John E

Love the photos, thanks for sharing.

Thanks for the comparison photos, and for shining some light on this topic. Some replies have been illuminating. They do show the importance of smooth light fall off especially when using dual strobes angled slightly outwards to get even light across the picture Personally, I think the very colour-saturated coral reef photos, whilst beautiful, are quite unoriginal now and get too much exposure, whilst ambient light pictures that more closely reflect what we really see under water (and preferably capture some of the magic of it) are mostly left in the dark. Before I warm too much to making bad puns I will cool off and go and recharge.

Like Interceptor121 says, the TG-6 is hard to beat for snorkelling (but definitely use a housing as without one the camera will eventually leak at one of the little door seals). The 130 degree wet lenses are better than the 90 degree wet lenses which Mark said he didn't like. But if you are a very experienced photographer and you already have the cameras, and you are snorkelling, your situation is different to most. I suggest an important criteria is what field of view you want. The TG-6 with a 130 degrees wet lens that can come off to do great macro is unique. I also have the Ikelite TG-6 housing with small dome and the Olympus fisheye converter lens for the TG-6, which gives fisheye to macro in a tiny system. But if you want better image quality, and you have the cameras already, that similar zoom range comes with a weight and size penalty that potentially impacts snorkelling fun. If fisheye alone is ok the Olympus is better due to the lens options as it is compact, but you will possibly find that too limiting. Then if you want a narrower field of view you are looking at 8 inch dome ports or a wet lens. If you want zoomable fisheye then both cameras need adapted lenses and you are looking at similar sizes and quite expensive systems with adapters, zoom gears, extensions and housing manufacturers that support that option. Likewise, either system would be a similar size with a 130 degree wet lens. If the choice was Sony in Seafrogs versus Olympus in AOI, (or either in Ikelite) it really comes down to the lenses and how much bulk you want to swim with. And if that works out too much then it brings you back down a notch to the better compact systems with a wet lens, which is what I would be learning towards, pretty much just like the system Fruehaufsteher2 showed.

Have you thought about an AOI housing for the OM1? Maybe you would get more help from Backscatter.

One of the advantages of the Sony A7RV is versatility due to the sensor pixel density being like the A6700. With combined port extensions where 20mm can be removed, this means the rig can be used with the Kenko and a larger port for best full frame picture quality, but also handily can be used without the Kenko and with a small fisheye port and shorter port when minimum housing size is needed, such as when freediving. Then it can be used in full frame mode or the 26Mp APS-C frame size with zoom range. I am not sure if it better to use the APS-C mode on the camera or stay with full frame and just crop. Maybe someone can confirm? I don't think it makes any difference in picture quality but having the APS-C mode on the function button menu makes it very quick to switch to help framing composition.

So what is the real world interpretation? If one has the choice between Sony 26-60mm + WWL-1, the Canon 8-15mm, Sony 14mm or Sony 16-35mm at it's widest, and is taking the same type of shot such as a reef scene, which would be the better option for overall sharpness? Assuming the correct extensions are used and the appropriate dome size, is the fisheye the worst option unless the specific style is needed, or does the close working distance reducing the amount of water in front of the camera offset any drawbacks and mean it is the best option?

Maybe it is worth a test in a pool and have the same composition i.e backed off on the non-fisheye - this would better reflect real world use - as Chris H points out about the shooting distance for a given subject. For the Canon 8-15mm fisheye, if you are talking about an APS-C crop wouldn't it also be relevant to try it wider than 15mm? (noting the Sony A7Rv has the same pixel density as the A6700). i.e. I wonder what is the fisheye pictures edge difference between the APS-C crop at around 10mm (or whatever is the exact equivalent) to full frame at 15mm? Then there is the question of the view at the fisheye edge being so oblique anyway.

This is an example of using the Canon 8-15mm fisheye plus 1.4 Kenko with a Sony A7Rv but doing some partial de-fishing in Lightroom just because of the straight lines on the coral nursery. This happens to be with an 8 inch dome as that is what I had.

