Chris Ross

I just upgraded from Z240 to Retras, the big thing I noticed was backscatter control was much better with the reduction rings installed compared to the Z240. Regarding the AOI strobes you mention macro will be fine with either I think, but I expect they may be a little under powered for wide angle particularly with a full frame camera. Does AOI offer reduction rings? I think I would want that for macro work. Regarding the Retras, seems they only offer the Pro Max II and the Maxi is on pre-order. I got a pair of the Pure model before they discontinued. They are quite an expensive option, though they are very well made and the light and the control of the light is excellent.

A lot of discussion already, the simple fact is that a 6"dome is really too small for a 15mm rectilinear lens. I would also mention that Seafrogs will get your camera underwater but they use generic extensions and often don't have the optimum spacings in their port chart, they will fit and take photos and generally won't vignette but are not always in the optimum position. For example the R5 plus 8"dome is said to work with 16-35 and 24 105 lenses(with EF adapter) and lenses. Nauticam uses 50mm extension for the 16-35 and 70mm for the 24-105. Regarding dome port theory this article is very good and includes a calculator to see where dome port virtual image is located. Understanding Flat Port and Dome Port TheoryOne of the key features of underwater photography is the dome port. Despite it's ubiquity, it's effects are largely misunderstood or at the very least, poorly explained. In this post I'm going to ta You asked about hyperfocal distance, this really isn't a thing underwater with dome ports. The lens is focusing on the virtual image very close to the port and is close to its minimum focus distance. To calculate minimum focus distance, UW you can make use of the calculator linked above, as follows: calculate how far the minimum focus distance is beyond the dome Set the dome size and aperture. The aperture is the size of the entrance pupil so set to minimum Change the object distance until the virtual distance = the minimum focus distance from the dome surface you calculated. You asked if it's better to have too much or too little extension. probably doesn't matter much, one way gives barrel distortion and the other pincushion. 'However too much extension causes vignetting as the dome shades start to show in picture. Regarding the 14-35 lens and your calculations, the critical things to estimate are the radius of your dome and the entrance pupil location, you didn't mention how you came up with those figures. You can calculate the radius from dome diameter and height with circular segment formula, but generally you need to measure the location of the entrance pupil. You want to use the entrance pupil location at the widest setting. I think at this stage and especially in a 6"dome you won't make a material difference in your photos by investing in another lens. Lots of things contribute to sharpness underwater and it's not all about the lens used though that can make a difference. On the subject of unsharpness, there are a few things to consider, what aperture were you using? I would think you should use f11-16, tending more towards f16 due to the small dome. How close were you? The first rule of UW photography is get close and if you think you are close enough, get closer still. Secondly you are using natural light it seems and while you can take nice shots in natural light, UW shots lack generally lack contrast. The third shot with divers for example looks very milky - this is because they are too far away and you are shooting into the light. If you were using strobes you could drop the shutter speed to darken the background water and illuminate the subject mainly with strobe light - of course strobe range is very limited and you want all your main subjects at a similar distance so you can illuminate them. Getting this right gives the impression of sharpness from contrast. In the meantime when shooting natural light, be aware of where the light is coming from, having it behind you tends to work best , UW the light doesn't get under overhangs etc and they come out black and the shadow side of fish for example tends to be very dark. On the topic of split shots, without strobes the biggest challenge is the wide brightness range. To focus in this situation remember the virtual image is very close and depth of field extends behind the focal plane more than the front. So focus on the UW part and have it quite close to you and use f22, you really need to be in relatively shallow water for it to work well. It is particularly challenging with a small dome as the virtual image is very close and optically the water line is very thick with small domes, not to mention that water movement makes it challenging to hold the split line where you want it. On the question of your calculations, it is nice to be able to do them to confirm things, however practically speaking are you able to obtain extension tubes close to what you have calculated? Sea Frogs only has a rather limited range available.

Video AF tends to be more problematic and I seem to recall that video AF does not work at all with the MC-11, this post mentions it: Metabones say theirs works but says: "Continuous video AF is functional in Advanced mode only but performance may be unsatisfactory." That same post says the adapter provides flawless AF on stills and video with the tokina adapter with a Sony A1 and Canon 8-15 lens. Reading through that thread may help you.

