At the bottom:

https://bluerobotics.com/wp-content/uploads/2026/05/WTE-DATASHEET-RevC.5-MAY2026.pdf

On 6/28/2026 at 8:24 AM, Atanas_Petrov said:

Thank you, Dave,

Yes, the glass I have is from the Zen WA-100-EP PEN DOME, and I measured it as 103.8mm.

I will try to find a Subal to n120 adapter, as it will be a quicker solution.

saga makes them in spain

Hi Dave,

It’s great to see someone else who is also interested in curved ports!

I own a Nikon Z8 and use the Nauticam NA-Z8 housing, so we have a very similar setup. Before introducing my configuration, I’d like to share some details about the curved port I use.

My curved port was modified from an INON Dome Unit IIIA. Here is the final setup with AFS 60mm(20mm N120 extension rings x2)

The curved port is made of aluminum and is compatible with Nauticam’s N120 port system. This allows me to use it with different extension-ring configurations, such as a 50 mm extension ring or two 20 mm extension rings.

Here are my test shots:

This is the very first image I took with the curved port. I chose this subject to test how wide a field of view this setup could achieve.

When shooting at a sufficiently close distance with curved port, the background can be rendered with a pleasing blur.

Furthermore, I also test it during blackwater dives, I am pretty satisfied the results, too. I was lucky enough to photograph a blanket octopus with this setup. I was surprised that I could fit the entire subject in the frame even from such a close distance.

You can see more images taken with this curved port(recent images with AFS 60mm) in my online portfolio. The images have been converted to AVIF format and use the Display P3 color profile, as I primarily work with Apple devices. AVIF images are displayed particularly well in Google Chrome on PC and Mac.

looking forward to having more discussion about curved port.

Edited July 14Jul 14 by jyuny1

1 hour ago, jyuny1 said:

Hi Dave,

It’s great to see someone else who is also interested in curved ports!

I own a Nikon Z8 and use the Nauticam NA-Z8 housing, so we have a very similar setup. Before introducing my configuration, I’d like to share some details about the curved port I use.

My curved port was modified from an INON Dome Unit IIIA. Here is the final setup with AFS 60mm(20mm N120 extension rings x2)

The curved port is made of aluminum and is compatible with Nauticam’s N120 port system. This allows me to use it with different extension-ring configurations, such as a 50 mm extension ring or two 20 mm extension rings.

Here are my test shots:

This is the very first image I took with the curved port. I chose this subject to test how wide a field of view this setup could achieve.

When shooting at a sufficiently close distance with curved port, the background can be rendered with a pleasing blur.

Furthermore, I also test it during blackwater dives, I am pretty satisfied the results, too. I was lucky enough to photograph a blanket octopus with this setup. I was surprised that I could fit the entire subject in the frame even from such a close distance.

You can see more images taken with this curved port(recent images with AFS 60mm) in my online portfolio. The images have been converted to AVIF format and use the Display P3 color profile, as I primarily work with Apple devices. AVIF images are displayed particularly well in Google Chrome on PC and Mac.

looking forward to having more discussion about curved port.

Very nice. I looked up that Inon part. Interesting modular dome available in glass or acrylic. It seems designed to mount on to various Inon base ports. How did you get it on an n120 ring? Did you make that part, or find something comercialy available? That acrylic version that you have is quite inexpensive at $135 usd and the glass is not a whole lot more. This could be a pretty good and easily available source of part for anyone that want to try a similar curved macro port.

I've been using my 3d printed port and extensions for a couple of weeks now and have about 4-5 dives with is completed. It's been really fantastic. Here is an updated photo to the final product, configured with a 40mm printed extension ring and port cap.

13 hours ago, Dave_Hicks said:

Very nice. I looked up that Inon part. Interesting modular dome available in glass or acrylic. It seems designed to mount on to various Inon base ports. How did you get it on an n120 ring? Did you make that part, or find something comercialy available? That acrylic version that you have is quite inexpensive at $135 usd and the glass is not a whole lot more. This could be a pretty good and easily available source of part for anyone that want to try a similar curved macro port.

I've been using my 3d printed port and extensions for a couple of weeks now and have about 4-5 dives with is completed. It's been really fantastic. Here is an updated photo to the final product, configured with a 40mm printed extension ring and port cap.

Finally waterpiexl is back! I lost my reply entirely Lol.

However, my partner and I have designed an adaptor to connect N120 extension ring and components from INON Dome Unit IIIA.

I originally wanted a hard cap too, but I eventually chose a soft cap made of synthetic rubber. Since I usually dive with my tech shorts, the soft cap is much easier to carry in my pocket.

Edited July 15Jul 15 by jyuny1

43 minutes ago, jyuny1 said:

Finally waterpiexl is back! I lost my reply entirely Lol.

However, my partner and I have designed an adaptor to connect N120 extension ring and components from INON Dome Unit IIIA.

