Before leaving for Indonesia tomorrow I was able to do a quick comparison between my new addition WACP-C and adapted 8-15 the photos of which I made back in spring. Disclaimer is that WACP samples were done with the strobe at ISO100 while for 8-15 I was using video light at higher ISO and so the results might not 100% comparable. Will reshoot when I have time.

First the costs and weights of both systems (8-15 quoted at used price level):

Both systems are kind of neutral-ish buoyant in this configuration:

The following screenshots have this system: first Fit view followed by 300% comp view with rectangle at left upper corner showing the part of the frame compared.

As I stated earlier I picked up samples which showed good focus for 8-15 as weaker light and also shutter speed without flash sometimes produced unfocused images. But these I think were sharp in the center and so let's get on with these.

8-15 TC2x in 140mm dome 55mm+35.5mm N100/120 vs WACP-C both F11:

... and 8-15 TC2x 55+35.5 in 180mm dome vs. WACP-C 28mm:

And finally 8-15 TC2x 55+35.5 in 140mm at 30mm vs WACP-C at 60mm

I am very happy with performance of WACP-C especially at 60mm as this is what I would be using for smaller subjects and crop heavily on 50Mpix image.

I will leave conclusions to yourselves :-). For me I realized that 180 degrees view is not as important as the DOF and native AF lens performance which doesn't mean I am going to sell 8-15 combo - yet. Cheers :-)

I think not exactly apples to apples comparison, this tests out the sharpness but does not consider the barrel distortion which tends to pull the subject forward in the frame in comparison to the edges. This effect becomes increasingly less obvious as you zoom in. @Alex_Mustard has chimed in when I have been comparing fields of view between fisheyes and other lenses with this observation on a number of occasions

Counting squares in the centre crop looks like the image scale is 1.16x for the WACP at 60 over the 8-15 @ 30mm which could be handy for some marginal objects but with MP available I think hardly noticeable in details captured. Interestingly my calculations say almost the same thing 1.16 vs 1.17 image scale factor.

To me the 8-15/2x combo has sharpness advantage in the corners at least at the wide end (just really looking at the 140mm - the 180mm as expected is a little worse).

just a side note - the pad was not photographed from the same distance for presented scenarios so the number of squares in crops and their size is meaningless in comparisons. the purpose of this comp was sharpness and rendering, perhaps CA, - not distortions or magnifications.

Edited July 1Jul 1 by RomiK

Thank you for these industrious testings, RomiK... 👍

From your test photos under controlled environment, I conclude that the 8-15mm/2xTC/140mm combo is at least as good as 28-60mm/WACP-C, maybe even a tick better (you agree?). The differences are subtile, I am glad to see that the 8-15/2xTC combo can keep up with modern wetlens solutions...

I derived to similar conclusions based on my own photos, but these were just UW photos of different subjects at different times and conditions, by far no control...

#1.: Concerning your listing of costs and the Canon 8-15mm combo, I think it is fair to add that the N100/N120 adapter, 140mm dome, both N120 extensions and Sony 2x TC are universal and can be used for various other occasions, both UW and OW as well (even the Canon 8-15mm with Metabones is fun to use over the water)...

With the WACP-C combo, one is left with a bold chunk of optical glass that is dedicated to its purpose plus one universal N100 30mm extension and a mediocre 28-60mm lens (o.k. the charm of the 28-60mm lens for OW use is its size, but I personally prefer the Sony 20-70mm that is bigger, but still not excessive, and provides clearly better IQ, both OW and UW)

=> I would say one gets a lot more with the Canon 8-15mm combo (also the 180° diagonal FOV, what the WACP-C cannot deliver) for a simlar amount of money...

#2.: I am surprised to see that the Canon 8-15mm performs optically better behind the rectilinear 180mm domeport, compared to WACP-C, maybe even a tick better compared to 8-15mm behind hemispherical 140mm domeport. This is completely unexpected for me, but in line with my observations when I used the Canon 8-15mm behind 140mm and rectilinear 170mm domeports with MFT cameras, where the smaller sensor scans only the central 25% area within the image circle. IQ with 170mm domeport there was at least as good compared to the 140mm, if not better (just comparison of regular UW photos, no controlled environment)...

Wolfgang

P.S.:At present, my WACP-C stays a lot at home, when I go for scuba travel (I am a big fan of 180° diagonal and miss it with the WACP-C; I also find the 8-15(2xTC/140mm rig more manageable OV and UW). Not enough time has passed, but maybe I will put my WACP-C in classified to help finance an EMWL some day...😊

Edited July 1Jul 1 by Architeuthis

Thanks for the tests.