Note that the MFO3 is used with flat ports not dome ports

It's certainly tight in there, one question is if your battery might be getting a little tired?

I think many camera batteries are 7.2V or around that voltage, a few small compacts use 3.6V cells

If you could find a Nauticam 26526 m14 offset vacuum valve you might have a chance but I think they are discontinued. With enough money Dive and see might be able to do something custom??

Hi Ben, perhaps you could hop over to this thread, it has some of the missing details. Unfortunately many of these types of solutions require some skills in electronic assembly, not sure how you are with this and selecting proper components for battery packs like charge monitors etc. For your case there are probably a few solutions - the simplest would be some sort of USB-C bulkhead. I believe you can charge the LX10 via the USB port which seem to be a mini USB. If you had this you could recharge the battery between dives without any sort of UW housing for the battery. If you go for an UW housed battery - The first thing to consider for an UW battery housing is if you can charge the battery while the camera is running via USB, many cameras cannot. In this case this is where the dummy battery would come into play. You might be able to find a second hand monitor housing to hold batteries, you could install something like some 18650 or 21700 batteries in a holder and just cut off the HDMI cable plug and use that cable for getting the power down to the camera housing. Something like this: battery holder This way you could use a land based 18650 charger to recharge the batteries and not need to build in a charging circuit. It would probably be fiddly using the fine wires in the HDMI cable for power and terminating them so they don't break and you would need to have some means to plug the USB cable in - inside the housing. The biggest barrier might be the M14 thread, many bulkheads for this sort of service are at least M16. I see Backscatter has a used Ninja housing on sale currently: used housing There's probably a few other items about you could utilise, for example subtronic have external batteries built into strobe arms which might be adaptable, but likely expensive.

That should be about the right spot then assuming the entrance pupil is about 10-20mm below the tip of the front element.

Looking at the port chart you use a 24mm extension with the FLP-04 or a 34 mm extension with the FLP-06 for the 60mm macro lens meaning the FLP-06 port is around 10mm shorter than the FLP-04 port. The chart also suggests the FLP-04 port for the 30mm macro and this implies the FLP-06 port alone won't fit the 30mm macro lens as it would be too short. You could use the port combination for the 60mm macro but the 30mm macro is shorter by 25mm which means the minimum focusing distance for the 30mm would fall inside the port, which means that 1:1 is not possible at ll and the max magnification you can easily use is lower. The FLP-06 alone would house the 14-42 EZ lens which might be a cheaper possibility, it's probably not the sharpest knife in the drawer but should be acceptable. You can zoom out to 14mm but the image quality will suffer in the corners due to the flat port at the wider end. Zooming in you can achieve about 0.23x magnification maximum meaning it will cover an area 74mm wide. You can add a wet lens diopter - the Nauticam CMC-2 focuses between 63 and 130mm and can get up to 0.6x - usable but not anywhere near as convenient as dedicated 1:1 macro lens. The MFO-3 of course allows you to get the 35mm macro and 60mm macro on the same dive, both with very good optical quality.

The specs say this lens is 76mm long and it appears that the entrance pupil is about 15-20mm below the front element. Using the housing flange to camera flange distance of 39mm and 120mm radius for the 230 mm dome I would say something like a 30-35mm extension. To judge this the tip of the dome should be about level the dome's aluminium base and that should get you close. If that setup doesn't vignette then shoot a split shot of a straight object sitting on your pool step to see if the width remains the same above and below, like is done in the first sequence in this post:

This is a difficult question to answer exactly as manufacturers use all sorts of different methods to describe their lenses coupled with the fact that most macro lenses reduce in focal length as they focus closer by varying amounts. the closeup lenses then magnify less with the shorter focal length of the lens. If you still had your +5 lens you could measure the magnification achieved to compare with the published magnification data for the MFO-1 which is found in the port charts. The reported magnification is 1.1 to 1.2x for 90/100mm 1:1 macro lenses and the RF-100 increases magnification from 1.4x to 1.6x. I would expect a +5 to give you 1.3 - 1.5x magnification with a 90/100mm depending on which particular macro lens you use.

