It's Time to Talk About the Nikonos RS 13mm Again

[Davide DB]

We should hide this thread 😉

[Barmaglot]

With the Nikonos RS system having been discontinued almost three decades ago, after just four years of probably low rate production, I doubt there's a pile of pristine 13mm lenses out there waiting to be resold. 

 

I wonder if any of the Chinese lens companies like Venus Optics or 7Artisans would be up to manufacturing a knock-off copy; they seem to be quite wiling to develop and produce very niche products like the the Laowa probe lens. 

[Alex_Mustard]

I had the chance to shoot the Sony converted RS-13mm (by @Isaac Szabo) on my recent trip to Raja Ampat and it definitely delivers the goods.

 

 

I’ll share some underwater photos when I get the chance to process some out.

 

Alex

[Isaac Szabo]

5 hours ago, Barmaglot said:

With the Nikonos RS system having been discontinued almost three decades ago, after just four years of probably low rate production, I doubt there's a pile of pristine 13mm lenses out there waiting to be resold. 

 

I wonder if any of the Chinese lens companies like Venus Optics or 7Artisans would be up to manufacturing a knock-off copy; they seem to be quite wiling to develop and produce very niche products like the the Laowa probe lens. 

 

I believe a little over 2000 were produced, though that was 30 years ago, so who knows how many are still around.

 

All I really need for my conversion is the glass itself, and since the optical formula is known, I do wonder about the possibility of having an optics company reproduce the elements. I just worry the cost might be too high, but I don't know for sure.

[Architeuthis]

In case someone persuades a company to produce such an UW fisheye lens, please tell them we want a zoom lens...😃

 

 

Wolfgang

[Alex_Mustard]

I think that the hard part for these small lens producers is making the lens AF and adjust the aperture electronically. Most of these specialist lenses are mechanical.

 

Further up this thread you can see the mechanical 13mm fisheye made by Nauticam. But it is manual focus and mechanical aperture, for the same reason. 

 

Alex

[ChipBPhoto]

4 hours ago, Isaac Szabo said:

 

I believe a little over 2000 were produced, though that was 30 years ago, so who knows how many are still around.

 

All I really need for my conversion is the glass itself, and since the optical formula is known, I do wonder about the possibility of having an optics company reproduce the elements. I just worry the cost might be too high, but I don't know for sure.

That’s actually a very interesting idea.  Unfortunately I have no connections in the glass industry to explore the cost and min quantity needed for an affordable production run. 

[ianmarsh]

5 hours ago, Isaac Szabo said:

 

I believe a little over 2000 were produced, though that was 30 years ago, so who knows how many are still around.

 

All I really need for my conversion is the glass itself, and since the optical formula is known, I do wonder about the possibility of having an optics company reproduce the elements. I just worry the cost might be too high, but I don't know for sure.

I have had the same thoughts about a modern re-creation. If it only comes down to the glass, and the optical formula is known, that should be doable. I believe Seacam has contracted someone to make the front port glass for those lenses that are scratched.

 

I would also note that at this point, the external part of the RS lens is immaterial. The only part that matters is the glass. When I bought mine from Japan in 2015, it was described as having some "balsam separation" and  "haziness of the rear element", which did not affect the image. The "haziness" was a crack in the inner of the two elements, probably from being dropped. Fortunately for me I was able to source the very last rear element assembly from Rene Aumann, and install it myself.

 

Best 100 euros I ever spent....

 

Bottom line; if the glass isn't perfect, Do Not Buy.

Edited February 6 by ianmarsh

[ianmarsh]

5 hours ago, Alex_Mustard said:

I think that the hard part for these small lens producers is making the lens AF and adjust the aperture electronically. Most of these specialist lenses are mechanical.

 

Further up this thread you can see the mechanical 13mm fisheye made by Nauticam. But it is manual focus and mechanical aperture, for the same reason. 

 

Alex

Alex, I assume the Nauticam mechanical version uses "new" elements rather than recycled RS 13 elements? If so then someone is already making them, and could Isaac put them into Sony 50mm lens bodies?

[Alex_Mustard]

I am amazed as many as 2000 were produced. I'd guess they are about 100, maybe 200ish, in active UW service for stills and video (plenty on RED cameras). 

 

I'd imagine there are some IP laws that would stop people copying and selling Nikon's design. Not sure what the rules would be for doing it for yourself. I don't know but I suspect Isaac's solution requires more than just individual glass elements.

 

Seacam have a process for polishing out scratches from the front element. Not making new ones, AFAIK.

 

The Nauticam design is a ground up one. Isaac's conversion benefits from a serendipitous similarity between the Nikonos 13mm and the donor lens - which is unlikely to be the case with other lenses.

 

I have a friend who said he was able to commission the new front element from an optical glass company. I tried to find a scratched Nikonos 13mm about 5 years ago to test it. But could not find one for sale. Suspect most have been thrown away when in that condition.