It is good to also see the price and weight comparison. If someone is starting from scratch very comparable, if someone already has components, or other uses for the lens, it looks like these can be bigger factors versus image quality in making a choice.

I do note the 1.4x Kenko and Sigma MC11 converter combination is quite a lot cheaper than the Sony 2.0x (or 1.4x) and Metabones V. I am not sure of availability of the zoom gear for 2x teleconverters but it seems most housing manufacturers make one for the 1,4x and 8-15mm.

I use an Isotta housing with an 8 inch polycarbonate dome (about 500g lighter than the Nauticam 140mm and needing less floatation). I can use the same extension and dome for both the Sony 20-70mm and the 8-15mm with 1.4. It means I can swap the lenses out on a multi-dive day small boat without changing anything about the housing, extensions or port. For example in Palau, changing from the 20-70 for sharks, turtles, fish portraits and people photos, to fisheye for the big wall, reef scenes and schooling fish pictures. Very handy and a good travel combination. If the dome gets scratched there is a good chance I can polish it so not as nerve wracking when other people handle the housing.

I also like the versatility of the 8-15mm being able to use it without a teleconverter in a 4.5 inch fisheye dome for minimum housing size for freediving.

It is great to have the options where image quality is comparable and personal circumstances mean different solutions.

3 hours ago, John E said:

I do note the 1.4x Kenko and Sigma MC11 converter combination is quite a lot cheaper than the Sony 2.0x (or 1.4x) and Metabones V. I am not sure of availability of the zoom gear for 2x teleconverters but it seems most housing manufacturers make one for the 1,4x and 8-15mm.

It is great to have the options where image quality is comparable and personal circumstances mean different solutions.

I think the big advantage of the 8-15 with 2x is it's versatility. it goes from a 175-180° full diagonal fisheye through to about a 28mm equivalent. I use the 8-15 with my OM-1 which gives the same range as available on FF with the 8-15 plus 2x. You would need to have a gear printed with the 2x but that should not be a major obstacle. It is effectively a 15mm fisheye, WWL-WACP with 28-60 and 14-28 lens in one package, albeit with some barrel distortion throughout the range. And it seems at least as sharp as the WACP/28-60 combination.

My calculations suggest the WWL-WACP/28-60 combination has the about the reach of a 32mm lens at 60mm compared to the 28mm reach of the 8-15/2x which is pretty close and I suspect would be sufficient for most users.

In fact I'm wondering if Nauticam could have perhaps worked with someone like Metabones to develop a custom 2x converter tuned to the 8-15 lens rather than developing the FCP port. It might avoid the limited depth of field the FCP seems to have at close focus. You could have a 1.5x model as well which could be used on APS-C and would also find application on full frame. All of this is possible due to the high optical quality of the Canon 8-15.

1 hour ago, Architeuthis said:

Thank you for these industrious testings, RomiK... 👍

From your test photos under controlled environment, I conclude that the 8-15mm/2xTC/140mm combo is at least as good as 28-60mm/WACP-C, maybe even a tick better (you agree?). The differences are subtile, I am glad to see that the 8-15/2xTC combo can keep up with modern wetlens solutions...

I derived to similar conclusions based on my own photos, but these were just UW photos of different subjects at different times and conditions, by far no control...

Yes I agree very much. Optically it seems there is no bad apple and the differences are subtle (apart from characteristics given by their nature (diopter vs dome). There is always some CA, some unsharpness but the central part of the image seems to be on par. Where did WACP-C really surprised (compared to WWL1) me was the long end which I considered with WWL1 very soft and I attributed it to the lens. So when I saw what I saw with WACP my jaw dropped. I will have to reshoot WWL with flash as it seems to me that we have to feed these optics (also EMWL) with a lot of light to produce good results.

1 hour ago, Architeuthis said:

#1.: Concerning your listing of costs and the Canon 8-15mm combo, I think it is fair to add that the N100/N120 adapter, 140mm dome, both N120 extensions and Sony 2x TC are universal and can be used for various other occasions, both UW and OW as well (even the Canon 8-15mm with Metabones is fun to use over the water)...

With the WACP-C combo, one is left with a bold chunk of optical glass that is dedicated to its purpose plus one universal N100 30mm extension and a mediocre 28-60mm lens (o.k. the charm of the 28-60mm lens for OW use is its size, but I personally prefer the Sony 20-70mm that is bigger, but still not excessive, and provides clearly better IQ, both OW and UW)

=> I would say one gets a lot more with the Canon 8-15mm combo (also the 180° diagonal FOV, what the WACP-C cannot deliver) for a simlar amount of money...

