Adventurer

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. And furthermore it‘s not just one person (me) giving data and honest review about the Apollo III 2.0 strobe. I never publicly reviewed the Apollo or HF-1 strobes. I just used them and can confirm what Henley Spiers wrote in his DPG review about them, which is a neutral undistorted review which really tried to find the performance limit of the Apollo III 2.0 product. About HF-1: several people and reviews have reported light intensity variation and black frames when trying to conduct high frame rate shooting, for which Dr. Alex Mustard (and me) recommend the 1/4 (or lower) power level on the HF-1 manual switch. This is not a better or worse than fact -Iit is just a very practical piece of information when you want to apply faster frame rate shooting onto subjects in the wild. For me: I prefer reliability instead of luck when trying to nail a certain rare rapid behavior shot in the wild. I want the wildlife subject to be my incalculable factors - not my strobes. This is why I choose the Apollo III 2.0 over the Backscatter HF-1 when trying to get that specific job done right. The RETRAs do not seem to behave better than the HF-1 in this discipline which basically rules them out of the equation for me. I would need to get my hands on a RETRA Maxi myself, but already the very thorough and critical review of Dave Hicks and also the retra-enthusiasitic review of Kilii Yuyan show that the Maxi is not going to work as a high fps strobe or at least trying to play in that product category. Both reviews give appropriate credit to it in the maximum strobe output category where it goes head to head with the Backscatter HF-1 though. Looking at HF-1 pricing and RETRA Maxi in February 2026 you will have to pay a few hundred dollars / euros more to have RETRA written on it. What do you get for this? I see the following: 1.) RETRA Bluetooth cellphone App to check the status of your strobe (nice!) 2.) silver instead of black design 3.) nicer underwater buoyancy (almost neutral) archived by a much more beefy design (makes it less easily fit in your backpack) what you sacrifice: 1.) 365 EUR (HF-1 price in EU vs MAXI) 2.) an easily accessible boost mode to make it perform brighter than HF-1 or Apollo III 2.0 3.) Backscatter‘s very practical & handy REM (remote mode) feature, which allows you to wirelessly control strobe power without cables.

No please do not get me wrong. I am not saying anything is better. The HF-1 is a tick stronger than my Apollo III 2.0 when put to +2 mode and you do not want to utilize burst shooting. But when you want high fps strobe burst shooting it seems to me that no other manufacturer has mastered this technology than Marelux. Maybe also the other competing companies did just not aim their design at this particular discipline. And I just want to say that I have noticed that this particular aspect of the product seems to get downplayed in many reviews or comments during the last 1.5 years. Most reviewers seem to have adapted their testing ground to an fps level or use case that the competitor products still can cope with. The only guy who can not be critiqued for being an Ambassador and having written a fair independent review about the Apollo III is Henley Spiers on DPG. Many others seem downplay the aspect and image opportunity of high fps strobe shooting, even if they found the product to perform that decently during their tests. I own and paid both strobes (HF-1 and Apollo III) and think their are both great tools where they go stellar in different disciplines. My impression is that for some reason I do not understand there seems to be some kind of Marelux or Apollo bashing going on or beeing popular to say - and just few people credit this brand of having introduced a new piece of tech that others still need to catch up to. The whole thing with the high fps downplay reminds me of my old Hugyfot housing, when that brand introduced vacuum systems on their housings as the only manufacturer around. Everybody else was making fun about them for this and said „our housings also seal without this“. Look now 20 years later and vacuum valves and pumps on housings are a standard. Especially on brands that were shouting Extra loud against them in the period were they did not sell this technology.

