1 hour ago, waso said:

Btw: has anyone used the Retra in TTL mode with Canon mirrorless yet?

Came here to ask the same question. Currently shooting with Panasonic GH7 and Inon Z240/Keldan 4 series, and I'm really interested in simplifying with a hybrid strobe. The options are the HF-1 or the Maxi, and I'm leaning towards the maxi but I'd love to hear some TTL experience since that's how I generally shoot.

In a few days I am leaving for a three-week trip to Raja Ampat. Nine days at Misool Eco resort, then 9 more days on the Emperor Harmoni liveaboard. I've only been shooting the Maxi's in darker cold water with limited visibility. Using them in bright clear conditions should add some additional perspective and the high dive count will be a good measure of their reliability and battery capacity.

I'm doing my packing for a trip today and considering what to bring along. My current planned camera loadout is looking like this:

• Nauticam Z8 system

• 2 Retra Maxi Strobes

• 1 Backscatter Atom Strobe with adapted OS-1 snoot

• 1 Backscatter MF-2 as an additional backup strobe

• Nikon Z105mm macro lens w/MFO-1

• Nikon Z24-50mm w/WWL-C

• Nikon AF-S 8-15mm w/140mm dome

• Macro setup with the Atom + Snoot for primary, Maxi with macro rings for secondary

• Wide angle setup with the two Maxi's, optional reduction rings & filters

I've shot the HF-1s lots of times in these conditions, so I won't bring them on the trip.

19 hours ago, Adventurer said:

Chris, no, please stop rehearsing this wrong and changing what was previously articulated correctly.

Two persons who reviewed the Apollo have written in their review that they considered „some sort of settings“ to be better to conduct their review - for some unknown reasons to the public. In these settings the Apollo is not allowed to out-perform the competing products. This is why they were able to win, not because of altered batteries or other reasons etc.

@Adventurer again people have been posting their test results to the forum using their own strobes and a supplier provided strobe in the case of the maxi and taking a lot of time to test and compile results to benefit the forum participants. You however again imply an ulterior motive as the reason your strobe doesn't win. As far as I can see the reviewers have detailed what their methodology has been and reasons behind it.

Please if you disagree with results or methods don't accuse (or imply) people of having ulterior motives, rather address the issue you have with their methodology, why you disagree with the methodology and what you suggest they should do instead and why. You can also agree to disagree. Implying ulterior motives is a form of ad hominem response and we discourage that on the forum. We are all for vigorous discussion about the subject being discussed as long as it is directed to the subject not the forum member.

As far as my question , I believe it a statistical possibility that can't be resolved with the samples at your disposal. You can only draw conclusions based upon the strobes you actually have available to you.

As far as a fair way to compare - my thought is that determining the max power level at which the strobe can rapid fire without dimming or dropping frames at a given frame rate (10 frames/sec , 5, 3 whatever the reviewer chooses) and comparing the light output when firing at that rate makes the most sense. The strobe with the highest light on the subject under those conditions wins. Any tests with dimming and/or frame dropping just makes a lottery of whether your shot is exposed correctly or not.

12 hours ago, Dave_Hicks said:

In a few days I am leaving for a three-week trip to Raja Ampat. Nine days at Misool Eco resort, then 9 more days on the Emperor Harmoni liveaboard. I've only been shooting the Maxi's in darker cold water with limited visibility. Using them in bright clear conditions should add some additional perspective and the high dive count will be a good measure of their reliability and battery capacity.

I'm doing my packing for a trip today and considering what to bring along. My current planned camera loadout is looking like this:

• Nauticam Z8 system

• 2 Retra Maxi Strobes

• 1 Backscatter Atom Strobe with adapted OS-1 snoot

• 1 Backscatter MF-2 as an additional backup strobe

• Nikon Z105mm macro lens w/MFO-1

• Nikon Z24-50mm w/WWL-C

• Nikon AF-S 8-15mm w/140mm dome

• Macro setup with the Atom + Snoot for primary, Maxi with macro rings for secondary

• Wide angle setup with the two Maxi's, optional reduction rings & filters

I've shot the HF-1s lots of times in these conditions, so I won't bring them on the trip.

Dave, we were on Harmoni last year. Brilliant! Best liveaboard we’ve done.

On 2/13/2026 at 3:10 AM, Chris Ross said:

As far as a fair way to compare - my thought is that determining the max power level at which the strobe can rapid fire without dimming or dropping frames at a given frame rate (10 frames/sec , 5, 3 whatever the reviewer chooses) and comparing the light output when firing at that rate makes the most sense. The strobe with the highest light on the subject under those conditions wins. Any tests with dimming and/or frame dropping just makes a lottery of whether your shot is exposed correctly or not.

This is exactly what I did back in 2024 when I was testing the strobes. I chose continuous shooting rates my Canon could support (3fps, 6fps and 12fps) and then for each strobe dialed down the power until it could keep up with that frame rate without any black frames for at least 20 frames in a row. Once I established what the setting/power level on the strobe was, I measured the GN of the strobe firing at that setting.

What I observed is that while it's indeed true that some strobes prioritize firing on each shot even at lower power (HF-1) while others (Apollo III in MTL) prioritize trying to keep all exposures evenly lit by not firing at all on some exposures to fully recharge their capacitor before firing, the end result once you dial down the power sufficiently is the same and indistinguishable -- a series of shots that are all lit with minimal exposure variance.