To me WACP even though dedicated it still is a tool and the main benefit would be the use of native AF and its performance. To me the use of native AF trumps all the other cards. Even without video in mind I am experiencing quite a few misses on 8-15 shots including the lab pictures from pool.

1 hour ago, Architeuthis said:

#2.: I am surprised to see that the Canon 8-15mm performs optically better behind the rectilinear 180mm domeport, compared to WACP-C, maybe even a tick better compared to 8-15mm behind hemispherical 140mm domeport. This is completely unexpected for me, but in line with my observations when I used the Canon 8-15mm behind 140mm and rectilinear 170mm domeports with MFT cameras, where the smaller sensor scans only the central 25% area within the image circle. IQ with 170mm domeport there was at least as good compared to the 140mm, if not better (just comparison of regular UW photos, no controlled environment)...

So much for universally adopted truth right?! :-) I was surprised too! => never trust these internet wisdoms until you see it for yourself :-). I'd say the CA was more pronounced towards the edges as expected but the horizontal lines stayed sharp until the end!

1 hour ago, Architeuthis said:

Wolfgang

P.S.:At present, my WACP-C stays a lot at home, when I go for scuba travel (I am a big fan of 180° diagonal and miss it with the WACP-C; I also find the 8-15(2xTC/140mm rig more manageable OV and UW). Not enough time has passed, but maybe I will put my WACP-C in classified to help finance an EMWL some day...😊

Oh god, I could have saved some money perhaps... or we could have swapped my EMWL (just kidding :-) ... I will see how I like WACP-C in Lembeh - Halmahera and also how I like and how it will work my new way of packing presenting housing+WACP+camera-handles-ballmounts as a personal item in addition to my carry-on :-)

7 hours ago, John E said:

Thanks for the tests.

It is good to also see the price and weight comparison. If someone is starting from scratch very comparable, if someone already has components, or other uses for the lens, it looks like these can be bigger factors versus image quality in making a choice.

I do note the 1.4x Kenko and Sigma MC11 converter combination is quite a lot cheaper than the Sony 2.0x (or 1.4x) and Metabones V. I am not sure of availability of the zoom gear for 2x teleconverters but it seems most housing manufacturers make one for the 1,4x and 8-15mm.

• one note is that MC11 doesn't support video and AF-C either

7 hours ago, John E said:

I use an Isotta housing with an 8 inch polycarbonate dome (about 500g lighter than the Nauticam 140mm and needing less floatation). I can use the same extension and dome for both the Sony 20-70mm and the 8-15mm with 1.4. It means I can swap the lenses out on a multi-dive day small boat without changing anything about the housing, extensions or port. For example in Palau, changing from the 20-70 for sharks, turtles, fish portraits and people photos, to fisheye for the big wall, reef scenes and schooling fish pictures. Very handy and a good travel combination. If the dome gets scratched there is a good chance I can polish it so not as nerve wracking when other people handle the housing.

I too love 20-70. For me it's the ultimate lens for where you expect unexpected :-) it's sharp like hell and cropping into 50Mpix at 70mm is like macro. It is less ideal for wrecks caves and big ocean but other that its amazing lens! The attached images of 3 nudis as well as stitched (!!) panorama were taken by it at Cape Verde couple months back.

3 hours ago, Chris Ross said:

In fact I'm wondering if Nauticam could have perhaps worked with someone like Metabones to develop a custom 2x converter tuned to the 8-15 lens rather than developing the FCP port. It might avoid the limited depth of field the FCP seems to have at close focus. You could have a 1.5x model as well which could be used on APS-C and would also find application on full frame. All of this is possible due to the high optical quality of the Canon 8-15.

My short experience with 8-15 and DOF is quite opposite - in reality I have to be very very close to the subject for it to have meaningful impact in the frame while shooting at wide angle. Which means that the lens is focusing at its or close to minimum focus distance which means that no matter aperture you throw at it the DOF will be quite shallow (as the hyperfocal distance is like 3m for this lens?). Because behind the dome the focus distance is like 1/3 right? So the subject 1m away - which is like a mile when at 15mm - will focus at 30cm. And subject right at your dome will focus at 15cm. With all implications for DOF.

While nauticams diopters will move the focus point like 3x away so the subject 0.5m away will focus at 1.5m which in turn will produce much greater DOF even with mediocre 28-60 sufficiently closed down. I think I demonstrated this in my other post about 8-15 and WWL1.