Olympus 7-14mm now sold Olympus 60mm now sold

I haven't used Weefine but have used AOI wet lenses. I have found the quality absolutely fine - but I now would avoid lower cost wet lenses that have a polycarbonate front element. Whereas it is possible to polish a dome port, to my knowledge the coatings on the polycarbonate front elements on wet lenses mean they can't really be polished, say if they get a scratch from a slight misjudgement when doing CFWA Getting a front element replaced then costs quite close to a replacement wet lens.

Housing now sold, camera and lenses still available.

I have for sale an Isotta housing + Olympus OM-D E-M1 Mark ii camera + some lenses. Other than the 12-40 mm lens, all items were bought new in 2022. Everything is in very good condition and fully functional. Comes with original boxes except for Olympus 12-40mm lens. Camera and lenses stored in a dehumidified cabinet. Camera only used in the housing. Items are in Queensland, Australia. Parcel post can be arranged. Isotta housing for Olympus OM-D E-M1 Mark II + Vivid Sentinel V5 plus manual pump (Asking AUD $1200) Olympus OM-D E-M1 Mark II body + Olympus FL-LM3 compact flash + 2 genuine batteries + Olympus charger (18,256 shutter count) (Asking AUD $700) Olympus 7-14mm f2.8 PRO lens (Asking AUD $850) Olympus 8mm f1.8 PRO Fisheye lens (Asking AUD $790) Olympus 12-40 f 2.8 PRO lens (Asking AUD $480) Isotta Olympus 7-14 zoom gear (Asking AUD $70)

I am a huge fan of the fish identification photographs of Gerald Allen, Roger Steen, Paul Humann and Ned DeLoach in books like Reef Fish Identification Tropical Pacific. I wonder if anyone knows what focal lengths they used. It strikes me that if you want longer reach MFT or APS-C is much more manageable and the amount of water you are shooting through is going to have a big impact on image quality and lighting anyway. (OM 90mm sounds appealing here) Another question is don't the 20-70 and 70-200 lenses extend a lot? Doesn't that effect image quality due to finding the best port extension length... eg difficult to get the right dome position on the 20-70 or vignetting at 70mm on the 70-200?

And you have to love the fish that need a fisheye lens. This reticulated whipray photo was taken on an EM 1ii with the Olympus 8mm.

I had (have) an EM1 ii i and now a Sony A7Rv. I just intended to sell the Olympus but have been hesitating. Both are really good but it is easy to underappreciate the Olympus. I have an Isotta housing and last year there was not a confirmation from them that they would make a housing for the OM1. (They do now.) I also wanted as high a resolution as possible as I am trying to take survey pictures of substrate and count coral recruitment. Hence my change to Sony. I can't see much benefit in the Sony in your circumstances except for the ability to crop, which could be significant. I am not sure about Nauticam but with the 102mm diameter port system on Olympus in Isotta I never have to remove a port to get the camera out of the housing even if using larger diameter lenses. I have found the 12-40 pro (thanks Chris Ross for the prompt) really good to use for medium size fish. I was using it with a flat port and extension that I had anyway and just the range from 40mm down to about 25 to 30mm. I assume it is considerably sharper than the 12-50. I was also using the 60mm macro. For me I really like versatility of the A7Rv (in APSC mode it has the same pixel pitch and resolution as the A6700). The autofocus is better but I didn't find it an issue on the EM 1ii. I tend to use back button and spot focus a lot as I am worried the focus will jump off my target. I've not found the AI on the Sony useful for fish so far. I have the 90mm and Canon 8-15mm fisheye and the Sony 28-60 which is probably not great for fish on its own (I have only tried it once - am waiting for a WWL-1 to arrive). I have not looked at the spec but assume the 28-60 has too long a minimum focus distance to be fun to use on its own. The viewfinder is very good. I have a 45 degree viewfinder on the EM 1 ii housing but haven't bothered using it yet on the Sony housing ( I very rarely use the LCD due to bright sunlight) The smaller and lighter lenses are something I miss when handling the camera on a boat. When I look back through my fish photos I can't tell by looking which ones are taken with the Olympus and which ones with the Sony. One thing about the Sony A7Rv is that, if I take a photo and it is not as sharp or detailed as I want, I now know it is is my fault and not the camera!