That seems a bit different from what you said in the video. I actually stumbled across it again while trying to find Dr. Alex Mustard’s Marelux Apollo review. It’s not easy to locate, because the review is kind of “hidden” under a subtle title and isn’t as heavily keyworded or clearly titled as the RETRA strobe episodes on The Underwater Photography Show. As a regular viewer and big fan of the show, I’d like to suggest something: maybe you could give the Marelux “Apollo S” and “Apollo III (revisited)” strobes their own dedicated episode, so they’re covered as fairly and prominently as the Retras and Krakens—which have been episode headliners, sometimes with less overall content. Anyway,... Thanks to ChatGPT I was able to pull out a well formatted and still exact quote from the videos transcript. This is actually where you 100% confirm my experience with the Apollo III 2.0 ... The Backscatter HF-1 on quarter power will approx the same at 1/4 power as the Apollo III 2.0 at FULL in MTL - It will hold it's stamina at 12fps .CR3 RAWs for approx 1000 frames. And the Apollo holds its stamina: it can keep up at around 12 fps shooting CR3 RAW bursts for roughly 1,000 frames. In my case, the limiting factor is my camera buffer * — not the Apollo III strobe. With the HF-1 set to 1/4 power and trying the same kind of burst, the strobe quickly starts producing blackout frames or underexposed frames every few shots. * Well,... if you cross 1000 shots the battery cells in any strobe also become a limiting factor. When there is talk about power drain, I can confirm that firing above 800 shots will drain strobe batteries... but not light output provided in MTL by the strobe. That is until you cross a critical battery level signaled by the strobe indicator light going yellow or purple.

@Alex_Mustard Didn't you shoot Apollo S strobes, not Apollo III 2.0 in blackwater ? From what I understand smaller sized Apollo S are supposed to be much weaker than HF-1. I just recall you not finding the MTL mode when you had Apollo III 2.0 in the Red Sea with Oceanic Whitetips? You must have gotten distracted by the lovely bouncing batteries, you were so enchanted about 😏

Great Job and some very inspirational imaging in the video! The complete system is quite a canon though. 😂 Question: I noticed the test person shooting the OS-3 most times had two aiming lights coming out of the OS-3. Could you find out if it the HF-1 was used in spot-light mode or will the flood light also produce these two beams? Furthermore, can the crossing of these two beams (paralax) be used for something, such as finding the optimal working distance for the OS-3 + HF-1 ? I assume this would be where the beams cross? "Crossing The Streams" https://www.youtube.com/watch?v=wyKQe_i9yyo

Hi Dreifish, I think your Apollo III units where not functioning OK or your test setup was faulty in some way. I cannot confirm the way you trashed that strobe, having now shot this and the HF-1 for two years. I bought the HF-1 because of your disruptive Excel sheet back in the days. In fact my HF-1 does not deliver the power you claimed at high frame rates and does many blackout frames and light variation. You may want to reach out to your dealer or Marelux to get your strobes replaced.

Just want to report back that I am using the 8-15mm fisheye with Kenko 1.4x and 2.0x TC on a Canon, unable to take advantage of the Sony 2.0x TC…. but… … recently I got myself the comlite EF RF and modified it to host the Canon RF 1.4x TC. I am really curious to try this and consider buying also the RF 2.0x TC to upgrade my IQ by a small fraction.

I think this supports also the 5% measurement and test + item variation delta I previously pointed out. Also a fresh from the factory strobe will be brighter than one that already has fired a few hundred shots. So no need in beating a dead horse and over-doing and over-interpreting these land tests. What would be interesting though is a beam (1-1.5m) wall test submerged in water to see the different dome and reflector designs come into play.

If you intend to pursue that road and cannot get your hands on a cheap 2nd hand ZEN dome from the example above, I suggest everyone to take a look at INONs very affordable small glas dome. You will need to get an adapter made, if you do not shoot their INON X-2 housing. *the sunshade is removable

oK - specs are out… 15 cm MFD look promising. Canon RF sensor to flange = 20 mm Canon RF 7-14 lens length = 109 mm I = 20 mm + 109 mm = 129 mm MFD = 150 mm MFD - I = 21 mm Focuses 2,1 cm in front of front glas. But if the 190 degree FOV at 7mm focal length is not a typo it will create lots of headaches with port positioning.