Unless I am missing something these diopters will in reality produce greater FOV - not smaller - than fisheye behind the dome 🤷

6 hours ago, Chris Ross said:

In fact I'm wondering if Nauticam could have perhaps worked with someone like Metabones to develop a custom 2x converter tuned to the 8-15 lens rather than developing the FCP port. It might avoid the limited depth of field the FCP seems to have at close focus. You could have a 1.5x model as well which could be used on APS-C and would also find application on full frame. All of this is possible due to the high optical quality of the Canon 8-15.

I wished Nauticam working together with a third party lens company (like e.g. Tamron, Sigma, Viltrox, Laowa etc.. etc...). The lens company produces an AF equipped zoom lens that is just a proto-lens and is not required to make in-focus photos OV. Nauticam produces a small and smart port for this lens where the front glass is an optical element that complements the proto-lens to become a water corrected 15-35mm (f/4 or f/5.6) zoom fisheye lens (similar to the Nikonos lenses modifications done by Seacam or Isaac Szabo)...😃

=> I do not think that development and construction of such an item is more elaborated compared to development and construction of WACPs/FCPs etc. (a lot of old patents/plans for water corrected lenses already exist; maybe even one of the optical engineers of the old Nikonos lenses is still alive and willing to participate). Especially series production of the port should be simpler (I also guess the number of items produced/sold would be quite high)...

=> When I consider the boring multiplicity and redundancy of lenses that are produced by third party companies (e.g. 85mm portrait lenses, but also many other focal lengths), I imagine it is hard for them to make profit. Such a unique proto-lens may be a very welcome product for their portfolio...

A very personal camera item 🤣

I'm fully with you @RomiK . It depends on individual preferences and both solutions have their advantages. I seem to have the same priorities and I'll stay with the WACP-C.

7 hours ago, RomiK said:

My short experience with 8-15 and DOF is quite opposite - in reality I have to be very very close to the subject for it to have meaningful impact in the frame while shooting at wide angle. Which means that the lens is focusing at its or close to minimum focus distance which means that no matter aperture you throw at it the DOF will be quite shallow (as the hyperfocal distance is like 3m for this lens?). Because behind the dome the focus distance is like 1/3 right? So the subject 1m away - which is like a mile when at 15mm - will focus at 30cm. And subject right at your dome will focus at 15cm. With all implications for DOF.

While nauticams diopters will move the focus point like 3x away so the subject 0.5m away will focus at 1.5m which in turn will produce much greater DOF even with mediocre 28-60 sufficiently closed down. I think I demonstrated this in my other post about 8-15 and WWL1.

It wasn't expressed well, but I was specifically referring to the FCP which is what an 8-15 with 2x emulates. Reports are that the FCP seem to have more limited DOF. I can't comment on the specifics of depth of field of the WWL/WACP, though I suspect they have similar lens designs to the FCP.

In general depth of field after you've accounted for aperture is related solely to magnification. The image scale at the wide means depth of field is generally pretty good and being behind a dome the depth of field is compressed into the virtual image which extends from touching the dome to about 3 dome radii. On a 140mm dome that's about the edge of the dome to about 210mm away. The lens also only knows about the virtual image as that is what it images.

So the end result is that depth of field is higher than shooting the same scene without a dome. The FCP though seems to be doing something different possibly making a much bigger virtual image or something similar as the examples showed in the thread back when it was released certainly seemed to have less DOF than you would expect.

Thanks for the tests, and the interesting conversation and observations.

In my experience, having shot WWL, WACPC, FCP, and WACP (I still own the last two) both in pool tests and in the real world, depth of field with the FCP is different: lower/less. I'm not smart enough to understand why, but the FCP disappoints in the depth of field department, at least for me, in the f5.6 to f11 range. f13 satisfactory, usually. f14 better. f16 no longer bothers me, other than for the higher ISO required....

However, the zoom range of the FCP (with the 28-60) is fantastic! At least three lenses in one.

I've been mostly pleasantly surprised with Canon 8-15 + Kenko 1.4x with 140, 170, and 230mm ports on Canon 5d4. Acceptably sharp, fast and accurate enough focus, and some appreciated zoom range. But still limited compared to FCP and 28-60 on Sony.

1 hour ago, Brandon Cole said:

Thanks for the tests, and the interesting conversation and observations.

In my experience, having shot WWL, WACPC, FCP, and WACP (I still own the last two) both in pool tests and in the real world, depth of field with the FCP is different: lower/less. I'm not smart enough to understand why, but the FCP disappoints in the depth of field department, at least for me, in the f5.6 to f11 range. f13 satisfactory, usually. f14 better. f16 no longer bothers me, other than for the higher ISO required....

