17 hours ago, Fred Courchamp said:

Thanks a lot Phil for your very insightful comment. Have you tried using the Sony FE 20–70 mm f/4 behind a flat port (as for the FE 28 – 60 mm F4-5.6), which would allow adding a CMC-2 (or possibly, a MFO-1 if useful) for very small fish? Nauticam port chart recommends a dome for the 20–70 mm f/4, but I'm wondering whether a flat-port setup could still work (considering I would certainly rarely shoot at 20 mm).

I would not recommend the Sony 20-70mm behind a flat port because other choices are so much better. I have tested the Sony FE 28-60 with the flat port using CMC-1 and two CMC-1's stacked. Remember the 28-60 only focuses to 30cm with 1:6.25 magnification so the added closeup lenses only get you to about 1:2.5. If you are looking for more magnification than the 20-70 or Sigma 20-200mm give you the macro range of lenses are a better choice with the Sony FE 100mm F/2.8 being the best followed by the Tamron 90 and Sony 90mm's.

Regarding the Sony FE 50mm macro now well over a decade old my recommendation would be the Marelux MV-60 or if you want everything Nauticam the MFO-3 on a flip adapter for both super macro and wider on the same dive. The MFO-3 works from 0-150cm while the MV-60 works from 0-infinity, the reason Tom Kline got his for the added distance.

According to the Nauticam portcharts, the Sony 28-60mm behind Nauticam N100 45 flat port gives up to 0,9x magnification and working distances between 55-80mm with CMC-1, while CMC-2 gives up to 0,7x and distances of 83-135mm (https://drive.google.com/file/d/1caMOa2cyCxucdcAiI8q9UsUu1YEg9ImC/view)

In addition, 28mm is probably the widest what one would want behind a flat port.

(I use Sony 28-60mm behind WACP-C, but never used it behind a flat port and/or with diopters, so what I say is theoretical)...

A lot of great information in this thread. I would only suggest that between the A7cII and the A7r, the extra mpix will be very welcome for the task you propose and the a7r will be less limiting.

It has been mentioned numerous times that TTL is important, but I would point out that the most expensive part of this is the TTL adapter that will work with whatever strobe you want. The simplicity of just having the correct exposure across those different fish is pretty key. And having bought a non-TTL and then a TTL... I went the most expensive route possible.

With a strobe, you light it up for such a short period of time it freezes the action even if there is movement. Not so with a video light so that also means greater success with a strobe compared to a video light if the fish decide to move at all.

My other thought, is a 180 dome floating around while you are trying to catch fish is a great way to get it beat up quick and a PITA. A flat port will be less likely to get scratched and that maybe of importance when deciding on your rig.

Thank you everyone for your generous responses. Thanks to your feedback, I am heading towards a setup based either on the A7CR or the A7R VI: I will try to get my hands on both housings before buying to see if the A7R VI is an acceptable size for me, otherwise I will go with the CR.

As for the lenses, I will go with:

• the sony 100mm macro with a 125 port + Marelux MV-60 on a flip adapter.

• A 28-60mm with a 45 flat port + CMC-2 (which I already own). The 28-60mm + 45 port combo is a modest investment relative to the total cost of the setup, and will be useful when diving in turbid waters and for dives dedicated to habitat photography.

I am trying my best to avoid a dome port, for the reason mentioned by @ColdDarkDiver (very high risk of scratches given my use case + I take a lot of photos of sand gobies, right at substrate level).

Three questions remain open:

• Is an MFO-1 wet lens useful (either with the 100mm or the 28-60mm)? The answer will also determine whether I buy a single or double flip holder. @Architeuthis, note that here I am only interested in the MFO-1 for its (potential) ability to improve autofocus acquisition speed and reduce hunting on moving fish.

• What about a 45° viewfinder? (Probably an INON, given the price of the Nauticam...). I am used to using the rear LCD screen on my G5X II, and I find it convenient to be able to shoot with arms extended in tight squeezes. But I know some people swear by viewfinders. I have no experience to draw on here.

• Nauticam, Marelux, or even Isotta (for smaller size) housing ? I guess here the answer is too subjective to be discussed...

PS: I am also going to upgrade my strobe, probably a Retra Maxi.
PPS: @Klaus, I am already very well equipped for photo post-processing—but I didn't know about the ON1 software, I will look into it, thanks!
PPPS: @Paul Kay, I am extremely jealous of your Jeffrey's Goby sighting :-). And the photo is incredibly beautiful!

Edited 21 hours ago21 hr by Fred Courchamp

10 hours ago, Fred Courchamp said:

Thank you everyone for your generous responses. Thanks to your feedback, I am heading towards a setup based either on the A7CR or the A7R VI: I will try to get my hands on both housings before buying to see if the A7R VI is an acceptable size for me, otherwise I will go with the CR.

As for the lenses, I will go with:

• the sony 100mm macro with a 125 port + Marelux MV-60 on a flip adapter.

