For Nauticam users who already own the n100/n120 35.5mm converter:

Based on my calculations (assuming the 90mm lens reaches the end of the Nauticam macro port 105), the best option for the 100mm lens would be to use the n100/n120 35.5mm converter with the macro port 87 N120.

This way, the 100mm lens would be positioned as close as possible to the glass.

It would also allow us to reuse the n120 20mm extension ring (that many of us already own), in order to use the 1.4x teleconverter.

These are only calculations based on the dimensions of the macro ports, I haven't done any tests

Edited Saturday at 08:07 PM1 day by JB_Cazajous

On 10/30/2025 at 9:27 AM, flowdesign said:

@Pietro This result is on air or UW? Asking this because I was just informed by Marelux that they are going to develop a new port for 100mm Macro, since they alreday tested with 15mm and 20mm extension ring. 15mm is too tight, 20mm will have vignetting with wet lens, I asked them about testing details but no reply yet. It'd be good if you can share more hands-on experience😆

Tested today underwater with 97 port plus 20mm, as the shorter was too risky, I followed @Alex_Mustard advice.

Everything was ok. Also no vignetting with diopters (smc-1 and inon ucl67m67 with flip) I’m diving again tomorrow if the sea it’s not too rough…

Is there any news /experience what nauticam EMWL Focus Unit has to be used with the 100mm Macro?

1 hour ago, Michi said:

Is there any news /experience what nauticam EMWL Focus Unit has to be used with the 100mm Macro?

According to the latest port chart for the EMWL the 100 macro uses the same #3 focussing unit as the 90 macro:

On 11/2/2025 at 5:47 AM, Pietro said:

Tested today underwater with 97 port plus 20mm, as the shorter was too risky, I followed @Alex_Mustard advice.

Everything was ok. Also no vignetting with diopters (smc-1 and inon ucl67m67 with flip) I’m diving again tomorrow if the sea it’s not too rough…

I got the 20mm extension ring on weekend, same result as you when I tested on land. Also did a very rough testing for the "real" magnification with 90mm and new 100mm, plus smc-1, the result is simliar with Nauticam port chart. So I assume using TC might be the better way to show power of 1.4X

4 hours ago, Gudge said:

According to the latest port chart for the EMWL the 100 macro uses the same #3 focussing unit as the 90 macro:

Nauticam's own tests with their dedicated port say UNIT 3 is best. It will be tricky to get it to work with a converted port from the 90mm as the spacing has to be perfect to avoid vignetting. UNIT 2 works too, but with some very small vignetting at some focusing distances.

I'll test it with Unit 3 this week - assuming I get the port. But if I am using the adapted 90mm port I'll probably just stick to testing the 1.4 x TC (I don't own a 2x), MFOs and SMCs this time. Been busy testing other gear so far this trip so far.