Hi all

As always, every time I go on another dive trip, I find the urge to change something in my setup.

I currently shoot w Sony A7R5 in Nautical housing - for wide angle I use the kit 28-60mm lens w Nautical WACP-C. I am mostly very happy but find myself constantly struggling with the weight and going over the 10kg hand carry limit (w only WACP-C, camera, lenses, macro port, and SMC-1). On my current trip to Halmahera I also found it not wide enough to capture the big schools of barracuda and jacks in Tifore - cannot get close enough for strobes to light while still capturing the full ball in the frame.

I previously used the 28-60mm w WWL-1B, and before that with the MWL-1, and before that had a Nikon APS-C which I used w Tokina 10-17mm and 4.33m mini dome. I find myself missing the 150 degree effect fov of the MWL-1 and the Tokina, and really miss the light weight of the Tokina set up. I sold the MWL-1 because I wasn't happy w the image quality, everything had a distorted feel to it especially in the corners.

So upon doing some research, I have stumbled upon the Canon 8-15mm fisheye in either 140mm glass dome or the 4.33" mini dome as another option. I already have the metabones V adapter and the 30mm extension, so would need to buy the lens, N100-120 port adapter, new zoom ring, and one of the domes. On the other hand I can sell my 28-60, the zoom ring, and the WACP-C -> so net net I don't think it will be a big cash outlay.

I have a few questions:

1) will changing to this be a dent on image quality?

2) is the mini dome viable and a decent option? Primary consideration is the weight savings. However I do see the 140mm glass dome recommended more.

3) what is the equivalent field of view at the 15mm end? can I still get normal rectilinear wide angle shots? I know the 8mm end is a full circular fish eye.

4) anything else I should consider?

Many thanks!

1 hour ago, jjmochi said:

3) what is the equivalent field of view at the 15mm end? can I still get normal rectilinear wide angle shots? I know the 8mm end is a full circular fish eye.

The 15mm end is an approximately 180 degree diagonal fisheye, similar to the 10mm end of Tokina 10-17mm on APS-C. Positions between 8mm and 15mm give you various degrees of corner vignetting. If you want a usable zoom range, you need to add a teleconverter - a 1.4x moves the 180-degree fisheye to 11mm, whereas a 2x gives turns 8mm into a diagonal fisheye and zooms in from there. Older 2x TCs produced significant degradation in image quality, but new Kenko HD PRO models are said to be fine in that regard. Sony TCs (with Metabones V adapter to accommodate the protruding elements) are possible too, albeit more expensive. You can find some sample shots here:

And here:

Edited May 5May 5 by Barmaglot

3 hours ago, jjmochi said:

1) will changing to this be a dent on image quality?

2) is the mini dome viable and a decent option? Primary consideration is the weight savings. However I do see the 140mm glass dome recommended more.

3) what is the equivalent field of view at the 15mm end? can I still get normal rectilinear wide angle shots? I know the 8mm end is a full circular fish eye.

4) anything else I should consider?

Many thanks!

Barmaglot has already linked treads with plenty of information...

I have Sony A7R5 and use it with 28-60mm/WACP-C, Canon 8-15mm (with and w/o Kenko and Sony 1.4x and 2x TCs; now I use it predominantly with Sony 2x TC when longer focal lengths are needed) and can say something, but it is from from my subjective experience, I do not make optical benchmark tests UW:

"1) will changing to this be a dent on image quality?":

IQ of the pure Canon 8-15mm fisheye lens is at least as good as the 28-60/WACP-C combo, even a bit sharper. Together with the 2x Sony TC the Canon 8-15mm provides very similar IQ, compared to the 28-60/WACP-C combo (maybe WACP-C is a bit better at 28mm, but gets a bit less sharp at 60mm).

"2) is the mini dome viable and a decent option? Primary consideration is the weight savings. However I do see the 140mm glass dome recommended more.":

I just used 140mm glass dome on FF. My wife is using 100mm glass dome together with the Tokina 10-17mm/0.71x speedbooster on MFT (Oly EM1II). Both give very good results in IQ. I did not use 100mm glass on FF, but several people write that this is a bad compromise for FF (most use it just for specialiced photis as very CFWA, but I find 140mm also very good for this). The acryl dome should not be different from glass, just the radius matters, except some flair when photos are made against the sun and acryl is much more prone to scratching (one does not see minimal scratches in most pohotos, but when photos are made against the sun these minimal scratches can show up without mercy).

