John E

Bit late (just saw this) but ... I used 60mm extension and happy with the IQ. Isotta recommend 50mm extension for the 20-70mm and 60mm for the Canon 8-15mm+teleconverter + adapter with a larger port. (They recommend 50mm extension for the fisheye 4.5 inch port.) The first photo is from Blue Corner, you would think it was a WWL or fisheye but it is the 20-70mm at 20mm. The second photo is the same set up at 70mm (a type of anemone I haven't seen before).

For Isotta there looks like a couple of options depending on what extensions and ports are already owned. I posted this earlier in the thread.. It looks straight forward for Isotta users like myself. They have both a 17mm and 20mm extension to add to the port for the Sony 90mm, or they have an 80mm extension that could add to the port for the Sony 28-60mm (since last year that port is available with the front 67mm threads specifically for use with the WWL-1B).

It looks straight forward for Isotta users like myself. They have both a 17mm and 20mm extension to add to the port for the Sony 90mm, or they have an 80mm extension that could add to the port for the Sony 28-60mm (since last year that port is available with the front 67mm threads specifically for use with the WWL-1B). I had a brief moment of excitement when I saw the 100mm f2.8 GM listed for AU$1927 before realising it is the older lens and not the new macro.

My wife and I spent two weeks day diving in Palau recently. A fisheye is great for the walls with fans and big caverns like Blue Holes. Turtles were very chill and easy to get very close to. Mantas at German Channel very close. Big schools of barracuda and jacks were cool. But.. we found sharks at places like Blue Corner and Siaes Corner really better off with a bit longer focal length. I had a Canon 8-15mm plus 1.4 teleconverter and a Sony 20-70mm. Both work with the same extension and port so I could change over in the open boat during the surface interval without hassle. The Sony 20-70mm was a great range for many dives. I left my Inon Z330 behind and used Inon S2000 to save weight. Sounds like your existing plan of two lenses with the same dome is a good one.... I just checked your profile and it looks like you have Olympus, maybe 8mm plus 12-40mm? This first pic is with the fisheye, all others with the Sony 20-70mm

Thanks for the review. I have used a lot housings made by AOI (Olympus TG. Fantasea Canon G16 and EP10 housing). I like them but I wonder about the serviceability. Do you know if factory servicing is done or other third party service agents are available? It is great to see them making these housings for Sony and expanding their port system but, whereas the small low cost housing are almost disposable, these more expensive ones hopefully are fully serviceable?

Hi Stig, I previously had the AOI EPL-10 housing with a 9-18mm. I wasn't that keen on the lens. I did use the camera also a little with the UWL-400 which I had already from a TG5 (super on that camera). Of the two set-ups you mention I personally would go with the wet lens. (But I don't have experience of the Panasonic 7-14mm, only the Olympus 7-14mm.) I didn't do any pixel peeping with the UWL-400 wet lenses but although the UWL-400 is on the OMD EM 10iv port chart, I assume the more expensive and heavier (1408g vs 606g) UWL-09 PRO wet lenses is going to be better quality and it has a glass front element. I have had two UWL-400 and scratched them, one of which had a costly factory repair. The front element is polycarbonate with a coating and can't easily be polished if it gets a scratch, unlike a dome port. The answer is to be careful doing close focus... It all really depends on personal use and preference (budget plus what field of view do you want and will you also have a macro lens) rather than one option being a clear winner.

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.

Looks really interesting... minimum focus distance of only 14cm....

Either sounds a good choice even if you had a big budget, so it really depends what look you personally like.... Out of those two I would also choose the fisheye, especially for freediving. The Sony A7Rv also does give you the potential for cropping if you want a narrower field of view.

Just to clarify.... is this issue of the autofocus not being accurate enough for you on the spot setting due to being unable to be made small enough on the Sony A7Rv when other brands like Canon mentioned can go smaller? On my Sony A7Rv it already looks very small to me (i.e. non-expand spot). Could it be an issue with the other Autofocus menu settings? Sony says.. "For [Spot], the subject should be large enough to cover the whole Focus Area (as a guideline). Having the subject at this size avoids the focus drifting to the background." On OM1 the smallest focus point can be adjusted to a smaller area... looks like down to a single autofocus dot on the screen? My understanding (moving from Olympus OMD EM 1ii to Sony) is that OM System has the best in camera focus stacking which is why it is popular for land macro, but I don't know if the stacking is usable underwater, and without it the big advantage of OM System is lost compared to a high resolution camera. Maybe the autofocus has an advantage because of the small spot customisation? wonder if Canon or Nikon have that? The pixel size on the Sony A7Rv is similar to the OM1, so if I crop to MFT size I get the same magnification with a 90mm Sony lens as I would with 90mm OM system and no loss of image quality by comparison, yet I have the extra versality of the large sensor too. I have not had an issue with my Sony A7Rv and also have custom button and lever set to adjust the focus area (C2) and tracking on and off (record button) (Isotta housing). Picture below is from the OM1

Have a look on AOI website. They have a new +6 called UCL-05N. The UCL-09 is discontinued but I have seen a review claiming good things for the UCL-09PRO. I haven't used either. Nor do I know how the new +6 UCL-05N differs from the discontinued +6 UCL-05L, but would like someone to get them and do an unbiased review! I think the Kraken maybe is made by Weefine (WFL08S).

Since at least last year Isotta can be used with the WWL-1B without modification with the correct port (e.g. H59 B120 for Sony 28-60mm). The WACP can also be used with an Isotta made adapter. There is actually a video that shows this ... Insider DIvers Youtube channel "Do Nauticam Wet Lenses work on Other Housings? YES, THEY DO"

Also consider a pre-owned Sony Zeiss 16-35 f4 which may be the lowest cost option with Seafrogs.

I have an Isotta housing with Inon 45 degree viewfinder. It is the same process as Tim describes for Subal. Changing the viewfinder is easy... The backing ring on the Isotta viewfinder, on inside of the housing, has two small indent holes. I am not sure if there is a specific tool, but to change I use circlip pliers to interlock with the indent holes to simply loosen, then screw off the backing ring by hand. The standard Isotta viewfinder then pushes out once the backing ring is removed. It is sealed with double o rings. To install the Inon 45 degree viewfinder, simply align two small pins with corresponding indents on the housing clear window then push the viewfinder into place and do up the backing ring. (The Inon viewfinder has a single o ring.) The Inon viewfinder backing ring has four small indents and a tool that comes packed with the viewfinder to turn the backing ring. Best not to be too tight and obviously have silicon grease on the o ring. Like Tim I do not leave the viewfinder in place for travelling (it looks a bit vulnerable sticking out) and is easy to change over. By the way, the viewfinder was pretty much essential on my previous Olympus OMD EM 1 ii, but easy to manage without on a SonyA7R5, though still useful for macro.

Not that I know of. A combination of three adapters such as Isotta B102 to B120, Isotta B120 to N100 then Nauticam N100 to N85 may get you a solution but then you have the length of the extensions to consider and an expensive and clumsy combination...