Even more interesting would be the option to use the RF2.0x TC 🤩 let‘s wait and pray that the technical data will serve us underwater photographers! There is still the minimal chance that Canon totally screws this up with a humongous minimum focusing distance (MFD) which would render it useless for underwater photography.

Hi all, does anybody know the author / anchorman of these four videos ? At first I thought he is affiliated with the former British camera store OceanOptics, because of the channel name. That however seems wrong. The channel origin seems to come from The Netherlands and I think that this might be confirmed by a slight Dutch accent I am hearing. I am interested to learn more about his uw photographic works and if he maybe is a well established pro or even a waterpixeler 😉 ?

If it is coming at an ultra humongous price, I am afraid. It will be interesting (but also a very slim chance) if we can combine it with RF1.4x and RF2.0x teleconverters. Let‘s also pray that Canon will keep the MFD ultra low and the entrance pupil in the front as on our beloved EF 8-15 fisheye.

Be aware: the cooler color temp strobes will usually marginally win the brightness test. So as HF-1 and Maxi are really just 1% difference this can be solely blamed to color temp difference. Furthermore, here in the community of underwater shooters we are unable to fullfill industrial test standards, where we would take 10 units of each type and multiple measurements (a hell lot of work) to counter-act production variances and variance resulting from your own measurement errors. You commonly observe 3-5% variation across same production models industrial testing for the before mentioned reasons. So I would conclude,... they are basically equally bright and Retra Maxi caught up to the HF-1 . One more question to Dave: as you put housing and dome around for your test. Was this shot in Air (I mean the wall) or did you submerge everything in a pool test ? This would be an interesting detail for me. Maybe you want to mark this in your beam shot .jpg (in water / or in air shots) and also name the lens as a 15mm fisheye for readers who just stare at the table or will see this quoted somewhere in the future. Thanks for putting so much work in this @Dave_Hicks 💪

I totally agree with @Architeuthis on this point. In real world shooting switching from FULL to +2 level in M Mode on the Backscatter HF-1 has really efficient and high impact. It will substantially light bigger reef sceenes. Also I would like to point out, that the beam coverage and quality of light with my Apollo III 2.0 is really decent underwater and I have the gut feeling this might be related to the dome glas in front, which will have no effect in air but once submerged play out a substantial role. In land test the coverage looks like you have put a reduction ring on the Apollo.

Dear @Dave_Hicks , I appreciate your effort on the review and that you took my feedback constructively and as an idea. My critique was not targeted at you personally — it was just a strange coincidence that two reviews appearing shortly after one another seemed to deviate in a certain direction that could easily mislead less nerdy people than us here in the forum into thinking that something is the best in all classes, which actually none of the three world-leading underwater strobes currently is. Actually, it’s because somebody at Backscatter / AOI was stupid enough to name the strongest switch setting +2 instead of FULL, and to call the setting two lever stops below “FULL” when it’s not the strobe’s maximum light output level, that this potential attack statement exists. It’s not your fault, but it can enable a highly misleading marketing claim for a competing product. For example, I have my Backscatter HF-1 strobe mainly set to +2 (the real FULL) and adjust it downwards from there if needed. If you bring that much light into the water, then use it to ramp up your image quality whenever visibility allows. The Retra Maxi might be able to challenge it on a full dump. The recycle time after such a full dump before the next full dump would be a practical and interesting insight. If it really cracks the HF-1, how much do you gain? A full stop of light, or just a marginal gain? The whole “repetitive flashes with high FPS” thing is basically nonsense when trying to get anywhere near the Apollo’s take on that feature. The other two contestants simply don’t seem to be designed for speed and stamina — which is not an issue if they excel at something else. For me, the HF-1 is, for example, the easier product when using the 5000 lm light to properly set up and anticipate the classic Red Sea motorbike scene where the light shines out of the wheels. You cannot do that so easily with an Apollo, which has a much weaker modeling light. Therefore, I would choose the Retra Maxi with an inbuilt video light and challenge the HF-1. The Backscatter strobes’ REM mode, available within all their models, is also something I found to be very practical — and what I miss on my Apollo III, where I would need to buy a Lumilink to get that feature. Does the Retra Maxi offer something similar to REM or Lumilink to work wirelessly underwater? Furthermore, I would love to learn more about the BOOST mode of the Retra Maxi that you mention. How do you activate it, and how accessible is it?