"3) what is the equivalent field of view at the 15mm end? can I still get normal rectilinear wide angle shots? I know the 8mm end is a full circular fish eye.": At 15mm you get 180° diagonal FOV with a fisheye on FF. When using the 2x Sony TC, you start with 16mm (approx. 170°, what is pretty wide) and end with 30mm (approx. 85°). This compares to 130° at 28mm up to 68° at 60mm for the WACP-C combo. I, personally, do not miss the 85°-68° range of the WACP-C, since the working distance is already often too large to give good IQ at this long range. On the other side, I permanently miss the range wider than 130° when I am with the WACP-C combo.

The WACP-C does not give rectilinear optics, but it gives fisheye look. Just more moderate fisheye look, just as longer focal length fisheye lenses do. I, personally, do not like extreme rectilinear WA UW. The Sony 20-70mm in 170mm WA dome is enough for me regarding rectilinear WA (Tamron 17-28mm is also very good, but zoom range is limited). When wider, rectilinear lenses produce extreme elongations towards the edges that I do not like at all (I also have Laowa 10mm that behaves o.k. behind the 140mm glass dome, but used it only for two dives, I really dislike the optics towards the edges)...

"4) anything else I should consider?": you could also consider the FCP-1 that gives similar FOVs as the Canon 8-15mm with 2x Sony TC behind 140mm dome, but I am not aware about strict tests that compare the optical IQ of both FCP-1/28-60mm and 8-15mm/2x SonyTC/140mm domeport (I believe the difference in IQ must be small, since some professionals still prefer the WACP-1 over the FCP-1 (because of IQ), when FOVs wider than 130° are not required)...

Wolfgang

Edited May 5May 5 by Architeuthis

13 minutes ago, Architeuthis said:

you could also consider the FCP-1 that gives similar FOVs as the Canon 8-15mm with 2x Sony TC behind 140mm dome

She's looking to reduce her travel weight; FCP-1 is a full kilo heavier than WACP-C.

25 minutes ago, Barmaglot said:

She's looking to reduce her travel weight; FCP-1 is a full kilo heavier than WACP-C.

Also the option with 140mm dome is not really cutting down from WACP-C (2.5kg with lens).

1.5kg 140mm glass dome

0.5kg 8-15mm

0.2kg Monster adapter

0.2kg TC

0.3kg N100-N120 adapter

39 minutes ago, Sokrates said:

Also the option with 140mm dome is not really cutting down from WACP-C (2.5kg with lens).

1.5kg 140mm glass dome

0.5kg 8-15mm

0.2kg Monster adapter

0.2kg TC

0.3kg N100-N120 adapter

Yeah, good point... that glass dome is no featherweight. Perhaps look at an acrylic dome option?

1 hour ago, Sokrates said:

Also the option with 140mm dome is not really cutting down from WACP-C (2.5kg with lens).

1.5kg 140mm glass dome

0.5kg 8-15mm

0.2kg Monster adapter

0.2kg TC

0.3kg N100-N120 adapter

It does get pretty heavy, the Canon 8-15 is a bit of a brick, though the 140mm dome doesn't weigh 1.5 kg, that I think is the shipping weight. I have most of this stuff so I can weigh it, the adapter/extension weight is of the n85-N120 34.7 with 35mm extension that I have, so will be close:

140mm dome 740 gr

adapter plus extension tube 550 gr

Canon 8-15 with metabones: 740 gr

Total : 2030 gr

While the 28-60/WACP-C/30mm ext weighs 2657 gr... You would need to add either the 1.4x or 2x TC if you want to get the reach you had with the WACP:

the fields of view are best visualized by looking at the diagonal field of view and also working out the equivalent 35mm rectilinear lens focal length, with just the 8-15 you get a circular fisheye or a full about 175° diagonal fisheye, no additional reach, if you want some reach as well you need to look at using it with 1.4x or 2x TC, the Sony TC produce better results than the kenko and can be used with the Metabones mounted in the order camera-TC-Metabone-Canon 8-15:

You can see that the 8-15 with 2x is close to covering the Full 180° diagonal fisheye all the way through to almost the full reach of the WACP-C by these calculations, while the 1.4x TC gets you out to about the field of a 16mm rectilinear lens. It will probably end up about the same weight once you add a 2x/1.4x and the required extension tube but, it does get you wonderful flexibility to shoot a school of Barracuda then drop down to shoot an anemone fish CFWA on the reef below. You could save around 200 gr with the 4.33"acrylic dome perhaps.

