I have been told that Nauticam has no plans to support either of these lenses, although they did suggest some port options for the Sony 16-25 including the 180 dome with 60mm extension.

 

But we need a zoom gear for the Sony 16-25. It looks like the Nauticam zoom gear for the Sony 24-50 f2.8 G lens should fit, as these two lenses have very similar configuration and dimensions and apparently were developed as a complementary pair.

 

Is anyone out there using the 16-25 with a Nauticam housing, and if so, what are you using as a zoom gear?

 

I reviewed the Laowa 10mm F/2.8 AF lens in uwpmag.com issue #141 using the Sony A7R V in a Marelux MX-A7RV housing using the 230mm port and 20mm extension. The conversion for Nauticam should be the N120 230mm dome and N100 to N120 35.5 port adapter. I have not tested this combo but should be close.

 

The upside to Sony FE 16-25 F/2.8 G is the 18cm minimum focus distance, which is better than most of the other 16-35 offerings. The 180/60mm extension sounds about right for Nauticam. Seems odd they would support 24-50 and not 15-25 although 24-50 can be used with WACP-C. It appears the 24-50 gear should work.

 

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I asked Nauticam if their zoom gear for the 24-50 would fit the 16-25, but they didn't reply.

 

After studying the dimensions and design of both lenses, I am 90% sure it will, and may spring for the 16-25 during the black friday shenanigans.

The big advantage of the 16-25mm over most of the Sony 16-35 lenses is the 18cm minimum focus distance v. most of the 16-35 lenses that are in the 25cm or greater range, Much better for use in a 180mm dome port. 

3 hours ago, Phil Rudin said:

The big advantage of the 16-25mm over most of the Sony 16-35 lenses is the 18cm minimum focus distance v. most of the 16-35 lenses that are in the 25cm or greater range, Much better for use in a 180mm dome port. 

Phil, have you tried the 16-25 in the 140 dome? Thoughts?

 

Always interested in the most travel-friendly options.

 

I'm finding the Laowa 10 very ordinary in the corners with the 140 (but good with the 8.5").

 

By the time you crop out the crappy bits in a 10/140 image, even at f16, you are back to 16mm equiv FOV or so.

Regarding the 16-25mm F/2.8 I have a custom gear and I have started with 55mm of Marelux extensions with Marelux 180mm dome. No results yet worth posting, only pool tests.

 

Regarding the Laowa 10mm the 140mm dome is not ideal but works in a pinch where corners would have been soft anyway.

On 11/24/2024 at 7:42 AM, dentrock said:

I asked Nauticam if their zoom gear for the 24-50 would fit the 16-25, but they didn't reply.

 

After studying the dimensions and design of both lenses, I am 90% sure it will, and may spring for the 16-25 during the black friday shenanigans.

 I have the lens and I received the zoom gear for the 24-50 today. Item 37178. It fits the 16-25 nicely, subject to the usual Nauticam gear fitting issue of shuffling the little bits of rubber until you get a firm grip on the lens without trashing it.

 

Incidentally I checked the Marelux port chart for 5" Sony and neither the Sony 16-25 nor the Laowa 10 are listed.

 

That leaves only Ikelite and Aquatica supporting the Laowa 10, and possibly only Ikelite (which has, or used to have the most flexible lens gear system), potentially supporting the Sony 16-25.

 

Others using other systems can advise if they like.

 

I will dive test the 16-25 when weather permits, trying it first with the 140 (for travel), then the 180 domes.

 

I estimated the EP for the 16-25 at 80mm from the lens mounting flange (at 16); 3mm longer than the 20-70 at 20. I will therefore start with extensions working for the 20-70, noting that the minimum focus distance is shorter for the 16-25.

How was your experience with the 16-25? Which 180mm dome are you using? The N100 180mm dome (#37129) or the N120 180mm dome (#18809)?

I attached some photos using the Sony FE 16-25mm F/2.8 in the Marelux Sony A1 housing with Marelux 180mm dome port and 55mm's of extension. That is 5mm less than I use with the Sony 20-70mm. Regarding using the 140mm port I would not expect to get great results at any f/stop. All taken in several springs in north Florida USA.

For Nauticam with the 180mm you will likely use the 35.5 adapter and 35mm extension for a total of 70.5mm of extension or 30+40 with an N100 port.

Edited April 15Apr 15 by Phil Rudin

On 4/15/2025 at 9:53 AM, shokwaav said:

How was your experience with the 16-25? Which 180mm dome are you using? The N100 180mm dome (#37129) or the N120 180mm dome (#18809)?

