Chris Ross

Interesting, however the sensor is only slightly larger than the current iphone pro it seems (11.4 x 8.6 vs ~10.2 x 77.5). The design of the lenses for these must be getting more challenging to keep them low profile as it gets more difficult as the sensor grows in size and also the depth of field steadily drops away as the sensor gets bigger. Have to wait for the reviews of the phone perhaps to see if it's an accounting feature (less sensors and lenses in the phone) or really does improve images ?

I would add that the MWL doesn't seem to have a lot of users, I recall various people asking about it but the fact they recommend using at f16 seems to be an issue, I only ever remember one review by Jack Connick and he confirmed that f16 was best and probably f14 the lower limit. the 150° field sounds closer to a fisheye but just looking at diagonal field of view is a little misleading, all these wet lenses have barrel distortion and this means the corners stretch out more than the horizontal axis. The WWL gets 130 diagonal which is about the field of a 13-14mm rectilinear lens and the MWL would have a 121° horizontal field which is the same as a 10mm rectilnear. A Fisheye lens is about 140° wide horizontally (175 diagonal like the 8-15). As you zoom in on a WWL the barrel distortion is progressively less noticeable and approaches the proportions of a rectilinear lens.

Just to compare my strobes here's my Z240 cap contacts and a swab that just wiped them over, this is the first time I've cleaned them: I can only see the slightest trace of residue being picked up. I agree though if you are getting corrosion on contacts regular cleaning will help. My routine with these strobes is that every time I pull the batteries the o-rings are removed shaken dry checked and greased and the water left in the o-ring groove dried out and cleaned, then replaced and sealed up. Because I'm diving regularly, the batteries normally go back in the strobe. The strobe is 10 years old. Even after soaking the strobes for 2 hours the water trapped in the cap between the edge of the cap and the o-ring in still salty (I've checked by taste). If I don't pull the batteries I end up with salt crystals in there as the water slowly evaporates. The O-ring on these strobes is not a super tight fit in the groove and it seems to me there is a risk of traces of salt water making its way inside the strobe unless I dry out the o-ring as described.

Sorry, you actually do need liquid water to setup an electrochemical reaction, a thin film of salt is enough to do it as salt is hygroscopic and will pull water out of the air. But unless the humidity reaches 100% you won't get any condensation and even pure water needs a little in the way of salts to become conductive enough to facilitate dis-similar metal corrosion. I'm quite familiar with corrosion mechanisms in my line of work. It won't happen if the contacts are dry. Leaking batteries of course can cause it as they leak electrolyte. Regarding copper, it is quite resistant to sea water corrosion, but tarnishes quite readily which can reduce conduction. Regarding Coca cola, it contains phosphoric acid which will clean away corrosion products. you just have to rinse it well or the residue will be hygroscopic and come back to haunt you at a later date. I just looked at my Z240 again, bottom contacts seem to be brass, maybe gold plated?? but totally tarnish free after 10 years, the spring contacts in the insert cap appear to be stainless steel. Stainless is much less prone to tarnish, it's electrical conductivity is not as good as copper/brass but I expect it's good enough.and you can compensate with thicker cross sections. I never opened them up under suspect conditions like on a boat with strong winds blowing, but always made sure no water was left clinging to the o-ring before re-assembly. I think the issue is the high currents required, they make a big deal about having properly rated batteries - unless the contacts are good the extra resistance will just reduce the current. I don't think they cause the corrosion as such but are more sensitive to the impact of it.

Hi Tim, welcome aboard, good to have you here. I dived Byron a couple of years back, must get back up there.

Must be made with poor quality material, I'd expect this for materials left outside for extended periods, but not metal that spends its whole life inside a battery compartment sealed off from the outside. My INON Z240 strobes i had for 10 years and the contacts in the little cap thing and inside look as new. Dissimilar metal corrosion requires some moisture to condense, now if you get a trace of saltwater inside that will draw in moisture and can start corrosion. I always pulled my o-rings every time I opened them as I could see water droplets clinging to them and dried them off and wiped out the water in the o-ring groove before replacing them, if any of that water gets inside it will cause problems. My new Retra strobes don't seem to gather droplets of water so readily so those o-rings stay on most of the time and they are serviced periodically. The best is my INON torch which has a sand seal which basically means water never gets on my o-rings.

