Hi, does anyone use this with Nauticam housing?

The port chart says to use N100-120 converter, extension ring 30, and 140mm dome. I have this exact set up for my other wide angle lens but when I put in 28mm F2 + fisheye converter combo I get vignetting on the outside.

Taking out the extension ring 30, with just N100-120 converter and 140mm dome, I am able to get no vignetting.

I'm curious if anyone else use this and can tell me if the port chart is just wrong, or if I'm missing something.

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For background, I took my gear to Mikomoto and Ito for the shark dives and did not realise I packed my Sony 90mm macro instead of my Canon 8-15+metabones+2x tele wide angle setup. In my defense they both had a black 3D printed zoom/focus ring on and somehow the 90 macro fits perfectly into the wide angle port urghhh. This 28mm F2 + fisheye combo was the only one that used the same ports and luckily I was able to pick up a used set in Tokyo for cheap. Curious to see how the quality compares - I would want the flexibility of the zoom setup for reef dives like Raja but I do hope the native lens combo has better auto focus for the shark dives... Took me until I was underwater in Ito shark scramble to realise... and even then I thought I messed up my zoom ring before I took it out and realised it was a macro lens... anyone else made such a silly mistake haha??

This a combination I borrowed from Nauticam and tested several years ago. When I did my first NA-WWL-1 review(issue #114 at uwpmag.com) this is the lens I used with Sony full frame. At the time the Sony 28-60 did not exist and this was by far the best lens for overall IQ well exceeding the 14-42 lenses I tested on M4/3 cameras.

The big problem with this combo is first cost, new the 28mm F/2 lens is $498.00 and the 16mm fisheye converter is $348.00. Today you have options new that will give better results and about the same price or less total price.

Second is minimum focus distance, the lens focuses to 29cm and with the converter it goes to 22cm. By today's standards this is not ideal when most newer fisheyes and fisheye zooms focus in the 15/16cm range. This may not seem like a big difference but it can cause focus issues behind small ports and as you have experienced vignetting. The F/2 number also changes to F/3.5 much like using a tele converter.

Bottom line is if you already own the gear you can make it work but I would never recommend this combo or the or the 21mm W/A converter that only auto focuses to 24cm.

It seems there are two Nauticam N120 140mm ports #18811 and # 18816 and the 16 version has 20mm of extension built in. Do you know which port you have?