dentrock

I estimated an EP of 45 at 1:4 focus for the Sony 50 macro. I haven't used the 180 with it because it's too clumsy for me for close-ups, but an extension of approx 40mm (or just the 35 adapter) should get you close with this lens and that port. The OC for the port on its own is approx 25mm behind the mounting flange.

No problem since extension is only 25mm. 140 dome radius is 70mm approx. 4" WA dome and 180 dome both 110mm radius (I think!). Don't know about 4.33" fisheye dome, but should be OK. Suggest align lens with EP estimated at about 30cm focus distance, since the entire focal range is greatly compressed given that the lens will be focusing on the virtual image which is between approx dome itself and 3x radius from dome at infinity.

It also has exceptional IQ across the full frame with a dome, even up to f5.6. But you lose working distance at optimal dome alignment, just a couple of cm at 1:1. Depends on the dome radius. Review Alex Mustard's curved port clip. As far as I can tell, the little port he describes has a radius of approx 110 mm (hard to measure). Optimal alignment with this port appears to be 40mm ext, but working distance is zero at 1:1. However, as he says, he gets good results with 16 mm ext, which should give 24mm WD. With this port I use 30mm ext. 140 dome with 25 adapter is also fine. Best application is about 1:2 on.

I can get fast moving pelagics with Sony 50mm and a dome, as well as the usual macro stuff. Try it in a shop and/or buy used and sell it if you don't like it.

Focus behavior of zeiss 50 on FF was a bit odd. Covers 1:1 square format OK (= approx 44 mpix of 61 mpix sensor). Sony 50 is a better solution for FF.

On my 6500 I called it my 'gentleman's lens'. Great result when it decided to focus! Way faster on 6400. 90mm perhaps a tad faster on 6500, but too long for routine photos. Need good viz and a reason to use it.

60mm is 60mm on FF and 90 equiv on apsc, or 120 on M43, or....!

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.