When travel weight is the primary concern, also WWL-1B with flatport and 28-60mm lens may be an option, probably the lightest combo for Sony FF (For Nikon Z a standard zoom lens exists, that allows to use the lighter WWL-C).

FOV of WWL-1B, however, remains the same compared to WACP-C (when I travel with my WACP-C, I always take the Canon 8-15mm/140mm domeport/N100-N120 adapter with me in addition, for the really wide WA)...

Maybe the Tamron 17-28mm with Zen DP170 (plus N100/N120 adapter and extensions) comes also into this weight range (I did not count the grams so far), but FOV is not extremely wide either at the short end...

It is certainly impossible to take all this in the cabin with handluggage. Domeports, WACP-C, extensions/adapters go to the check-in lugagge and we (two UW photographers) have always two additional suitcases ("diving" luggage) of check-in luggage. When we go with little airplanes to small islands, we have to book an extra-seat for the additional luggage with the airline. Of course, when some check-in luggage gets delayed or even lost, this is a problem, certainly on the arrival-trip...

Edited May 5May 5 by Architeuthis

Another option is the Nikonos RS 13mm fisheye converted to Sony. It's smaller, lighter, and sharper than anything else, though without the versatility of a zoom (it's fixed at 170 deg). And finding an RS 13 copy to get converted can be a little challenging.

This discussion got me curious about the weight of the RS 13 setup. Looks like the port plus inner lens comes in at around 1070g.

The issue is two fold - a wider field than WACP/WWL and maintain reach while not getting too heavy.

A fisheye like the 8-15 gives you the first one, but no ability to zoom beyond 180° nominal diagonal fisheye. You could add a fisheye and exchange the WACP for a WWL, but you can't do them both on the same dive. and it's more weight. The 8-15 with 2x effectively combines the diagonal fisheye with a WWL/WACP. If you don't use the long end of the WACP much you could probably use the 1.4x.

The first Fisheye I tested with Sony was the all manual Samyang/Rokinon 12mm fisheye and Sony A7R II around ten years ago. I used the Canon 8-15mm F/4 on Sony (with A1, A7&R 11, 111 VI, V, A7C, CI & CR) for over nine years in a verity of ports for the Zen 100mm to Matty Smith 12 inch port for splits. I also used a verity of both manual and AF lenses over the years and I have now added the excellent Sigma 15mm F/2.8 EX DG Fisheye with the Sigma MC-11 Canon to Sony lens adapter. This lens is very close focusing and while the AF is a bit noise it works well. My favorite combo is with the Marelux housings, 20mm port extension and the excellent Marelux 140mm dome port. This port is excellent because it includes a bayoneting sun shade which is easy to remove underwater when you want to go to 8mm and you can just slide it over your arm while shooting and then replace it for the 15mm end of the 8-15 zoom.

Upsides to the Sigma 15mm include small size, compact system, no need for zoom gears for standard lens or when used with tele converters. I just started testing the Kenko 1.4X DGX HD Pro tele converter for Canon mount with 40mm extension and MX-140mm dome port and it looks very promising.

I find it sad that over eleven years into mirrorless full frame cameras that Canon, Nikon and Sony haven't offered a native fisheye, not even a simple 15/16mm much less a quality zoom. After market sellers Like Rokinon, Tamron, Sigma and more have also over looked fisheyes as well even though they have been used by most sports and nature photographers for many decades.

Attached are with the Sigma 15mm, MX-housing, 20mm extension and MX-140 dome port.

Edited May 6May 6 by Phil Rudin

It might be reasonable to compare effective weight (Port + Lens) to see the real advantage of 8-15 in terms of portability:

WACP-C + 28-60 2.733g

ZEN 100 + 8-15 1.825g

(including the port extension).

Difference 900g... less than expected.

While the WACP-C is more bulky it delivers better IQ off-center but has less angle of view. It also gives a little fisheye bu much less than the 8-15 at 15mm with the small dome.

I personally will use the WACP-C for the majority of dives but the ZEN-dome with the 8-15 has its own areas in which it shows its advantages.

Interesting though that the Nikonos performs much better in terms of size, IQ and weight.

Thanks everyone and apologies for the belated reply. I spent a week after my Halmahera trip diving Lembeh and just got back home 2 weeks ago, and am now finally starting to process/look through the photos from the trip.

So upon a bit of deliberation I think my top priority is to get wider reach than WACP-C but still maintaining most of the range. The narrower end I rarely have any great keepers from, it's more hey I saw a Denise pygmy on a WACP-C dive and can get a decent image to remember I saw it.