The port charts list the two 30mm macros and the 12-50 so it seems it would work with the 45mm. I'd estimate the field would be be a bit wider than the 12-50 - about 24mm FF equivalent in terms of horizontal field. The MWL seems like a great idea but never really took off and there is probably a reason for that. For one thing it is said it needs to stop down to f16 to be at its best which is well into diffraction softness with m43. It seems not too dis-similar to my situation in Sydney, I mostly dive Macro and regularly see things that would benefit from the MFO3, but possibly might see a big subject - a grey nurse shark shows up occasionally as do other things like wobbegongs, large rays etc. I still dive with the macro setup and now the MFO3 as it covers 95% of what I shoot very well. There is FOMO of course but I'd rather have a system that does well on the most common subjects. I'll occasionally dive with something wider at this site.

No I don't have a tether, just need to pay attention when mounting the lens. It's worked OK so far. I used cargo shorts in lembeh, but reverted to a dock on the float arm diving in Sydney. The weight of the lens causes the shorts to fall down over time when walking any distance - not an issue when you are just falling off a boat but a real problem shore diving.

It seems to me that a 30 macro will do several things but mostly none of them well. It's really not wide enough for a really big subject and you need to back off too far, while it is fiddly to use on average size nudis and the like as you are in too close, I don't know what your dive sites are like but I find the housing contacts the rock the nudi is sitting on if I have to get too close -unless it is on the edge and I also don't want to shoot down as it's not that interesting. This is also an issue on a wall. The short port doesn't help at all. So basically I stopped using it. A little extra working distance and the longer port for the 60mm macro means you are shooting at a shallower angle in this situation. I would also suggest diopters are not really needed with m43 1:1 lenses, on the 45mm macro the working distance is about 60mm from port glass at 1:1 - the diopter only eats into this. None of the options discussed so far would be great for a Giant Pacific octopus. Seems like better approach would be do macro dives sometimes and CFWA others?

I suspect you'll find the smaller range challenging with the 30mm macro lens, the field at 0.5x is 34mm wide which is about right for a 20mm nudi and you need to be 25mm from the port to do this. The 60mm will let you capture 10mm nudis with reasonable working distance and adding the MFO-3 will get you subjects about 500mm long at a maximum - it only focuses out to 1.5m, The post I linked above showed a shot of a trumpet fish about 500mm long and EXIF reported the lens was at infinity. The best option probably varies with whether you are mostly shooting small things or leaning towards mainly larger subjects. If you mostly shoot bigger something like a 12-40 in a 170mm dome would do well or a CFWA setup of some type. If by octopus you mean giant pacific octopus, the MFO combination won't get you there as you'll be too far away. But for subjects between 10mm and 400mm the optical quality with 60mm/MFO3 will be great and better than what you have with the 12-50. The 30mm macro will be slightly better for big stuff, but will suffer compared to the wider views from the 12-50.

Even things like my Atomos monitor has a single button that you need to hold for 5 seconds to turn off, then there's the lights that need endless combinations of short and long presses to change settings. Are they trying to save money on switches? very annoying.

I've used the 30mm a little around Sydney, a couple of things to note with it. First it's sharp and AF is snappy, however the practical limit for magnification is about 0.5x, the working distance is very small, it's about 25mm from the port at 0.5x, which can make approach and lighting a challenge. I'm not sure what the subjects around Vancouver Island are like - are you thinking most of them are on the larger size?

I do it's the neoprene bag the lens came with, it doubles up to keep the lens from drying out till I get home and soak it in fresh water. I'm planning to see if I can find a neoprene sleeve and cap that's more stream lined for longer term use

some pics, first the docking adapter on my float arm second the MFO3 mounted. You have a similar adapter mounted to the port to accept the bayonet mount, line up the white marks, insert then turn till it clicks. You can see it is a big lump of glass. Roughly same size as 60mm macro port. Honestly if you are just boat diving a quality flip adapter will be easier to use, just doesn't seem practical for me when shore diving from rocky entries, which is why I went with the bayonet.

Alex Mustard used it on a flip adapter, so it will work. I found it fine to carry in cargo short pockets and went that way as I will use a lot at home where I am making sometimes a little rough shore entries and exits, but from a boat the flip will be fine I think as long as its fairly robust. Here is a link to Alex's review. also I replied to your original post asking what to use: