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 PM2 days 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.

Some further points of reference for Nikon Z and Nauticam N120 port system users who might consider using this lens for the benefits of high native magnification and teleconverter compatibility, based on desktop/in air testing:

On a Z8, autofocus works well with the Megadap ETZ21 Pro adapter. Not quite as fast as with a native Nikon Z 105MC lens but not too far off. This also applies with diopters (MFO-1, SMC-1, MFO-3) and at both close and far distances.

With the Sony 1.4x TC and Megadap, autofocus still works well but not quite as well as without the TC. Still very usable.

With the Nauticam N120 port system, a Macro Port 87 is ideal. A Macro Port 90 (e.g.60+30) also works with slightly more lens clearance. The 1.4x teleconverter at 17.06mm flange to flange distance fits quite nicely with a 20mm port extension.

Nikon users who already own an EMWL system are likely to have the #1 focussing unit. From what Alex has said above and what Isaac Szabo has reported elsewhere on Waterpixels, it seems likely or at least possible that there may be some vignetting with the #1 focussing unit as opposed to the Nauticam recommended #3 unit but if so perhaps that may be minor and liveable with? I plan to explore this underwater later this month.

Edited 20 hours ago20 hr by MarkRD
Mistype

I tried it yesterday in two dives, which are definitely not enough, but after this first test my impression is that the 100 mm is slightly better, although there aren’t any big differences compared to the 90 mm in normal use (tested with the A1 body).

Sharpness seems just as good as the 90 mm (same diffraction at the same apertures at first sight... f/13 looks perfect, then from f/16 to f/18 the detail starts to decrease)

Autofocus feels a bit faster, and I found it slightly easier to focus with diopters and on distant subjects.

Also, when using diopters, I didn’t notice any significant differences as magnification and working distance are almost the same.

The biggest advantage is the 1.4x magnification without any wet lens.

I’d like to give it another try as soon as possible, curious to hear Alex’s thoughts from Lembeh.

Quick update on the ports. Nauticam's new port for the lens made it to Lembeh today - and it obviously fits the 100mm perfectly.

I've only tried it briefly, but the 90mm port is problematic - as the front part of the 100mm lens does not fit neatly into the inside of the Nauticam port for the 90mm, so the lens ends up not being able to get right up to the front glass. Which won't be an issue for most things, but I suspect would impact using the EMWL. I will test more in the coming days.

I have a shorted Nauticam flat port here (32 - I think) - which accommodates the front of the 100mm lens better. And this plus a lot of a port extensions might be better for accommodating multiple macro lenses, while keeping travel bulk down. Ultimately, though, the new 100mm port is not heavy - so maybe the best thing might just be biting the bullet and getting the new port.

Although as Pietro notes above - maybe shooting through water limits how far this lens stands above the 90mm Sony - and especially the 90mm Tamron.

15 hours ago, Pietro said:

The biggest advantage is the 1.4x magnification without any wet lens.

So it seems that best option for super macro is to use TC1.4 plus 100mm lens only, no wet lens attached, but it will lose the flexiblity of changing focal length underwater.