Weight and IQ are second order considerations. Cost is a third order consideration. So with all of the above feedback I am now debating between 1) 8-15mm w 2x TC, vs 2) FCP

For 2x TC, is there consensus on whether the Sony vs the new kenko is better? Looking through the linked threads it seems people have had good results with both. I am leaning towards Sony since I figure I can also use it with my 100-400mm Sony GM lens on safari (which is my next trip).

First, are these the right models? Sony being almost 3x $ the Kenko?

Kenko https://www.cathayphoto.com.sg/photo-video-accessories/lens-accessories/kenko-teleplus-hd-2x-dgx-teleconverter-for-canon-ef?srsltid=AfmBOopZSBgVI8ij29OVpu6QfMHCts-RfpVsjWH0zgVW5uYvOhuE5KCg

Sony https://www.cathayphoto.com.sg/cameras/lenses/sony-fe-2x-teleconverter

Would the correct set up be A7R5 > Sony TC > Metabones > Canon 8-15?

Vs A7R5 > metabones > Kenko TC > Canon 8-15? but kenko TC (since it specifies for Canon EF) being unable to use w Sony 100-400?

For the dome, I see 140mm glass dome but also a reference to Zen 100. The 2 seems to be around the same price. Is the advantage of the ZEN only weight? At the cost of slightly better IQ of the 140mm glass dome?

Lastly, would the extension needed be N100-120 adapter + 30mm extension? I'm unsure whether the zoom gear will work since the 8-15 will be behind at minimum a TC and maybe a TC+metabones? And can I reuse my existing 30mm N100 extension that I'm using with the WACP-C?

So would it be housing > 30mm N100 extension > N100-120 adapter > 140mm glass dome?

I'm actually not super concerned about IQ. So just trying to work out exact set up for 8-15mm so I can make a comparison of cost/weight against FCP. Seems like the 8-15mm set up will be ~3k cheaper and 1.5kg lighter.

I also want to get the new SMC-3 and MFO-1 as well as a used EMWL so if I'm only losing the 68-85 degree range with the 8-15 vs FCP and IQ is pretty comparable I think the choice is clear.

Edited May 23May 23 by jjmochi

3 hours ago, jjmochi said:

For 2x TC, is there consensus on whether the Sony vs the new kenko is better? Looking through the linked threads it seems people have had good results with both. I am leaning towards Sony since I figure I can also use it with my 100-400mm Sony GM lens on safari (which is my next trip).

First, are these the right models? Sony being almost 3x $ the Kenko?

Kenko https://www.cathayphoto.com.sg/photo-video-accessories/lens-accessories/kenko-teleplus-hd-2x-dgx-teleconverter-for-canon-ef?srsltid=AfmBOopZSBgVI8ij29OVpu6QfMHCts-RfpVsjWH0zgVW5uYvOhuE5KCg

Sony https://www.cathayphoto.com.sg/cameras/lenses/sony-fe-2x-teleconverter

Would the correct set up be A7R5 > Sony TC > Metabones > Canon 8-15?

Vs A7R5 > metabones > Kenko TC > Canon 8-15? but kenko TC (since it specifies for Canon EF) being unable to use w Sony 100-400?

I have the 2x Kenko TC that you have linked (Teleplus HD 2x DGX). IQ with the Canon 8-15mm is clearly worse in comparison with Sony 2x TC. I one of the treads linked above, Massimo (now "guest") shows images obtained with the better Teleplus HD Pro 2x DGX and they look much better, very similar to the images with Sony 2x TC. See here for the currently available Kenko TCs: https://kenkoglobal.com/catalog/teleconverters/

Sony TC is more pricey, but shorter (=less extension) and can be used with Sony lenses as 100-400mm (Kenko works with Canon EF lenses, as Canon 8-15mm fisheye). The setup is correct...

3 hours ago, jjmochi said:

For the dome, I see 140mm glass dome but also a reference to Zen 100. The 2 seems to be around the same price. Is the advantage of the ZEN only weight? At the cost of slightly better IQ of the 140mm glass dome?

So far, I only used the 140mm dome which I find pretty small and handsome, so cannot say from own experience whether Zen 100mm also is o.k.. There are, however, multiple reports here in the treads that performance of Canon 8-15mm with Zen 100mm on FF is suboptimal (my wife used Tokina 10-17mm on MFT with the Zen 100mm and IQ is very good). I understood the postings this way that people use the Zen 100mm with FF only when they want to get very close in CFWA and the 100mm dome is a little bit smaller then (but now, since the EMWL is available, I guess many people switch to EMWL for such purpose, since this is clearly the smallest)..

