Adventurer

Also have a look if you can fit the RF28MM pancake prime behind your WACP.

So you insist on shooting f2.8 for low light underwater and that’s you goal ? Congratulations… expect dismal performance of your high $$$ gear! Cranking up the ISO a few stops will give you better results then spending tons of $$$ on one more camera or lens. If you are desperately in search for an F2.8 candidate try to get that Canon RF 28-70mm F2.8 IS STM running behind your WACP and maybe live with a slightly limited zoom range on the Tele end.

True. But I think also mainly due to the fact that companies such as Nauticam and their dealers are not willing to deal with smart-ass customers who will complain about vignetting in online reviews. As in this forum you will not find the average Joe I would like to offer you a more geeky take on this problem and a viable solution: As Canon RF shooters we have various optics that use digital lens corrections which are heavily debated online. This results in quite a few RF lenses that will not project a full image circle on a full frame sensor at their widest focal length, such as the RF 24-50 STM, but also highly-priced L lenses , such as the RF 14-35 F4 L and RF 20-50 F4 L. (sony with the 28-60 has the problem too, but nobody seems to talk about it) What can you do about this? 1.) Look beyond Canons zoom range values and get a WACP/Aquista lens candidate that starts at 24 or 20mm instead of 28mm, as these will usually project a full image circle on sensor when zoomed in. 2.) don’t get an L lens with a wide opened front glas, get the more lightweight grey non-L version of a RF lens instead, to avoid having issues peeking through a tight porthole. Here the best example is choosing the RF24-105 STM over the more expensive USM L version. You will not need / shoot the more wide open aperture when shooting underwater. 3.) be okay with not using the full zoom range, so the RF24-105 STM will not extend too much and not move the entrance pupil dramatically when zoomed from 24-70mm. Various land-based reviews of the Canon 24-105mm STM validate it as an ultra-sharp competitor and point out that it‘s worthwhile saving $1000 when choosing it over the constant more open aperture L version. On my Ivanoff Corrector Port I can use it up to 90mm, which makes it even more flexible. It has proven to be one of the sharpest underwater knives in my toolbox and I highly recommend it to underwater photographers and videographers. However it’s not listed in any of the manufacturers portcharts, probably for the above mentioned reasons. I encourage everyone to give it a go. The zoom gear that you purchase for an RF15-30 with your housing brand will also fit the RF 24-105 STM.

Does the camera allow you to turn off lens corrections (in-camera) or is this one of those Canon lenses where lens correction is forced in camera? @JayceeB thanks for sharing the images. I think, the marelux 180 glass dome or their 210 acrylic will not add much volume or load and dramatically improve lens performance. I assume the freshly introduced Marelux Aquista 135D - which is Marelux‘s take on Nauticam‘s WACP lineup - will give you the highest image quality with that lens, @JayceeB . @WhoTippedMyCoW it was said that mx is launching that lens with adapters for various other housing brands, too. Worthwile watching that progression.

Christopher Frost says in this video at 7:10 timecode that the black corners disappear at 24mm focal length:

Looking at the MFD data of that lens the 140mm should be too small,… did you add a diopter to the front of the lens to compensate for it? I think the 180mm MX dome or the giant MX fisheye dome will perform better concerning corner sharpness. Also the new MARELUX Aquista 135D and this lens look like they will magic. @JayceeB could you upload a lens image taken of a white wall (land-use), with deactivated lens corrections in Lightroom to see if there is a full image projection to the corners or if they are black @ 20mm focal length ? Also if without lens correction you have black corners, at what focal length will they disappear? ( 22m , 24mm , 26mm , 28 mm)

Whow that’s strange! Does this happen when you turn lens corrections in Lightroom ON or OFF ?

That’s great compact looking news. Looks like 2026 is the year in which the high-end underwater optics monopoly is finally broken up. I took a quick glance at the Aquista 135D port chart and the Canon selection of lenses is still very limited. „Must-have Candidates“ that I would love to see listed: Canon RF 20-50mm F4L IS USM PZ most important new candidate! Canon RF 24-105mm f4-7,1 IS STM (will need a zoom limiter, but Marelux RF15-30 STM zoom gear fits this lens) Canon EF 28-70mm f/3.5-4.5 II (the historically best Canon Zoom lens recommended for use with the Nauticam WACP-1, costs just approx $70 in the used market and needs a Canon RF-EF Adapter to work) Canon RF 24-50mm f4,5-6,3 IS (dismal lens, but the noobs love it, so MARELUX gotta list it for completeness; as it will very likely work) Canon RF 28-70mm F2.8 IS STM (very likely to work)

The Canon EF-S 60mm Macro is a very affordable and pretty much underestimated macro lens. The above, written by Chris is true for Canon Mirrorless full frame bodies, as the Canon MILC will auto-switch to 1.6x Crop mode. There is a work-around for this, by setting your desired aperture first and then slightly unrotating the lens from the bayonet. This will trick your Canon to consider it as a manual focussing third party lens. Surprisingly it will only exhibit very little vignetting on a full frame sensor. But you have to live with using it as a fully manual focus + fixed aperture lens throwing the very fast and silent AF of this lens over-board. Sony, MFT and Nikon users can adapt this lens with full AF features and will have it working as a full frame lens with slight vignetting in some focus positions. Ahh,.. and if you intend to use it for video the 16:9 aspect crop will also help to get rid of the dark corners on a full frame body.

Wow, what a statement and test series.

Welcome Don, great you joined. Looking very much forward to your posts and thoughts and contributions! ..especially first hand reports in the OPP thread.

