Chris Ross

No not exactly - the suggestion is to work out if you regularly find critters that require that amount of magnification. My experience with the 60mm macro is it's very rare for me to find something small enough that I feel like I need a diopter. From a week in Lembeh with over a hundred critters found only one or two were small enough that a diopter might have been useful. Your experience might be different, I think it depends on where you dive, how good you are at finding small stuff etc. The CMC-2 will be challenging to use at max magnification for sure, I'm not suggesting don't use it, rather I don't see it as an either/or situation with the MFO-1 as they have different magnification ranges and I would choose based upon how much magnification I need. If you find you are getting down to 1:1 all the time currently and wishing for more and are OK with lighting subjects right on 1:1, then a CMC-2 is possibly the next logical step. The 90mm macro I think would be a lot easier to use at high magnification, it has about 65mm working distance at 2x compared to 22mm with the CMC-1 also at 2x, but it's an expensive lens, needs a new port etc. I'd want to be sure I would make use of it and could live with the extra working distance. At 1x it's only maybe 10-15mm more working distance than the 60mm, at 0.5x (35mm wide frame) you are at 170mm then 330mm at 0.25x. So for 60mm long subjects you are getting quite distant. I have the 90mm macro and use it a lot on land, but have not been tempted to take it UW.

Thanks for the update. I suspect it is something similar to what i see with e-shutter on my OM-1 . In focus stacking I do on land with an Olympus flash - the flash fires very rapidly on low power. I trialed doing a short stack UW, using the mini flash on manual at 1/64 power for triggering. The little strobe can fire rapidly at such low power but it was like it was waiting to confirm the flash was ready again before firing. The standard way of getting around this is to make use of the X-sync on the camera, which it basically a mechanical contact built into the shutter - the camera doesn't recognise there is a flash attached and fires every time the contact has closed as long as it has charge. Did a little searching to find this, seems the problem is by design from Nikon:

The MFO-1 should be thought of as a high quality low power diopter. In the case of the 60mm macro it only improves magnification to 1.1x while the CMC-2 achieves 1.7x but it will only focus between 33 and 122mm. Based on the focus distances there might be a little overlap with the CMC-2. It seems there are some benefits on image quality on full frame sensors and also prevents hunting with some macro lenses which readily switch to the background. However it seems that for m43 lenses there is no reported improvement. It seems to me that whether to keep it or not comes down purely to whether you can find subjects in the magnification range covered by the diopters. There is less case for diopters with m43 lenses, first the working distance is small and diopters work by reducing working distance, second the field covered at 1:1 with these lenses is 17mm across, half that covered on a full frame sensor. The CMC-2 covers a field 10mm across at a working distance of 33mm which means it is difficult to aim and to light the subject. Because diopters like the CMC-2 limit the focus range to a a limited working distance, they are in general more difficult to use compared to a bare macro lens, the MFO-1 limits the range but the maximum working distance is over 1m so you can use it just like a regular macro lens, you can find the subject from a distance and close in while looking through the viewfinder, not so easy to do if the subject isn't in focus until you close right in on it.

If you can fix it. but only have one cable, try running the other strobe with a bare port it will likely trigger off the other strobe. If you need to cut the cable to repair it - DO NOT use scissors, a sharp box cutter or razor blade is what is needed, it needs to be cut at right angle to cable.

Unfortunately the evidence is that the cables are not putting enough light through, the INON strobes are usually easily triggered. The strobes should trigger through the cable with an IR remote. try the test with the strobe in manual - first thing to try is to get it working in manual - a strobe in manual is better than no strobe. It's not 100% clear from what you have said, you mention more light coming out of the cable at position 0 compared to position 1, however some questions to clarify: Have you tried to trigger strobes in both positions 1 and zero with the trigger? Have you tested both cables? Are you testing with the cables plugged into the housing? If so have you confirmed the LEDs are well seated in the fibre ports, i.e. pushed all the way in? The instructions mention this and I recall a few times this was the problem people had with triggering. Is there someone else there who has a cable being used with a LED trigger that you could borrow briefly for testing purposes. What were you triggering the strobes with before this trip? A different trigger? an onboard flash? It's important to check all of these things and report back if we are to have a chance to successfully troubleshoot.

