Isaac Szabo

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.

That's great to hear, Pete! Looking forward to seeing your freshwater photos!

I've already told Andrew this, but others might be interested. A friend of mine used the Canon 100mm focusing unit with the Sony 90mm with the 130 and 100 objectives with no apparent issues. I suspect that all the focusing units might work with all the listed lenses with the only difference being that if you're using a focusing unit designed for a longer macro you'll get a slightly wider FOV and vice versa. There is also the possibility of vignetting when going wider, but we won't know for sure until it has been tested. I have been interested in trying the Nikon 105mm focusing unit with my Sony 90mm to see if it increases the FOV but haven't had the opportunity so far. John's setup (90mm focusing unit with 105mm lens) should provide a slightly narrower FOV.

Hi Ian. I answered this via email, but since it was raised here I'll answer here too. Since I am only using the glass from the 13mm, any previous modifications shouldn't affect my ability to convert the lens to Sony.

Thanks Chris!

Thanks Davide! Happy to be here. Good job team on the new forum.

Thanks Tim!

I use the EMWL on a non-Nauticam housing. I incorporate the Nauticam bayonet into my custom macro port, but you can also switch the EMWL mount over to M67 and forgo the bayonet, allowing the use of any M67 port.

Making my way over from wetpixel. Into freshwater photography and DIY projects.