I originally wanted a hard cap too, but I eventually chose a soft cap made of synthetic rubber. Since I usually dive with my tech shorts, the soft cap is much easier to carry in my pocket.

Super. My cap is also rubber for the same reasons. The open mesh design makes it a lot easier to remove and install underwater and makes rinsing simpler.

10 minutes ago, Dave_Hicks said:

非常棒。我查了一下那個 Inon 零件。有趣的模組化圓頂，有玻璃或壓克力可選。看起來是設計來安裝在各種 Inon 底座接口上。你是怎麼把它裝到 n120 環上的？是你自己製作了那個零件，還是找到了市面上現成的產品？你那款壓克力版本只要 135 美元，相當便宜，玻璃版本也沒貴多少。對任何想嘗試類似彎曲微距接口的人來說，這可能是個不錯又容易取得的零件來源。

我已經使用我的 3D 列印鏡頭罩和延伸環幾個星期了，大概完成了 4-5 次潛水。效果真的非常棒。這是最終產品的更新照片，配置了 40mm 的 3D 列印延伸環和鏡頭蓋。

Hi Dave,

I have designed an adopter, like you did, to connect glass and N120 extension ring.

I originally want to have a hard cap but now I have a soft cap made of synthetic rubber considering I dive with tec shorts as soft cap is easier to put into my pocket

43 minutes ago, Dave_Hicks said:

Super. My cap is also rubber for the same reasons. The open mesh design makes it a lot easier to remove and install underwater and makes rinsing simpler.

I am also interested in learning how to further improve the optical performance of the curved port, as I understand that the final image quality can vary depending on the combination of components used.

In particular, I believe the length of the extension ring plays an important role in determining the port’s performance. I noticed that you are using a 20 mm and a 40 mm extension ring, giving you a total extension of 60 mm, whereas I am currently using two 20 mm extension rings, for a total of 40 mm.

I have not yet done the optical calculations or conducted a systematic comparison to determine the optimal extension length. I would therefore be very interested to hear your thoughts on extension-ring length, port positioning, corner sharpness, field of view, or any other factors that may affect the overall performance of this setup. Any suggestions or practical experience would be greatly appreciated.

29 minutes ago, jyuny1 said:

Hi Dave,

I have designed an adopter, like you did, to connect glass and N120 extension ring.

I originally want to have a hard cap but now I have a soft cap made of synthetic rubber considering I dive with tec shorts as soft cap is easier to put into my pocket

I am also interested in learning how to further improve the optical performance of the curved port, as I understand that the final image quality can vary depending on the combination of components used.

In particular, I believe the length of the extension ring plays an important role in determining the port’s performance. I noticed that you are using a 20 mm and a 40 mm extension ring, giving you a total extension of 60 mm, whereas I am currently using two 20 mm extension rings, for a total of 40 mm.

I have not yet done the optical calculations or conducted a systematic comparison to determine the optimal extension length. I would therefore be very interested to hear your thoughts on extension-ring length, port positioning, corner sharpness, field of view, or any other factors that may affect the overall performance of this setup. Any suggestions or practical experience would be greatly appreciated.

What is the spherical diameter of your dome? You need that to figure out the optimal position of the dome.

For my 100mm dome I calculated the base mount of the dome should be 59mm from the housing mount. So my dome port mount is actually a 19mm extension. This positions the inside surface of the dome at an optimal distance from the focal plane inside the 60mm lens. I'm not absolutely certain that is exactly correct, but it seems to be working out quite well. If I discover that it could be better positioned I can always adjust the base extension length. I can print a new extension ring overnight if needed, so it's not difficult to make adjustments.

Edited July 15Jul 15 by Dave_Hicks

1 hour ago, Dave_Hicks said:

What is the spherical diameter of your dome? You need that to figure out the optimal position of the dome.

For my 100mm dome I calculated the base mount of the dome should be 59mm from the housing mount. So my dome port mount is actually a 19mm extension. This positions the inside surface of the dome at an optimal distance from the focal plane inside the 60mm lens. I'm not absolutely certain that is exactly correct, but it seems to be working out quite well. If I discover that it could be better positioned I can always adjust the base extension length. I can print a new extension ring overnight if needed, so it's not difficult to make adjustments.

Hi Dave,

I will check spherical diameter for my dome and report to you later this week

Edited July 15Jul 15 by jyuny1

For what it's worth, here's an image illustrating some of the key distances from when I made a dome port for the Nikon 60mm for Matthew Sullivan. To optimize image quality, you want the center of curvature of the dome to be aligned with the entrance pupil of the lens. I measured the Nikon 60mm entrance pupil to be around 34-42mm behind the front of the lens (it varies with focus distance, so I went with a central value of 38mm). As an aside, the photons to photos optical bench theoretically puts the entrance pupil a few millimeters farther back (I'm not sure which is more accurate). Anyway, Matt has said that this setup is exceptionally sharp edge to edge, so the design seems to have worked out correctly.