I haven't posted any results because I haven't finished testing the 16-25, and have also been busy optimising other lenses behind domes. Plus dive opportunities are rare where I am (endless winds).

However, I found the 16-25 to perform quite well (better than expected) with the N120 140 dome and a total extension of 60mm (25 adapter + 35 ext).

I use a simple system to rate sharpness across the frame. First I flip the question of "corner sharpness" to one of "how large is the central area of acceptable sharpness", using the centre of the frame as a reference point, as (assuming it's in focus) it's always sharp regardless of port type or alignment.

I then look for where sharpness falls off, at 100%, using images that should have elements that are sharp (i.e. in focus) at the edges.

Yes this is still subjective, but it's surprisingly easy to detect where sharpness declines, and you always have the centre as a reference in your own image.

No need to rely on someone else's opinion or equipment as the reference.

Finally I rate the results as 1 for a 12mm circle (of acceptable sharpness at 100%), 2 for 24mm and 3 for 36mm.

2 and 3 correspond to touching the long and short sides of the 36x24mm FF image respectively.

Now a "1" is pretty much a no go. You can get away with some CFWA, but you will have large horrible corners (which might be hidden in blue water).

"2" is my minimum requirement for stills. Others may have different opinions.

"3" is probably as good as it gets for a rectilinear WA lens behind a properly chosen and aligned dome.

So getting back to the 16-25 behind the 140 dome with total ext of 60mm, at 16mm I rated the corners at 2 for f8 and 2-3 for f11. The 25mm end was an easy 3. Useable (for me) as a compact travel solution.

I next tried the 16-25 with the N120 180mm dome with a total of 75mm extension. I expected great things but in fact the results were slightly worse. Same score at the 16mm end but slightly less than 3 at the 25mm end. Or to be brutal, not good enough at f8 if I have to carry the bulky 180 dome!

I am not sure whether I need to increase or decrease the extension for better results with the 180 dome, so will check when I can with a split to see how the underwater component aligns with the topside, before further testing.

Phil is suggesting a bit less.

Some other test results:

I can confirm that the 20-70 works ridiculously well with the 180 (total ext = 75; Nauticam port chart says 70), but performance is not really good enough with the 140.

I have not found an acceptable combo with the Laowa 10 (tried various exts with 140 and 8.5"). I think it needs a custom 8"(or larger) port, as per the Aquatica solution.

I even compared the Sony 50 and Zeiss 50 macros behind flat ports, vs the 140 dome. Scores were "1" behind the flat ports, and "3" behind the dome... a huge jump in IQ (and "apparent" DOF), but with some AF focusing issues with the dome (tracking AF can jump off the target with still subjects).

In terms of comparing Phil's results with Marelux ports, I don't have any figures for where the optical centres for Marelux ports lie.

With Nauticam, the optical centre is 6-7mm behind the port flange for the 140, and 25mm behind for the 180. Of course these are starting points only, for your own tests.

On 4/16/2025 at 12:14 PM, dentrock said:

I am not sure whether I need to increase or decrease the extension for better results with the 180 dome, so will check when I can with a split to see how the underwater component aligns with the topside, before further testing.

OK I have done some test splits with the 16-25 in a fish bucket, after rechecking the EP which I have revised from 80 to 78mm, at 16mm and 50cm focused distance. I tested the 16-25 at 16 and f/11.

Results:

35 adap + 35 ext (total 70): in water portion is slightly larger, which means a longer ext is needed.

25 adap + 50 ext (total 75 - as tested diving): in water portion still slightly larger but the difference is about half that in absolute terms cf the 70 ext variation.

35 adap + 50 ext (total 85): in water portion now slightly smaller (ext too long) BUT bad vignetting!

Conclusion: using this method, 80 total ext is probably about right, but will likely still vignette.

So back to 75mm, which I already dive tested, concluding that f/8 is not really good enough if you have an important part of the subject approaching the corners. Pretty spot on with my theoretical calculation. Not ideal if you are trying to balance the light eg. under a jetty. Plus I can get just as good results with the 140 dome, which is a lot easier to light close-up at the 25 end.

Next dive tests will be MFO with 90 macro, then Sigma 17 with 140 (I had a bad GAS attack when I saw the Australian distributor for Sigma had cut the retail price in half for the 24 and 17). Phil has previously given the 17 a good wrap. Both lenses focus super close, are tiny compared to FF zooms, and get great land reviews, so let's see...