However, the zoom range of the FCP (with the 28-60) is fantastic! At least three lenses in one.

My initial thoughts would be that because you get to the subject closer with FCP your lens behind it focuses on shorter distance which means that hyperfocal DOF will be shifted towards the camera. Like if a lens DOF is 2m-inf at F11 (which means you are like 60cm from subject with wacpc) then with FCP you need to get closer with that wonderful 180 to have the same size of subject in the frame which means now you are focusing at 1.2m being only 40cm from subject and then you are getting 1.2m-3m DOF at F11. I am taking focus point as a mean point in DOF expression, what is before that doesn’t interests me for this explanation if it makes sense. This would be my take on why DOF is different with FCP from WACP with the same lens. And that’s when we think the magnification is the same 0.36. If it would be different the principle is the same with just another variable. Or I am completely wrong 🤣.

Edited July 2Jul 2 by RomiK

8 hours ago, RomiK said:

My initial thoughts would be that because you get to the subject closer with FCP your lens behind it focuses on shorter distance which means that hyperfocal DOF will be shifted towards the camera. Like if a lens DOF is 2m-inf at F11 (which means you are like 60cm from subject with wacpc) then with FCP you need to get closer with that wonderful 180 to have the same size of subject in the frame which means now you are focusing at 1.2m being only 40cm from subject and then you are getting 1.2m-3m DOF at F11. I am taking focus point as a mean point in DOF expression, what is before that doesn’t interests me for this explanation if it makes sense. This would be my take on why DOF is different with FCP from WACP with the same lens. And that’s when we think the magnification is the same 0.36. If it would be different the principle is the same with just another variable. Or I am completely wrong 🤣.

Depth of field with just a lens at constant aperture varies directly with magnification. So if you frame up the subject the same way with the same size in frame depth of field on the subject will be the same or very close when just using a lens without domes and virtual images. As you get closer and the subject gets larger the the depth of field goes down. You can frame it with a longer focal length from further away or up close with a wide angle - if the subject size is the same the depth of field remains pretty much the same.

Behind a dome the depth of field goes up as the min focus to infinity image is compressed into 3 dome radii. Of course the dome needs to be positioned properly if the lens is too far inside the dome you lose some of the in focus range as it's inside the port.

Now if you compare the 8-15 with 2x behind a dome and the FCP, the zoom range is near identical just slightly more reach for the long end on the FCP and both focus on the dome so they can achieve the same subject size. In this situation the FCP has less depth of field than the 8-15. It only makes sense to compare DOF at the same magnification, a bigger subject size in frame means the depth of field will be less.

As to why the FCP has less depth of field I don't know, perhaps the virtual image is not as compressed and you lose the DOF advantage you have with a lens behind a dome?

The way the background appears does vary with focal length so taking an image right up close with something like a 24mm lens then taking the same image with a 500mm lens (on land) you will see a dramatic difference in the bokeh or background blur, but in UW photography you don't get into such extremes

On 7/1/2025 at 8:41 AM, RomiK said:

level):

I would like to point out that this Calculation for a native Canon shooter and MARELUX target user runs much more affordable and lightweight:

Canon EF 8-15 FE: 600-750€ (used) / 540g

EF-RF Adapter: 89€ / 109g

Kenko 2.0x TC: 190€ (used) / 166g

Marelux 60229 Zoomgear: 209 € / 48g

Marelux 51406 Zoomgear: 209 € / 66g

MX 30mm Extension: 319 € / 250g

MX 50mm Extension: 339 € / 340g

MX 140mm Dome: 1369€ / 754g

= 3324 € / 2273g

Let‘s you run the system with and without Teleconverter.

Note that you cannot buy the 8-15 lens and Kenko Teleconverter new anymore. They can be found in the used item market. I have friends which were able to get their hands on a pristine Canon 8-15 fisheye for 550€.

You may even shrink this down by not buying the parts you need for running the lens natively with zoom to make it more comparable vs. the FCP or WCAP road.

So for Canon RF Users it’s actually a no-brainer to go and get this setup. And the sentence would go,..

What does 2750 € get you ?

37 minutes ago, Adventurer said:

Note that you cannot buy the 8-15 lens and Kenko Teleconverter new anymore. They can be found in the used item market. I have friends which were able to get their hands on a pristine Canon 8-15 fisheye for 550€.

Didn't realise it's discontinued. Doesn't bode well for UW photographers. Even if Canon bring out an RF version it won't be readily adaptable to other systems like the EF version.