Chris Ross

Reverse pressure won't impact most o-rings. Piston seal o-rings seal equally well both ways, a surface o-ring is generally not so good at reverse pressure, THis is the type which can trap a vacuum in a housing when taken on a flight, particularly if the clamps are not super tight. The force on the flat back plate is quite high and can cause it to lift and let out the internal pressure. When the plane descends it's like taking it for a shallow dive and it will trap the vacuum. See the diagram on this page: https://www.applerubber.com/seal-design-guide/oring-basics/dimensional-considerations/ The top one, the face seal may not do reverse pressure as well depending on clamping force applied, typically used on some housing backs for example which may have only 2-3 clamps around the perimeter. The other two seal both ways.

May be if it was AOW and 40 dives rather than "or" 40 dives, some places will spit out an AOW diver with 8-10 dives. Though even that doesn't guarantee a diver with decent buoyancy control.

It would be interesting to compile all of these reports to look for common threads. I can see no reason why a strobe would leak after some period sitting sealed up with the batteries inside after working on the first dive. O-rings are not that complicated they should just work if they are installed without any grit or hairs present. Pressuring, de-pressuring and re-pressuring should make no difference, we do this all the time to the control o-rings in housings and probably quite often to port o-rings, when we leave the same port in place for multiple dive days. There are several different designs of o-ring installations including a surface groove with a flat plate sealing against it and various variations of piston mounts including screw on caps and variations of push and turn. Each have their own risks, for example it is possibly more likely for a surface o-ring to leak via a hair laying across the ring, especially if a vacuum is not used to seat the plate. Is one type more susceptible than others? O-rings whether they are installed in strobes or camera housings or torches should behave the same way. The only difference these days is that strobes don't have vacuum systems, while a great many housings sold today have one. One possibility is if it's a small leak with only a few drops it may take time to kill the batteries. Quite possibly the o-ring leaked and the batteries kept going but after sitting for hours to days the water has worked its way in and done the damage. As the strobe was not opened after the dive it is not possible to prove or disprove this. Maybe moving the strobe around again after the time it was sitting is enough to get the water to move somewhere it can do damage, or the damage is minor but accelerates when the batteries are loaded?

Just to be clear red/blue flashing is low battery when the system is first turned on, you can pump it down, it will turn to green and continue to function at least initially -eventually the battery will be too low. When you release the vacuum, it then flashes yellow then red. Not red/blue. I tried this just a day or two ago, my battery was due for replacement and it flashed red/blue when switched on, pumped down to green and when released went flashing yellow then red. Flashing red/blue anytime other than than this is something else, either a fault or resetting the system due to loss of power if the battery is low at the time. My manual says flashing red and red/blue is loss of vacuum, the guide linked above only mentions flashing red for loss of vacuum. It's clear from the behavior of my system that red/blue only happens when first switched on.

The red/blue flashing is supposed to be when you first turn it on only. My battery recently started flashing red/blue when I turn it on, I didn't replace the battery immediately. Pulled the vacuum, went for a dive, came back and dried housing to release vacuum and it only flashes red. The red/blue only happens when it first powers up, pulling the vacuum it goes yellow then green and when releasing turns yellow the red. I also note that when vacuum starts to drop when releasing vacuum, the initial response is flashing yellow, then flashing red when the vacuum is nearly gone. SO if you have a slow leak it should start flashing yellow first eventually changing to flashing red. If you are not getting yellow first a slow leak seems unlikely to me. Your water drops sound very much like water clinging to the o-ring, getting rid of them is near impossible, I run my blower along the seam to blow water out, but there's always some clinging to the o-ring and on the housing. I'm resigned to wiping it off then pulling the o-ring to shake dry and drying the groove every time I open up after a dive. What I am not clear about is the difference between flashing red and flashing red/blue in the table - the table says both are an issue with vacuum. I don't get red/blue flashing when releasing vacuum. You could get the red/blue coming on if you momentarily lose power, possibly an issue with the battery holder, the wiring or the switch, that would effectively re-boot the system and it would start red/blue flashing as if it just powered on. That one is a bit hard to test as you would need to be under vacuum and green then play with the wiring. Maybe see if shaking the housing a bit triggers anything??

First I think refer to instructions when diagnosing: Alternating blue and red is saying the vacuum has gone, but you report the the vacuum still present, indicating perhaps a problem with the pressure sensor. The moisture alarm is separate to this and is described on the previous page on my manual. It talks about testing the moisture alarm by shorting the two wires of the probe. The response to this is a loud alarm and a flashing red light - not a red/blue light. You're not mentioning hearing the alarm and not reporting the flashing red light so this says that the moisture alarm has not gone off, only the vacuum alarm. You need more than a drop or two to set it off unless it drops directly onto the little sensor. Basically it needs enough of a flood to cover the two wires and complete the circuit, something like 2-3mm in the housing base. That's not to say the drops of water aren't involved, perhaps the humidity or drops of water have made it onto the pressure sensor somehow? The sensor seems to be within the little black box of the alarm electronics, there is hole on the box which looks to me to be the sensing element. Reading up the sensing element doesn't seem particularly moisture sensitive, but condensation on the electronics may cause issues. Probably the most likely cause for a drop or two of water inside is water beading on the o-ring and stuck behind it when you open the housing. I always see a drop or three clinging to the o-ring and on the sealing surface when I open up. This is water that has beaded on the o-ring - the o-ring needs to be exposed to water pressure to seal and it will bead up the the o-ring and sealing surfaces. It is held inside the groove/joint by capillary forces. I always remove the o-ring and dry it off to make sure it doesn't get pushed into the housing when closing the clam shell type back,. Where exactly in the housing do you see the water drops - in the port, inside the housing itself or only along the o-ring sealing surfaces?