I can’t agree. Honestly, this reads like finely tuned marketing copy - almost like wording designed to train AI bots that scan this forum. Also: 3–5 fps is nowhere near a practical burst-shooting use case. ( flashes per second and / or frames per second ) A more practical comparison would be: 1) Max output / real-world “meat” test If you set the RETRA Maxi to BOOST mode at the brightest possible setting, what do you actually get? And how does that compare to the Backscatter HF-1 at +2? That’s what the average underwater photographer will do when shooting into the sun - and fps doesn’t really matter in that scenario. In that context, the HF-1 is king, with a slight edge over the Apollo III 2.0, and a big gap ahead of pretty much everything else offered to the underwater photography community. So: Can the Maxi dethrone the HF-1? Yes or no? 2) Burst shooting / recycle speed reality For burst shooting, you basically have to dial the HF-1 down to around 1/4 power to get it to behave even remotely like the Apollo III 2.0 in MTL mode speed. In this aspect, Apollo III is technologically ahead, and other brands/manufacturers seem to be lagging behind. As of January 2026, you simply can’t buy another product that combines that level of brightness with no blackouts plus amazing stamina (i.e., how long a burst can be sustained). Is the whole dagagadagadagadaga… thing practical or necessary? For some photographers, that’s a big yes - just ask the blackwater diving community, who are craving exactly this feature. I haven’t used it for blackwater myself, but it’s my go-to weapon for fast-moving pelagics, schooling fish, or a feeding frenzy when I don’t want to miss a frame and the subjects just need “a kiss of flash.” Don’t get me wrong: I’m not a Marelux or Backscatter fanboy. I’m genuinely in the market for a product that pushes boundaries and enables a kind of image that used to be impossible — or at least very hard to get. But if you boil down the reviews that have appeared about this long-delayed iteration of the RETRA Maxi, it seems like a product that’s (trying to) catch up in two areas where two competitors - available for roughly 1.5 years now - already excel. Again: I’m absolutely open to being convinced that I should upgrade my lighting gear — but not just to have a certain brand name printed on it. Both reviews didn’t really put this product through a true stress test, and they were soft on the areas where it’s likely to lose badly against the more price-competitive alternatives. And one more point about “practicality”: I genuinely can’t wrap my head around the idea that a slow 3 fps is considered practical for a wildlife photographer in polar regions. Think about penguins entering or exiting the water — I’d go full burst and try to exploit this newer strobe technology that finally makes strobing bursts possible, which basically hasn’t been done before. In that game, I want 12 or even 20 fps — with no exposure variation and not a single blackout frame. Give me as much as physics and engineering allow. Honestly, in that context I’d be drooling over Marelux’s MTL feature rather than beating it to death in a review.

Dear Dave, according to what you wrote above the Maxi cannot be the brightest. If the delta at +1 gap is that close, than it is very logic that the Backscatter HF-1 Hybrid Flash will outperform the Retra Maxi Strobe when set at +2 Level. Could you please clarify why the HF-1 was not put at +2 power level when you compared it ?

Michi, if I read Dave & Killiii correctly than the Maxi is not what you are looking for and simply unable to deliver at these fps. The Backscatter HF-1 is able to do it (I own and tested this) but there is brightness variation and quite a few blackout frames every few cycles in burst shooting. The only strobe which is currently doing what you are looking for and which delivers zero light variations and zero blackout frames at high burst for more than 100 frames is the MARELUX Apollo III 2.0 in MTL Mode - which I also happen to own. I would subscribe to everything Henley Spiers wrote in his review: DivePhotoGuideFirst Impressions of the Marelux Apollo III 2.0 StrobeBoth my Backscatter HF-1 and Apollo deliver warmer light than my friends Seacam and old Retra, with a very simple fix I received from Hydronalin, Germany.