 

Alex

[Isaac Szabo]

I can do my conversion with just the individual glass elements. 

 

It is Andrej Belic of NJU System who has had replacement front elements made. The first 13mm I bought to experiment on had a scratched front element. Several years ago I contacted Andrej about the cost of sending me a replacement and was quoted 1000 € plus shipping. 

 

I wouldn't necessarily say it was serendipitous that the 13mm elements fit inside the Sony 50mm. I put a lot of thought/research into which donor lens to use, comparing optical and mechanical designs, etc. I selected the 50mm because I determined that it was the best candidate.

[ianmarsh]

35 minutes ago, Isaac Szabo said:

I can do my conversion with just the individual glass elements. 

 

It is Andrej Belic of NJU System who has had replacement front elements made. The first 13mm I bought to experiment on had a scratched front element. Several years ago I contacted Andrej about the cost of sending me a replacement and was quoted 1000 € plus shipping. 

 

I wouldn't necessarily say it was serendipitous that the 13mm elements fit inside the Sony 50mm. I put a lot of thought/research into which donor lens to use, comparing optical and mechanical designs, etc. I selected the 50mm because I determined that it was the best candidate.

Yes, It was Andrej that offered that service, come to think of it.

 

It still blows my mind that you are able to do this with just the glass... how on earth you honed in on the Sony 50mm is beyond me. How fortunate that one of their cheapest lenses happened to be the one. We usually don't get those kind of breaks in this business.

 

Well done,  Isaac.

 

ian

[ianmarsh]

Another thought I have had is how different is the optical formula between the Nikonos 13 RS and the Nikon 16mm AF-D lens or even the 16mm manual focus ai-s lens ? The schematics look very similar and maybe(?) only the front element is different? Air vs water contact?

 

These lenses all use the same rear element filter holder, so dimensionally may be close.

 

All three lenses were manufactured at the same time, and I wonder if there were any common glass parts.

 

[Isaac Szabo]

27 minutes ago, ianmarsh said:

It still blows my mind that you are able to do this with just the glass... how on earth you honed in on the Sony 50mm is beyond me. How fortunate that one of their cheapest lenses happened to be the one. We usually don't get those kind of breaks in this business.

 

The low cost of the 50mm certainly played a role in me choosing it. The conversion would be less viable if an expensive lens had to be sacrificed.

[Isaac Szabo]

1 hour ago, ianmarsh said:

Another thought I have had is how different is the optical formula between the Nikonos 13 RS and the Nikon 16mm AF-D lens or even the 16mm manual focus ai-s lens ? The schematics look very similar and maybe(?) only the front element is different? Air vs water contact?

 

These lenses all use the same rear element filter holder, so dimensionally may be close.

 

All three lenses were manufactured at the same time, and I wonder if there were any common glass parts.

 

 

I have read somewhere that the 13mm optical design was based on the 16mm, and yes, the diagrams do look very similar. I have my doubts that they are the same excepting the front element, but perhaps I should purchase and disassemble a 16mm and try to find out. 

 

Edit: I went ahead an ordered a 16mm. Even if the optics don't turn out to be identical to the 13mm, they might be similar enough to work well behind the 13mm front element. And if that's the case, perhaps Andrej can still supply the front element, providing an alternate pathway for people to acquire this lens. 

Edited February 6 by Isaac Szabo

[ianmarsh]

57 minutes ago, Isaac Szabo said:

 

I have read somewhere that the 13mm optical design was based on the 16mm, and yes, the diagrams do look very similar. I have my doubts that they are the same excepting the front element, but perhaps I should purchase and disassemble a 16mm and try to find out. 

Perhaps you should....

 

When you think about it, the inner elements simply look out the front glass, which if water corrected, would "see" the same thing as it was seeing through the air corrected front element. Maybe that is simplistic thinking.

 

Both the AF-D and Manual focus 16mm's are selling for under $300 usd... boy, that would make a difference. Although if it worked, we would probably soon be paying $2000 for a used 16mm...

Edited February 6 by ianmarsh

[Isaac Szabo]

5 hours ago, Isaac Szabo said:

Even if the optics don't turn out to be identical to the 13mm, they might be similar enough to work well behind the 13mm front element. And if that's the case, perhaps Andrej can still supply the front element, providing an alternate pathway for people to acquire this lens. 

 

After thinking about this more, I don't expect the 16mm to work well as a substitute for the inner lens. The inner lens, when modified so it can focus on land, has poor edge sharpness. This tells me it too was likely specially designed for underwater, not just the front element. I'll still try it out though, just in case.

[Alex_Mustard]

Isaac, one question I have is what would you expect to happen if I used the inner lens of the Sony RS-13 behind a large dome port for shooting split levels? At present I have to travel with the Nikon 8-15mm for shooting splits. I’ll try it on my next trip, but that is in March.