• A 28-60mm with a 45 flat port + CMC-2 (which I already own). The 28-60mm + 45 port combo is a modest investment relative to the total cost of the setup, and will be useful when diving in turbid waters and for dives dedicated to habitat photography.

I am trying my best to avoid a dome port, for the reason mentioned by @ColdDarkDiver (very high risk of scratches given my use case + I take a lot of photos of sand gobies, right at substrate level).

Three questions remain open:

• Is an MFO-1 wet lens useful (either with the 100mm or the 28-60mm)? The answer will also determine whether I buy a single or double flip holder. @Architeuthis, note that here I am only interested in the MFO-1 for its (potential) ability to improve autofocus acquisition speed and reduce hunting on moving fish.

• What about a 45° viewfinder? (Probably an INON, given the price of the Nauticam...). I am used to using the rear LCD screen on my G5X II, and I find it convenient to be able to shoot with arms extended in tight squeezes. But I know some people swear by viewfinders. I have no experience to draw on here.

• Nauticam, Marelux, or even Isotta (for smaller size) housing ? I guess here the answer is too subjective to be discussed...

PS: I am also going to upgrade my strobe, probably a Retra Maxi.
PPS: @Klaus, I am already very well equipped for photo post-processing—but I didn't know about the ON1 software, I will look into it, thanks!
PPPS: @Paul Kay, I am extremely jealous of your Jeffrey's Goby sighting :-). And the photo is incredibly beautiful!

The housing brand question is a real challenge with no one right answer. I went Marelux, not only for the housing cost but every accessory adds up very quick and when I priced the housing I was able to get much more. The flip side (for better and worse) is that Marelux all uses the same size port... which is just a weeee bit bigger than the N120 that Nauticam uses on many of their housings... except the Sony's which use a N100. This means the camera housing is larger even if the body is smaller. On the other side - all marelux housings use the same ports so if you change cameras in the future you are still good to go.

As for the 45 degree viewfinder - I just invested in one. I like it. I would not get it for the A7c(series) as the EVF is not good. The reason why i really like it is because I need reading glasses and means I can see the screen crisply. The 45 degree viewfinder is also a big beast that is one more thing to bounce around. This is another place where the difference in cost between other companies and Nauticam is apparent. 780 USD (Marelux) vs 2000 USD (Nauticam). The Nauticam may be better? But for the A7c(r) or A7cII the evf is not why one would choose this camera.

22 hours ago, Fred Courchamp said:

Three questions remain open:

• Is an MFO-1 wet lens useful (either with the 100mm or the 28-60mm)? The answer will also determine whether I buy a single or double flip holder. @Architeuthis, note that here I am only interested in the MFO-1 for its (potential) ability to improve autofocus acquisition speed and reduce hunting on moving fish.

• What about a 45° viewfinder? (Probably an INON, given the price of the Nauticam...). I am used to using the rear LCD screen on my G5X II, and I find it convenient to be able to shoot with arms extended in tight squeezes. But I know some people swear by viewfinders. I have no experience to draw on here.

• Nauticam, Marelux, or even Isotta (for smaller size) housing ? I guess here the answer is too subjective to be discussed...

I have never owned a MFO-1, but I am/was using adapted Canon 100mm IS macro/Sony 90mm macro/Sony 100mm macro on the Sony A7RV. Even with the adapted Canon 100mm macro AF was o.k, but a liga below the native lenses. AF is great both with Sony 90mm and Sony 100mm on this camera body, but there were several complaints that AF is slow/pumping on Sony A7RIV and downwards. AF may be even better with A7RVI and it should be on par with A7RV on the A7RC, but I did not use this camera ever...

In the MFO-1 portchard (https://drive.google.com/file/d/1YcKS767I57nPedgq5vG3WVlElsp3XVLF/view) the Sony 28-60mm is not listed as compatible/tested, probably not useful for this lens (AF from the model A7RV upwards is very capable without any special diopters, however)

I started by using the back LCD on my first UW camera, an Olympus EM5II (and previously the Panasonic TZ5 and Olympus EPL-7 from my wife). Upon upgrading to EM1II, I got a 45° viewfinder together with the second hand Nauticam housing. Since then I greatly enjoy using it (also now with Sony A7RV). It helps a lot in getting a slightly upwards from the bottom perspective without bending body and neck too much...

I would not switch back to a plastic housing these days (e.g. like the initial Panasonic and Olympus housings of my wife, that I could use occasionally). My first alu housing (EM5II) was Nauticam (at this time very good quality (what is still the case) at a low price (unfortunately not valid any more)). Since then I use Nauticam. I presumably will not switch to Isotta or Marelux upon updating to a newer camera model, since (i) I know Nauticam as reliable and very ergonomic (I cannot say about the other brands, I never used one) and (ii) when switching to another brand I would have to deal with adapters for my other gear, i.e. (dome)ports, extensions, wetlenses, that is more expensive than just a bare housing ...

Edited 5 hours ago5 hr by Architeuthis