Interceptor121

I am curious of how other users focus the camera for wide angle shots using a dome or a water contact optic Feel free to elaborate on why you use that option

This may be of interest at the bottom there are link to pool tests of all the rigs I always spend time in a pool before going to open water with new equipment to avoid suprises https://interceptor121.com/2023/02/04/moving-to-full-frame-without-increasing-bulk/

1:1 is a frame 17.3x13mm which is very small CMC-1 makes this 9mm which is extremely small… Many users can’t even get 1:1 with the 60mm Sent from my iPhone using Tapatalk

If you look at the distance that does not overlap 70-122mm you see that there the camera already focusses with the bare lens and therefore the benefit of the CMC-2 over the CMC-1 is little The other issue is that for supermacro where you are in manual focus it does help to make sure you are close so a strong lens is good so that you know that once you are in focus you are achieving more than you had with the bare lens

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The olympus 60mm has a very short working distance of his own making the weaker options (CMC-2, Subsee, Inon UCL-90) not useful I use and recommend the Nauticam CMC-1 alternatively you can try the Inon UCL-67

The canon 8-15mm also works with the zen 100 which is heavier than the acrylic 4.33 but a little bit smaller The wwl-1 on my a1 has similar weight to the canon 8-15 a bit more actually and heavier than the acrylic The zen will be in the same ballpark So wwl-1 and canon 8-15 options on my a1 are on the same ballpark WACP C or 1 will be heavier dry. The WACP-C only few hundred grams in fact but at the end you will still need a fisheye. As I recall the RF system housings are also heavier than Sony and generally you are looking at WACP-1 Only the Sony system is a bit more compact but still pretty negative in water and the housings cost less too It was the reason for me to get an A1 the camera costs more but there is more choice of underwater ports Sent from my iPhone using Tapatalk

It is not complicated If you look at the WWL-1 analysis i did on the A1 https://interceptor121.com/2023/03/11/nauticam-wwl-1-on-sony-full-frame-what-to-expect/ You can see that the WWL-1 supports lenses that are physically small those fit in a flat port Lenses that are bigger (filter size > 52mm) don’t fit a flat port and require a dry mount Canon has not made small and slow RF lenses is focussed on premium products and those are big Most canon and nikon compatible lenses are obsolete kit lenses of previous generation Sent from my iPhone using Tapatalk

https://interceptor121.com/2023/03/18/canon-8-15mm-with-kenko-1-4-teleconverter/ I did not have my test props when I took those shots but it gives an idea I believe

The WACP WWL-1 field of view is narrower than the Tokina 10-17mm on APSC The closest option is Canon 8-15mm with 1.4 TC Sent from my iPhone using Tapatalk

it was a type 20-70 but again it makes no sense that port chart period I don't need to bore you guys you are happy with what you have fine so be it

It does not matter what port system you use. You cannot have the same lens having one time a longer extension for one dome and another lens shorter it does not make any sense. Your comment about the port chart difference between the nauticaj and this one simply means the camera is more recessed indicating less precision in the manufacturing process. If Nauticam is 25mm in this one is 38mm in. Few examples of Marelux port chart Sigma 24-70mm lens 180mm dome 80mm extension 230mm 70mm extension Sony 27-70 lens 180mm dome 50mm extension 230mm dome 60mm extension Sony 24-105mm 180mm dome 70mm extension 230mm dome 70mm extension What would be the logic to make sense of those recommendations? The ports are physically the same and based on construction either one needs longer or shorter (equal is unlikely) cannot go around like this It just shows that there is lack of rigour here besides most of those lenses have design details available so it is relatively easy to rectify if you know how to. If someone has any logic argument to make sense of the above example I look forward to an explanation I believe a fundamental issue with rectilinear lenses especially not too wide is that the extensions 'suggested;' are many times totally off while for fisheye lens the rule go forward until it vignettes works much better. Those few example that work well are mostly out of coincidence not choice.

I am now looking at the marelux port chart there is no 35mm port adapter in the port chart and the extensions look all over the place in some cases the two ports take the same extension in others one is longer than the other and then viceversa. The product look pretty much copies of Nauticam designs the dimensions are identical I would not trust that port chart for any practical use it is inconsistent all over

180mm port depth 83 mm 230mm port depth 112 mm 83+50=133 112+30=142 I do not see how the lens would hit the 230 port before it hits the 180mm port Besides both need the 35.5mm N100 to N120 port so add 35.5 and 25mm the port is recessed in the housing you get 133+35+25=193 142+35+25=202 Both dimensions are far away from the lenght of the lens fully extended The 230 port is always deeper and physics normally works well and the reason why the 230 port needs to be longer is because the radius is 1cm longer however if this was 60 cm the combination would go to a whopping 232mm which is not required and will induce pincushion distortion Edit I am now looking at the marelux port chart there is no 35mm port adapter in the port chart and the extensions look all over the place in some cases the two ports take the same extension in others one is longer than the other and then viceversa. Ouch!

those recommendations make no sense. the 230 port is almost an hemisphere while the 180mm port has an angle of view that is reduced the port is 83mm tall requiring always 2 cm more compared to the 230mm port It looks like they are continuing to use vignetting as a criteria so of the two the 180mm port extension is the one that is nearer what is required. The 230 port should be 20mm shorter and 60mm is possibly way too long 30mm would be a better option if you had that port Of course manufacturers know better except when they don't!

