Barmaglot

Yes. The Smiling Seahorse liveaboard does at least one per trip, sometimes several when there is enough interest and conditions allow. They also run one blackwater-focused trip per season, where they do a blackwater dive each evening, sometimes two. As a matter of fact, I'm coming back from a Myanmar (Mergui Archipelago) trip right now; we did two blackwater dives - one near Black Rock, another... somewhere, but sure exactly where. On the Thailand side, they usually do it in the Koh Bon/Koh Tachai area, there's about 70-80 meters of depth there.

There are multiple EF to X mount adapters (the Fringer one seems to get the best reviews), so Tokina 10-17mm should be possible. 15-45mm zoom works with WWL-C, and 18-55mm f/2.8-4 works with WACP, albeit in a limited zoom range.

Why? You shoot a fisheye lens for the fisheye perspective; why get rid of it?

Oh, didn't notice that... Yeah, that's a deal-breaker.

There's a Tamron 28-75mm f/2.8 that Nauticam has on the WACP-1 chart, but not on FCP chart. I wonder if that's because it doesn't work with FCP for some reason, or simply because they haven't tested it yet.

Have you seen the new 24-50 that Sony announced? Supposed to start shipping in May.

I've found that Retra's reflectors help a lot in marginal visibility conditions. For example, this was shot in marginal (not terrible, but not great, probably <10m if memory serves me right) conditions from about 2-3 meters away using the 90mm (f/5.6, 1/160s, ISO 100): The reflectors form two very sharply defined beams which you can converge on the subject and avoid the backscatter between lens and target, and shallow depth of field prevents the particles from showing up.

I mean, it's not featured on Nauticam's charts, so there's gotta be some reason they left it out. It's possible that they consider the 230mm or 250mm domes too large for the typical APS-C users, or there could be some physical barrier. Looking at other manufacturers, Isotta doesn't have any domes larger than 8" (which they do recommend for 10-18mm), Aquatica charts are almost nonexistent and Ikelite also tops out at 8". Sea & Sea don't have any Sony crop housings, but for some reason they do have SEL1018 on their system chart, with a range of port options including their 230mm dome (with 20mm extension). Easydive seem to list every dome they have as compatible with both 10-18mm and 10-20mm, from 95mm microdome to 230mm glass and 240mm acrylic, but only 125mm and 160mm domes are marked as 'recommended'.

Aside from being cumbersome and expensive, is there any reason why a 230mm dome couldn't be used with either 10-18mm or 10-20mm?

I've never been to to California, much less dived there, but I've used the 90mm on a6300 in conditions where I could barely see my outstretched hands. You can see that there's so much stuff in the water that it is getting in the way even at macro distances - this sea moth was maybe an inch long. Still, this was an extreme case, and at when shooting macro, visibility doesn't matter so much.

Pete Atkinson did a mini-test of that a few years back, on a Nikon Z50, comparing a Sigma 8-16, WWL-C on 16-50Z and a Tokina 10-17mm. https://wetpixel.com/forums/index.php?/topic/67658-angle-of-view-comparison-wwl-c-and-16-50z-with-sigma-8-16-nauticam-85-dome

14-42mm + wet lens is also an option; a WWL-1 will focus right down to the glass. I don't think 170mm dome will work well for CFWA, as the dome's size will work against getting the lens close up to a subject.

Yes, all wet lenses currently available on the market give you significant barrel distortion ("fisheye effect"). WWL-C, AFAIK, is identical to WWL-1 in this regard. On wildlife images it is fine and often even desirable; on wrecks, it's a matter of personal taste - some people don't mind it, others prefer keeping straight lines straight. To me, the corners of your 10-20mm image look just fine - I mean, it's just sand and rubble there, who cares? - but if you want to improve them, a bigger dome would help. Another option is to use manual focusing to shift the focus point closer to the camera - as I understand it, autofocus is biased towards putting more DoF behind your focus point (I've seen figures of 2/3 behind 1/3 in front), which further degrades your corners. Using manual focus can alter this behavior, although looking at Nauticam's port chart, there is no native option for it - I suppose that if you use an N85 to N120 port adapter with knob (as they specify for the 180mm glass dome), you could print your own gear to connect the focus ring to the adapter knob, while zoom ring is connected to the housing's knob.

Not quite a wreck, but here is a comparison shot of WWL-1, WACP-C, WACP-1 and a 16-35mm behind a 230mm dome: https://web.facebook.com/NauticamThailand/posts/pfbid02Rx7a3XcKJzRSHnjVT9bx5G7XPVNBmVY1GpuxP24QNRqHCAAKpC6c4hbvWWYwvzn7l?_rdc=1&_rdr If you're concerned about corner sharpness with 10-18mm/10-20mm, you could use a larger dome such as 180mm.

There was a thread discussing this back on Wetpixel, and the general consensus is that it works, but there are some caveats. Monitors in general are significantly more bulky than viewfinders, and add a lot of drag, which gets significant if you have to swim against a current. They also add a bit of lag into the display pipeline, which may or may not be tolerable for you. Weefine monitors in particular have some rather unfavorable opinions on them from users, see these threads: As a budget alternative, Divevolk offers a WiFi extender kit for their SeaTouch phone housings. This would allow you to connect to your camera using the Sony Creators' App and even operate it from the phone screen. Downsides are increased lag and reduced frame rate, plus the extender must be mounted over the housing's display window and thus block part of it. Using WiFi also cuts into the camera's battery life.