The other thing I noticed is that pretty much every strobe starts out brighter for the first 2-3 shots in the series and gradually dims until shot 10 or so in the series after which it basically settles into a steady-state brightness for the following 20 shots. I measured the brightness based on those latter 20 shots where the shot-to-shot variance was low.

I'll be the first to concede that this is more of a technical capability test than a real life test, in that probably if you're really shooting high frame rates to capture behavior, what you care about is the first 10 shots, not the tail end when the strobe settles into steady-state. And there may be real difference in how each strobe handles those first 5-10 shots. I wasn't testing for that per se.

Finally.. yes, I had one of the earliest production batches of the Apollo III strobe, before they came up with a 2.0 version. But as far as I know, the 2.0 version is physically identical, the only changes are to the wireless control protocols. Light output and recycling time should be the same between the two models. (Gemini claims: The main difference between the Marelux Apollo III and the Marelux Apollo III 2.0 is the updated wireless communication system and internal software that improves stability for various flash modes. The 2.0 version was primarily introduced to allow better integration with the Lumilink 2.0 wireless transmitter.)

My theory is that the HF-1 is able to put out more power in high frame rate mode because of better batteries -- I was using the HF-1 with the nitecore 6000mah 21700 batteries, while the Apollo III had 3 generic 18650 batteries that it came with. Believe the 21700 batteries are just newer/better technology.

4 hours ago, DreiFish said:

My theory is that the HF-1 is able to put out more power in high frame rate mode because of better batteries -- I was using the HF-1 with the nitecore 6000mah 21700 batteries, while the Apollo III had 3 generic 18650 batteries that it came with. Believe the 21700 batteries are just newer/better technology.

Thanks for this, though possibly better 18650 batteries may now be available? I suspect you method has some validity, if the strobe has more power in your test it probably is also brighter in comparison for a quick burst, but I guess it depends on how the strobe is programmed to deal with continuous shots. In addition using 3 18650 (assuming) in series, the voltage is higher so less demanding on amp draw.

4 hours ago, DreiFish said:

The other thing I noticed is that pretty much every strobe starts out brighter for the first 2-3 shots in the series and gradually dims until shot 10 or so in the series after which it basically settles into a steady-state brightness for the following 20 shots. I measured the brightness based on those latter 20 shots where the shot-to-shot variance was low.

Thanks Dreifish, the above is something I did notice on the HF-1 but not on the Apollo III 2.0 that I happen to own. This is why I recommended to get your strobe checked. I am aware that the 2.0 in official documents just refers to the wireless protocol but from what you describe, I would not rule out that there is also other improvements in the product or the chance that you received a „Monday model“ series, as we say in Germany. The findings in Kiliis and Henley Spiers reviews that included Apollo also point into that direction, that it‘s not flawed.

Have a look at the Henley wall projection MTL 12 (full power in fast mode, that is):

source: DivePhotoGuide.com

The variations or blackouts I get on my two HF-1 strobes (and the HF-1 of my friend) are extreme compared to the Apollo III 2.0 - pretty much like the the Retra and OneUW blackouts and light variations in the DPG reviews. I used the fully charged recommended batteries that are in the Backscatter manual for the fast shooting high fps test.

Another potential conflict I would like to put the spotlight on is the fps you can set in the cameras vs what the strobe manufacturers guarantee you.

I think MARELUX will grant you 10 fps solid according to their manual in full MTL power. But like your camera I just have the option available to to do 7 fps or 12 fps on my R6 Mark II. That said, the Apollo‘s kept up with Zero blackout frames @ 12 fps. I explored that mystical feature further by digging into the real net frame rate that our Canon cameras will offer. Canon says the fine wording „up to“ depending on settings and batteries used etc. When shooting a stop watch on my iPhone at the high fps setting I found that the camera actually varies in speed between 10.5 to 12 fps in series burst shooting with strobes. This explains to me why the Marelux Apollo III strobes on my desk seem to be able to easily keep up with this pace. It looked like camera and strobes could do this endlessly forever so I stopped the test after a few hundred RAW .CR3 frames and seconds.

Coming back to the HF-1 and blackout frame behavior there is also a 2nd source online confirming my experience with the other pretty fast strobe in the leading gang,… Nicolas Remy digged into the high fps possibilities of the HF-1 and also confirmed blackout frames and light Variations, which I do not experience with Apollo III 2.0 in MTL. Have a look:

Full HF-1 review on: theunderwaterphotographyclub

Hybrid Flash HF-1

Table 2: Hybrid Flash recycle times and number of flashes at the three most powerful settings (source: Backscatter)

Power Setting	Burst Speed	Light Decrease Between Shots	Number of Flashes Before a Black Frame	Frequency of Black Frames After First One	Total Number of Shots Taken	Comment
1/4	10fps	Smooth	9	Every 2–3 shots	49
1/4–0.5 f-stops	10fps	Smooth	14	Every 2–3 shots	42
1/8	10fps	Very smooth	43	None	43
1/4	8fps	Smooth	16	Every 4 shots	37
1/4	6fps	Very smooth	24	None	37	Decrease during first 24 shots, then stable
1/2	5fps	Smooth	5	Every 1–2 shots	26
1/2	4fps	Very smooth	7	Every 3 shots	25
1/2	3fps	Very smooth	13	None	25	Decrease during first 13 shots, then stable
F	3fps	Noticeable	2	Every second shot	15