17 hours ago, Walt Stearns said:

Jordi, to answer your question, the Megadap ETZ21 Pro adapter works well enough for the job with Sony E mount lenses. I I recently had some auto focus lag on my Z8 but after updating the Megadap firmware that problem went away.

Thanks for the info Walt

@Isaac Szabo
Late to this thread and your endeavors with the RS 13mm but just wanted to say I am super impressed you made it work and I love the ingenuity of housing it it in a cheapo fifty:)

I also really like how you managed to make a waterproof 3D-printed port work.
Now, not to upset anyone, but I do once in a while catch my own dinner underwater whilst freediving. And I have made some of my own parts to help with that. Some of which were 3D printed and had to hold about 30 bar of or air pressure (my fish catching device is pneumatic).
The way I ended up making it work was to impregnate the 3D printed part with epoxy resin.
First I tried vacuum impregnation but what ended up working even better was pushing the resin through the part under pressure.
Perhaps being very particular in your print settings and "only" having to deal with larger water molecules at less pressure meant you didn't have to go to this extra step. I do recall that printing at slightly higher temps and with zero retractions already helped a lot. This was before modern Prusa/Orca type slicers so a lot of the fine tuning settings weren't really available back then. Now that they are, I can imagine it may have taken even longer to dial in.

Either way, as I said, much impressed:)

I may try to rehouse the internals of a Nik V 15mm myself at some point. You mentioned you might give that lens a go, too if you found the time. Can I ask if you did?

Edited Sunday at 10:20 AM5 days by GeckoSub

Thanks @GeckoSub!

There are lots of slicer settings I change to get watertight/airtight prints, but the most fundamental one is increasing the flow rate/extrusion multiplier to the 1.15-1.2 range. If you cut a cross section of a normal FDM 3D print and view it under high magnification, there are air gaps between all the lines of extruded plastic, whereas I'm extruding enough extra material to make the prints completely solid.

I have done some work on a Nikonos 15mm conversion, and I'm hoping to find time to finish that project this winter.

31 minutes ago, Isaac Szabo said:

Thanks @GeckoSub!

There are lots of slicer settings I change to get watertight/airtight prints, but the most fundamental one is increasing the flow rate/extrusion multiplier to the 1.15-1.2 range. If you cut a cross section of a normal FDM 3D print and view it under high magnification, there are air gaps between all the lines of extruded plastic, whereas I'm extruding enough extra material to make the prints completely solid.

I have done some work on a Nikonos 15mm conversion, and I'm hoping to find time to finish that project this winter.

Thanks for sharing - it's likely those voids I managed to push epoxy into under fairly high pressure. I can only imagine how much time it took you to get to a working recipe. Took me long enough back when I tried - and I still had to go with the resin.

Good luck with the 15mm.
I just found a cheap Gen 2 in Asia in decent shape. If I buy it, it means I now have to make the housing for the camera. That's how the universe works...;).

Edited Sunday at 04:39 PM4 days by GeckoSub

On 9/27/2026 at 4:22 PM, GeckoSub said:

I just found a cheap Gen 2 in Asia in decent shape. If I buy it, it means I now have to make the housing for the camera. That's how the universe works...;).

Curious and a bit offtopic, but how do you tell the various generations apart from the lenses? I have one but no idea if its a gen 1 or , thanks!

1 hour ago, waterpixel said:

Curious and a bit offtopic, but how do you tell the various generations apart from the lenses? I have one but no idea if its a gen 1 or , thanks!

As far as I know and this is just info I have picked up elsewhere:
The real telltale is that Gen 1 has lens elements protruding rear of the mounting flange. It's quite substantial. Gen 2 does not.
The change was made when Nikon went from the Nikonos III to IV as the latter had TTL and the light reading sensor is pointed back towards the film plane and the Gen 1 lens would block the reading.

Here's a Gen 1 lens:

Versus a Gen 2 which ends at the bayonet:

Also, Gen 2 is supposedly quite a bit heavier. 600-something grams vs. 300-something for the Gen 1.

As for serial numbers, anything above 200000 is supposedly Gen 2.
In other words, if your serial starts with 1, it's a Gen 1.
To me it also seems that Nikon, at some point, may have started fresh at 300000 so perhaps a small Gen 3 upgrade exsist but I haven't found any writing on that, yet.

Now, whether the stickout is an issue on modern mirrorless bodies I have not seen a definitive answer on, yet. To me, there are two things at stake here:
First, does the lens block the light sensor like it would on a Nikonos IV/V. Not on a Sony A7 series or other modern mirrorless as they use the image sensor itself as the light meter, so there's nothing to block. So, we should be good on that account.

The second one is more nerdy. But having the rear element very close to the sensor means the light rays exit at much steeper angles to reach the outside edges/corners of the sensor compared to a lens that sits further from the sensor. Not an issue on film which absorb light even at these angles but digital sensors are really bad at it and you (can) get really bad vignetting and pretty nasty color shifts.
This was a huge problem on early digital Leica M bodies. But because Leica has a large back catalog of lenses that also sit "deep", they worked on different fixes - something to do with tilting the microlenses that sit on top of the pixels to better "catch" the light.

But it's my understanding that neither Canon nor Sony had to do this. Starting from scratch, they didnt't have lenses needing it and they supposedly optimize modern lenses to have the light rays exit as close to perpenducular as possible. Even for wide angle lenses.
All this to say that the real issue with a Gen 1 may be muddy, color shifting corners and multiple stops of vignetting. But it's speculation on my part.

OH SHOOT - I thought we were in the 15mm thread. Sorry! @waterpixel if you wanna post over there, I will move my reply, too or perhaps an admin can move these last two posts for us.

Edited Tuesday at 01:37 PM3 days by GeckoSub

Thank you for such a detailed response! Then it's a gen 2 that I have

I think a gen 1 wouldn't work on mirrorless. Based on what you say, the protruding element makes the lens longer, and my guess would be that it would not fit the adaptor (Nauticam). I would even question whether the adaptor works for a Gen 1 Lens.

(admins, feel free to move my lens to the correct thread)

9 hours ago, waterpixel said:

Thank you for such a detailed response! Then it's a gen 2 that I have

I think a gen 1 wouldn't work on mirrorless. Based on what you say, the protruding element makes the lens longer, and my guess would be that it would not fit the adaptor (Nauticam). I would even question whether the adaptor works for a Gen 1 Lens.

(admins, feel free to move my lens to the correct thread)

You're welcome:)
It was just stuff from my notes, picked up in my research and some probably from here or Wetpixels.

As for the adapter working on Gen 1 lenses, Fotosub mentions in the 15mm thread that Gen 1 works but you will have to reduce the diameter of the knobs to make them clear the adapter.

Edited Wednesday at 06:51 AM2 days by GeckoSub