18 minutes ago, Isaac Szabo said:

For what it's worth, here's an image illustrating some of the key distances from when I made a dome port for the Nikon 60mm for Matthew Sullivan. To optimize image quality, you want the center of curvature of the dome to be aligned with the entrance pupil of the lens. I measured the Nikon 60mm entrance pupil to be around 34-42mm behind the front of the lens (it varies with focus distance, so I went with a central value of 38mm). As an aside, the photons to photos optical bench theoretically puts the entrance pupil a few millimeters farther back (I'm not sure which is more accurate). Anyway, Matt has said that this setup is exceptionally sharp edge to edge, so the design seems to have worked out correctly.

Thanks for sharing!

I will try adding another 20mm ring and do some pool tests with both 79mm and 59mm. (19 + 20 + 40)

24 minutes ago, Dave_Hicks said:

Thanks for sharing!

I will try adding another 20mm ring and do some pool tests with both 79mm and 59mm. (19 + 20 + 40)

No problem. I suppose I should have mentioned that I calculated the center of curvature of the Zen dome to be around 64mm from the base of the dome, just in case anyone wants to use the Zen dome for other port designs.

Hi, just for curiosity: what about the Minimum Focussing distance (MFD) of the lens? With the very small domes positioned on the entrance pupil, the positioning problem is solved; but not the focussing distance of the virtual image, I think.

So it’s very likely these macros cannot utilize their full focus range, or do they?

Did you guys add any diopters to the lens to solve that?

@Adventurer In the case of my Nikon 60mm and Zen dome example above, there is no loss of focus range since the MFD of the lens is only a couple of millimeters beyond the dome. However, in other scenarios in which proper dome positioning involves placing the dome significantly closer than the lens's MFD, a small amount of close focus range can be lost. But you don't use a macro dome if you want to maximize magnification. It's for improving edge sharpness and/or restoring the air FOV so you can better shoot slightly larger macro subjects. I haven't tried using a diopter on the macro lens in these scenarios, but it seems like it could maybe work as long as you don't lose too much of your far focus ability.

Hi @Dave_Hicks and @Isaac Szabo ,

I took the relevant measurements and used GPT-5.6 to calculate the estimated extension length. The dimensions and calculation results are shown in the figure below.

I estimated the required extension length by aligning the center of curvature of the curved port with the entrance pupil of the Nikon 60 mm lens.

The distance from the Z8 sensor plane to the front of the lens is approximately 135 mm. The entrance pupil of the Nikon 60 mm has been measured at approximately 34–42 mm behind the front of the lens, so I used the central value of 38 mm:

Sensor plane to entrance pupil:

135 − 38 = 97.0 mm

The distance from the sensor plane to the Nauticam N120 housing interface is approximately 45.2 mm:

Housing interface to entrance pupil:

97.0 − 45.2 = 51.8 mm

For the curved port, the measured outer chord diameter is 109.8 mm, and the sagitta is 28.0 mm. Assuming a spherical surface, these dimensions give an outer radius of curvature of approximately 67.82 mm. The center of curvature is therefore:

67.82 − 28.0 = 39.82 mm behind the chord plane

The complete curved-port assembly is 55 mm deep, while the exposed curved acrylic section is 28 mm high. Therefore, the chord plane is:

55 − 28 = 27 mm in front of the curved-port mounting plane

This places the center of curvature:

39.82 − 27 = 12.82 mm behind the curved-port mounting plane

To align this center of curvature with the entrance pupil, the required extension length is therefore:

51.8 + 12.82 = 64.62 mm

Based on these measurements, the estimated ideal extension length is approximately 65 mm.

Since the entrance pupil may vary from 34 to 42 mm behind the lens front depending on focus distance, the corresponding extension range is approximately 60.6–68.6 mm.

Here is the online calculator, please correct me if it is wrong!

Edited Sunday at 10:35 PM3 days by jyuny1

@jyuny1 Almost everything looks correct to me except for "The distance from the sensor plane to the Nauticam N120 housing interface is approximately 45.2 mm". Did you measure that yourself, or did you look it up somewhere? I believe 45mm is the distance for Sony N100 housings and that the correct value for Nikon N120 housings is 82mm. If I'm correct, I think that would result in an ideal extension length of around 28mm, so a standard 30mm extension should work well.

1 hour ago, Isaac Szabo said:

@jyuny1 Almost everything looks correct to me except for "The distance from the sensor plane to the Nauticam N120 housing interface is approximately 45.2 mm". Did you measure that yourself, or did you look it up somewhere? I believe 45mm is the distance for Sony N100 housings and that the correct value for Nikon N120 housings is 82mm. If I'm correct, I think that would result in an ideal extension length of around 28mm, so a standard 30mm extension should work well.

oh my bad, it should be 82mm!

according to the calculator, the final result is 27.82mm

I will try 25mm and 30mm and have a feedback!

thanks @Isaac Szabo

Edited Monday at 06:49 AM3 days by jyuny1