Hello everyone,

 

I am new to this forum. I'm an ichthyologist looking to upgrade my UW fish photography gear. I currently use a Canon G5 XII with a CMC-2 and an Inon D-200 strobe, which gives me a very versatile magnification range, but I'd like to switch to a mirrorless system with better autofocus, a larger sensor, and higher resolution.

 

My goal is to be able to photograph, during a single dive, a ~1 cm goby sitting on the sand, a moving damselfish swimming past at 0.5–1 m, and larger fish up to 0.8m in size. I don't do true wide-angle or aesthetic photography: I "just" want sharp photos where I can count the scales and fin rays. I would also like to keep the setup fairly compact for snorkeling, rough water entries, or when squeezing between rocks.

 

I have a generous budget, up to $15k.

 

After quite a bit of research, I'm considering several Sony options (I am open to other brands but they do not seem to offer what I am looking for), but none completely satisfies me:

• A6700: compact but APS-C, relatively small sensor, getting pretty old now (it pains me to put a lot of money into a model that will be replaced in 1 or 2 years), flash sync limited to 1/160s.

 

• A7C II: compact as well, but also getting a bit old, sync limited to 1/160s.

• A7CR : more pixels but sync limited to 1/160s, and also getting a bit old.

 

• A7R VI + 100mm macro + MFO-3 (+ possibly MFO-1 on double flip): lots of resolution for cropping, excellent AF, the MFO-3 would allow a wider field of view for larger/closer fish. But the whole setup seems bulky.

 

• A7R VI + 28–60mm + CMC-2 on a flip adapter (+ MFO-1 if useful?): this option would better replicate the philosophy of my G5 X II: versatile, more  compact and lighter than 100mm+MFO-3, but I'm afraid of losing a lot of working distance, magnification, and perhaps ease of focusing on very small fish.

 

My ideal lens would probably be a small macro zoom, for instance something like a 40–100mm capable of going from infinity to 1:1, but that doesn't seem to exist. Failing that, a compact 50–60mm macro with extremely fast autofocus might be the best compromise, but the Sony one gets bad reviews.

 

I would appreaciate any advice.

My best

Fred.

I don't know if you read the ongoing endless debate FF Vs Crop, anyway I will try to stay away from it, but I do not know for how long 😁

Let us say that regardless of the camera and its format, the current mainstream solution is to have a macro lens in the 90/100mm range and a double flip MFO-1 and MFO-3.

This solution works with both FF and M43.

Just my 2c.

From the setups you are considering, I would go for A7R VI + 100mm macro + MFO-3 (+ possibly MFO-1 on double flip):

MFO-1 will not bring much, but with SMC-3 (2,4x magnification) instead, a 10mm fish will fill approx. 68% of the width of the photo (i.e. approx. 36mm). With the bare 100mm lens (1,4x) a 10mm fish will fill approx 39% of the photos width...

Concerning FF vs. crop sensor, you can crop the photos made with the 67 Mpixel sensor also in postprocessing to the dimensions of APS-C or MFT without any loss of IQ (in case you do not mind the big setup)...

In case size matters, I would go for MFT with Zuiko 60mm +/- MFO-3 (CMC-1 is required only when very small objects are going to be photographed)...

Edited August 24Aug 24 by Architeuthis

Just a small comment, as I'm also looking around to upgrade for a more ergonomic kit (read: newbie wants to move from a Seafrogs housing to Nauticam world - ha! should have paid more attention to all the feedback I got here :D )

I also thought that newer models are likely just around the corner (a Sony A6900 for 2027...?), but not only they aren't here yet, housings will also take a while to come around (I read 6-18 months after a new body is released). That adds quite a long time window to any model that isn't here yet. I'm leaning for the A6700, mostly because I find very marginal the gains of FF for what I do and the increase in bulkiness is substantial. That said, cropping from a A7R VI most be such a pleasant experience ! :)

Whether the cropping is a benefit depends on how shy the fish are. You can count the scales the better the closer you are when the photo is taken. Fish from 1 cm to 80 cm seems to be a classic dilemma (and I have nothing to add to the suggestions). But it will always be better if you don't need to crop because you were close enough to fill the frame.