Have you considered Fujifilm? They're kind of unique in that their top-end is medium-format rather than full-frame, so they're not afraid of their APS-C lineup cannibalizing full-frame sales, and put their best tech into APS-C (X-H2, X-H2S, X-T5).

I'm also shooting an a6300 (in a SeaFrogs housing, so not far removed from your Fantasea), and I've just moved to an a6700 for better AF. Between these three, unless you're really hurting for resolution, a6700 is an easy choice, as it has Sony's latest AF (shared with A7RV/A7CII/A7CR). A7IV and A7RIV have the previous generation AF - since you're mostly shooting macro, AF is important. A7RIV has a significant resolution advantage, so there's that, but A7IV doesn't have that many more pixels over a6700 (33MP vs 26MP), although it will give you some extra detail in your shots by the virtue of being FF. An FF camera would also give you a wider field of view over an APS-C one, but lose DoF at the same framing, so that's something to keep in mind. Speaking of DoF, among these three cameras only a6700 has focus bracketing, so given a static subject and a tripod, you could do focus stacking. Now an A7RV or an A7CR have the a6700 beat in just about every respect, but given what they cost - 6400₪ for an a6700 vs over 15,000₪ for an A7RV - I would expect them to. Note that a6700 has only three housing options at present - Nauticam, Ikelite and SeaFrogs. Nauticam costs $2513, Ikelite is $1195 but doesn't have a fiber optic bulkhead - electric sync only! - and doesn't let you access the front dial, while SeaFrogs costs about $450 and lets you access all the dials, but not the photo/movie/S&Q switch and doesn't have an 'AF-ON' thumb lever, only a regular button. Someone here on the forum mentioned that Isotta support replied to them that they don't plan to release an a6700 housing - I guess their a6600 housing didn't sell all that well. I wouldn't expect one from Marelux either; the only non-FF housing in their portfolio is an OM-1 one, and that one doesn't seem to be actually available. I'm going on a liveaboard in a week, and hopefully the a6700 housing will arrive before then - if it does, I will share my experience with it when I come back. Note that if your primary interest is macro, you might want to consider an OM-1 setup. Used OM-1 bodies seem to be available on ebay remarkably cheap - $1200-1300, down from their $2500 list price. The AOI housing is $999 including a vacuum system and flash trigger. What really sets it apart though, is the wealth of lens options - you have 30mm, 45mm, 60mm and 90mm, the latter of which can do 2:1 supermacro without add-on lenses, and given the smaller sensor size, a full-frame camera would have to do 4:1 magnification to match the same framing. The AOI port for the 90mm even lets you access the focus limiter switch. The 90mm lens is expensive, to be sure, but you can offset some of its cost by selling the Sony 90mm, which should not be difficult.

To be fair, the opening has double o-rings (one on the plug, the other on the housing), so it should be fairly reliable (unless you get a hair or something similar bridging both o-rings, in which case, OUCH), but I concur with you that it's a stupid system, and I wholeheartedly recommend the Leak Sentinel to every SeaFrogs housing owner. It's a shame that this option is not advertised anywhere except by word of mouth.

I see, thank you. If a previous version had the keying slots not removable, then I can see how that would be a problem. Thread depth should not be an issue; even if it gets in the way, it's easy enough to grind off some plastic on the front of the port. I use a UWL-09F (not pro) with SeaFrogs and Sony 16-50mm, and I've been considering getting the bayonet system for a while now, but the exorbitant cost (over $300 for mount base + lug ring + caddy, and then I would need an M67 adapter and another $122 caddy for a close-up lens) has been putting me off.

Yeowwwch!!! Good to know I wasn't simply paranoid about this, always padding the top of my housing around the Leak Sentinel with soft things when packing my bag for travel...

Huh, that Leak Sentinel V5 XB looks very different from mine. For one thing, it has a quick disconnect plug on the wires, which I thought was a feature of V6 - is it stock, or did you modify it? This is what my sample looks like: If you don't mind me asking, when is yours from? I got mine in January 2021.

Could you please elaborate on this? Looking at the QRS-01-MB1 installation manual, I don't see anything that would interfere with mounting it on a SeaFrogs port. What am I missing?

Funnily enough, size what what I don't like about the Leak Sentinel. The tall thin post sticking out the top of the housing always has me worried about some stray knock wrenching it out of the socket, or snapping it in half. Perhaps an irrational fear, but it's there nonetheless. At least the V6 can be easily removed when packing the housing; V5 - not so much.

Yeah, that's probably the best way to do it. I do have a set of calipers, so I can measure both width and depth of the existing o-ring groove and replicate it. Fingers crossed that the housing gets here before I leave for a Myanmar liveaboard trip on March 4th - I ordered it on February 7th, but due to Chinese New Year it didn't ship until the 20th, and right now tracking shows it as 'Leaving from departure country/region' yesterday.

Overhead. If they want me to check it - explain that it's full of very expensive camera gear; if they insist - well, into the hold it goes, it's not like there is any other choice.