Chris Ross

I am converting to using a Canon 8-15 adapted on a metabones along with the 140mm dome from Nauticam and it covers the range from an 8mm fisheye all the way through the 14mm end of a 7-14 so I don't need a rectilinear for reach, the only reason to do so would be I wanted straight lines for wrecks or similar purposes. I agree the 6"dome is a bit too small for for the 7-14 lens, sure it will work but the corners will be a quite soft and as you have the entrance pupil forward of the optimal point you introduce some distortion. You could look at the Olympus 8-25 instead of the 7-14 as it will be less demanding on the dome. Isotta offers a 6.5"crystal dome which is a much closer to a full hemisphere and allows you to position your lenses correctly. Being in Isotta you could struggle to replicate the 8-15 rig I use so it may be simpler to stick with your Olympus fisheye. Sounds like you already have the Isotta 4.5"dome and assuming it's the fisheye dome (B102-H47) that would be the ideal setup to use with Olympus fisheye. If you were to buy the 6.5"crystal dome (full hemisphere model) you could probably use that for both the 8mm fisheye and the 8-25mm recognising that the corners won't be at their best with the 8mm end of the 8-25mm.

I think the response perhaps need to be qualified to confirm the Depth of field is less at the same framing - meaning the subject is the same size in the frame. You will shoot closer with the fisheye compared to the WACP to get the main subject the same size but for regular lenses on land this will result in the same amount of depth of field with varying background coverage. What also happens on land is the blurring of the background detail comes in faster with longer focal lengths even though the actual depth of field is the same. Again with regular lenses depth of field is purely a function of magnification and f-stop. I think if indeed the FCP reduces depth of field it probably indicates something about how it works. I have read that dome ports actually increase depth of field - perhaps the FCP works like a lens in air and gets the depth of field that a lens in air achieves?

Typically the firmware upgrade is to deal with new camera bodies and lenses which often won't work with the old firmware. Metabones also has upgradable firmware. It seems the Metabones works with more lenses, but if the lens/camera is on the compatibility chart you are generally OK. I picked up my Metabones used also. Also Metabones will respond to email support questions. Also you just want the T Smart adapter model, the Speed booster ultra includes a 0.71x optical element which you might use to for example on a 10-17 with a m43 camera to get full 180° coverage at the wide end. Not needed with the 10-17 on Sony APS-C. Read through the notes on the EF-Sony lens adapter here: https://www.metabones.com/products/details/MB-EF-E-BT5

In domes the lens needs to focus on the virtual image about 3 dome radii from the dome surface so quite close, pre-setting focus can work on land, not so much underwater. Also typically you want to work very close with a fisheye, almost touching the subject in many cases and precise focus then becomes critical.

Yes that should be fine as long as you can use the zoom control knob on the housing with that lens.

You won't need a new dome, just the right extension. looking at the charts for the 18414 and 18408, the glass 18408 needs about 10mm less than the acrylic 18414 so I would guess it's going to be in the range of 45mm in length +/- a few mm. It's rather annoying they go by part numbers, every other supplier just calls it an xx mm extension ring and the part numbers are in random rather than increasing size order. Regarding the macro port, you will want the right length extension, the 48462 is 39.5mm so the 48461 is likely to be about 6-8mm longer than that. The lens will probably fit but diopters won't work as well if the lens is further away and you lose a touch of working distance depending on how tightly the 48462 extension fits. If you don't use diopters it would probably be fine as you would have about 135mm working distance at 1:1 with 105mm Z lens.

Seems there is a grand total of one lens in this class that focuses that close, the Nikon Z 17-28, all the other Z and F lenses focus at either 280 or 290 mm apart the F mount Sigma art 12-24 f4 which gets down to 240mm. But a 17mm is a somewhat narrower field. I would be playing with the fisheye in your 6"dome to see how you go before shelling out more cash. Having said all that there are lots of people somewhat happily shooting with 16-35 class lenses that focus around 280mm in 230mm dome ports and using the S&S correction lens while reporting good results. The S&S lenses are meniscus lenses which are commonly used as field flatteners in other applications.