Don't know where you are, perhaps the dive shop could loan a screwdriver or are there any hardware stores around? The little dials don't require much force to turn so perhaps a small nail file might work? Probably some other household or kitchen items might be put to use.

It would depend on the type of coating, but I expect it would require strong mineral acid to have any impact, magnesium fluoride is often used as a glass coating and it's reported to be quite resistant to acids. Searching showed that magnesium metal is treated with HF to provide a MgF coating which resists corrosion by acids, much more so than the bare metal.

the method shown below using Levels will automatically setup your colours - providing you have a full histogram with a bit of room at each end to allow you to make the needed adjustments. https://www.photoreview.com.au/tips/editing/advanced-levels-adjustments/ It will properly correct a photo that is under flashed for example, very occasionally it might need a little more green removed or blue added, which you do with the midtones slider in the appropriate channel. Sometimes you might need to tone down specular highlights, but it works well for 95% of images.

The cheapest path would be to adapt what you currently have most likely. Recently another member was looking at switching from Aquatica and went with an Isotta housing and an Aquatica adapter ring: Isotta is well supported in Australia with a few dealers selling them and they also have solutions to use WACP/WWL with their system. Aquatica also have a dealer in Cairns. You could start out with a metabones adapter with your Sigma fisheye. For easy travel a small dome with a fisheye is hard to beat IF a 180° diagonal fisheye has enough reach for you. Another Australian member recently went with an adapted Canon 8-15 on SONY along with the Sony 2x TC. A few members are using that solution it's not as sharp as the bare 8-15 but gives superb flexibility zooming all the way from 180° diagonal to a frame that is wide as a 28mm rectilinear WA lens. I don't shoot Sony but I use an adapted 8-15 on an OM-1 and used it for the entire trip when I went to Walindi in 2024 I get the same field of view range with the bare 8-15 on a m43 sensor.

Where did you see this?, I find Sea Frogs documentation for this hard to follow. It seems they have two different ports with built in extension for their plastic housings so don't really attempt to precisely position the lenses behind the dome. The citeria seems to be just make sure it doesn't vignette. I see they have extension rings listed now, but don't see them mentioned anywhere in their lens charts. On the 8-15 on full frame - it's either 8mm circular of 15mm diagonal fisheye so unless you want circular fisheye you don't need a zoom gear and if you can use it at 15mm without vignetting it's probably as good as you can get in this system. On the 15mm fisheye, it's probably a bit short for your stated interest in big animals, particularly sharks and rays where you can't get quite that close.

Acid won't harm glass, it is alkaline solutions that can etch it. Certainly though whenever you clean glass ports do not let the water dry on there. It causes any salts in the water to concentrate, distilled water in theory should be free of salts but you may mobilize some salts whenever you rinse. The answer is to blow off most of the water (a blower bulb is good for this) then thoroughly dry - use a microfibre cloth.

Welcome Sabine, good to have you here, hope you enjoy the forums.

I waved it around the end of my cable while pressing the TV on button and it quickly fired both on the cable and the sensor itself (on retra strobes) A cable issue is quite possible and I would suggest assuming that is the problem till proven otherwise. The older TV remotes with the LED poking out are easiest to align of course , but a I used a SOny TV remote and it quickly fired by passing the window section over the acble end. In any case Pavel has provided some advice and I would certainly try that first.

This one is relatively easy, Google AI hallucinated and gave you the Nikon F (SLR/DSLR cameras) flange distance. I would think when measuring the flange distance you would want a piece of film in place as it has a finite thickness. Using google without the AI, there are multiple references to the dimension being 28mm and at least one where somebody measured and found 32mm.

A lot of people use them , they are cheap for a reason. Among other things the ports are setup for multiple lenses, but can only have the right positioning for one of them. They will let you get your camera underwater and seal properly and certainly you can take quite good shots with them. The vacuum system is not recommended as it can only be used to test, it's not water tight so you don't keep the case under vacuum while diving, which defeats part of the purpose of pre-loading the o-rings. There is a third party solution though. You could check with UW technics when the time comes if they support YS-110a. They are getting quite old now though.

