Adventurer

These INON Float Arms serve me for several years now: https://www.hydronalin.eu/inon-mega-float-arm-s-mit-390-gramm-auftrieb_2058 They come in various shapes. Very lightweight, durable and have two M5 threads on which you can connect accessories such as LensHolders, Actioncams etc.

I am happy we got introduced to this approach again in underwater optical design. Putting together the (distorted) sample images by Don Silcock, Alex Mustard‘s Infos on his 20mm and Zeiss Version plus my own experience with such a corrector port design I would conclude the following. The strength of theses systems lies in hosting / correcting lenses above 20mm focal length on full frame. If you go wider the distortion starts to look odd and you may also suffer corner sharpness IQ loss. The strength of theses system group lies in being able to correct high quality lenses with large front glass elements and offering a very flexible uw corrected zoom range at small size and weight factor. I think it was a sad marketing mistake that Seacam let the test pilot go to shoot with a 16-35mm focal length. The real sweet application will be lenses in the 20-60mm zoom range (Panasonic FullFrame L Mount has one) and in the 20-70mm focal length range. In reality these will be up2date 24-70s or 28-70s with major camera brands. Therefore it would be beneficial if Seacam and other manufacturers would not design the System fully afocal and give it a slightly widening punch factor of 0.8x or 0.75x I hope to see this in the market and some nicer test shots with such an Ivanoff revival in 2026. As the technology had been patented in the past it is now public domain and all camera housing manufacturers could enter this product segment with high end underwater optical designs without risking IP infringements.

Yes,... that's something different: Canon/Nikon/Sony-Lens + WetLens on Land with slight vignette will in most cases dissapear when dipped in water. Canon/Nikon/Sony-Lens pure on Land with sensor vignetted RAW will not.

The test image ist actually dry and without a water contact conversion optic. I did not shoot it. It's from a public review. These exist in various forms on the net. But I have my own RAW files shooting a white wall. This "dry" and dismal projection of lenses cannot be fixed by water or water contact optics, as far as my testing confirms. I assume it has very much to do with the last projection array of glas inside a dry lens. Water contact optics or domes working in front of the optical system cannot cancel these out. Can somebody else confirm that? It would make me feel more comfortable with my analysis and thoughts on this matter. Having said that, I think a very much workable way is to shoot these wide vignetters at a focal length that is bearable. With my RF 24-105 STM for example the whole thing is very usable @ 28mm onwards. But as the 24-105 STM has a much larger front glas element and extends during zooming it is a more suitable candidate for dome ports and my Ivanoff style underwater correction port.

Our very own @DreiFish took the efforts to compare and test this in a formidable thread that deserves to be pinned:

Sorry Phil, but that is wrong. Nauticam lists WWL-1C combination with Canon RF 24-50mm STM in their port chart: https://drive.google.com/file/d/17vlICB0Gn6bbeTGaIR9yd3HHOIfIG9kK/view

Sorry for maybe not being explicit enough about this in my thread opener: the Canon 24-50 STM is intended to be used with underwater corrective optics, which will turn it into approx 130-70 degree FOV being equivalent to your 10mm with the RF10-20. By the way, you highly expensive RF 10-20 suffers from a similar flaw at even higher level: With disabled distortion- and vignetting compensation, the image corners are black at 10mm. https://opticallimits.com/canon/canon-rf/canon-rf-10-20mm-f-4-l-is-stm-review/

I’ve been examining the Canon RF 24-50mm STM lens on full-frame bodies and noticed something important: this lens, often recommended by housing manufacturers, does not actually project image corners onto the sensor at 24mm and not even fully at 28mm in uncorrected RAW. In other words, the much-discussed corner sharpness that underwater photographers focus on isn’t even present at those wide ends, because the image simply doesn’t cover the full sensor corners natively. Even a fancy underwater correction optic such as the Nauticam WWL-1 WACP FCP or Marelux Aquista 110 or 130 or cannot fix this. The corners of the frame are just not recorded and a pure digital fantasy mashup of reality. This improves slightly at 28mm and is gone at 35mm. However, there are reasons why this lens is still a favorite for underwater setups with water-contact corrective optics. Let me summarize the key points: • Compact and Lightweight: It’s extremely small and light, making it easy to handle in underwater housings. • Small Front Glass Element: It’s one of only a few Canon RF lenses with a very small front glass element (just 37 mm), which makes it suitable for water-contact optics. • Retracting Design: At 24mm, the lens is fully extended, and as you zoom to 50mm, it retracts inward. This makes it physically convenient for flat port designs and is a unique trait among Canon RF wide-angle zooms. In essence, while the lens doesn’t project full image corners at the widest focal lengths in uncorrected RAW, the practical benefits—compactness, compatibility with corrective optics, and convenient physical behavior—explain why it’s still a favored choice in the underwater photography community. Is it to you? I bought the lens a few month ago and also got a Marelux Zoom Gear for it, but ever since sinking it in a bathtub it is giving me a lot of headaches. This is why I called it „the shard“ in another forum thread here. I hope somebody can change my mind and give some value to this piece of glas. If you’re looking to have a flexible wide-angle zoom that you can combine with underwater contact optics or teleconverters, here’s a quick comparison of the zoom factors for some of these solutions: Canon RF 24-50mm STM (without limiter): 2.08× Canon RF 24-50mm STM (with 28mm limiter): 1.79× Canon EF 8-15mm Fisheye with 2.0× Teleconverter: 1.88× So, these are some theoretical findings and empirically validated facts. I’d be interested in reading your practical experiences and thoughts on the Canon RF 24-50mm STM lens. If you’ve found better alternatives or reasons why this lens stands out as the ultimate wide-angle solution for you, please share your images and thoughts !

