that you fell out of power after less than 3 dives. I don't have such issue even though I have a PRO (less efficient for battery use) and I am NOT using the Supercharger for macro dives.

I don't know who wrote this non-sense about comparing the use of a snoot with the ability to provide a black background, this is not the very purpose of the tool. A snoot is mainly used to funnel the light on specific areas, not for the whole background.

You can easily achieve black background at F/18 and 1/200s (my standard setting for macro) and just positionning the strobes accordingly, this without a snoot.

4 hours ago, jjmochi said:

I did notice SLOWER recycle compared to my Inons? This is without the booster. I was turning the dial to the same % as what I used to do on my Inons (so with the understanding that half = 0 / 6). Was I shooting way too high power for what I understood the same setting to be?

Because you're wasting too much power on HSS as explained above. Forget the HSS for macro, that is useless.

Note that Retra strobes can fire without being totally recycled unlike some other strobes.

4 hours ago, jjmochi said:

I also notice the colour straight out of the camera is a lot more warm (yellow/orange-ish) compared to the Inons. I suppose I need to change my white balance settings. What do other Sony users set theirs at?

Yes Retra are warmer than Inon (4800K vs 5500K If I'm not wrong).

I would recommend to set your color temp at 4800K in your camera if you want to have the .jpg straight out, even though it won't impact the slightest bit on the RAW files.

4 hours ago, jjmochi said:

For the snoot, I currently use a backscatter MF1 with optical snoot, which my guide carries and points it for me (the privilege of having affordable private guides in Asia) Is it a big difference for LSD snoot vs the mini flash? Would it be harder for a guide to point the LSD snoot for you since it's attached to the camera rig?

That's also what I am doing : I use a private guide who helps me for the snoot lighting.

I recommand you change the last segment of your flash arm with a quick release system and also a long optic fiber for one of your strobes that you will use when snooting.

I have tested a few systems, Carbonarm or Flexarm are IMO the best (Scubalamp system is crap, the lock twirls and breaks after one year use) https://carbonarm.com/en/quick-release-arms/366-carbonarm-18-with-quick-release-0806808286321.html.

Whenever you have to use your snoot you can detach the flash easily and give it to your guide (who will be happier holding it if you don't use your supercharger -see discussion above- ).

1 hour ago, CaolIla said:

The idea is putting some reduction in the tube and why not some extension with lens in it.
BUT there is a BUT with a lens when the distance is the focus length the light is like a donut because the tube of the retra a circular.
I need to but a diffusor on the retra side...

More than a diffusor that you need but rather a fresnel lens of something equivalent, the problem without any converging lens is that all the power will be lost. (That's what happens with the crappy Scubalamp snoot which is only equiped with a diffusor device, used it on one trip, never again, back to Retra snoot now) .This is why the Retra snoot is for me the most efficient one : you see for instance there is a sweet spot according to the distance you aim at your subject, the "halo" of the snoot will get sharper whenever you're on the ideal distance.

Edited Saturday at 12:44 PM2 days by Luko

5 minutes ago, Luko said:

  1 hour ago, CaolIla said:

The idea is putting some reduction in the tube and why not some extension with lens in it.
BUT there is a BUT with a lens when the distance is the focus length the light is like a donut because the tube of the retra a circular.
I need to but a diffusor on the retra side...

More than a diffusor that you need but rather a fresnel lens of something equivalent, the problem without any converging lens is that all the power will be lost. (That's what happens with the crappy Scubalamp snoot which is only equiped with a diffusor device, used it on one trip, never again, back to Retra snoot now) .This is why the Retra snoot is for me the most efficient one : you see for instance there is a sweet spot according to the distance you aim at your subject, the "halo" of the snoot will get sharper whenever you're on the ideal distance.

Diffusor or fresnel lens it is more or less the same... I'm using a fresnel on my other snoot.

I also use as first step

and one or more lens to focus the light on one point, small disk

I had some problerm with water comming in.. need to build a new one with some changes... but no time at the moment to many work.

The last "snoot" is for me a simple and light snoot that cost nothing other as a little bit time to print I will try it during the next trip.

(I'll also use the retra I bought from you ;) )

Thanks all. I have a more pressing issue now where my left strobe (the same one that ran out of power yesterday) would not fire at all on this morning's dive.

Used both with booster, battery check shows full.

Other strobe fires fine so it's not the trigger

Tried changing the fibre optics cables around and the one connected with the non-working strobe works with the working strobe so it's not the cable.

I have tried the non-working strobe on manual - at half power, full power, quarter power, can't get it to fire at all

Have tried turning it on and off a few times

No water or leak alarm

What else can I try?? What could it be??

Could I have damaged it yesterday when it showed battery empty but I turned it off and on again and got a few more flashes out of it?

That being said I was quite impressed with what my singular strobe could still do in the direct 12' position - seems coverage is wider and less hot spots compared to the Inon.

Yes I think HSS killed my battery yesterday. Most of one dive was on HSS

I will look into the quick release arm for the snoot, that sounds ideal

So testing again on the boat the non-working strobe is working again. I changed nothing.

And I'm also noticing when I switch on the strobe to BATT/TEST, it will sometimes show CHG (despite full batteries), and if I turn it off again and turn on again it will show the battery icon with all 4 bars. Prob it's user error but I'm not sure why this would be. I'm using envelop pros - a few years old but was working fine on the Inons...

And I cannot seem to connect the strobes to the Retra app. Strobe shows BLE running but my phone/app cannot find it. This is both strobes...

For the $$$$ of these strobes I am having way more issues than I should!

3 hours ago, jjmochi said:

So testing again on the boat the non-working strobe is working again. I changed nothing.

And I'm also noticing when I switch on the strobe to BATT/TEST, it will sometimes show CHG (despite full batteries), and if I turn it off again and turn on again it will show the battery icon with all 4 bars. Prob it's user error but I'm not sure why this would be. I'm using envelop pros - a few years old but was working fine on the Inons...

I spoke too soon. Non working strobe remains non working on dive 2.

I turned off wireless flash setting on Sony and was able to get it to fire during the surface interval. But once I got underwater it refused to fire. And the working strobe also refused to fire until I turned the wireless flash setting back on.

Back on the boat I have swapped the fiber optic cables, the batteries from working to non working strobe. Tried with and without the booster since it worked yesterday without the booster. Tried to put it in calibration mode and it shows CAL but the strobe does not fire. I am beginning to question whether it’s just user error or really dead at this point. There is no water or any visible damage to it.

What else can I try?