dentrock

Not sure this holds true for all fisheyes. My experiments with 7 Artisans 10mm manual FF fisheye showed it was sensitive to 10mm variation. In the end I couldn't get what would have been the best extension (needed another 5-10mm) because vignetting was bad, even with the 140 Nauticam shade removed. The least sensitive lens I have found when it comes to extension length / dome alignment is the Sony 50 macro. I have found its excellent corner sharpness hardly varies with 20mm alignment variation. I don't know why this should be. Alex Mustard's Curved Ports clip confirms this if you watch carefully. He talks about using custom 16mm extension, then says he goes longer for optimal sharpness, without saying how long. I used the same 4" WA port as him and found 20mm custom is fine, with 40mm best theoretically (and fine practically), with 30mm a good compromise (you lose working distance with the longer extensions - at 40mm 1:1 is touching the dome).

So if I'm reading this correctly, the Howshot 140 comes closer (by about 6mm) to being the full half hemisphere compared to the Nauticam 140. This would make it potentially a better option to optimise corner sharpness, when vignetting precludes a longer extension (and therefore ideal alignment), as happens with some lenses behind a 140 dome?

In addition to the above, try under-exposing by about 0.5 to 0.7. In other words ETTR - expose to the right - towards the highlights. Dark shadows can easily be rescued in post, but clipped highlights not so much.

Thanks James, that's exactly what I wanted to know. When I eventually get mine, I will test it with another 10mm out of curiosity. Just waiting for black friday... Now.... looking forward to your detailed review, especially an analysis of the corners at say, f8 to f11.

Yes, but what is the actual length of the extension on the new port? Results from the Sony NZ ambassador on page 1 of this thread suggest corner sharpness is not that good with the old port and just the 35.5mm adaptor. I wonder if the built-in extension is actually a bit more than 35.5mm to optimise it for this new lens? Surely someone can help us out here!!!!!

Thanks. Perhaps for the rest of us who already own the standard Nauticam 140 dome, and don't wish to spend AUD 2500 dollars on the new 140 just for this lens, you could give us the measurement from the new dome glass outer to the port flange? Assuming both domes have the same radius, that will allow us to compare the built-in extension in the new dome, with the extensions we might have available to try with the old dome! I could ask Nauticam but have no faith that they would respond...

Flat chart may also not be the best for testing lenses underwater if the lenses exhibit field curvature, as many do. I prefer real world dive conditions, using complex subjects like seagrass, or subjects surrounded by macro algae. I look for something sharp in the corners that should be sharp, comparing that with the sharp centre. They may not be in exactly the same plane, although they generally are at macro distances. With wider fov, corner sharpness is often better behind the subject plane.

It was fine with the Nikonos 15 (same fov). I think the term cfwa was coined about then.

Yes. That's why I suggested it... To add to my comments, I suggest you go back to 1st principles and review loads of shark photos (your own and others) and work out which ones engage you (meaning which ones do you come back to / look at again and again). There is an awful lot of wide angle stuff published which is frankly, dull. Which do you want to emulate? Then figure what lens you would need to take your favourite shark photos, with the least amount of cropping. It occurs to me the 20-70 could be perfect for the Galapagos, since it would be good for the lizards, all the sharks, tortoises, most fish and so on. Potentially good on land too. A lightweight rig should also help. But each to their own. Well, yes, but then the alternative is no photos. But if you CAN get close in poor viz, a close-up photo could have way more impact than an attempt to 'get the whole animal in'. Think 'snout, eyes and teeth'! Nobody seems to mention this now, but I used to teach that you should try to limit subject distance to 1/5th of the viz... so 3m viz = 60 cm max distance... Of course, just another rule that can be broken, but still something to consider.

You don't need a very wide lens unless the sharks are large and/or very close. And of course you can get get head shots if your lens is too narrow for the whole animal. I have nice shots of Galapagos whalers from Lord Howe with a 60mm micro and flat port... these top out at about 1.5m but they can come close. Of course I would not recommend this setup, so I suggest the Sony 20-70 with 180 dome would be a good choice for small to medium size sharks, plus let you get good fish shots and even some close-ups as well. For pure shark photos I would use my 16-25 with either 140 or 180 dome. No wider unless they are big and close perhaps.

I don't think gobies on the sand are particularly difficult targets. I shoot a lot of Nesogobius gobies in my local patch, generally in low viz and dim conditions (under a jetty). I have relatively poor vision yet I can shoot them with my Nauticam, A7CR and std VF (the one that comes with the housing). Typically they are 25-40mm long. The tricky bit is maintaining focus on the eye, as it's a fairly small target. I use tracking, AFC, medium spot. I get between 50-75% success rate with Sony 100 (better with Sony 50). Success depends on how steady I am on the day! I bought a 45 degree VF and used it for a while. It certainly helped with bottom dwelling stuff but was a pain for occasional mid-water stuff and impossible for verticals. It has sat in my cupboard now for a couple of years!

Yes, 1 to 2 would be good, since it's easy to 'take turns on who is first'. Kri is that. I will avoid 1 to 4 in future. FYI I didn't do 2 or 3 P to P resorts because I decided I hate packing and unpacking mid way through a trip! I get settled in to a room then like to focus just on the photos!

On that trip last year I ended up only doing Lembeh / Murex resort. The diving pretty much met my expectations, although the room was a bit ordinary. Food was incredible though. Guides were mostly very good, but I'm not keen on queuing up to take a photo, and some divers were really good at messing up the viz. I don't know if I would return, but I doubt if other operations are any better. Have been some renovations this year. Not sure if they improved the rooms though. Also just returned from Siladen Resort (in the Manado / Bangka area). Resort is lovely and I really like the traditional style rooms with outside bathroom etc. Diving however focuses on Bunaken wall dives. Biodiversity is very low on those, so unless you are happy with turtles and drift dives, a little wall diving is more than enough. There is almost no large fish, and even the range of small critters is very restricted. Muck dives at Manado were much better / more critters / more diversity, but I had to work hard to convince the dive operator to go there. I won't return, not because of the resort, but because of the dull diving. I have just booked a return trip to Kri Eco resort (Raja Ampat) in July 2027, which has the best house reef I know of. And cute over water traditional cottages!

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...!