Probably yes providing it's just an adapter that you need and you don't need to use the zoom/focus knob if one is fitted. If you do need to use the knob, the zoom gear won't mate up any longe. It might be possible to make a custom gear to get around that if you needed to

First of all I assume the dome shade is square and properly oriented. Does your port seem to have any built in extension compared to the current 18414, which from photos seems to have none? Is the front element sitting well down inside the extension? You shouldn't need a new dome, just different extensions, if you are vignetting you need less extension. Your current extension is the 54.5mm The next smaller size is the the 39.5mm 48462, which is 15mm shorter. You can combine a 16.5 and 28.5 mm for 45mm as well. You could estimate how much extension is required if you setup your camera and the port (no housing) in the same position inside the extension as it is when in the housing. support the port/extension tube upright and place the camera on some books or similar so it is centred in the extenion and adjust it to get the same vignette. You could measure the distance from housing to camera flange to help you position the camera. Then slide the camera forward until the vignette is longer seen. Measure how much you moved the camera and that is how much less extension you need. Use the next smallest extension combination to what you just measured.

Yes I know, no one mentioned the G2 version, the post is responding to a question about the Tamron lens that is on the port chart which is the 28-70 f2.8 Di-III RXD which also has a 67mm filter thread.

Article here with eye witness reports, unconfirmed reports of someone missing and harrowing reports of guests rescuing themselves, plus accusations of issues with safety equipment on board. Cause variously reported as a cable fire and starting in the kitchen. https://www.thescubanews.com/2024/03/01/eyewitnesses-share-insights-into-sea-legend-fire-sinking-and-missing-diver/

The 4.33"dome is slightly larger at just under 110mm than the Zen 100mm dome. Image quality may be slightly less than the 4.33" but I doubt there would be much in it. There are several varieties of the Zen dome and because you would need to mate it with the the recommended n85-n120 adapter for the zoom gear to work you need the version without extension I believe which is the DP-100-N120T. You might also be able to use the 4.5" Isotta dome if the lug ring on it is removable, you would have to ask Isotta about that.

You'll probably need to use the tools in Lightroom to remove purple fringing in the corners, I know I did need it for some shots in the corners with Panasonic 8mm fisheye and Zen 100mm dome. Apart from that nothing special I don't think. Agree on not de-fishing , while it can be done you lose a fair bit of the frame in the process and the corners are expanded so the quality declines quite a bit. An example of a de-fished reef scene with Panasonic 8mm , first frame is a large coral close to surface but the reef top is bent by the distortion, de-fishing crops in quite a lot. Ignore the colours as for some reason uploads into the forum from me (no one else it seems) are washed out.

This is an English translation on the news page in Indonesian: https://voi.id/en/news/361622

It's in the port charts it says you can zoom between 28 and 45mm. Nauticam list the available zoom range for all lenses behind their wet lenses.

It looks like it hits the port at 45mm zoom - possibly more of an issue with the FCP?

It will depend on a lot of things including how bright your trigger source is and what strobe you are trying to trigger. With a mini-flash and an INON strobe I suspect it would be easy. With an LED trigger and a YS-D2 you would probably struggle. I think splitting is probably not going to work and what to do depends upon what problem you are trying to solve. If you have a single fibre port, the twin hole INON bush will allow you to have two cables in one port, BUT if you are using a trigger with this I have seen reports of it not working as the narrow LED beam is not aligned under the cable properly . If you have two strobes at the end of a long cable run, daisy chaining them triggering second strobe off the output of the first would be a good solution. INON also have what they call a wireless connection system - a couple of mirrors to direct light from a trigger into a second strobe: http://www.inon.jp/products/strobe/optical/wireless.html though that probably risks being triggered by other strobes in the area.

Yes but you are restricted to subjects in the 1"(25mm) size range, as soon as you want to shoot say a 4-6"(100-150mm) subject you need to back way off. California is similar in some ways to Sydney, I've dived both, though i Was lucky to get 15m + vis when I was in CA. But in Sydney a long macro lens really does push you towards small subjects. MY 60mm Olympus macro is marginal in Sydney dues to the size range of subjects I get there (120mm full frame equivalent vs 135mm equivalent for the Sony 90mm on APS-C) I guess my point is you can adapt to the conditions but on your home dive sites it'd be nice to be able to shoot a range of subjects without having to wait for a once or twice a year day to shoot bigger subjects.

