John E

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...

Isotta have two port sizes B102 and B120 and the Olympus/OM System cameras use B102. There is a B102 to B120 port converter and a B120 to B102 port converter. They also make converters to use other brands of ports on Isotta housings. They have a B120 housing to Nauticam port N120 converter and to Nauticam port N100.

Hi Sauther1, I also have an A7R V in Isotta housing. I also have the Canon 8-15mm, Sony 28-60 +WWL-1B and Sony 20-70mm (and Sony 90mm macro). Smallest for freediving is the fisheye Canon 8-15 with the small glass fisheye dome port and a small port extension. On its own with a Metabones or Sigma adapter you are using 15mm as a full fisheye (no usable zoom unless you use APS-C mode, which is still a good option if small system size is your priority). Isotta do a zoom gear for this set up. Next smallest is adding the Kenko 1.4 teleconverter and an extra 20mm port extension to get a nice zoom range. Isotta make a zoom gear for this with the Metabones or Sigma adapter. Both these are negatively buoyant if you are not using floats on strobe arms but not bad. Getting larger, the same lens can be used with the 8 inch acrylic port. This is almost neutral in the water with the dome slightly tilting upwards unless you add some weights to the dome shade. The Canon 8-15 plus 1.4 Kenko is what I use for snorkelling with wide angle. Another good option for wide angle zoom is the H59 B120 port which is made for the Nauticam WWL-1B with it's bayonet mount and the Sony 28-60 lens. . I use the Sigma MC-11 adapter for the Canon 8-15mm which does not have autofocus for video. This can be worked around with fixed focus (see the Backscatter video review on the Sony A7RV) but the Sony 28-60 and WWL-1B would be a better option than an adapted Canon 8-15mm if you are doing video. There are port converters to switch from Isotta to Nauticam. I don't know if these are usable with the Nauticam dry optics like WACP-C as these will be a few mm extra in extension due to the adapter, but the WWL-1B is supposedly same/similar optical performance to the WACP-C. I can't see the larger Nauticam optics being optimum for freediving! For rectilinear, I use the Sony 20-70 with the same extension and 8 inch done. Isotta also have a zoom gear for this even though it is not on their website port chart. Although not as wide as other options, those are covered with the zoomable fisheye. This still give a field of view as wide as the old Nikonos 15mm but also does decent larger macro, so it is a versatile option when you don't know what you will find. I also use this with a small arm and small single or double strobe (Inon s2000) for freediving. Lastly, there are lots of supported wider rectilinear lenses like the Sony 16-35 or Tamron 17-18 which would use the 8 inch dome or larger glass dome (not sure about the inconvenience of a 9 inch dome for freediving...). These are on the Isotta port chart on their website but they may also have other options for recently released lenses.

In Australia the price of the Photography plan (20GB) annual, billed monthly plan is changing from A$14.29/month to A$23.99/month.

I agree with Chris about fisheye lens positioning and port charts. Also, from what I can work out with my system, the Canon 8-15mm with the Sigma MC-11 adaptor and the Kenko 1.4x has a minimum focus distance of about 25mm from the front of the lens. With my 4.5 inch fisheye port and manufacturer recommended extension this puts the minimum focus about level with the glass. With the slightly longer extension that my "chessboard" test suggests, the minimum focus would be inside the port. So the port chart recommended extension is better for CFWA. Since this is an important aspect of this lens I believe manufacturers take this into consideration.

It's fantastic... so many great sequences. Thanks for posting. I also agree with you about colour. Not sure when you were there but the link below is interesting and writes about the coral bleaching in Raja Ampat in December. https://theseapeople.org/2024/12/18/coral-bleaching-raja-ampat/

My understanding is that compromises are involved, and with the Canon 8-15mm the perfect theoretical positioning does not necessarily line up with the best extension, depending on what type of photos you want and what dome you use. For close up wide angle shots, because the maximum effect is possible with a small fisheye dome, taking advantage of the minimum focus distance, and placing the dome closer to the lens, makes a big difference to the effect, creating a larger main subject and a better photo than having a longer extension which theoretically improves image quality but reduces the size of the central subject. For a larger dome, which is not ideal for close-up wide angle anyway, this doesn't apply.

Thanks Chris, it was small.. The bottom jaw does look a little bit long but that must be it.

This small flathead (?) was on shallow reef on the northern GBR. Any help naming it would be appreciated. Picture is with a Sony 90mm macro lens. Thanks.

Hi Adventurer, When you are referring to different wavelengths of light being absorbed at different rates it is obviously with distance travelled through water, nothing significantly to do with time.... as you say "speed of light in water is nearly identical for both wavelengths". So I can't understand how exposure time (shutter speed) could possibly make any difference to the relative proportion of different wavelengths of light reaching the sensor (i.e. colour). I use shutter speed to vary the deepness of background colour from pale blue to dark blue. I use Inon strobes and a Sony camera on auto white balance with white balance adjustment in Ligfhtroom. If I didn't use the warming diffusers it would be the same change in deepness of background colour but with slightly more green aspect.