dentrock

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.