9 minutes ago, Klaus said:

Whether the cropping is a benefit depends on how shy the fish are. You can count the scales the better the closer you are when the photo is taken. Fish from 1 cm to 80 cm seems to be a classic dilemma (and I have nothing to add to the suggestions). But it will always be better if you don't need to crop because you were close enough to fill the frame.

For small and shy critters the capability of the Sony 100mm GM f/2.8 to work with TC's (1,4x and 2x) is another benefit: magnification as well as working distance is increased proportinally when TCs are used - with TCs at a species-appropriate working distance even cropping may not be required...

Only the very best for scientific documentation (and the setup fits the budget too)!

(I must admit that in my former life I have been a scientist, hence comes this inclination)...😆

Edited August 24Aug 24 by Architeuthis

It's just a bit difficult to change a tele-converter during the dive when the 80 cm fish shows up...

Scientific work should not be limited by equipment, I agree, but coming from a G5 with CMC2 the larger kits may be challenging to handle at first. I suppose that for macro / flat port setups all of the sensor options (MFT to FF) will end up not all that different in size. Probably it's when you use a dome port that the bulk for a FF system increases significantly?

Let's not forget that the D200 strobe might be begging for an upgrade, too. Something that recycles really fast.

28 minutes ago, Klaus said:

It's just a bit difficult to change a tele-converter during the dive when the 80 cm fish shows up...

Scientific work should not be limited by equipment, I agree, but coming from a G5 with CMC2 the larger kits may be challenging to handle at first. I suppose that for macro / flat port setups all of the sensor options (MFT to FF) will end up not all that different in size. Probably it's when you use a dome port that the bulk for a FF system increases significantly?

Let's not forget that the D200 strobe might be begging for an upgrade, too. Something that recycles really fast.

The argument that Fred may be shocked by the size/weight of a FF macro setup with double flip is very valid - so better have a close look at the different setups in real life and get the hands on them before making a decision...

(I should ad that during my life as a scientist, I was a biophysicist/molecular biologist and fish documentation was never my target; I am, however, sure I would choose A7R6/100mm macro setup (and Sony 16-35 GMII with Seacam PPO for fish >35cm). Even now, with 70 years of age and beeing a hobbyist UW photographer, I am strong enought to lug around my FF setup without wailing 🤣)...

When setup size is compared, my personal experience is the opposite to what you are writing (MFT (Oly EM1II) vs. FF (Sony A7R5); I cannot tell about APS-C from my own experience, so others should comment):

#1.: I can say that the big difference in size and weigth is in the macro setup (both Nauticam housings: EM1II/Zuiko 60mm is perfectly small, smart and light, whereas A7R5/Sony 100mm is the biggest/most monstrous setup I ever handled (- but with best IQ ever))

#2.: For moderate WA (fishportrait): size/weigth difference between EM1II/Zuiko 12-40mm pro/Zen DP170 and A7R5/Sony20-70mm G/Zen DP170 is small. Both deliver excellent IQ.

#3.: More WA (not requested by Fred): similar with EM1II/Canon 8-15mm/Nauticam 140mm dome vs. Sony A7R5/Canon 8-15mm/2xTC/Nauticam 140mm dome. I see no essential difference, but fisheye is not the lens of choice for scientific documentation. Better take rectilinear WA: EM1II/Pana 7-14mm/Zen DP170 vs. A7R5/Tamron 17-28mm/Zen DP170 - pretty similar in size and weight (I would, however take A7R5/Sony 16-35mm GM2/Seacam PPO for that purpose (rectilinear best IQ with low aperture number))...

Fred's complaints (with G5 and a single D200 strobe) are better AF, bigger sensor (why?) and more resolution. Maybe he wants one small setup to do it all, similar to the G5 compact setup...

Then Sony A7CR/Sony 28-60mm/CMC-1(WWL-1) may be the setup that meets his requirements best, with similar photography experience comparable to the compact camera?

There is, however, no free lunch and fish from 10mm to 70cm will always be a (pretty flawed) compromise with a single lens setup. To have both categories at best IQ (and long enough working distance, what is certainly important for scientific documentation) requires ILCE with different lenses/ports...

Of course two capable TTL flashes are the most important upgrade, even when continuing with compact camera...

Edited August 24Aug 24 by Architeuthis

It’s going to depend on how close you can get to your 1cm goby. A 100mm macro lens will do it, however it will only take up 1/3 of a full frame sensor horizontally. Then the 0.8m fish will have a lot if water between you and the subject, challenging strobe power and increasing chance of backscatter and reducing resolution.