Yes you can replace the 140mm with acrylic there is a recent article but is on full frame As adapter I do not recommend deviating from Metabones yes it costs more but you know exactly what you get For the GH5M2 it is a nice upgrade for video and for higher ISO photography but underwater you will be mostly at ISO 200 so right there the difference is 1/3 of a stop. I would prioritise the lens

For the Tokina you need the 34.7mm N85 to N120 adapter and the Tokina acrylic dome port 4.33 plus the zoom gear for the lens You don't need to use the 140mm dome which has some benefits because it has antireflection coating but optically you won't see anything in most images In terms of lenses the canon 8-15mm is a better lens but is much more expensive the N120 140mm dome is not 1.3 Kg but 630 grams actually not sure where the 1.3 on the specs came from

Thanks for the photo For clarity to others here you don’t need to use N100 20mm extension you can use N120 and have the same set up of the kenko My question was if the nauticam zoom gear worked and the answer is unknown as that is a custom gear The vignetting comes from the fact that the sony tc is 2mm shorter so the lens is slightly behind the ideal point this combination will not offer the same field of view of the kenko but the difference is small As I see it if you already had the sony TC this is a viable option However if you only had to get the teleconverter for underwater use it would not make sense as the kenko is substantially cheaper I bought mine new for £149 Sent from my iPhone using Tapatalk

If you have the TC already you can try but the entrance pupil is now going back 3mm and the gear is off 2mm The kenko teleconverter is designed for the canon ef mount so it is flush to the metabones The metabones itself is 26mm while the sony tc protrudes 16.6mm so the tc won’t go right on the back of the lens the converter may act as a mix of extension tube and teleconverter and non longer focus at infinity This is not an issue inside the dome provides the lens can still focus at the virtual image infinity point Few questions 1. How does the zoom gear work? 2. At which point it stops vignetting? 3. How does the focus work? Sent from my iPhone using Tapatalk

Correct The kenko TC is 19mm requiring a 20mm to extension and a special zoom gear. The diagonal field of view goes from 172 degrees (15mm end) to 124 degrees (21mm end) There is overlap with water contact optics only at the tele end so the two options are not alternative but complementary You need a metabones adapter to work with the kenko and autofocus works well Working with a Sony 1.4TC you have an issue with the N100 extension length not recommended Sent from my iPhone using Tapatalk

I guess some subjects are fairly simple take a cooking class you learn by doing But you wouldn’t leave someone to experiment chemistry without any learning before hitting the lab The recurring theme with wide angle lenses is something new comes up and people who don’t have the lens and do not own the underwater parts are curious to know if this combination is going to work Generally there are things you should be looking for but it really helps to know the lens construction as that will give you an almost accurate idea of the behaviour of the lens The other complexity are the underwater ports only few of them are complete hemispheres the others are cuts with smaller angle of view and they are also built differently one another With that in mind it is clear that two ports of this nature should require different extension but in most cases you look at the port chart and that’s not the case. You know then that the manufacturer hasn’t actually tried too hard the compatibility When you don’t have all those parts available it really helps to know how things work to optimise your spend One thing that is apparent is that the prevailing empirical approach which is find the longest extension until you see vignetting and then step back produces good results only when the lens field of view is very similar to the port field of view In the case mentioned here the lens has 94 degrees while the port has 143 They are far apart so the extension when the lens vignette is far away from the ideal placement point and they empirical approach becomes suboptimal Sent from my iPhone using Tapatalk

I was not intending to offend anyone I was reacting to this rather unconventional statement from David Haas which I think is dismissive and diminishing of who tries to do an effort for the benefit of others. As to how well the new Sony 20-70mm lens may work for certain shooters I'll wait for Phil's zoom gear testing plus manufacturer's advice and real world shooting versus calculated measurements. My point is that in the largest majority of cases lens design is known or can be calculated quite easily for what is needed to implement the correct dome port. As I said it requires basic trigonometry to know which dome can fit what even without having the lens design. I am growing increasingly skeptical of the lack of rigour that there is in the sector despite the high value of the items involved that generate costly mistakes. In order not to make those mistakes I have developed my own method that works well. So far there have been a number of solutions not on the chart that have proved to work without being officially supported. With few parameters available is entirely possible to calculate what a combination can or not do and the idea that we need to wait some advice from real world shooting (besides I do my test in a pool it is still underwater after I have done a model) and nothing can be said is a very extreme view and to dismiss who tries to put some order into this is in my view a mistake Perhaps going forward I should just keep my considerations to myself as otherwise there is a risk that this is not even welcome simply because someone can't understand the logic and neither I want things to become a lecture and spend to much time explaining myself

I have tested the Kenko 1.4 with the Canon 8-15mm on my A1 in the pool and I am going to put up some considerations on my blog during the weekend It remains a distorted image like the Nauticam Water Contact Optics but the field of view only overlaps when the 8-15mm with TC is full zoomed. So the two solutions are complementary not exclusive You use the Teleconverter with the same port you use without it so Glass Dome 140mm or if you fancy Acrylic 4.33" No need for larger dome ports for the Canon 8-15mm

My analysis was aimed at photography with the 50 megapixels A1 I intend to also go for 4K video with the same combination. I think as a video user you need to consider a few factors: 1. Will you use filters 2. Will you take the lens off 3. Do you really need a macro lens or we are talking more about close up My experience of the Red Sea is that you do not really have tiny macro subject as main stream so the lens could be there most of the time The reef are relatively well covered by ambient light and filters or even custom white balance works very well Although the WWL-1 needs to be stopped down to f/11 for edge sharpness in photos for video f/8 is fine as the extreme edges are cropped and 4K video with things that move is not really going to be one for the pixel peeper WACP-C would be also ok if you do not want to use filters or not planning to do close up with the flat port and prefer a dry mount I will do a write up for the WWL-1 in video in the next weeks I need to go through other 2-3 test cases so it may be in April

Yes tests indicate is a better lens across the frame I believe most people including me use those optics because of the zoom I wouldn’t bother as prime option Sent from my iPhone using Tapatalk