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Well that does not match Phil's picture posted above. And while it makes sense, that diffent camera brands (Nikon Z, Sony E, Canon RF) have different flange to housing distances and therefore different port charts, it would not make too much sense, if Sony E Mount Camera Model X has different flange distance than model Y and Z. In that case camera X, Y and Z would need new different port charts. I think the source of 4mm gap: 43mm (measured by Phil) versus 39.1 (measured by @Isaac Szabo customer and confirmed by Marelux engineering) might have a more simple explanation. @Phil Rudin, could you be so kind and have a look if there is a blank space at the beginning of your ruler, that you have put onto the cameras flange? This is something we could not see in the two images provided.

Yes, the MFD of 30cm is too high. You will need a dome diameter of approx 52cm for it. What you can do as a solution is to put a +4 diopter on the lens to improve the focus on the virtual image. The lens entrance pupils sits approx 3.3cm too far inside the housing for optimal position of the entrance pupil behind the dome. Hydronalin in Germany has a solution for making affordable INON Glas domes work for that lens and the RF 35mm, if the +4 diopter does not do the job for you.

@Pavel Kolpakov as you are an expert on HSS as I have read here: https://wetpixel.com/articles/fundamentals-of-ttl-strobe-control-by-pavel-kolpakov/P3 Does this old statement from you, when there was mainly just the RETRA strobe supporting HSS, still hold: „For uniform illumination of the frame with such a shutter operation, the flash should be a long sequence of short flashes with a repetition rate of about 30 kilohertz, firing all the time while the open shutter slit moves along the window. The total burn time of these flashes is about five times longer than that of a mono-flash, while its intensity is noticeably lower. It is customary to regulate the power of the HSS flash by changing the frequency of these pulses.“ As you explicitly market „no HSS banding“ for your upcoming strobes. Were there strobes which showed this on some occasions? Do the current HSS capable strobes act differently? Meaning mainly: 1.) RETRA 2.) Marelux Apollo III 2.0 3.) Backscatter HF-1 Hybrid Strobe 4.) Marelux Apollo S Backscatter writes in their manual that in HSS mode the strobe power dial does not have any function and the HF-1 will fire HSS always in same strength. Contrary Marelux seems to allow adjustments in M-HSS mode. Does your 30 kHz and five times longer duration statement from 2021 still apply to the HSS strobes mentioned above and your upcoming strobe?

Well,.. HSS implementation seems to differ quite a bit depending on the strobes used. If you consult the Backscatter HF-1 manual, it says that the HSS mode always delivers same power output. This also means the picture will darken with increased shutter speeds heading towards 1/8000. Contrary to Marelux Apollo III 2.0 when in M-HSS mode you can use the strength dial and influence something.

Yes Klaus, actually that is an experience I have had for many years. There can be backscatter in video clips but actually is not as strong as the strobe. And while you mention that: In a really dirty conditioned water, when I take two shots and I manually ramp up my strobes. The backscatter discs may very often appear larger when you fire at them with more strobe power.

I think we can rule out the particle movement thing (left to right etc.) as things happen so ultra-fast, when getting strobed. Maybe electron rotation will do it's cause but not bigger molecules moving through the frame.

Congratulations. The specs read truly unbelievable and too good to be true. Especially the 120 fps above somehow contradict to the 0.8 sec recycle time two lines earlier. They would require 1/120 sec -> 0,0083 sec recycle time. 😵‍💫 😵‍💫 🤯 that's 100x times faster then the recycling speed after a full dump. I am sure all this will somehow make sense, but maybe you can elaborate a little and "demystify" this claim.

Chris there is a threshold when different matter (objects) in this universe start to reflect. https://www.researchgate.net/publication/367009373_Threshold_When_Does_a_Reflection_Become_Noticeable When there is water column between subject and light source -> this energy absorbing effect might be amplified.

Four new strobes on the horizon with unpredictable future in highly increased competition and shrinking markets.

🫣 YAFS ..suicidal tendencies among various market participants.

What do you think about this suggestion?

If you have nothing factual to contribute moderating could sometimes just mean reading, Chris. The port chart of manufacturer X does not help users of brand Y or Z. RomiK showed pretty well that EF 8-15mm is not invincible against raping it behind the wrong domes in wrong distances. Dreifish showed in this thread that the Nauticam port chart is far away from decent and prudent control pays off. Dreifish and I demonstrated multiple times with fisheyes and rectilinear lenses that every milimeter matters and very often can easily improve your IQ at almost no additional costs. If your housing brand does not offer extension rings in min. 5mm steps you should consider changing brands or buying ports and extension rings from third party port-makers.

I would not draw any conclusions from the cited article as there is not a single photo in it which wasn't cropped and heavily processed. 😁

As I already explained and illustrated in picture before, the accessory is not the issue. Even when the uw-technics TTL trigger (that's the accessory you refer to) in my housing is removed you are unable to put your trigger on top of the camera. The structural element which holds the cameras upper side in place and prevents it from misaligning with heavy lenses in the housing blocks your TRT trigger box hot shoe. The turtle trigger cannot be mounted as a non-mobie version in MX-R6II housings, please accept that. Please start offering mobie versions for all of your products.