The 7"dome port is quite big and floaty, I've seen one or two in the field, it may improve things a little but hard to be sure. You could use a 230mm dome, Nauticam probably haven't tested it for Sony APS-C probably because it dwarfs the housing. You just have to work out how much extension to use. As far as the 10-18 performing better if it's not so good topside it can only go one way in a dome UW and that is down (worse). You could also likely use the 7"dome with the 10-20 provided it's long enough, the 7"dome has quite a bit of extension built in. If the 10-20 is the same length or longer than the 10-18 you should be able to use it in the 7"dome, if the 10-20 lens is shorter it would possibly vignette. Regarding the DSC01971 I basically used that of an example of composition which would not work so well with barrel distortion as the straight beam across the top would bow outwards you could correct some or all of it in post processing but you might need to leave space for cropping as the software bends the corners outwards. It certainly seems sharp enough except the far corners. I don't have a feel for how noticeable it would be with a WWL, but a fisheye would certainly show it. Have a look at what the distortion is like with the Canon 8-15 on a door frame here: The WWL would be somewhere between the 8mm and the 15mm view of the door frame, probably slightly closer to the 15mm view than the 8mm view.

The wide range of the 28-80 certainly seems attractive. If you assume the formula for an equisolid angle fisheye is correct the it's interesting that the focal length multiplier for this formula gets smaller as the focal length increases. You have to iterate on the focal length to match Nauticam's fields as reported in the port chart. I usually calculate the horizontal field from the diagonal field to compare between wet optics and rectilinears as the corners stretch more than the horizontal field does, so this means the 35mm end of the 14-35 is closer to a 15mm rectilinear lens, but has the diagonal field of a 12mm rectilinear. At longer focal lengths the difference between horizontal and diagonal fields when comparing this difference is a lot less so just comparing diagonal fields to a rectilinear is close enough.

Welcome onboard Jack, hope you enjoy your retirement.

The dome is not that big when you see it in person and will only get in the way of getting up close to the smallest subjects. I did some comparisons a while back and the Canon 8-15 covers the field of view of an 8mm fisheye and the 7-14 lens, pretty close to 100% of the available fields of view. If you experiment with a fisheye lens the size of subject you can "fill the frame" with reduces dramatically in the last little bit before you touch the dome port and that seems to me to be the advantage of smaller domes. I think subject selection is really the key - it kind of needs to be in a spot where you can approach closely and get the background reef in the frame without close-by objects sticking in from the side and producing weird distorted shapes. I'll probably only really be able to answer the question properly once I try it out.

A 6"dome is really a little small for a rectilinear lens that wide even on APS-C. The 6"dome from Fantasea is not a full 180° dome so the geometry likely means the lens entrance pupil is positioned forward of the dome centre of curvature to avoid vignetting so is not optimal. A bigger dome helps of course but the largest offered by Nauticam is the 180mm dome. You could use the 8.5"acrylic dome and it seems to use 10-15mm more extension than the 180mm dome. Focusing closer has also been mentioned you don't need Manual focus to do that, just use back button focus to focus on something closer in the scene and stopping down to the f11-13 range will also help your corners. As far as distortion goes, all the wet lenses have some level of distortion probably best handled by where you place straight lines in the composition, they bend more as you go towards the corners of course, so for example the image DSC01971 you posted above would have obvious distortion with those straight lines top and bottom of frame.

To be fair though the centre softness goes away when stopped down which you would do anyway behind a dome, the lens is obviously designed with astrophotography and infinity focus in mind so the minimum focus distance is quite long and correction at f1.4 when at MFD not a priority. A rough calculation shows that it could focus at its closest approx 1m from a 140mm dome but in a 230mm dome could focus on an object about 0.2m away from dome surface, so it could be used for reef scenics with a bigger dome. However there is probably little reason to do that when an adapted Canon 8-15 fisheye works as well as it does.