Adventurer

In an inner zoom or inner focus design the entrance pupil will just hop around like crazy without you beeing aware of it. So "Yes", but that view on the optical performance behind a dome is kinda outdated, old-schoolish. It's not a big issue with many of the recent Canon RF lens designs, which have an extending tubus. Actually many of the non-L Canon lenses without a red ring perform much better than their L-Series siblings. Note that surface lens reviews (especially of very expensive lenses) don't tell you much about the optical performance behind an underwater dome. @stillviking pointed out correctly the most important feature: MFD = 20 cm looks promising. I am waiting for that lens to appear on optical bench hub to have a closer look.

Well yes that's what I did, but of course with shutter closed, which might explain the 1 mm offset. Good to reflect a little bit on that. Also the IBIS can make the sensor wobble a lot which might be interesting. Having said that, the Nikonos bayonet is also kind-off weird and allows you to shift the lense a little back and forth when properly mounted. I guess the water pressure will always push that lens towards sensor direction. But overall there might be some tolerante for the focus plane.

Great Info Chris, where did you look that up? What is the source? Official from Nikon / Canon? I did my own measurement and got 19mm on my Canon RF. Indeed the extruding knobs are going to be an issue. I am thinking about cutting or replacing them to be able to move the port adapter more inside. Thanks @Alex_Mustard for sharing your wonderful images. They are indeed dent sharp and extra-immersive. I also find it very interesting that it seems flexible enough to shoot medium sized fish portraits. Obviously due to the small min. focussing distance. Just to make sure: the parrotfish shot are also the the 15mm Nikonos and not a Nikonos Macro? May I ask what aperture you mainly shoot it ? There is an old rumor that @ F8 everything usually is sharp with that lens.

Hi Friends, for some reason I happen to own an old Nikonos III + 15mm underwater lens which I got more than 10 years ago on ebay. It's been a beloved pet project for me to dive this lens again on a full frame DSLM camera such as my R6 Mark II. Mainly because of IQ and the very compact size. I am aware that it's not a fisheye and equivalent to a 20mm lens, my favourite wide angle range underwater. There are two versions. The earlier one only fits on Nikonos I, ii and iii since it blocks the TTL-sensor of the Nikonos IV and V. The earlier lens is told to be the better performer due to its retro focusing design. This makes it even more mouthwatering after reading this optical benchmark done by Pawel Achtel from 2014 : https://wetpixel.com/articles/test-optical-performance-of-nikonos-15mm-flat-and-dome-ports It resulted in some cinema products: https://achtel.com/3deep/ I am also aware of this tinkering thread by @ianmarsh ( thank you Ian ! ) https://waterpixels.net/forums/topic/418-nikonos-15mm-service-manuals-and-schematics-was-do-15s-need-servicing/ I have some questions though, matching with my previous experience. In the Nauticam Sony NEX-5 days and Nikonos NEX Adapter, the Version III would not mount on the crop camera as it's derriere would have hit the image sensor. You needed to get a Nikonos 15mm in the V (five not three) version to make it work. I never did 🙃 If I remember correctly this was the reason why the III Version of the Nikon Nikonos UW-Nikkor 15mm f/2.8 would not mount on APS-C type. Now will full frame and mirrorless I see that Nauticam has a Nikonos-Full-Frame Adapter in their portfolio, but it's just for the A7 Sony camera series, not for Canon. https://www.nauticam.com/products/nikonos-adaptor-for-na-a7 In another thread together with @Phil Rudin and @Isaac Szabo that I recall but did not find we learned that Nauticam has different bayonet to camera flange distances between their brand housings. Some SONY models seem to sit closer to the Nauticam Bayonet, especially closer than the Canon DSLMs. Nauticams Nikonos Adapter for full frame just seems to work for A7/A7R/A7S System - anybody around using it with a 15mm lens and can report about the experience? In my MARELUX the Canon R6 II sits even deeper inside the housing, which may provoke a collision with the two knobs for focus and aperture control. I have exactly this set including the viewfinder: https://www.pacificrimcamera.com/rl/01394/01394.pdf Seeking your advice and comment in hope to make my pet project come alive.

I use the Marelux single dome 140mm for a versatile one fits all solution / backup. Go for the 8-15mm fisheye and do not invest in the 14-35mm zoom. The results of the 8-15mm TC 1.4x and 2.0x will be more pleasing than trying to rape the 14-35mm behind a small dome. Instead think about getting the RF 35mm 1.8 macro, which also can be utilized behind the small 140mm dome with a +4 diopter and which give you a flexible very sharp distant shark plus semi macro lens, without having to buy a flat port. I also own a 230mm dome. About your questions: 1.) not an issue to worry about with major brands, it’s awesome on Marelux but also fully functional on an INON housing, a friend owns. 2.) skip the 180 idea. The 140mm is full sphere with marelux and nauticam, the 180 is not. Unless you are heavily targeting for over-under split shots the 140mm dome is the way to go for many lenses, especially the 8-15mm FE. 3.) looking into this as I own the 1.4x RF TC and the two Kenko TCs seem to drive down IQ a little bit. There is zoom gear for all three scenarios by Marelux for the 8-15mm. I would need to test if one of the gears also would fit the much thicker bit. There is zoom gear for all three scenarios by Marelux for the 8-15mm. I would need to test if one of the gears also would fit the much thicker Canon RF TC 4.) good approach, however I would see that complementary to the 8-15 FE with TCs not redundant.