What strobes do you currently own? The ikelite strobes have their won proprietary TTL system that only works with the ikelite TTL triggers which are now a little cylinder that connects to a housing bulkhead. They used to line inside the housings. I know at leats one person who has had ongoing issues with these triggers. But there is more than one way to solve the problem The new external UW technics triggers could be used on ikelite and assuming you have compatible strobes you should be able to use them . If not compatible you have a wide choice of other strobes you can use. I still think you should consider jumping to m43 generally a great system to use, with a lot more choices for housings and lenses, depending upon which body you choose. You could even use your 10-17 with the metabones speed booster.

Welcome aboard, good to have you here.

First thing to try is a new battery in your trigger. Double check the dial on the trigger is set to the right number. Definitely try it with manual position. Next see if you can trigger your strobes through the cables. Point a TV remote sensor into the cable and press any of the buttons. point the IR emitter into the fibre end. You might need to move it around. If this doesn't work point it into the sensor on the strobe. The IR remote should readily trigger most strobes.

Perhaps, but keep in mind Achtel is built around cinema where fisheyes are not favoured and the there is nary a mention of the Nikonos 13mm, though he does list the availability of some of highly specialized fisheye lenses, though it is not clear if they are water contact lenses. The issue as always is the lack of UW lens tests, air based tests can of course point you in the right direction, but not all lenses take well to being taken underwater for various reasons - one recently discovered parameter is a short minimum focus distance. I suspect there are others such as curvature of field which is readily taken care of on land by depth of field but if it bends in the wrong direction it might not play well with dome ports. I have not seen a convincing explanation of why some lenses are great on land but don't play well underwater - The Nikon 14-28 f2.8 lens is one I know of, there must be a reason for this and quite likely has something to do with not handling the curved virtual image very well. Another is they may be poorly optimized for performance at minimum focus distances.

Interesting ..... Achtel is located 5 minutes drive from where I grew up and less than an hour from home by car going by the address on the website. I don't that I would say forced to use conservative f-stops. You can only force yourself to make that choice. Me, I would rather stop down to where I need for depth of field or - say for a fisheye to get around the dome port issues than get the ultimate resolution - the overall image is most important and it's always a compromise. It seems to me that if you accept the statements from Achtel.com that domes reduce resolution to less than high definition partly due to the curved virtual image that you will be looking at fisheye lenses or water contact optics of some type for the highest resolution. Rectilinear lenses have a flat plane of focus parallel to the sensor while the virtual image is curved at some number of radii of the dome port in use. Fisheye lenses do not have a flat plane of focus, generally it is curved surface which may or may not be equivalent to a hollow sphere. Depending on the fisheye projection the focal plane may be circular or it may be flattened. But in any case it is much closer to the shape of the virtual image formed by the dome than the flat plane of best focus of a rectilinear lens. As an aside the S&S corrector lens attempts to do something like this - basically flattening the virtual image so that the host lens can digest it more readily I expect that the ability of water contact optics to operate at larger apertures is related to the fact that optic acts like a fisheye lens and it converts that image in to a flat focal plane that the rectilinear lens inside can digest. If all of this this is correct looking at land based tests of lenses probably only helps with center resolution it would seem??

Welcome to the forum Chris, good to have you here!

Yes that is indeed the difficulty. It seems to me that the suggestion of looking at Bali might e a good one if timing for the Maldives is not good, the advantage being that there is a huge range of options and flights to get there. this website seems to suggest Nusa Penida might indeed be a good option for the OP. https://www.zubludiving.com/articles/zublu-insights/manta-ray-seasons-in-indonesia

Unfortunately that's internet forums for you people run off on tangents on things that interest them. But seriously - please continue to dig and find resources and test images to make your points.

IMO, you are chasing a tiny improvement at best, there's thousands of great shots taken with the Canon 8-15 with the recommended dome dimensions. The test shots displayed on here of the banknotes certainly didn't set the world on fire. I would be interested to see some shots also - test shots are generally preferred as they are a shot of a flat surface and you don't have to work out if the softness is due to optics or if the foreground is falling out of the depth of field.

It depends on how small a subject you find and want to photograph, the MFO-1 reduces the frame covered from 36mm wide to 30mm wide providing 1.2x magnification. The SMC-3 gets 2.3x with the frame being 15.5mm across with 47mm working distance. The SMC3 focuses between 47 and 103mm and I expect it won't give you any overlap with the MFO-1 range. For me I would also factor in how often I find these things, if it's once on the entire dive trip maybe a better solution for this one critter is to crop?