Isaac Szabo

Really interesting info, @MarkRD. Thanks for sharing. I had assumed the Monster screw drive adapter was working reasonably well on Sony cameras since Seacam was advertising it, but your experience makes me wonder. It's too bad that stacking the adapters didn't work for the Nikon Z camera. I'll try to figure out away to test my Sony converted 13mm with a Nikon Z adapter in the near future.

Yes, the parts are waterproof on their own. If you were to use normal print settings the parts wouldn't be waterproof, and you would have to do something like cover them in epoxy to make them waterproof. I used to smooth out the o-ring surfaces with epoxy or by turning them on a lathe, but then I discovered that it wasn't necessary.

I'm not sure I'm completely following you here, but no I haven't noticed that any extra care is needed. The ridges from 0.10mm layers are not very significant.

Yes, there are many variables at play including material type, printer model, nozzle size, and many different print settings. One important aspect of 3D printed o-ring groove walls is a small layer height. I use 0.10mm. Obviously, the walls won't be completely smooth due to the tiny ridges of the layers, but the compressed o-ring will span enough layers to make it watertight. For example, a compressed o-ring with a 1.5mm flat surface will span 15 layers. Using large/soft o-rings helps with this.

My 13mm port has 6mm thick walls. I had planned to pressure test different wall thicknesses to failure and plot the results so I could have actual data on how thick the walls needed to be, but even the thinnest port I tried survived the max pressure of the chamber. So I didn't have a meaningful reason for going with 6mm other than that it seemed like it was much more than adequate. I recently got a stronger pressure chamber and tested the port down to 145psi/100m/330ft with no issues. I use PETG. I've tried a number of other materials (including some more expensive/exotic), but PETG has a number of advantages over the others I tried including good print quality, water resistance, layer adhesion, toughness, price, etc. I'm very busy at the moment fulfilling 13mm conversion orders, but I might be willing to print your design for you if you want since it might be difficult to find someone else who has the waterproof settings dialed in.

Standing on an aluminum can is not similar to a pressure differential. Instead you can put your mouth over the opening of an empty can and suck the air out. The can walls will collapse with little effort. Those are issues when trying to dial in the ideal print settings, but you only have to go through that process once. After you've figured them out you can apply them to all future projects. Of course those are viable options too. They're just more expensive/difficult. I'm guessing you might be able to buy a 3D printer for the cost of having a port machined (unless you can do the machining yourself).

I use 3D printed ports and have done some pressure testing. At one point I was trying to get one to fail so I could better understand their limits, so I made one with intentionally thin walls of only 2.5mm (I normally use more like 5-6mm). Surprisingly, it withstood the limit of my pressure chamber which equated to 225ft/69m. So 3D printed ports/extensions can certainly be a viable option. However, FDM 3D prints are not watertight using standard printing settings, and figuring out the right settings can be difficult. There are other challenges too including lots of CAD work, dimensional tolerances, and as you mention the horizontal overhangs. It can all be figured out, but it will probably require quite a bit of work/experience before one gets really good results.

For what it's worth, Alex's link/website seems to be working properly for me. I'm skeptical of the virus claim.

Unfortunately, I wouldn't expect that to work well. If you try shooting the inner lens topside, you will see that the image quality is good in the center but degrades towards the edges. I think the inner lens needs the 13mm front element and to be underwater in order for the edges to sharpen up. That said, I haven't tried it underwater with a regular dome, so it might be worth trying just in case. I'll also note that you can shoot splits with the 13mm in calm water, though obviously a large dome is better for that.

After thinking about this more, I don't expect the 16mm to work well as a substitute for the inner lens. The inner lens, when modified so it can focus on land, has poor edge sharpness. This tells me it too was likely specially designed for underwater, not just the front element. I'll still try it out though, just in case.

I have read somewhere that the 13mm optical design was based on the 16mm, and yes, the diagrams do look very similar. I have my doubts that they are the same excepting the front element, but perhaps I should purchase and disassemble a 16mm and try to find out. Edit: I went ahead an ordered a 16mm. Even if the optics don't turn out to be identical to the 13mm, they might be similar enough to work well behind the 13mm front element. And if that's the case, perhaps Andrej can still supply the front element, providing an alternate pathway for people to acquire this lens.

The low cost of the 50mm certainly played a role in me choosing it. The conversion would be less viable if an expensive lens had to be sacrificed.

I can do my conversion with just the individual glass elements. It is Andrej Belic of NJU System who has had replacement front elements made. The first 13mm I bought to experiment on had a scratched front element. Several years ago I contacted Andrej about the cost of sending me a replacement and was quoted 1000 € plus shipping. I wouldn't necessarily say it was serendipitous that the 13mm elements fit inside the Sony 50mm. I put a lot of thought/research into which donor lens to use, comparing optical and mechanical designs, etc. I selected the 50mm because I determined that it was the best candidate.