I own and shoot the R6mark II in a Marelux housing and Canon 8-15mm Fisheye plus some other lenses. I can highly recommend this setup. The housing has made some minor improvements even over Nauticam housings, which was actually hard to think about; but the reason why I decided on MARELUX.

Thank you so much for this feedback. I truly appreciate it. It is especially rewarding after having had quite a few exhausting discussions in an online forum, without anybody saying „thank you“. I am very glad I could help.

Hi guys, the RETRA test mentioned is land based, correct? Same as the private beam shots by Dreifish in this forum. I would like to point out that any strobe that utilizes a dome (such as Seacam, Z330, Marelux) will give you a highly distorted impression of the real beam pattern that will be produced underwater. Once the dome glas is submerged in water it acts like a lens increasing the beam angle and evenly softens the output. -> The quality of light will improve underwater. Just keep that in mind when comparing land based shots.

That non-HD version has a horrible reputation of crushing your IQ to pieces. I would try to replace that with the new version or the Sony.

I think so too.

The likelihood is very high that my cameras and housings frequently see much more wet salt than yours. 😉 You are dead wrong about the mm thing. Prioritize correct NPP positioning and be amazed. You can lab / pool test this, which is the way to go, before you spend multiple thousand dollars with a dismal travel camera setup in your bag.

This is very nicely put 😁☝️ Cudos Klaus!

I am curious: was the optical performance on land acceptable for you with the 2.0 TC ? Then you might have sold it too quickly and it was just missing the optical punch by a good sized, well positioned dome underwater 🤔 My guess from the limited unvalidated data donoring in this forum is that you might need 85mm of extensions with the 1.4x TC and 140mm nauticam dome. The slightly larger 180mm Nauticam dome might yield much better results with the 1.4x or 2.0x in the game.

Hey @fruehaufsteher2 and @Architeuthis, very glad you chimed in on this and that you are interested so much in the materia. I‘ll try to put this as simple and practical as I can, being a non native speaker: I understood the situation with both of you, is that you abandoned WACP or FCP etc in search for better IQ. Manufacturer portlists (Marelux, Nauticam, Ikelite etc. ) target to a extension ring + dome combination that will give you maximum zoom range / flexibility on that Canon EF 8-15. Mainly because they might not want customers complaining that the dome sunshade or parts of the extension ring are in the picture, because it’s an obvious thing to complain about if you have no clue and just bought expensive glas 😁. The dilemma is that the dome is positioned to close to the lens to archive this flexibility. A fisheye sees „everything“ which is right in front of the entrance pupil (180 degrees diagonal or even circular). So you must use a full sphere dome. Bummer: none of the Nauticam domes is a real full sphere, like the large Matty Smith domes are… the 140mm dome is missing a tiny fraction in the end which causes a significant offset in the NPP position. This is very practical but does not help your hunt for maximum IQ. I measured and computed this for my 140mm Marelux Fisheye Dome and there you would need a 7.5mm Extension behind the dome for exakt positioning. Nauticam will be very similar to this I suppose. The 140mm dome with Nauticam/Marelux itself has a small tunnel section of another 7mm, so you can easily see how quickly 1.5cm unwanted offset sneak up on you. Bottom Line: So even the dome you thought which to be a full sphere for your fisheye is not. As you already own the Teleconverters (TCs) the logic step is to use them to shrink your field of view. Then you can use domes which are not full sphere, such as the medium sized 180mm dome, @RomiK used for some test shots in this forum. You can of course also do this with the 140mm dome if you already own it. Next Step: ditch flexibility and abandon the 8mm focal length end -> as a sacrifice for IQ the 15mm zoom end is the preferred operation mode for you. With TC 1.4x you get 21mm focal length. With TC 2.0x you get to 30mm focal length. Put your metabones adapter / sigma MC 11 plus the Teleconverter and lens on the camera and mount it inside the housing. Measure the distance from housing port flange to the red dot on the Canon EF 8-15mm sunshade. This is the minimum length of the extension ring you will need from Nauticam. I suppose even 7mm to 1cm more because of what I wrote above about the 140mm domes. You will loose some of the wide angle part of this fisheye zoom, as the lens sits now more deep inside the extension ring tunnel. But honestly, would you have used that portion very often underwater? I hope my best practice is comprehensive for you. If something is unclear just ask.

Putting a TC1.4x or TC2.0x in the system + getting a loooong port extension to use the 8-15 @ 15mm zoomed in -> 21mm / 30mm focal length with domes will give you better IQ and build the CFWA system you mention.