Adventurer

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.

Actually this was the MAJOR FIND and great recommendation for Canon Full Frame Shooters. With Marelux there is 15mm and 20mm which can help you construct 35mm. Also their 140mm Dome allows you to quick unlock and lock the sunshade underwater. PS: I was very glad Dreifish took my initial test-setup idea for the Samyang 14mm and took so many lenses and port combinations out for a real impressive test drive. And many thanks to @Architeuthis for reminding me of this thread recently - which I totally had forgotten, even though I previously participated in it.

Well,... yeah I wish it would be like that, but in reality even the Nauticam and Marelux full sphere 140mm domes are missing a few degrees curvature, where their glas is mounted into the aluminum frame. The most practical thing on the Canon 8-15mm is to keep an eye on the entrance pupil: It's located approximately directly under the red dot when you have the (original Canon) land sunshade mounted. You can keep an eye on it, if it sticks out sufficiently out of the black port tunnel of your underwater housing. So the native lens without teleconverters would need the 140mm Marelux and Nauticam domes with 47,9 mm Extension to be perfectly positioned, but as these two domes finish their sphere a little too early a 35mm extension is the absolute maximum you can use, before dark corners (vignetting) kicks in with these ports. However the fact that we might all be approx 13mm to short with the extensions explains the less optimal performance @RomiK illustrated in chromatic abberation test-shot when he used the lens natively. Hence the teleconverters shrink the FOV a little, so we can live with non-full sphere domes such as the 180mm with conical portside. However if the TCs decrease the optical quality or the slightly offset dome is to be judged.

So I did my parallax testing on a nodal rail to verify / de-myth the whole thing. The result: the above stuff I read on the internet and which seemed to be confirmed by two reasoning AI models is complete bullshit. The NPP / rotation point / entrance pupil will stay exactly where it was! Looking from the frontglas side at the Canon 8-15mm Fisheye F4 L it is stays at 17.98mm (@15mm zoom position) or at 19.12mm (@8mm zoom position). No change if you add a 1.4x TC or 2.0x TC in between. So assuming your dome position was already perfect before adding the TCs you will have to add: 18mm port Extension for the 1.4x Kenko and 35mm port extension for the 2.0x Kenko But as you may very likely have used a too short port extension to be able to use the full zoom range of the native 8-15mm without vignetting, adding a 50mm port extension for Marelux Housings is the way to go for the 2.0x TC. It is very likely to be the same for Nauticam when using their 140mm dome.

Well, it depends what you define as "awful". 😉 This is usually a very subjective expression of the situation. More objective would be: miimeter distance of the entrance pupil milimeter distance of the port (required vs available extension rings) stronger image compression able to shoot the lens more oben (F4 or F8 instead of mandatory F11 or F16) priority on zoom flexibility priority on corner sharpness priority on avoiding chromatic aberrations priority on travel weight lightness In physics and underwater photography there is usually no free lunch. Meaning there is one death you have to die (as we say in German). My approach will be to verify the theoretical moved position of the entrance pupil, with a paralax test on a nodal rail. For that I do not need to go diving or get the system wet. Again, thanks for sharing your results @RomiK ! However, I think there are combinations that will perform much better considering IQ in your rig. I hope you will also be able to benefit from the findings in this thread.

Coming back to the initial question and topic, the theory and some formulas suggest that by using the TC the entrance pupil (common name nodal point) will move into the direction of the cameras sensor plane. So if the Kenko Teleplus HD 2x DGX for Canon has 35mm length, an additional extension ring of just 15mm might be enough; if you keep using the same dome and it was absolute precisely positioned before you added the teleconverter. In this example we assume the entrance pupil moved 19.78mm towards the sensor. This is just an example to give you a general idea on how it works and what might be going on, with the real 15mm port extension not computed nor tested / verified.

Can you double check that Chris? My Kenko 1.4x PRO 300 DGX for Canon is just 18mm thick. This also corresponds with INONs Extension Ring 18mm which was especially developed for that Teleconverter.

True! With Canon MIL cameras that dome might work even in the 16mm diagonal fisheye setting that you archive when using the 2.0 TC - might be worth trying on your Sony A1 as well.

Thanks @RomiK for posting the examples. For correct optical performance you have to get the dome size and positioning exactly right on a millimeter level. You are introducing quite a bunch of variables by changing dome size and TC at once. Knowing that Nauticam and Marelux 180mm domes are not full spheres your test was destined to fail. The 180mm dome with conical rear part was simply not made for that lens. The Canon 8-15 FE without the TC is very likely to perform better behind the 140mm dome, which is (almost) full sphere and suitable for fisheye lenses.

I will be utilizing 2.0x and 1.4x Teleconverters with a fisheye zoom lens behind a dome. Currently doing the math for optimum dome positioning and sizing. I am under the assumption that the entrance pupil will move by adding a TC. And I mean by that, not equivalent to the 31mm physicial space that the teleconverter adds between camera and lens. Can you share your thoughts and maybe even the math for this endeavor?

Initially I was looking for some smart inputs to ditch cto gels or warming diffusers on strobes with cooler color temperatures and harvest the maximum photon energy of these cooler illuminators while still getting decent blues in tropical waters. I can adjust the hue and tint in my cameras auto white balance by several mired. In fact more mireds then some of the suggested gels or diffusers mentioned in this forum. I have the assumption that the additional color dynamic range when firing warm light into the foreground may not be needed (anymore) with recent full frame mirrorless cameras.

I am a huge fan of your spreadsheets works @DreiFish but the MARELUX value looks wrong to me. I think I measured 51mm could someone i.e. @Phil Rudin confirm this? I think sensor to bayonet distance in Marelux Canon housings is exactly 70mm.

Fantastic, just as fantastic that your manual triggers auto-switch to HSS mode once you shoot faster than 1/250sec. I would love to have this as a feature in a manual smart trigger for my Marelux MX-R6 II housing. However your trigger design keeps me away from using it, as I cannot fit the box on top. There is a physical camera holding element hindering me from using anything larger than a very thin hot shoe cable in the Marelux housing. I tried the manual trigger of a friend and like the functionality. My friend said I should get your mobie version to get around that problem, but you do not seem to offer that for your latest trigger generation anymore.

I like the Seahorse with blue bokeh very much and also the red bokeh behind yellow fish 🐟… but these two are not done with the TTArtisan 100mm soap bubble bokeh lens, are they? Is the last one with the nudi really trioplan copy ? It does not exhibit the typical soap bubble bokeh you can archive with it. Also I am curious how you got along with the working distance of that 100mm vintage lens. In total a very impressive trip portfolio. Nice work Chris, as usual.