[Isaac Szabo]

3 hours ago, Alex_Mustard said:

Isaac, one question I have is what would you expect to happen if I used the inner lens of the Sony RS-13 behind a large dome port for shooting split levels? At present I have to travel with the Nikon 8-15mm for shooting splits. I’ll try it on my next trip, but that is in March.

 

Unfortunately, I wouldn't expect that to work well. If you try shooting the inner lens topside, you will see that the image quality is good in the center but degrades towards the edges. I think the inner lens needs the 13mm front element and to be underwater in order for the edges to sharpen up. That said, I haven't tried it underwater with a regular dome, so it might be worth trying just in case.

 

I'll also note that you can shoot splits with the 13mm in calm water, though obviously a large dome is better for that.

[MarkRD]

New Monster Adapter LA-FE2. 

 

Like a few here, my love of a digitally converted Nikonos RS13mm Fisheye on DSLR as a compact high quality and versatile optic has been part of my reason to delay entering the mirrorless world underwater. But time and technology march on. Not wishing to change to a Sony system for reasons partly related to topside shooting I have been thinking about options for deploying the RS13mm on my new Nauticam Z8 system. To work on Z series cameras, firstly an autofocus system is needed that either adapts to the screw-drive focus or replaces it. Secondly, there needs to be camera control of aperture and thirdly there needs to be a mechanical adapter that can connect from the lens to Nauticam’s N120 port system.

 

Isaac Szabo’s conversion of RS13s to work on Sony systems using a donor lens autofocus system and front element separated and mounted on a N100 housing port is reported to work very well for autofocus and aperture control on Sony systems. It is likely that the Megadap ETZ21 PRO adapter would allow Nikon Z cameras similarly to autofocus and control aperture well as the donor lens is listed as compatible with the Megadap adapter. But, as far as I know, Isaac hasn’t yet produced a front element/port that would work on Nauticam’s N120 port system with Z series Nikon cameras.

 

The recently announced Monster Adapter LA-FE2 is the first to contain both aperture and screw-drive autofocus motors and adapts Nikon F mount lenses to Sony cameras. I was therefore interested to explore the performance of this new adapter both on a Sony camera as designed, and stacked with the Megadap adapter on Nikon Zs and I acquired one of the first ones off the production line. First experience of use dry on the bench is not encouraging.

 

I used a Sony A6500 body that is listed as compatible with the Monster adapter and tried five Nikon F-mount lenses familiar to many underwater photographers. 

·      Firstly, the AF-S Micro Nikkor 60mm f2.8 G ED (internal focus motor) that is listed by Monster as compatible. This did not autofocus at all on the A6500. There was no aperture control and the camera displayed f1.0.

·      Secondly the AF Nikkor 28-70mm f3.5-4.5D (screw-drive control) that is not on the current Monster compatibility list. This did not autofocus at all on the A6500. There was no aperture control and the camera displayed f1.0

·      Thirdly, a Nikon F-mount Tokina 10-17mm f3.5-4.5 DX Fisheye (screw-drive control). This lens is not on Monster’s compatibility list. This did attempt to autofocus using both AFS and AFC, but only occasionally achieved correct focus, generally with close objects. Often the error message “Focus Cancel” was displayed by the A6500. There was no aperture control and the camera reported f1.0.

·      Fourthly, a Nikkor AF-S Fisheye 8-15mm f3.5-4.5E ED (internal focus motor) that is listed by Monster as compatible. This autofocussed quite well most of the time and the aperture was controllable and reported correctly. However, there were occasions when it all seemed to go wrong and needed to be reset by switching off and back on, sometimes accompanied by remounting the lens.

·      Finally, the digitally converted Nikkor 13mm RS Fisheye (screw-drive control). This lens did attempt to autofocus in both AFS and AFC. As expected, this water-contact lens was not able to focus on infinity in air but did achieve correct focus on very close objects perhaps half the time. It often moved in small increments and took some time to get to a correct focus point. Aperture control was inconsistent, sometimes working and sometimes not.

 

I then stacked the Monster adapter with the Megadap adapter so producing a unit similar to a Nikon FTZ F-mount to Z-mount adapter but containing a screw-drive autofocus motor. The unit did physically fit within the NA-Z8 housing although the non-removable tripod foot meant that the unit had to be mounted on the camera body before the housing camera saddle was attached. Using my Andrej Bellic made adapter that has bayonets for both for the N120 housing and the RS13mm lens I could mount the lens on my housing and engage with the camera body at the correct distance. However, this arrangement forced the Z8 into manual mode focussing (although there is no manual focus capability on the RS13mm) and there was no aperture control.