Interesting, at least one more lens on the Sony front. You do not know by any chance if they also offer it for Canon Lens and which one they decided to pick ? ..would be interesting to see the progression of this system. My personal opinion is that if you go for rectiliniar lenses and wider than approx 20mm focal length, things are likely to look odd / weird underwater, even if the lens has been well corrected behind a dome or OPP style optic. It would have been very interesting if @Alex_Mustard would have elaborated more on what zoom level the presented images in the video were shot and how much he cropped in each RAW. Especially the sweet lips shots and some other look to me like he is not at the ultra wide end of the setup. I also think some of Don Silcock's initial sample images - which were heavily debated at DEMA and in the community - suffered a little bit from shooting this too wide. But I may be wrong, would be interesting to see a follow up in the show and in more detail.

Good news everybody! The lens has already made it to optical bench hub: https://www.photonstophotos.net/GeneralTopics/Lenses/OpticalBench/OpticalBench.htm#Data/US20260029629_Example06P.txt,figureOpacity=0.25,AxisO,OffAxis Two some very good indicators that suggest it to be a good uw candidate: 1.) Entrance Pupil just moves 4.35 mm during zoom 2.) Just 42mm front glas diameter (will work with many water corrective optics) 3.) Minimum subject distance in Front of the lens = 123,2 mm = 12,32 cm 94° diagonal FOV @ 20mm behind a dome

Here is how I would rank it, IQ sharpness wise: 1.) RF 24-105 STM (the sharpest!) 2.) Canon EF 8-15mm with original EF-RF Adapter 3.) Canon EF 8-15mm with comlite EF-RF Adapter (I have not shot this combination, as the comlite seems to exhibit some dismal AF performance compared to the Camon EF-RF adapter already on land) - so this is a „I suppose“ line 4.) Canon Fisheye 8-15 with original Canon RF-EF adapter and Kenko 2.0x TC 5.) Canon Fisheye 8-15 with modified Comlite RF-EF adapter and Canon RF 2.0x TC

I am happy Canon made this lens. 20mm is the sweet spot before rectilinear lenses start looking odd. I hope the lens design pops up on optical bench soon, so we can have a closer look.

Having done a few more snaps in the field and tightly comparing the sharpness of my lens line-up, I must conclude: Newer RF lenses are more razor (sharp) than older EF lenses. This basically confirms also various land based tests I churned through on the internet. Surprisingly my RF 24-105 STM is the sharpest lens in my lineup and it outperforms the EF 8-15 fisheye in overall IQ sharpness on average. I even think the RF 24-105 is sharper than the Canon RF 100 mm macro behind a flat port on many occasions. Also I am currently under the impression that the EF 8-15 combined with the Kenko 2.0x PRO TC performs better than with the RF 2.0x comlite adapter.

@TimG my condolences! What a nightmare. I hope you are not too traumatized by the experience and the gear loss aftermath.

So you made the jump to new strobes @waso … were you already able to take them out for a test drive ? … interested to see your first results with them soon.

Similar complaints from my better half here, too. She usually says something like: „Oh nooo, are you going to watch Shrek again,… ?“ before she leaves the room. 😅 🥴

Looks like that is what they added to the the 2.0 version of the apollo S strobe.

I do not use Apollo S myself, but according to marelux the Apollo S 2.0 has two dedicated switch position on their left rotary dial called M-PRE and M. The M-PRE position should do what you are looking for and cancel out the preflash. M-PRE is supposed to fire out just one flash. They have this on their Apollo S and Apollo Y but not on my III 2.0.

Ehhhrmm,… which sony are you talking about? Your sony A6400 ? … should not be an issue with that one. Furthermore I am pretty sure all their Apollo strobes successfully handle pre-flash. If I wanted manual strobing on my Apollo III with preflash in my cam I will simply put it in MTL mode.

Very nice read @Alex_Mustard ! Given that Don Silcock tested the prototype for approximately one year, the official announcement was back in November 2025, and we are now in April 2026, it is a little disappointing that only one lens in the Nikon system still appears to work with Seacam’s OPP. That probably says something about both the technical complexity of this optic and the level of commercial demand for it. I really hope Seacam succeeds in expanding compatibility to more camera brands and, even more importantly, to a wider range of interesting lenses.

Very interesting Wolfgang, even though I am not a Sony User but this would supports the initial thesis of a very good air based „exit-glas“ (lens) bringing the right photons to the table 😉 Could you specify with a link which Sony 20-70 exactly you mean? Also interesting that you consider the 8-15mm a slightly less sharp performer. Have you ever used/tested WACP-1 oder WACP-2, Wolfgang and an impression on that one to compare?

I‘ll be bringing that setup to the water soon with the Canon RF 2.0x - I have also extensively shot the canon 8-15 with the Kenko 2.0x and love it. The IQ degradation is acceptable from the Kenko 2.0x as a trade for the enormous flexibility. That said, I always look forward into finding more optimized image quality gear. Special thanks also to @ChipBPhoto for sharing his extensive impression on WWL and WACP family. It confirms my impression that the only interesting candidate is the WACP-1 which comes at higher costs and weight. If you already operate an 8-15 Fisheye then the barrier to buy this is quite high as two good teleconverters will get you almost there as well. However I must gnarl that the Canon 2.0x TC is also a heavy beast compared to the Kenko 2.0x 😅 I think the best example for simple design and truly lightweight and absolute superior optic ist the old Nikonos 15mm (equivalent to 20mm prime). I wish we had more of that and an option to utilize it in the Canon RF mount system.