The MFO-3 will help , but has a limitation that its max focus distance is about 1.5m away. Different lenses will have different fields at this distance. I shoot with the OM-1 and 60mm macro, a fish about 700mm long fills the frame at max focus for the 60mm macro/MFO3 combination. I posted a thread on using this combo a while ago now:

The trumpetfish in the photo from this post is about 500-600mm long and the frame is slightly cropped, so it looks like it will scrape in for your 0.8m fish requirement.

The Olympus is certainly a smaller lighter option in Nauticam compared to full frame housings. It has 1/250 sync speed and can get 1/400 using the Nauticam manual trigger.

You asked about gobies, this is a whip coral goby from Lembeh, OM-1 with 60mm macro, it's probably about 70% of the frame so some cropping, certainly could have gotten closer to this one.

Certainly it's a decent option, some cropping is possible if photo is sharply focused to start with It will be lighter than most full frame options, though the Sony A7C will be a smaller housing I think - by a little bit. I get in and out over the rocks with some swell most of the time at my local dive site in Sydney and it's relatively easy to handle.

The OP wants to photograph a range of fish sizes on the one dive, but doesn't mention if he is time limited (surveys?), or if the aim is solely fish photography.

There is a world of difference between having to get any shot of say, a juvenile wrasse for later ID, then quickly moving on to continue a survey; vs a dive where you can chase your damsels and wrasses as much as you like. Several of the options suggested could work for the latter case; but if time limited, flip-flops and other water contact options won't cut it, so a macro lens is the best option.

The OP didn't mention his typical dive conditions. In good viz, a 100mm macro should do the job on FF, but will not be much good in low viz; say 2-7m, so a 50-60mm macro makes more sense for FF there. Assuming as an ichthyologist he dives all over, then he will need both lenses; or at least the 100mm + the MFO-3, if he doesn't mind the extra length.

The 100 may also prove a bit of an issue to physically track those damsels and wrasses. Physical tracking is certainly easier with more FOV, especially if you are time limited. And I get what others say about not cropping; but the fact remains that you can get good images allowing scale and fin counts even heavily cropping 60+ mpx sensors, including of 20mm gobies. We would all like not to crop, but it's not illegal!

Not sure which housing system he is leaning towards, but if he favours Sony APS-C, I would steer clear of Nauticam, as the N85 port system is a curse.

On the other hand, if size is a big consideration, then Sony A7CR is worth a look, as it is hardly bigger than the A6700, and he can still shoot APS-C if he wishes. More to the point, the Nauticam housings for these are similar size and weight; but you get the big advantage of the N100 port system with the A7CR housing, plus better fibre optic connections; something that the influencers never mention... When I owned both Nauticam rigs for Sony A7CR and A7RV, I measured the weight difference at 1.1 kgs (housing + body), with corresponding size difference.

If size is not an option, then Canon and Nikon may offer macro options that perform better than Sony, though I haven't seen much of a size / weight difference between FF and APS-C rigs with those brands, so FF will make sense.

As a working fish nerd myself, I don't find the quoted Sony 1/160 synch speed limiting, and it is in any case 1/200 in practice.

Hi,

thanks to all for all the answers.

@dentrock is true that I should have given some contextual information. The only purpose of the dives is to photograph fish, and to capture them. Usually I take a picture, and then I try to catch the photographed fish (with chemicals and handnets - then my camera, attached to me, floats above my shoulder - it needs positive buoyancy). I am diving in NE Atlantic and Medit. Viz can be good, or much lower than 2m...

"I don't find the quoted Sony 1/160 synch speed limiting" -> this is very informative as it makes A7CR a good option, thanks.

@Chris Ross @ Architeuthis I had not considered Olympus/OM so far. Spontaneously, 20Mpixels seemed to few to me: this is what has my CanonG5xii, and I am currently frustated by the lost of details when I crop (compared to a colleague who has a D850, for exemple). So the benefit would be mainly to have a better autofocus, no ? Yet evidence are there, and Olympus/OM seems definitely a route to investigate. Thanks

For the housing, I like Nauticam.