3 hours ago, jjmochi said:

Lastly, would the extension needed be N100-120 adapter + 30mm extension? I'm unsure whether the zoom gear will work since the 8-15 will be behind at minimum a TC and maybe a TC+metabones? And can I reuse my existing 30mm N100 extension that I'm using with the WACP-C?

So would it be housing > 30mm N100 extension > N100-120 adapter > 140mm glass dome?

When the (standard) 35.5mm N100/N120 adapter is used, 30mm N120 additional extension is for the pure fisheye, without TCs. For the Sony 2x TC an additional 30mm extension is needed (60mm N120 extension in total; for the Kenko 2x TC 70mm extension are needed). You need a custom 3D printed Zoom gear (I believe one is available here under 3D parts) or a simple 3D printed extension ring, fixed by 3 Allen screws to the Nauticam zoomgear (I have the latter and it is for download under 3D parts)...

Possibly the 30mm N100 extension could be reused. It needs to be mounted of course between A7R5 housing and N100/N120 adapter and the zoom gear need to be extended for the 30mm then...

Wolfgang

Edited May 23May 23 by Architeuthis

On the Canon 8-15 vs FCP, one thing to note is that for CFWA it seems to have less depth of field than a fisheye as is discussed on this page:

The 8-15 with 2x approximates the range of the FCP without the DOF penalty it seems maybe at a slight cost of image quality?? Wolfgang seems to be quite happy with the IQ he's getting with that combo and the versatility is certainly nice.

On the issue of TC order, the N100-N120 adapter places the Canon 8-15 zoom gear at the right spot to work with the bare 8-15, swapping position with the extension means you have to adjust your zoom gear to compensate. It would move the gear knob on the extension forward with respect to the lens.

If I'm not mistaken the N100-N120 with knob engages with the unmodified Nauticam zoom gear to use the bare 8-15. If you add an extension (30mm) below the N100-N120 adapter then the knob/gear on the adapter moves forward by 30mm. If the Sony 2x is exactly 30mm thick it should then mesh again with the Nauticam zoom gear as the Sony 2x moves the 8-15 zoom ring forward by 30mm. If it's not exactly 30mm a simple adapter ring should allow it change position as required to be able to mesh. Wolfgang ( @Architeuthis ) should be able to confirm the dimensions.

It should also be possible to do what I did with my OM-1 and 8-15 and design a zoom gear to use the zoom control knob on the housing to zoom. That would end up being quite a long zoom gear.

16 hours ago, Architeuthis said:

I have the 2x Kenko TC that you have linked (Teleplus HD 2x DGX). IQ with the Canon 8-15mm is clearly worse in comparison with Sony 2x TC. I one of the treads linked above, Massimo (now "guest") shows images obtained with the better Teleplus HD Pro 2x DGX and they look much better, very similar to the images with Sony 2x TC. See here for the currently available Kenko TCs: https://kenkoglobal.com/catalog/teleconverters/

Sony TC is more pricey, but shorter (=less extension) and can be used with Sony lenses as 100-400mm (Kenko works with Canon EF lenses, as Canon 8-15mm fisheye). The setup is correct...

Ahh ok thank you! They don't have the pro version here it seems. And shipping from the US would not be much cheaper. So Sony it is!

16 hours ago, Architeuthis said:

When the (standard) 35.5mm N100/N120 adapter is used, 30mm N120 additional extension is for the pure fisheye, without TCs. For the Sony 2x TC an additional 30mm extension is needed (60mm N120 extension in total; for the Kenko 2x TC 70mm extension are needed). You need a custom 3D printed Zoom gear (I believe one is available here under 3D parts) or a simple 3D printed extension ring, fixed by 3 Allen screws to the Nauticam zoomgear (I have the latter and it is for download under 3D parts)...

Possibly the 30mm N100 extension could be reused. It needs to be mounted of course between A7R5 housing and N100/N120 adapter and the zoom gear need to be extended for the 30mm then...

Can you link me to the 3D parts? I'm not sure where to look.