HA !! Good news for the MARELUX Canon Shooter Community: The 140mm Marelux Dome works excellent with the Canon RF16 F2.8 lens. Dent sharp at F11 - you can even keep the sunshade on - while it might blow off your socks 😉 As I learned in another thread the reason for this might partially be that we have an approx 8mm (exact 7.9 mm) advantage over the Nauticam Canon housings concerning the flange distance, needed for this lens to get us to straight chessfield-lines (exact positioning of the entrance pupil for doing proper split shots). Here are my quick and dirty test shots, proofs for you. There are some things (catches?) to be aware of, though: Using such a very small dome gives you a heavily bended virtual image, with any manufacturer. You can see that the alignment of chessboard fields is the same above and below water in the center of the frame, while they start to magnify towards the edges. I suppose dome compression of the virtual image is the root for this. I can imagine that will disappear when using a larger diameter dome or the affordable INON dome with a port-adapter. Second, as the entrance pupil moves quite a bit forward when this lens is focussing more close you will be able to "make it come out of it's housing cave" by getting really close to your subject. In other words the closer I moved the camera and dome towards the chessboard -> the more the entrance pupil came out -> the better the above and below water alignment (similar size of the squares on the chessboard) got. The I-P delta is 6.14 mm for the nerds out there doing the math. To give you a reference: the widely appraised I-P delta of the EF 8-15 Fisheye Lens is just 1.63 mm and the for underwater superb Sony SEL-20F18G 20mm F1.8 has a I-P delta of ZERO. Which means that lens does not move it's entrance pupil at all when re-foccussing. It is also a nice verification and proof that every millimeter of positioning counts, when working with full frame camera and small dome ports. Exited to learn, if Super-Moderator @Chris Ross will finally swallow this and agree ? 😉 When you look at the minimum focussing distance chessboard images in large, with LENS CORRECTION ON and OFF processed in LR you will actually learn that this 16mm is a little bit fishy (leaning towards the barrel distortion of a fisheye) and Canon lens corrects the hell out of this optic to get it straight. This will also effectively give you a FOV and look of a 20mm prime lens in topside use. In topside use it's welcome underwater you might want to turn it off and enjoy the vignetting, as a special look of this lens. When you turn LENS CORRECTION of you will have small black corners, though.

That looks like solid 43mm for MARELUX SONY flange, Phil.

WTF ?!?!?! 😄 Best free advertising a company in this industry ever received. Who build this and why?!?!?! I guess Seacam is harder to make because of the Silver color. 🤣 And "YES" it's a Canon 😜 @Muellema I agree with your thoughts about shark diving safety on this site.

Good luck in a free world and free market! If you want this just decide on another housing company such as INON or SEACAM where you can have TTL-triggers and 2nd curtain sync all integrated from one brand. Also good luck explaining the raised costs of housing because of LED triggers to videographers who do not need strobe triggers at all. Be happy and thankful that companies like uw-technics @Pavel Kolpakov and TRT @TURTLE-Balage give innovative solutions to us, for underwater housings and photographers who appreciate them. I have had very positive experience with both companies and their products. So sorry that I cannot join in on your rant and bashing. Can we please not try to hi-jack this thread ? The TRT TURTLE trigger developer and owner introduced here something really interesting and innovative. I would appreciate if we do not scare him off and frustrate him. As I said before: I really would love to use this on a Canon in a Marelux housing, but there needs to be a technical solution for this. I would even swap out my uw-technics LED trigger occasionally for this, because I like the 1/250sec auto-switch to HSS function on TRTs manual Canon triggers.

Stop it 🫣🤣🤣😅 YAFS ( Yet Another Fuckin‘ Strobe ) How come the market is finally getting flooded with so interesting competition in this product class, just when less cameras and housings which need strobes are sold ? I wish we would have this plethora and galore of strobes five to seven years ago. Now many of these R&D projects will not make break-even and we risk that the strobe manufacturer on which we have put our bet on will not exist in a few years. The shrunk market is just too small for so many models and brands.

The above reads a little more solid than the other mm values exchanged here. I‘d like to put my finger in a wound with salt: If the flange distances of the underwater housing manufacturers are really displaying substantial variances for one camera brand mount (i.e. Canon RF portchart, Sony E Mount Port Chart, Nikon Z Mount Chart) they have been giving their customers really bad advice and dismal optical configurations for years. A lot of port charts have to be rewritten then,… phew. 🤐 This struck me after sleeping one night over this sensitive topic. 💣💥

Those „I don‘t think will make a difference“ errors pile up 🥴 slowly. In the end the sum of all errors will heavily put you on the wrong track. When you have done all the math and measurements precisely you can make a practical rounding decision as a final step, but not so early in the process.

To me this looks clearly indisputable like 51 mm (metric). I have attached two images to see if we are both talking about the same distance. The sensor plane is 19mm more towards the camera, so from sensor to marelux bayonet it is 19+51 = 70 mm Any thoughts or comments ?

Sorry Balage, but you know it wrong. Enclosed is a picture of the MARELUX MX-R6II housing and your manual trigger in the same frame. The part circled in red is where the pointer points is the MARELUX orginal design which keeps the camera positioned stable in the housing even when exposed to shocks, during rides in rough sea or a zodiac etc. I do not want to remove that part for camera safety reasons and make the precise housing design, fail. Also on the right in the picture is your TRT manual trigger for Canon. It simply does not fit and you cannot recommend this product to Canon owners. Anyone who buys it will be unable to push it onto the hot shoe. In picture two you see your competitor uw-technics who does it right. You also see the space that is available. I would love to use your trigger, but I am unable to get there without a hotshoe extension and holder that will properly locate it in the dedicated housing space for triggers, designed by Marelux.