I believe a little over 2000 were produced, though that was 30 years ago, so who knows how many are still around. All I really need for my conversion is the glass itself, and since the optical formula is known, I do wonder about the possibility of having an optics company reproduce the elements. I just worry the cost might be too high, but I don't know for sure.

The $3K one has been lowered to $2.7K, but that's still high in my opinion. Currently it seems like most of the ones available at reasonable prices were bought up over the last couple months and now there's a shortage. Hopefully more show up on the market before too long and the prices don't get outrageous.

The FCP looks like a great option for those wanting the added versatility of a zoom and circular fisheye. But yes the 13mm offers advantages in image quality, size/weight, and price. A few measurements of my 13mm port (including hood): Diameter: 108.6mm/4.28in Length: 108.3mm/4.26in Weight: 519g/18.3oz Note that the weight might be slightly different since I weighed a prototype and the final version has a few minor changes.

@Barmaglot That's basically correct. Though I will note that $3500 USD has been on the high end so far. Obviously, it all depends on how much one spends on the 13mm. Several people have recently been able to purchase them for between $1500-1800, and the one I'm currently starting work on was somehow snagged for $1200. That said, I'm sure if demand increases your figure will soon be more typical.

The vignetting is absent at very close distances and increases as the distance increases. With my A7R II and metabones IV, I consider the vignetting mild enough that it can be ignored from about 12in/30cm and closer from the sensor plane (in air, underwater might be slightly different). Here are examples taken at 10in/25cm, 12in/30cm and 16in/40cm. So for small macro subjects at close distances the vignetting is not an issue, but for large macro subjects from farther away it could be for some people. In that case perhaps the Nikon 60mm could be a better solution.

There is no wet adapter for the 13mm. So yes currently I think the only way to use it with your a6600 would be to get it converted to the Sony 50mm body with separate port. However, so far I've only done that conversion for the N100 mount, so I would have to see if I could also do it for the N85 mount. Also, and this is probably obvious, but you wouldn't get the full 170 degree fisheye on APS-C. It would be more like 100 degrees.

No problem, Chip! The 90mm is reported to be very fast on the latest generation cameras like the A1, so I'm confused by you saying it's slow (though I haven't tried it myself on the A1). I would not expect the adapted 60mm to be as fast/accurate as the 90mm on the A1, nor would I expect it to match its performance on Canon DSLRs. But if you're looking for a short macro, it could be better than the native options. I'm using a custom DIY port, so unfortunately I can't help you there. I'm not very familiar with the Nauticam port/extension options.

I think Alex Mustard has been using it some so he may offer some insight. I haven't tried it but have heard it's very slow focusing. I'd say it's mostly just an option for static subjects.

I use the Canon 60mm with Metabones IV as one of my macro options for my A7R II. It covers the FF sensor at macro distances but vignettes at farther distances. I haven't done blackwater, but focus speed has been fine during daylight (I'm sure better than the Sony 50mm). Image quality is good in the center but degrades towards the edges (not uncommon with short macros behind flat ports). Overall image quality isn't as good as the Sony 90mmm and Sigma 105mm that I also use. The Nikon 60mm is another short macro option to consider, but I'm not sure which performs better with the adapters. Here is an uncropped example shot with the Canon 60mm (full resolution linked below): https://www.isaacszabo.com/images/A7R03209.jpg

I'm curious why you don't reduce your ISO and shutter speed for static scenes like that? In low light I'm commonly shooting longer than 1/10 (sometimes multiple seconds). As an example, dropping down to 1/10 would lower your ISO to 1250, which would surely get you into range for proper strobe exposure. And even if there's slight camera movement during the shot, your subject will remain sharp since it is predominantly strobe lit, and the background probably won't look much different since it's already out of focus. Of course, using ND filters on the strobes will work too, but you'll still be at ISO 5k, which obviously will yield lower image quality than ISO 1250.

No problem, @Davide DB. That makes sense. Yes, I think it would be worth testing with any focusing unit you can get your hands on. But I'll note that the Sony unit (#3) is the recommend one for the Leica 45mm, so it sounds like you might have the opportunity to test the recommended setup.

I'm not sure I understand your question either. But Nauticam lists two M43 macro lenses as being compatible with the EMWL: the Olympus 60mm with focusing unit #1 and the Panasonic 45mm with focusing unit #3. What I'm saying is that I suspect you might be able to use any of the 3 focusing units with those macro lenses and get acceptable results, with the only differences being slight variations in FOV.