Thanks Whiskeyjack, I have the EM-1 ii. Interesting to know what Isotta recommended for you although the EM1 series and EM5 have different port charts (EM1 extensions being shorter) and the EM1 has the zoom cog is on the housing.

Hi Whiskeyjack, would you be able to provide the port extension length you use with the Canon fisheye lens Thanks. John

Glad to hear that is possible. I use Canon 8-15 with Sony. I have both Olympus and Sony Isotta housings but do not have the EF to MfT metabones adapter. Was planning on selling the Olympus but also thinking about keeping it. I use the B120 to B102 adapter so extensions and ports are interchangeable. For Canon on Sony they list zoom gears for use with an adapter only, and with adaptor plus teleconverter. I expect the part is like those gears with the different length to match the zoom cog in the housing body? They don’t seem to list the extension length on their port chart but have a wide range, so sounds like that would be simple. I doubt any custom parts would be needed.

Thanks. I hadn't noticed the two different 6.5 inch ports.

With this set up in an Isotta housing I am trying to find out what (if any) the sharpness compromises are on a smaller (4.5 inch fisheye dome) versus a 6 inch dome, and if small apertures and no need for circular fisheye, or absolute 180 degree coverage, mean the 4.5 inch is fine. I notice Zen have a 100mm fisheye port for the Canon 8-15..... a European company gives diameter in inches and an American company in mm ¯\_(ツ)_/¯

Thankyou Massimo. Your tests were a big help in me choosing the Canon 8-15 and newer Kenko 1.4 on Sony A7Rv. On this camera there is also the versatility of using APS-C mode and getting a good zoom range with the same image quality as the A6700, but having both options works well.

Hi Sundeep, I also learnt a lot from Massimo, Wolfgang and also Chris Ross. I'm not sure if Massimo is referring to Nauticam ports? I have Isotta and OM-D EM 1 ii (also now a Sony in Isotta). The 102mm port diameter is a bonus with Isotta. I have the 8mm with the 4.5 inch glass dome and the 7-14 with the 8 inch dome. Both really good, although as Chris says there is also now the OM system 8-25mm which sounds a good range but it's minimum focusing distance is still 23cm so not sure how that effects things with a 6.5 inch dome? If you don't mind a change, the Tokina with an adaptor sounds like a great zoomable solution to cover both lenses, but as Chris says the Isotta port chart doesn't cover it so you would have to figure the extension out, or maybe Isotta can tell you. Check the thread about the advantages of fisheye zooms, there is a chart with the zoom ranges of different options.

If they are about the same price the Metabones would be a safer bet than the Sigma. In Australia the Sigma is about half the price. I have a Sigma MC-11 on Sony A7Rv ... works great on photos, doesn't focus on video.

Hi Phil, It is true Isotta's port charts list the options but don't say which is the optimum image-quality solution for each lens, which would be better, but that is easy to find out when purchasing form a dealer. (I think naïve is not a fair description.) The same thing seems common practice with other manufacturers. From what I can see, Marelux lists their 7 inch and 9 inch domes as being suitable for wide rectilinear lenses. They even have a 5.5 inch fisheye port listed for the Nikon 14-24 F mount lens (minimum focus 28cm at 18-24mm), but not 14-24 Z mount (minimum focus 28cm at all zoom positions) along with the 7 inch and 9 inch domes, but no information on which is optimum.

Just to avoid possible confusion, the current "premium" quality Kenko 1.4x tele-converters are called "Teleplus HD Pro 1.4X DGX". There isn't "premium" in the name. The other cheaper current model is the Teleplus HD 1.4X DGX