 

When removing the RS13mm from the housing I had a period of panic as the housing F-mount release button would not operate and the whole assembly appeared to be seized up. After reflection, I realised that the F-mount release lever on the Monster adapter is in a slightly different position compared with the Nikon FTZ adapter. I was able to get a finger in from the back of the opened housing to depress the lever and release the lens. Panic over.

 

So, at this moment, the Monster adapter is not looking like a good candidate to get the RS13mm underwater on Nikon systems. It is possible that for Sony, better results would have been achieved with one of the more recent full-frame camera bodies but I don’t have access to one to test. I note that Seacam have reported success with their adapted RS13s, the Monster adapter and unspecified Sony cameras – recent full frame ones I suspect. For Nikon I am not surprised that stacked adapters from different manufacturers didn’t work together electronically. It is possible that in future adapter firmware updates will improve compatibility, but I was particularly disappointed that the Sony A6500/Nikon 60mm that are listed by Monster as compatible did not in fact work. I am also concerned that with the lens/adapter combinations that did work there was inconsistency over time as to how well they worked.

 

From my perspective as a Z8 user, hopefully Isaac will come up with an option for adapting the RS13mm for Nikon mirrorless users soon! A screw-drive FTZ adapter from Nikon would be even more welcome but we have waited so many years for such a think from Nikon or a third party that I’m not holding my breath.

 

 

 

 

[Isaac Szabo]

Really interesting info, @MarkRD. Thanks for sharing. I had assumed the Monster screw drive adapter was working reasonably well on Sony cameras since Seacam was advertising it, but your experience makes me wonder. It's too bad that stacking the adapters didn't work for the Nikon Z camera. I'll try to figure out away to test my Sony converted 13mm with a Nikon Z adapter in the near future. 

Edited March 1 by Isaac Szabo

[Isaac Szabo]

On 2/7/2024 at 6:32 AM, Isaac Szabo said:

 

Unfortunately, I wouldn't expect that to work well. If you try shooting the inner lens topside, you will see that the image quality is good in the center but degrades towards the edges. I think the inner lens needs the 13mm front element and to be underwater in order for the edges to sharpen up. That said, I haven't tried it underwater with a regular dome, so it might be worth trying just in case.

 

Following up on this, I tested the 13mm inner lens behind a 9" dome port and wasn't impressed. I suppose the images could be usable in a pinch, but sharpness wasn't as good as a regular fisheye behind the same dome. 

[MarkRD]

On 2/29/2024 at 6:37 PM, Isaac Szabo said:

Really interesting info, @MarkRD. Thanks for sharing. I had assumed the Monster screw drive adapter was working reasonably well on Sony cameras since Seacam was advertising it, but your experience makes me wonder. It's too bad that stacking the adapters didn't work for the Nikon Z camera. I'll try to figure out away to test my Sony converted 13mm with a Nikon Z adapter in the near future. 

The mediocre to poor performance of the Monster LA-FE2 on my Sony may relate at least in part to the age of my A6500 testbed. That camera was brought out 7 years ago and has a different autofocus system from the newest Sonys, but it is explicitly listed by Monster as being compatible with the new adapter. I hope to have the opportunity of testing the new adapter with Alex M on his A1 within the next couple of days. I am optimistic that it will perform better there, but how much better ....? I'll report back.

 

Hoping that stacked Monster/Megadap adapters would work on the Zs was always a long shot, but at least I have shut that down in my mind and for others. I have confirmed that it more or less works physically with N120 housings but that's no help if the combination doesn't do the job.

[MarkRD]

Following up on my earlier posts, I was able meet up with @Alex_Mustard yesterday and do some further testing. Sadly, the Monster LA-FE2 adapter performed no better with either the AF-S Micro Nikkor 60mm f2.8 G ED or the Nikkor AF-S Fisheye 8-15mm f3.5-4.5E ED on Alex's Sony A!. Both of these lenses are listed by Monster as compatible. It is of course possible that the adapter I have purchased is faulty but either way, I'm not encouraged to explore this further at present.

Of much greater interest to me was trying Alex''s @Isaac Szabo converted RS13mm Fisheye lens (converted to Sony mount) on my Nikon Z8 together with the slim Megadap ETZ21 Pro Sony to Nikon Z adapter. Within the limitations of the dive show environment where we met up, the RS13 autofocus and aperture control both performed very well. To the best of our knowledge this is the first time that an RS13 has been used with autofocus and aperture control on a Nikon Z system camera. The Megadap adapter sells for just over £200 in the Uk and about $250 in the US. Now we just need a N120 mount for the RS13mm front element from Isaac and Z system users will have a route to using their old RS13s on their new Nikon mirrorless systems. Watch this space!

 

Mark

[Isaac Szabo]

Thanks for testing that, @MarkRD! Hopefully I'll be able to offer an N120 port within a month or two.