@Klaus For the strobe : my INON D200 (I also have 2 S2000) have a descent recycling time (1,5 sec). 20 GN is not a lot but it is usually enough for me. I read that popular strobes like Retra Pro Max II does not recycle faster. But I should investigate other brands. It is true that recycling time is limiting for me. This is why I have considered buying a powerful video light (like weefine solar pro) and test using burst mode photography, but fish seem to be very sensitive to such lights, so no sure this is a good option. Prehaps investigating a Backscatter Hybrid Flash HF-1 ?

Is there alternative to Sony macro 50mm (=other brand) that could fit the Sony A7RVI, and that would be compact (like the Zuiko 60mm) ? Even if not, one option could also be to use the A7R VI + 28–60mm until a good 50/60mm macro is out (it would not be very expensive to secondarily by a lens + port if I already have a good camera body + housing).

Edited August 25Aug 25 by Fred Courchamp

2 hours ago, Fred Courchamp said:

I had not considered Olympus/OM so far. Spontaneously, 20Mpixels seemed to few to me: this is what has my CanonG5xii, and I am currently frustated by the lost of details when I crop (compared to a colleague who has a D850, for exemple)

Do you dive with your colleague?

Have you ever handled hisl D850 kit underwater?

Except for the housing, the ports are the same for any FF kit on the market.

"The only purpose of the dives is to photograph fish, and to capture them. Usually I take a picture, and then I try to catch the photographed fish (with chemicals and handnets - then my camera, attached to me, floats above my shoulder - it needs positive buoyancy). I am diving in NE Atlantic and Medit. Viz can be good, or much lower than 2m... "

In this case (catching the fish after the photo, that is just intended for documentation) a hughe setup, providing the best IQ, may not be ideal (but it could work in case there is a colleague to help out (e.g. holding the hughe setup while catching the fish and holding the catching gear (and the already caugth fish) while making the photo)?).

A compact setup (e.g. A7CR/Sony 28-60mm/CMC-1) with a single, TTL operated, compact flash is probably better suited to do the job. Flash mounted close to the housing (suboptimal lightening, but compact).

A7CR certainly fulfils the requirement of better AF and (much) more resolution compared to most cameras and certainly compared to an old compact camera as the G5 is...

There are comprimizes with very small and also the large fish, but one can crop for the small fishes...

On special occasions, one could even deviate from the universal concept and mount Sony 100mm macro/SMC-3 (on flip) for small fish or a water contact optics (e.g. WWL-1) for large ones, in order to get better IQ?

Thanks @Davide DB and @Architeuthis . Yes I have seen the D850 set up (with nauticam) : it is too big for me, mostly because of the housing. I have also seen the A7CII + 28-60 set up (with nauticam) : it is perfect. I think I could even tolerate a slightly bigger housing. I have never seen the housing of A7R5/6, it seems to be in between that of D850 and A7CII.

On the paper, the A7CR seems the ideal camera for me, especially if the 1/160 sync is not an issue (I had read that some poeple complained about this but I do not remember if this was based on real experience or not). My only remaining concern is that it has been released in 2023. Psychologically, it is difficult for me to put such an amount of money for something that might soon be replaced. But I have a grant to buy this equipment, I cannot wait to spend it. And if this is currently the best option...

@Klaus For the strobe : my INON D200 (I also have 2 S2000) have a descent recycling time (1,5 sec). 20 GN is not a lot but it is usually enough for me. I read that popular strobes like Retra Pro Max II does not recycle faster. But I should investigate other brands. It is true that recycling time is limiting for me. This is why I have considered buying a powerful video light (like weefine solar pro) and test using burst mode photography, but fish seem to be very sensitive to such lights, so no sure this is a good option. Prehaps investigating a Backscatter Hybrid Flash HF-1 ?

Sorry, my wording was imprecise. If you had a more powerful strobe, then it will not use all the capacity for the flash and you can get another shot very soon after that. The recycling could happen in the background, so to speak. I should thus have written … a stronger strobe with fast recycling … or so. And, as said before, in your situation you certainly want to rely on automatic TTL strobe exposure. The HF1 could be a good choice but I don’t own this strobe.

5 hours ago, Fred Courchamp said:

On the paper, the A7CR seems the ideal camera for me, especially if the 1/160 sync is not an issue (I had read that some poeple complained about this but I do not remember if this was based on real experience or not). My only remaining concern is that it has been released in 2023. Psychologically, it is difficult for me to put such an amount of money for something that might soon be replaced. But I have a grant to buy this equipment, I cannot wait to spend it. And if this is currently the best option...

