dentrock

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 Note that if you watch the last video, there is a link to an unpublished extra clip.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.

I used to be a half press guy, but now I've joined the dark side with BBF, since Nauticam ergs are very good for BBF. But I haven't disabled AF with shutter, so it's there if I need it.

Well it does. But depends a bit on the skill of the photographer I suppose. But don't take my word - check out Alex Mustard's clip on "Curved Ports". He is quite a fan of the Sony 50 macro - especially behind a dome - as am I.