14 hours ago, Chris Ross said:

If I'm not mistaken the N100-N120 with knob engages with the unmodified Nauticam zoom gear to use the bare 8-15. If you add an extension (30mm) below the N100-N120 adapter then the knob/gear on the adapter moves forward by 30mm. If the Sony 2x is exactly 30mm thick it should then mesh again with the Nauticam zoom gear as the Sony 2x moves the 8-15 zoom ring forward by 30mm. If it's not exactly 30mm a simple adapter ring should allow it change position as required to be able to mesh. Wolfgang ( @Architeuthis ) should be able to confirm the dimensions.

So this means if I go Housing > N100-120 adapter > 60mm extension > 140mm glass dome, I can use the Nauticam zoom gear as is but turning it with the knob on the adapter? But is that accounting for metabones or for native canon? It seems the Sony TC is 40mm so may not line up nicely if I put my existing 30mm N100 extension in front of the N100-120 adapter.

So I went to buy the Sony 2X TC and the Canon 8-15 today, and it does NOT fit with my metabones. The protruding part of the Sony TC cannot fit into the metabones. I think i have the mk4 and have to track down a mk5

Hi jjimochi,

I did not know that there is a difference between mark 4 and 5 of the metabones adapter. Also nobody else reported about it, it seems you are the first to find out...

Here I have deposited the Nauticam zoomgear extensions for various adaptations of Canon 8-15mm and Tokina 10-17mm. Only the ones were "Sony" is in the name are for Nauticam Sony housing, the rest are for adapted Nauticam Olympus housing: https://www.dropbox.com/home/Zoomgears

The extension for the 2x Sony TC/Canon 8-15 is currently not among them. I can put it there (from my server at home) on Monday, when I am back from diving (currently Sveta Marina/Croatia 😊). Alternatively you can take any for the Canon 8-15mm lens and elongate the ring with a simple program (I use "Tinkercad")...

In this link Gudge (post from February 6 2024) shows an entire zoomgear for the adapted Canon 8-15mm, I think for Sony/Nauticam (w/o TC): https://waterpixels.net/forums/topic/671-proven-3d-printed-parts-for-underwater-imaging/

Wolfgang

Edited May 24May 24 by Architeuthis

8 hours ago, Architeuthis said:

The extension for the 2x Sony TC/Canon 8-15 is currently not among them. I can put it there (from my server at home) on Monday, when I am back from diving (currently Sveta Marina/Croatia 😊).

Wolfgang

Hi. Wolfgang,

in addition to what @jjmochi said: the Sigma MC11 and the Sony TC are not compatible. But as I already own a 2x TC I might upgrade to Metabones V, but then I need the long zoom gear also. So if you are back and add the 2xTC gear..

What company could be recommended for printing?

Thanks a lot!

I have printed here until recently, it was always o.k., but it comes at a cost: https://i.materialise.com/de/Account/Login

Now a good friend of my son has acquired a 3D printer and it costs practically nothing (I gave him a six-pack for the last printout and he said this is much too much). So better have someone in the neighborhood to print it out...😄

Edited Saturday at 05:06 PM5 days by Architeuthis

23 hours ago, Architeuthis said:

In this link Gudge (post from February 6 2024) shows an entire zoomgear for the adapted Canon 8-15mm, I think for Sony/Nauticam (w/o TC): https://waterpixels.net/forums/topic/671-proven-3d-printed-parts-for-underwater-imaging/

Wolfgang

That 8-15 gear is for Sony either alone or with a 1.4x, it's reversible to do both services. Probably need to make it longer to use with a 2x.

I have put now the 3D file(s) into the dropbox (https://www.dropbox.com/scl/fo/dzjpn1s8wbfhbkyru8l4j/h?rlkey=u8ne953g3iymcyexmgczbmj9e&st=85dnwgtz&dl=0). I must admit that the current extension ring works, but it is not perfect: when I screw it to the Nauticam Zoomgear, I have to do it so that there remains a small gap (1-2mm) between the gearwheel and the extension ring, to make it a little bit longer to make the zoom function work smoothly (i.e. the gearwheel of the camera housing and the zoomgear fit exactly): Canon815_2xSony.stl

Canon815-2xSony.stl is 2mm longer and should fit perfectly (maybe it needs a little bit of abrasion, but I still have to print it out and test it). I would print out this version, but I cannot guarantee: Canon815_2xSony&2mm.stl

Wolfgang

P.S.: I fix every extension ring with three headless Allen screws (M2) to the zoomgear and the ring cannot detach during using it UW (or by mechanical agitation during transport etc...). The tools for making the treads in the plastic can be acquired at every hardware store for little money and it is easy...

Edited Monday at 06:34 AM4 days by Architeuthis

Thank you so much, Wolfgang!