Sounds like you found your partner! The best results will come from equipment that you are familiar with - whether it’s is new or top-of-the-line does not matter if you can’t find the button for making a particular adjustment. I shoot a 12 year old m43 and it’s not the camera that limits my shots…

As I mentioned, your « partner ». 😉 we keep those around for a while…

Hi Fred,

I have been following your quest for useful insight and this is my take. Most fish are larger than 1cm and will fit into a 1:2 minimum focus distance frame. The 90-105mm macro lenses are most useful for images from the minimum 1:1/1.4:1 hangout to about 1:6 before you are putting to much water between the lens and subject, vis is a contributing factor in some cases. So while I wholeheartedly endorse the Sony FE 100mm as the best macro lens on the planet, (I have one with 1.4 & 2X tele converters) I believe you have a chance of a wider range of subjects with a zoom lens. The attached photos were taken with the Sony A7R V in Marelux housing with the Sony FE 20-70mm F/4 lens using a 180mm dome port. This lens has a 1:2.56 minimum magnification. The camera is 61MP so cropping is no problem for your use I would think. Marelux and Nauticam both support this lens with a zoom gears. Marelux uses an extension ring 50 and Nauticam uses the N100 to N120 35.5 port adapter II and extension ring 35 with the 180mm port. This is a $1200.00 Sony lens. With this lens you would really shoot at less than about F/8/F11.

While I have been very happy with the Sony 20-70mm when I know I will be dealing with a verity of subjects sizes I have now found what I consider to be an even better mousetra, the Sigma 20-200mm F/3.6-6.3 DG a $900.00 lens. This is a lens that at this time is only supported by Marelux with a zoom gear. What makes this lens unique is that it focuses to 1:2 from 28 to 85mm behind the 180mm dome and can extend out to about 130 to 150mm before it quits focusing because it gets to near the dome glass. Additionally the Sigma will stop down to F/40 in the macro range.

My guess is that I am older than you Fred and I have been using the Sony A7R VI, A1 II and A7C both II and R all with Marelux housings and dual Marelux Apollo S and Apollo Y TTL strobes. Like some other strobes in the market these include HHS which solves the /1/160th sync to a degree, TTL, and multi frames settings.

If you decide to go with the A7C II/R I have a like new Marelux housing and very low milage A7C II and A7C R camera bodies for sale.

Those were all shot with the 20-200mm behind a 180mm dome?

I miss the ability of my m4/3 12-50mm as a generalist lens for photos of opportunity. Being able to find something similar for Sony FF is very appealing.

The photos are with the Sony FE 20-70mm F /4. I now have a 180 port in house and will be testing the Sigma soon.

The OM 12-45mm F/4 is a 1:4 lens so about the same as FF at 1:2.

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).

Edited August 25Aug 25 by Fred Courchamp

I specialize in shooting salmon under water in Alaska where I live now having done it digitally for over 20 years. My very first digital underwater shoot was with a Nikon D1X that yielded the cover shot for a book published by the American Fisheries Society. (I am a fish scientist: an aquatic ecologist specializing in using stable isotope analysis) The technology has come a long way since. I used the Nikon D2X as my main camera for about the first 8 years. Both The D1 and D2 cameras were APSC or DX in Nikon-speak. From participation on Wetpixel I learned the DX limitations could be overcome by the full-frame Canons such as the 1Ds2 which I got and literally used alongside the D2x. I even shot a pic showing this which I tongue-in-cheek titled Nikon vs. Canon: https://www.salmonography.com/Salmonid-Topic/Photography-techniques/i-KS7Jjpz/A

I considered the D2X a 400 ISO camera and the 1Ds2 a 1600 ISO camera. Today’s cameras can do much better but there remains this 2 stop ISO advantage due to a larger sensor. The D2X was Nikon’s flagship camera when I bought it so had the best tech available to Nikon at that time. The sub-flagship cameras typically had poorer performance and this still applies today. The “flagship” model changes frequently within each brand. I would say the Sony R6 is their flagship today although they may not agree.

