Chris Ross

The histogram on the SONY page looks quiet different, the blues and greens have peaks in similar spots to lightroom but the reds have a peak much lower. I'm not sure how you could achieve that with moving the blue-Yellow colour temperature slider and Green-Magenta Tint slider alone. I use a different method using levels and it seems to work quite well as long as the image is well exposed and has enough red channel to play with.

Thanks for posting. I would think that the grinding is only required for 5 series camera - OM-5 EM-5 mkIII etc. They have the lens mount very low on the camera body, while the lens mount sits higher up the body of the OM-1. EM-1 MkII etc. so the Metabones adapter might clear the tray on those models.

Salt water is not a problem for glass, you dive in it after all. As this water evaporates the salts become more concentrated and I expect the pH will also increase and eventually reach the point where the glass can be etched. This is a slow process and repeated evaporation events are needed before it becomes obviously visible. A plastic cap could work but only if it is tight fitting to prevent the water that evaporates from escaping once humidity reaches 100% under the cap no more evaporation. Most improvised caps won't be able to seal well enough to be useful. Glass corrosion or etching can be removed but requires much more effort. Glass domes will be ground and polished to reach the surface finish that they require - same as glass lens elements. People report using cerium oxide for this and this is a common polishing agent for optical glass, however it requires much more elbow grease to have any impact. A neoprene cover should be adequate. If the weather is hot re-dunk it occasionally or add a splash of water from a drink bottle.

Probably little you could do about it unless you could get the lens to report the focal length with the WWL. That's probably something around a 14mm rectilinear frame (full frame equivalent) on the horizontal axis. You could probably only tell by trying it and see how it handled.

A neoprene port cover significantly slows drying of the port surface and this is a significant benefit. The article is wrong because it is incomplete, the port cover needs to dry out to cause the damage, but this is not going to happen on a day boat unless you leave your housing in the sun. If you are going to apply your port cover you need to be sure to keep the neoprene wet. My experience shows when shore diving around home I apply the port cover coming out of the water and leave it on between dives and the transport it home, the cover is still wet several hours later. The port cover is soaking wet as it has been in the water with me. Leaving a port uncovered to sit between dives the surface will dry out and the drying out is what causes the damage as the salt become more and more concentrated as the water evaporates. You also do not want to have fresh water dry on the port - when drying it blow off excess water and wipe/polish with a clean micro fibre cloth. I would not apply a dry port cover to a port when getting out of the water as it will absorb water and the dome surface can dry out. The port cover is removed as I pop the housing into fresh water to soak and it is also rinsed out then soaked to remove salt.

When you want to embed images, choose the files and with your cursor where you want the image, hover over the thumbnail and you will see the link "insert"appear click that and it will insert where you had you cursor. I think you then delete the images at the bottom. You have to do it while it is still editable, the abailty to edit a post has a time limit.

Thanks for supplying the parts list. Looks like a straight forward solution. For information of others looking to copy this setup, The gear is SKU 3546 is "EF 8-15mm f/4L Fisheye USM + Adattatore Olympus (EM5)" The 40 mm extension SKU 2548 is the 40mm extension with zoom mechanism. Let us know how it fits together once you get all the parts.

It's not just the minimum focus distance it's also the length of the lens and the 8-25 gets longer when expanded for use. The formula is 230mm - flange distance - lens length = working distance. The lens is 88.5mm long and expands by 28mm when in use. So working distance = 230-20-88.5-28 = 93.5mm while the radius of a 6.5" hemisphere is 83mm. So it's going to be close to focusing on the dome depending on where the entrance pupil is located. The partial domes I suspect won't allow you to place the entrance pupil at the centre of curvature. Even if it doesn't quite focus on the dome it doesn't mean its suddenly unusable.

I'm not sure that anyone has come up with the parts list to do this with Isotta. To adapt the 8-15 you need the Metabones T smart adapter and then you need to figure out the appropriate extension to use with your chosen Isotta dome. The other thing you need is a custom zoom gear. On Nauticam with their N85 ports this needs to mate up with the zoom knob on the N85-N120 port adapter. This requires a 3D printed adapter for the zoom gear to get it to mesh with the gear on the zoom knob, on that system the zoom gear needs to be placed 5mm lower on the lens. The small diameter of the N85 port means that there is no possibility to use a standard zoom gear with the housing zoom control. On Isotta there is only one B102 extension ring which a zoom knob. This may or may not be appropriate to use with the proposed setup. However the Isotta ports are a lot bigger than Nauticam n85 and this may allow the use of a custom zoom gear and use the housing zoom control. I see on Isottas website they have a lot of gears for adapted Canon 8-15 lenses and one of these might do the job, the descriptions on their website are not that clear. There is one labelled as Olympus adapter but there is nothing to clarify that, you would need to ask Isotta. If they have made an adapter they can probably also advise what extension you need.

I would add that Isotta list 3 6"domes, the polycarbonate one is a partial hemisphere while one of the glass models is a part hemisphere and the other a full hemisphere. To get the best out of the fisheye you would want the full hemisphere, to allow you to get the entrance pupil somewhere near the dome centre of curvature. . It of course will still produce quiet OK images with the part hemisphere domes, you just have to have a look at the Ikelite compact travel dome they sell for CFWA work with full frame fisheyes. https://www.ikelite.com/blogs/buying-guides/when-to-use-a-compact-8-dome-port-underwater The pics they post look OK at that scale and many people would be happy with them , even though the dome centre of curvature is well down inside the dome extension and possibly 100mm behind the dome surface. Fisheyes seem to be less sensitive to this issue at least for edge sharpness. However if you want the very best the camera can deliver you would want to get the centre of curvature better positioned. On the issue of a 61MP image being more demanding yes it's true the greater resolution will show up lens errors more readily, but only if you view them in a manner that allows you to see that. If for example you thought the corners were OK on a 30 MP image, you still have 30 MP grade resolution (as set by 30MP chip pixel size) in the corners on a 61 MP image. I'd also question if you achieve 61 MP resolution shooting at f11-13 range, shooting through water and also contending with the air-water interface and all the issues that brings with it.

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