If you are freediving UW weight is likely to be important I would think. The Canon 8-15 is a nice solution, however with a small housing and dome it ends up quite heavy UW. I have an OM-1 in Nauticam and use the adapted 8-15 with 140mm dome and it has an UW weight of nearly 1.8kg. I use two Isotta float arms with 670 gr buoyancy each, they are 70mm dia x 220mm, so quite bulky and I'm still 400 gr negative. The Isotta housings are quite compact, however in certain combinations makes them quite heavy UW. This means large floats if want to get close to neutral.

The typhoon season is extended if the waters stay warm, this is what drives them , so not unexpected that late season typhoons are becoming common with warming oceans.

I assume you have tried it out for fit, I would expect the macro lens to work fine as is without accessories, vignetting seems unlikely with that sort of focal length. The power of a diopter generally reduces if it is mounted further from the lens, so magnification would drop a little, whether it introduces other issues is hard to predict. If you already have the lens you can always try it out before buying a new port. The port designation indicates the nominal port length 87 vs 80 as you saw with the Z lens having around 7mm gap comapred to the F mount 105mm. Looking at the port chart if you happened to have a Macro port 60 you should be able to add a 20mm tube to get the equivalent of the macro port80. The port chart actually lists the macro port 60 plus a 30mm tube for F mount 105mm - which would leave about a 3mm gap. For that combo they show the same magnification and working distance for use with an SMC-2 on both macro port 87 and the Macro port 60 plus 30mm extension. You are looking at a 7mm gap versus a 3mm gap which doesn't seem like it will change things much. There's some discussion on the MFO mounting in the thread about using the full or reduced range on the 90mm Sony macro, discussing an adapter that comes with the lens to screw it in.

On the Zeiss macro the main point would be to check if it has the same impact it does on the 90 macro. I only say this because others are reporting in this thread they are pleased with how the MFO is auto-focusing with the 90mm macro, plus Alex Mustard is using it as well, though maybe with the A1 rather than the A7RV. It's always possible your 90mm is playing up. on the focus limiter, second post of this topic says that is what you should do. Infinity focuses on something just over 1 meter away with the MFO according to the port chart.

Yes it seems significantly heavier than my setup, the backpacks are a similar size and weight mine being 65mm narrower. Mine is lasted at 2 kg empty so not a lot of weight that could be saved. I pack mine with camera/lenses/housings/ports and batteries only. Other bits and pieces including strobe arms etc go in the checked bag. My OM-1 + housing is 2.6 kg while the R7 is 2.85, a bit heavier but not that much. I think you had the Supe zD-pro strobes, they are double the weight of my Z240s, but I seem to be carrying more lenses and ports than you do.

I can see the argument about AF getting better with the MFO, but not sure how it could make things worse? I think you said the sharpness improvement was there so it seems to working as advertised there, but I'm not sure how it could cause the camera/lens combo to hunt and be slow to AF, I may to be totally missing something But I would look in the direction of the camera/lens more so than the MFO as it is "just" a mild diopter with air/water correction turned on. You could perhaps try it with the Sony 50mm macro - it is on the port chart for the Panasonic (m43) 45mm macro so you would think it would work on either of the 50mm macros to see if it degrades the AF there as well. The other question is if you popped the MFO off during the dive to see if the the bare 90mm was an improvement? Perhaps a good first approach would be to compare camera/AF settings with others using the 90mm/A7RV combo.

Not a technical pack but shares some of the features like a waist belt and a sternum strap, I use the think tank Streetwalker harddrive pack, which meets carry-on dimensions but perhaps not the weight once it is loaded up. In the pack I've got Left to right: EM-1 MkII housing, spare batteries Macro port for 60mm macro, INON Z-240 x 2, Zen 170mm dome Zen 100mm dome for fisheye, Panasonic 8mm Fisheye, 60mm macro,Olympus 12-40, Panasonic 7-14 I also used to take my OM-1 housing, 140mm port/extension/n85-N120, macro port, 8-15 fisheye 60mm macro, 12-40 lens and strobes to PNG last year. Weight as shown is about 10-12 kg, it has a laptop sleeve under neath as well. I've had it at least 15 years now and still going strong.

I don't use Word, I've got Libre Open Office Write, here's copy and paste: This is a comment written in Libra open office Write checking to see if it will paste into Waterpixels It pasted but ignored an Indent on the second line. I just used Ctrl-C and then right click to paste. Not sure why it wouldn't work for you. I'm on Win10 and using Firefox.

No problem. On the topic of cyclones they are more likely at the end of the season than the beginning as water temperatures are lower then. The Water could still be cool in Fiji in November, though Thanksgiving is closer to December, cyclones south of the Equator are rarer then, but not unknown. Heard good things about Okinawa, however they do have a maximum age limit for diving, a potential issue for me, perhaps not for you. When I visited Lembeh it was second week of November and rain had just started, but it didn't impact us at all. Being close to the Equator you just have the wet and dry seasons and cyclones are not an issue.