One aspect of comparing cameras is to look at the Photons to photons website. I took the opportunity to plot a few select cameras on it. See attachment. You can see the leap from the D1X and D2X to the D850 and now to the R6 - technology advancement continues to march forward! I would not spend a lot of money on older tech. Nikon is overdue with updating theirs. I have a Z9 but only use it for topside shooting. Its secret super power is that the cameras has NO shutter so is truly silent. I gather the Z8 does not too. This is great for wildlife photography. I gather the R6 still has a shutter in it. The Z92 will likely be too late for you. I am all too familiar with the need to spend grant money within a specific time - mostly being the federal fiscal year here in the US.

As for housings, if the Nauticam model is too large you might want to look at the competition as they might be smaller (at least the controls and grips may not stick out as far). As you are in France you might want to consider one made in the EU. Service for one will be much easier. I have been using Seacam as my housing brand. They have an R6 housing development as does Subal and Isotta: https://www.backscatter.com/Seacam-Sony-a7R-VI-Underwater-Housing

Scroll horizontally to see the various brands.

If the Viz is good you will be able to do a lot with the 100mm macro. Basically any true macro lens (various manufacturers) will blow away the lens on your compact camera. I use the Nauticam wet lenses on my Nikon 105mm and 60mm lenses with Saga ports (Saga is located in Barcelona). Instead of the MFO-3 with its 1.5m limitation I bought the new Marelux 60 add-on that fits just like a Nauticam one. To shoot larger things here in AK (0.8m is similar to the subject width of many of my salmon shots showing a female with her mate just behind her). I use mostly fisheye lenses and to a more limited extent the 16-35 zooms at 16mm (both C and N). The 16mm lenses need more working distance so get used more late in the season when the air temps get below freezing ( glaciers upstream stop bleeding in silt). Many shots with these lenses are on my website (exif data avail at the tiny dot with the i on it),

As for underwater strobes I VERY STRONGLY suggest you get the Retra Maxi. I was using mine just yesterday with my Nikon D4S shooting in continuous mode at 5 frames per second!!!!! Forget about recycling times. Already a lot has been written on the strobe on this site.

Edited August 26Aug 26 by Tom Kline

A few further comments:

1. Re Sony 50 macro, I like it a lot! Especially behind a dome, where it gives excellent sharpness right across the frame, even at say, f5.6. And I'm not the only one. Alex Mustard has a very interesting clip on 'curved ports' which features this lens. I have good pics of fast moving pelagics with it. But others call it a dog... They are cheap, so suggest you get one, or buy a used one and flog it if you don't like it. It's my 'go to' lens with the dome, and I don't bother with flat ports for this lens, as they destroy the corners. Downside is 1:1 is very close to the dome.

2. Re 20-70, an excellent choice for general photography, especially at the 70 end, but for the smaller stuff, the big 180 port required for the full zoom range gets in the way a bit (subject can move before you find it again in the VF). I have had good results with the now defunct very compact Nauticam 4" WA dome, but the zoom range is limited to 45-70. I haven't tried it with a flat port, but I would expect a similar zoom range, with poor corner sharpness. It has very fast AF, and I can get 1:2.7 mag with it.

3. Re strobes, I use 2 x Inon S220 now, and used S2000 for many years before that. Reason is small size, and perfect for macro, although I use them for everything else as well. I wouldn't go back to a single strobe, unless solely shooting small fish in mid water. 2 x is always better...

4. Unlike seemingly everyone else I come across, I use the shortest strobe arms that will do the job ( 1 x 20cm each side, with 2 x ball joints). Great for shooting in caves or crevices.

On 8/25/2026 at 2:07 PM, Fred Courchamp said:

then my camera, attached to me, floats above my shoulder - it needs positive buoyancy).

@Chris Ross @ Architeuthis I had not considered Olympus/OM so far. Spontaneously, 20Mpixels seemed to few to me: this is what has my CanonG5xii, and I am currently frustated by the lost of details when I crop (compared to a colleague who has a D850, for exemple). So the benefit would be mainly to have a better autofocus, no ? Yet evidence are there, and Olympus/OM seems definitely a route to investigate. Thanks

For the housing, I like Nauticam.

First your housing floating, I always find positive housings to be annoying to use . You can get adjustable float arms from Kraken that allow you to get the housing perfectly neutral so it stays where you let go of it. Might be worth thinking about.

Regarding cropping - do you crop as you can't get close enough or do you run out of magnification?