I have the 30mm macro, the Panasonic version, nice lens but I find the practical limit for it is about 0.5x, theoretically it does 1:1 but this is achieved about 10-15mm or so from the front port glass, hard to get that close and also light your subject. It does indeed work well for medium size subjects and I've taken some nice shots with it. But for me if you also want to shoot smaller stuff in the 0.5 - 1.0x range it doesn't cut it. I couldn't imagine using a diopter with it as it focuses so close already. The MFO-3 allows you to have the 60mm 1:1 capable lens and a 35mm approx lens on the same dive, much greater flexibility. In Australia at least the required port plus the lens purchased new for Nauticam would be more expensive than the MFO-3.

The newly released Nauticam MFO-3 does just this, it increases the field of view of macro lenses. In your case it would be the equivalent of about a 35mm macro lens. It is not available just yet, but due very soon. Attaches either with a bayonet of flip adapter or M67 thread. I've ordered one as I have the same issue as you with seahorses, larger fish, weedy sea dragons etc. You would need to check compatibility with your AOI port. Your other alternative might be either a 12-40 or 12-45 lens in a small dome. The 12-40 achieves 0.3x at max zoom, which is about 55-60mm across the frame, but it gets significantly wider field than the MFO-3. These lenses won't work well with a wet lens as they extend when they zoom. A third alternative is the WWL type setup using one of the 14-42 lenses, but this doesn't get as much magnification as you can get with 12-40 lens

I think they are saying both o-rings are small. This strobe has a third "sand" ring designed to keep particles from getting into the o-rings and they are very effective, I have one on my INON torch and it's also usually dry inside, so no water droplets on the o-ring, but I don't think it is a completely reliable seal. It may work for the first few dives but eventually water gets through to the under sized o-rings. This could explain the strobe working for a short while then flooding. Has the issue of the different sized o-rings been presented to Backscatter, has anyone measured to the cross section with calipers? If you look at their website this photo shows an apparent difference in the size of the two o-rings installed on the strobe. It may be an optical trick, but it is worth raising with them.

Welcome onboard!

This may be true, however it should not be happening after 6 dives. I think the report of differing cross section o-rings is a concern though.

The problem with wet macro lenses is the very limited range they actually focus in, however the weaker they are the wider this range. This is a problem as it can make getting what you want in focus tricky sometimes. As to what to start with this depends on what size critters you manage to find usually. With the UCL90 assuming equivalency with the CMC-2, you can shoot portraits of critters that are around 35-70mm long (filling 70% of frame in horizontal axis) at a guesstimate based upon the working distance range provided. It seems that the UCL-90 is something like 10% more magnification than the CMC-2 It is also reported that the UCL-90 gives more working distance than the Nauticam CMC-2. It's reported that the the frame at min focus distance for the RX-100 is 100mm across so through a flat port would cover 130mm so it would be usable for 90-100mm long subject without the close up lens. You can check what the bare lens can do for yourself on land, I only found a random internet post with data. Note that land based measurements need to be corrected for flat port magnification, while I believe the Nauticam data already covers this. This leaves a gap for objects 70-90mm long, but you could probably handle that with cropping the bare lens or maybe zooming out a little with the UCL-90, assuming the Nauticam data is for the lens at maximum zoom. It seems like the UCL-90 might provide a reasonable range of subjects sizes without needing to get too close. Also assumes your subjects you find won't try and leave (like fish and other mobile animals). For reference this video shows testing results for the CMC 1 and 2 and the UCL 67 and 90 lenses. IT is tested with a different lens but the relative performance will be similar for your lens, so the relative differences in magnification and working distance will be about the same.

