dentrock

Ask them where the optical centre of the dome is then (in relation to the port mounting flange).

Sure, perhaps no adapters if you have a N100 housing. But it remains to be seen what, if any, extensions are required. Plus the Nauticam range of extensions for N100 (and N85) is miserable cf N120 extensions. Let's hope they increase their selection.

It's a beautiful lens on a later Sony body such as the 6400. AF a bit slow on earlier bodies. Make sure you have the upgraded firmware - FOC but has to be done by Zeiss. It's the only APS-C lens I kept when I changed to FF - couldn't bear to sell it!

Someone needs to measure / estimate the lens EP (distance to mounting flange) then we will all have a base to work from.

OK I've checked out the Sigma's specs and rewatched Christoper Frost's reviews. Main points: Frost says it does 1:2 mag between 28 and 85mm which is handy. Optics look quite good. Lens is very narrow - zoom ring is said to be 70.4mm D in Sigma specs. Also zoom ring is at the back (closest to camera) which is also handy and will easy fit N100 system. Can't imagine Nauticam could be bothered to offer a zoom ring since it's clearly not interested in supporting non-mainstream stuff, so closest I have is the ring I use for 16-25 (actually 24-50 ring). Diameter of that lens is 74.8 so zoom gear could be padded out to work with Sigma. Would I buy it? Definite 'yes' if I didn't already own the Sony 70-200 macro (which takes a TC if that's your thing)... This one is a bit big for my liking for UW, and anyway, it doesn't go to 20mm. Don't need both, but...!

Thanks, Phil. I will have to check dimensions and see if it could fit in the N100 ports system. Your Marelux prices on zoom gears are a steal compared to Nauticam!

That's interesting about the Sigma 20-200 offering 1:2 mag over that range. I had been thinking about that lens for 'one lens' land travels, but had ruled it out for UW. Care to share your extension used with the 180, and if possible, a photo of your zoom gear so I can figure whether I can cobble up something out of Nauticam bits?

I would add the Sigma 24 and Sigma 17, but frankly, the Sony 16-25 makes these redundant. However if you fancy a prime, those Sigmas are great. Another goody is the Zeiss Batis 40mm CF with a suitable dome, but that is surely a niche lens. I bought and sold the Laowa 10mm, because I couldn't get decent corners with either the Nauticam 140 or 8.5" domes, and wasn't prepared to go larger. So that one is not recommended for casual users who care about IQ.

Nice review - thanks! Did the lens vignette at 14mm (FF) with the dome shade? Or only when you go circular?

Re tests with 16-25 which I own: With 180 dome, A7CR / A7RV body, 25mm adapter, 50mm ext - alignment is theoretically perfect (0mm misalignment of OC at EP). IQ score at 16 is corners 2 at f8, 2-3 at f11. At 25, score is almost 3 at f11. I have explained my scoring system in previous posts, but for a quick recap, I look at the area of central sharpness at 100%, to see where it falls off (stuff that should be in focus is in sharp focus - quite easy to judge). 2 = a circle of 24mm diameter (touches mid long sides of 3x2 FF frame), 3 = 36mm (touches mid short sides of frame). With 140 dome, 25mm adapter, 35mm ext - alignment is -3mm (i.e. 3mm too long). Score is identical to the above (surprised me). As a variation you could reduce ext to 30mm with alignment of 3 (needs 3mm more). You could also use 35mm adapter + 20mm ext. Re Nauticam port charts, I emailed them and spoke to their agent about including this lens - no joy there (unsurprising given their lack of customer support). NB - you will need a zoom gear. Not available from Nauticam but fortunately the gear for 24-50 fits well (these two lenses are a matching pair from Sony). Final point: given you have 20-70 on your list, I would buy this first - it may be that 20mm is wide enough for you. About 10 degrees difference to 16, and works well with 180 dome, plus giving you handy close-up ability. Unfortunately, 20-70 does not work well with 140 dome (radius of 70mm is too small to accommodate the lens extension of about 40mm at 70mm FOV, so you cannot achieve decent optical alignment). However, 140 should be OK with new fisheye (fingers crossed)!

I agree with Phil that the Sony 16-25 is worth a look if you are OK with the shorter range, and cheaper too. Not only does it work nicely with the 180 dome, it works equally well with the 140 dome.

Based on my tests with the manual version, it needs a full hemisphere dome for proper alignment. You can order a custom one, but I don't know of any off the shelf full domes. The Sony fisheye seems a much better option.

Thanks Chris. They look nice, but we need to know if they are uncropped, aperture, and ext / adap / dome used. Plus advice on shade or no shade helps those of us who like to protect the dome...!

Many thanks Simon. I downloaded a couple of the dolphin shots. Nice, but a bit soft in the corners. I'm guessing adding a short extension (10mm?) would help, but might introduce vignetting with the shade on (at 14mm). My guess based on what appears to be the Metabones V length of c. 26mm. Or maybe extra 5mm is enough, in which case you could go 25mm adapter + 15mm ext... If you feel like trying either of these, that would be great...

Simon, Just to confirm, you are saying your test rig is: No vignetting with Nauticam 140 dome plus shade, and 35.5mm N100-N120 adapter, no extension ring? Thanks for your excellent summary.

Some good stuff in those clips. But the master hasn't done anything for many months now, and doesn't reply to comments. Note that if you watch the last video, there is a link to an unpublished extra clip.

Sony 50 macro extends 25mm. Check out Alex Mustard's curved port video. Sony 50 macro seems very forgiving of dome misalignment compared to other lenses. Don't forget, measure EP at close distance eg 1:3 (not infinity), because this is where the virtual images will be.

Doesn't Canon make a 50 macro? That should work fine with a 140 dome. My Sony 50 macro is great with 140 dome.

Looking forward to you testing it Phil, and seeing if you can get good corners and no vignetting! I can get one or the other, but not both, with the manual version, which is 185 degrees (140 dome, no shade).

A few further comments: 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. 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. 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... 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.

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.

Christopher Frost is also worth viewing. Usefully he follows the same format for every review, and shows test charts separately for the centre and corners. If you open multiple browser windows, you can directly compare results for different lenses. However he doesn't measure field curvature - but then, who does?

I look up best on-line prices then go straight to my local bricks and mortar store - Camera House in Geelong. They always match the best price if it's Australian stock and not some dodgy code discount. I reckon support your local store if you have one. It's the only place you can go to see some gear before buying.

I use Sony C-AF (with tracking) all the time underwater, and mostly BBF. I could be mistaken, but I sense that BBF makes it quicker to acquire focus in tricky situations. On land I rarely use BBF, because the Sony ergs are not so good for that. In the end, it's whatever maximises your keepers.