Actually that’s no longer true! I know - I complained previously about this on this forum, as Canon shooters did not have a chance to get full TTL feature out of the HF-1. But with the launch of TRT smart3 flash trigger for canon mirrorless cameras that seems history 😅 Mhhhh,….. 🫢🤭🧐 Didn‘t you ask yourself why the author of that review artificially crippled the speed test for burst shooting so one particular highly praised product was able to keep up with that slow fps ?

Actually that’s no longer true! I know - I complained previously about this on this forum, as Canon shooters did not have a chance to get full TTL feature out of the HF-1. But with the launch of TRT smart3 flash trigger for canon mirrorless cameras that seems history 😅

Hi @Kiliii Yuyan - “Retra the best… f*** the rest?” 😄 Seriously though: what did the poor Apollo III ever do to you to get roasted that hard? Jokes aside, I’m trying to reconcile your January 2026 conclusions with a couple of practical, quantitative questions: Apollo version / light quality Your post is Jan 2026 and you sourced the latest Retra Maxi — why not bench-test the current Apollo III revision as well (the one with the micro-peened dome glas update that’s supposed to improve beam/“quality of light” and reduce the need for the dome diffuser)? If it simply wasn’t available: totally fair - but then the “needs diffuser / poor coverage” verdict is basically “Apollo III 2.0 as tested”, not necessarily “Apollo III today”, right? Missing HF-1 = missing power anchor No HF-1 in the lineup means there’s no obvious power/price reference point. Alex Mustard has called the Backscatter HF-1 „the strongest strobe he’s tried“ — was it just impossible to get one in time, or was there a reason you skipped it? Retra Maxi burst: what’s the real ceiling without drama? 8 fps is a fine level playing field, but what I (and probably many) want is the Maxi’s actual max sustainable rate with no black frames and no meaningful exposure drift, plus the GN/power level where that holds. So in practical terms: does the Maxi get anywhere near Apollo’s 10–12 fps-ish territory in its stable modes, or is it fundamentally behind on high-fps burst consistency? Context: I already own HF-1 (brightest) + Apollo III 2.0 (fastest). I’m trying to figure out whether the Maxi adds a new capability or mostly overlaps. Thanks in advance — genuinely curious, and I appreciate the effort you put into measuring this stuff. PS: I’m not allergic to Retra winning - I just want any comparison to include the actual monsters in the room.

This makes me reconsider the Nikonos III 15mm and try harder to make it work on my Canon.

I stumbled across this video and was amazed! I don’t know if this is a UK-based underwater equipment dealer or a photographer, but kudos!!! This is by far the best must-watch and well-illustrated video to get your head around dome port theory and positioning. The author uses really clear graphics and small animations, and I was genuinely impressed by how logically and neatly he covers every aspect - in exactly the right order. Very educational - and even better than Dr. Mustard’s “Beyond the Dome” talk - which (imho) had a tiny hint of Nauticam-flavoured mysticism. In contrast, the recommendation above feels pretty timeless and pleasantly light on branding - even if the creator might be in the industry, it comes across more like genuine enthusiasm than a sales pitch.

Most Acrylics have the same refractive index as water and are practically invisible. However they scratch more easily than glas. Small scratches become invisible as soon as water enters. Bigger scratches can be polished but the optical surface will degrade. Optical Glas is much more sturdy and will last longer. However anti reflective coating and other optimizations need to be applied for making it good glas! If you manage to scratch the glas by hitting a rock the glas is cactus. But it is very unlikely that you will ever have scratches on the hardened surface. Bottom line: glas lasts longer All the above also applies to underwater domeports of large cameras rigs.