The working distance is relatively short with the RX-100, Nauticam publishes the magnifications and working distances achieved with their close up lenses here: Google DocsN50 & Compact System 2025-06-20.pdfThe CMC-1 is close to the UCL-67 in power, while the CMC-2 is close to the UCL-90 lens. The CMC-2 at max magnification covers 48 x 32 mm, which is about 0.75x, so getting close to what you can achieve with a 1:1 macro lens on full frame, however it only focuses between 80 and 124 mm. The RX-100 alone covers about 100mm across the frame, so the UCL-165 will achieve somewhere between that and what the CMC-2 will achieve. I would guess that the UCL-165 is probably quite usable and could fill the frame with small subjects you could expect to be able to find in the relatively short time you have on the bottom free-diving. The issue I find with closeup photography is that finding the subject is hard part for small subjects, while 30-40mm nudis etc are generally a lot easier to spot. You would be the best judge about your ability to approach and shoot objects at the distances we are talking about.

I've not been, though I know the author of this website and it gives a reasonable rundown of Whale swimming in Tonga and how to get there and what to expect - for example the country is pretty much closed for business on Sundays. I know a few others who have been and they all sing its praises, IndopacificimagesHumpback Whales of Tonga - The Complete Guide | Indopacif...The Complete Guide to the Humpback Whales of Tonga has all the information needed to plan that once in a lifetime trip to this special place

I think the article was quite clear that the filters remove light and this is their limitation. The article also goes into having the right sort of red filter that doesn't just block everything below red but transmits some deep blue as well to help get nice looking water colours. The article's primary focus is on the limitations of the auto correct algorithms that artificially boost red channel which means you can't colour grade them afterwards as it brings on strange casts and fluro colours. This makes sense as the grading in the video software assumes certain things about the light spectrum and all falls apart if the auto correct has done strange things to the colour data. It seems to me that the primary problem in processing video from such cameras without filters is the inbalance between the channels, the red channel has much less information in it than the green and especially the blue and without a filter red needs significant boosting, while trying to control the blues and greens. When you add a filter you end up with a balanced histogram but with a bit more noise in all the channels. You have to stretch each channel a little bit less and this is generally good for not having the image fall apart. Having them all even makes processing such as noise reduction easier as each channel needs the same treatment In stills this basically means the RGB channels when viewed in the histogram are all full, So each of the RGB channels runs all the way from 0 to 256. If the red data is all bunched at one end it breaks apart as it is stretched to fill out the histogram. This is effectively what you are doing when you are trying to colour balance an image. 10 bit vs 8 bit helps a little with this but can only do so much. For all this to work properly the right filter is vital it needs to attenuate each channel by the right amount so you have a good histogram in each channel and it is balanced.

I know they only list their strobes, however if it can run their strobe in manual it should work for any strobe and likewise should work with any RC mode capable strobe and there's a few of them out now. Not sure how that works with a SOny camera though.

I saw a Giant frogfish in a discarded washing machine when I was there last and seems there's no shortage of rubbish around the place. I'm tossing up whether to bring a wide lens when I go, ( also in September (19-26) as it happens) I'm tacking it on prior to a work trip so luggage space might be a little tight. I've ordered an MFO-3 so hopefully it might arrive before I head out. The dive guides should certainly know.

The flash trigger is interesting, it's a new concept the Hotshoe module has 5 electronic contacts that connect to corresponding contacts built into the housing. The battery to run the trigger and also the vacuum system is built into the housing as are the trigger LEDs. The hotshoe module includes an old style screw down ring to secure it, presumably to ensure pressing the contacts together doesn't force the trigger back and lose contact. Hopefully it will give a reliable connection, particularly as the camera just sits in the housing without any lock in tray. As for service, I think in theory they are serviceable and some retailers will do service on them. Maybe ask your dealer before you commit? For example Olympus housings are made by AOI, but Olympus doesn't sell parts. Some retailers however will service them, mostly limited to o-rings, circlips and springs.

The solution I think is to trial it in a systematic way. Take some water shots in maybe auto ISO and check your results. Take shots with the sun behind and in front and see what they are like. The camera will try to make the water middle grey in tone and you may need some exposure compensation. Hopefully the exposure comp will be the same for the two extremes. You will probably also need to try different apertures and shutter speeds to get the exposure right at the extremes of lighting, no good for example being at ISO200 with the sun behind you and only being able to go as low as ISO100 into the sun if you go the auto ISO route.