The G5X covers 21x18mm field at max magnification and 67mm working distance with the CMC-2

The OM-1 covers 17 x 13mm at 1:1 with about 80mm working distance

The Sont A7C covers 26 x 17mm at 1.4x and 90mm working distance

So the Olympus 60mm gets more magnification on the sensor covering a smaller area at the same working distance as the Sony A7CR with the new 100mm macro. AF and finding subjects is easier with a proper macro lens compared to a zoom with a diopter.

On the issue of latest models, yes there is a bit of FOMO, but from an image quality perspective, the improvements are incremental these days, comparing sensors from 15 plus years ago there are big advances but in the last 10 years improvements have come in readout speeds, computational photography and other aspects, rather than image quality measures. Improvements in noise and dynamic range are very much incremental, they are not non-existent but IMO not enough to choose one system over the other.

By the sounds of your requirements, a macro is really what you need, many domes options allow you to get close and up 0.3x magnification, but the dome gets in the way for example trying to shoot a fish sitting on the bottom you have to shoot from above.

If you are interested to look my website has a lot of UW images and there are quite a few fish of various types, you could look at this folder, all images are OM-1 with 60mm macro and select images with the MFO3.

Australian Natural Images

Dear Fred,

another thing you may want to consider for your grant money is a computer / workstation for image processing. I don't know if you are already well served for that at your institute, but image processing can become part of your routine - if you decide that it's appropriate.

Using AI to improve image quality is certainly a difficult thing for scientific purposes. The borders of what's acceptable and not are blurry and also depend on the field of research (i.e. whether and how the community accepts these technologies). For cell biology, this is starting to become applied to improve signal/noise of e.g. fluorescence images, in particular before automated image analysis in "-omics" projects. But one has to be very vigilant that the "improvement" does not "iron out" true information or, in your case, introduce artifacts that you may count wrongly as a fish scale. Let your own judgment and gut feeling guide you as to how far YOU find this acceptable.

Now, that said, AI processing can make counting scales a lot easier for you. I process my images with a program called ON1 photo raw, the also offer a Photoshop / Lightroom plugin for just the de-noising and sharpening. I wrote a tutorial about it on this site some time ago, certainly the tools from other software companies will be comparable.

What can this do for you?

Here's an out-of-camera jpg from last summer (Olympus E-PL5, 14-42 RII kit Zoom and Inon UWL-100 wide-lens without the dome):

And here is the same image after processing:

There's a bit more going on than just the sharpening / de-noising, but I hope the difference is visible even after the website has down-sampled this a bit more. The second picture will make it much easier to count the scales, but if you squint you can see them all in the camera-jpg as well.

ON1 offer a free 30-day trial with full functionality (google on1 photo raw). You can try it out on photos from your current setup, see what this can do for you. It will work on both jpg and raw but obviously raw gives better results. If you try this out, you will see that you need a reasonable graphics card for your professional needs - otherwise it is way too slow. The GPU's are viciously expensive these days, so count ~3000 € or above for that workstation.

This is a crop from the 16 Mpx M43rd sensor, the E-PL5 has the same sensor as the original Olympus E-M5 from 2012. Here's the full image (processed), limited artistic value but this is a technical discussion.

Edited August 26Aug 26 by Klaus
addeed full image

I have undertaken a lot of fish photography for scientific purposes. The problem is that a versatile set-up will work adequately but probably not as well as a more limited set-up, depending on subject. I find that I use a full frame camera and 60 or 100 lenses. IF type lenses are usually faster to focus, but again it depends. If you are wanting photos which are good enough to count fin rays and/or scales then your technique needs to be precise too and you are probably balancing depth of field with diffraction. I find on full frame f/11-16 probably offers the best compromise, and everything is starting to become a compromise when you are shooting fish which can move in any direction unpredictably, or are smaller than the dimensions of the format and the light and contrast are never as good as might be hoped.

My fish 'system' of choice would probably be a decent MPixel camera (~25MPixels, maybe more) with a macro (90/100/105mm) and a flash with light which switches off during exposure. That said I've been successful with 60mm macro (I use a Nikon now as the 50mm Sony has not proven to be my favourite) lens too, and even an 18-35. It depends. This Jeffrey's Goby (~4cm long) was shot on a 60 macro in temperate seas off Scotland a couple of weeks ago - the elongated second fin ray confirms its identity and is the feature I needed to capture.

Edited August 26Aug 26 by Paul Kay