Great moderation remark Davide! ❤️‍🔥 I would like to add a thought, roundup for everyone’s consideration: OsmoAction and Insta360 Action have introduced newer models and in 2025 no GoPro 14 HERO Black was introduced. Generally the ActionCam space seems to have matured and 3 competitors seem to take the segment with different angles of attack. Insta360 did not introduce an AcePro3 and instead was fostering the mini project GO and GO3S. GoPro while falling behind was the last to offer HDMI output via their media mod, which could have been important for external underwater monitors. Having said the above: the main weakpoint in this product segment actioncams for divers is the very tiny LCD these small cameras offer. On the other hand their main core advantage is beeing tiny. With the advent of ultimate smooth image stabilization in these cameras is sticking them into spaces where large cameras cannot go. So that takes you to re-considering macro shooting in actioncams which is a little bit like shooting macro on a Nikonos V these days. INON has introduced quite a variety of macro lenses for all the GoPros, Instas and DJI Osmos and I am strongly considering to try these. I used to be very convinced to put the action cam on a camera tray but this is not my goto idea for the year 2026. I plan to put it on a stick and basically get a cheap Nauticam EMWL with it. Instead of moving a large mirrorless rig with an $$$$ lens around, why not move the tiny lens including camera around and see what it will catch. Just an idea to move your action cam footage to a new level… instead of looking onto an external monitor, look over the camera onto two distance sticks 🤔😏 - let’s see how this turns out.

Yes, and from the information I was given that exact adapter would also pair with Aquista 110 (production series, not prototype) and vice versa. It would be nice if someone could confirm this.

Yes, I totally agree to that Davide. This should be the main purpose of 3rd party action camera housings. ..as well as giving access to magnified screen ( via HDMI or USB-C ) option. However... with the GoPro HERO 13 being the last ActionCam to offer an HDMI-Out and no HERO14 introduced in 2025 the future for buying an external monitor and moving this onto the next action cam looks dim. For Cameras like the Osmo Action 6 or Insta Ace Pro 2 you need to grab the screen signal via USB-C (Webcam Mode).

Hey everyone, I wanted to share a perspective I’ve often recommended to fellow underwater photographers when it comes to shooting blue water sharks, especially when you’re working with natural light and strobe combinations. One of the key points is that most shark species have a pretty neutral, silvery-grey coloration. In other words, you’re not trying to bring out a riot of colors like you would with a coral reef and fisheyes lens. That means you don’t have to worry as much about maintaining warm color fidelity at longer distances. In fact, if you have good visibility, you can shoot from over a meter or more away without losing too much detail. And when it comes to lighting, the idea of a cooler color temperature strobe can actually be a real advantage. Cooler strobes will penetrate the water more effectively over distance because the red wavelengths get absorbed quickly anyway. So you’re focusing on sharpness and light energy rather than trying to preserve warm tones that aren’t really there. In practical terms, using a strobe that’s a bit cooler and then adding a warming diffuser only if needed is a flexible approach. For typical shark photography—like shooting reef sharks in the Red Sea, where they don’t come extremely close—keeping your strobe on the cooler side and not worrying about warming accessories can give you the best reach and clarity. And one more thing I’d like to add is about your lens choice. If you’re used to working with a really wide lens like a 15 to 30mm, you might find yourself falling a bit short when the sharks stay a little further away—like in the Maldives or the Red Sea where you’re not always going to get them right up in your face. In those cases, I really recommend something with a bit more focal range—like a 28 to 70mm or even a 24 to 105mm. That way, you’ve got the flexibility to handle those sharks that come in nice and close, but also the ones that hang back—like hammerheads or thresher sharks. Hope that helps round things out! So that’s the gist of it. Hope this helps some of you thinking about how to set up for your next shark shoot.

Sorry for the mess. I should not give precision optical advice late in the evening without my glasses on! I simply overlooked the III behind puttsk‘s lens. But about the other remark by Phil: I got the info from a friend that at least WWL-1 and Aquista110 production units have similar bayonet and can be swapped. I think he even got the info from a Marelux employee. Can you please double check + confirm or deny this, Phil?

Actually I also had a long period, where I thought, I might be missing out on something, not owning a WAPC-C or other Nauticam Water Contact Optic. They are just so heavily hyped and raved by various (officially not paid) talking heads on the internet. The death sentence for WAPC-C was this very honest review by Interceptor121 : Interceptor121 Photography & Video WorkshopsNauticam WACP-C vs WWL-1I am conscious that a post like this is destined to create some stir, however it reflects over one month of testing of the two Nauticam water contact optics with my A1 and summarizes my conclusion …

Then you least cost route would be buying the WWL-1B + Aquista Mount: 55803 and the Macro Port 97 31302 ..both on stock with a dealer near you. Sorry, I did not see that you are from Thailand and thought you were Czech. 🤦‍♂️😅 I have also looked into Aquista 110 there and asked a ton of questions about it. The mount is identical to WWL-1 requirements and you should be able to plug your WWL-1B into the front. I am quite curious how this old lens will perform behind Aquista 110 or WWL-1B. Please report back with impressions and results if you will go that road.