Chris Ross

I think these days modern sensors are so good as long as you don't badly clip your image it doesn't matter , many sensors are ISO invariant and tweaking up exposure is no different to raising ISO in camera. Where it does help is in judging you haven't had too much flash as increasing exposure in post brings up flash as well and you wouldn't see it necessarily when reviewing the image when UW. But again if you have a histogram like shown above in my post you are not blocking shadows or blowing highlights and in fact you are only using 60-70% of the available dynamic range, so a high dynamic range camera does nothing for you. Stretching this histogram out with a levels adjustments maps the brightest pixel to just below clipping and dimmest pixel to just above blocking up and the contrast comes up and image is 90% of the way to being the finished product. So underwater all you do is expose to approximately centre the histogram and don't overdo the flash. What is happening is the strobe is not really brightening up your subject but adds enough reds that you can successfully pull the colours up and get a decent white balance. So in effect it's an ambient light shot with some warm colours added into the mix which enables you to achieve a satisfactory white balance when you adjust everything. Forget about balancing WB on the water vs the subject, you are not going to achieve deep tropical blues, but it will look OK. The other thing is that you'll only light up a 4m wide section of wreck or so at most with your strobes on the best of days so you are effectively shooting ambient light and colouring up some foreground objects with the strobes.

If you are proposing to do this UW - good luck!, I do a lot of focus stacking macro on land and anything but the stillest condition will make it near impossible, then your strobes need to keep up and there will be limitations on how fast you can shoot. You need to solidly mount your camera then rack it in and out to get the near point in focus then guess how many frames you need and give it a try and then check that the last the frame gets the most distant part you want in focus. Then you do all that and get home and find that you missed on getting the closest bit in focus as it was another part of the object that was actually closest and you go back and try again. I use an external monitor and magnify the image 2x on it to check the focus point for the start of the stack and again the check I got full coverage. Underwater - no thanks I'm not that much of a glutton for punishment.

I would suggest that these days there is little to pick between sensors in UW cameras you can either have a 20-30MP FF or a higher pixel count in the 45-60 MP range. Pick your poison in MP count then look rather to other features like flash sync speed, and the range of available lenses as well as housing support from various vendors. Also important is battery life, can it charge over USB through a bulkhead? what is flash trigger support like, all practical things that make life easier living with an UW housing. If you are looking at Nikon vs Sony in Nauticam that means N120 ports for Nikon and N100 ports for Sony. Practically speaking the N120 port range is not as good as N120 and you can end up needing an N100-N120 adapter (not cheap for Nauticam - but then again neither are their N120 extension tubes these days. In Isotta they both use N120 ports. Personally I'm not a fan of the Sony flash hotshoe it's a known weak point with lots of fine contacts which give connection trouble periodically, there have been a few people on here having issues with their hotshoe as I recall. Beware of paralysis by analysis though - just setup a costs spreadsheet to get what the lens types you want to use housed and UW and compare costs.

The argument here is you need high ISO as you are relying more on ambient light - basically the strobes are turned down to avoid blowing out the water. The real solution to this flat low contrast image is to set your black and white points - here is the histogram of an under flashed ambient light image: and here is is the adjustment in a levels tool: Now the difference this makes is quite significant, this is just a throwaway shot, but it is under flashed in murky water and it shows what happens when you set you white and black points properly- the LH side is out of camera, the RHS only has levels adjusted and shadows boosted a little: There's more that could done to fine tune things, a standard curves tweak, a bit of fine tuning the WB, brightness, etc, but what we are doing with this shot is compensating for the low dynamic range in the scene. The time taken to do this is way less than explaining what has been done, you just grab the white and black points on the histogram and drag them in. Higher dynamic range will make no difference at all to what is going on. It's not that you don't get the benefit of high dynamic range - it's that you don't need this benefit. As an aside you can also do your colour balancing with this tool by adjusting the black/white points on each individual channel.

If you stay within the Nauticam eco-system, this is mostly true however there are some examples I can quote: First a Sydney diver using a D850 wanted to downsize, they went I think with a Z5 camera. The Nauticam housing was the same size and weight as the Seacam for the D850, however the Isotta housing gave significant size and weight savings as it is much more compact in the way it is laid out. Second as recently discussed on here the Nauticam Z5II/Z6III housing is significantly smaller and also cheaper than the other Z series housings. The first Nauticam Nikon(and Canon )mirrorless housings were a lot larger partly as the set the camera back further in the housing by the thickness of Z-F converter so the F mount lenses and their zoom/focus gears would work with the same extensions as they did with the F mount cameras/housings. The new style housings accomplish this by using a Z-F adapter with it's own zoom gear so that the F mount lens zoom gears will work and you don't need to buy new ones. You still have the large ports and extension rings etc and the big lenses but the housing can be made smaller.

As I recall Nauticam stated that they used the 28-70 kit lenses from Ca-nikon as they had the required entrance pupil size and that faster f2.8 zooms wouldn't work because of their larger entrance pupils. A few people stated that a 52mm or smaller filter size was about the limit for lenses that worked with the WWL-1. It was also speculated that the limitation was related to the size of the rear element of the wet optic the flat port in the case of the WWL-1 or the rear element of the WACP series, which seems to imply a geometric limitation in getting the light bundle from the wet optic into the lens front element. See this from Massimimo on his website for example: https://interceptor121.com/2023/03/11/nauticam-wwl-1-on-sony-full-frame-what-to-expect/ All of this is somewhat speculative, but I have yet to see anyone who has posted "I put a 28-xx lens not on the list behind the WWL or WACP and this is what the images looked like" or similar posts. So we just have these bigger lenses are incompatible but no real reason why and no one has tried done behind one of these wet optics and published what they found at least I don't recall seeing any such posts. Some examples might include will the EF 28-70 f3.6-5.6 lens work behind a WWL-1 on full frame or will a 24-70 f2.8L lens work behind a WACP-1, the question has been asked but I don't recall seeing anyone posting what the result is if you try it.

I'm not 72 yet but I feel every kg these days, while it's certainly tempting to want to take your favourite camera UW, there's lighter options that are every bit as good these days. Not saying don't do it but check out the size and weight of a housed D850 and how you would travel with it before leaping in.

Yes there are plenty of examples where FF might have an edge, if the particular scenario is important to you, sure, If you dive it once or twice and don't come back to it FF, APS-C or m43 will all likely produce an acceptable result. I'm not sure how particulates come into your example to favour full frame though. Low light sure particularly with a constant light source, though video lights on a wreck can only illuminate a very small proportion of it I would think.

I don't doubt there are solid reasons for using a FF system and one of them is no doubt, I want one, I can afford it and I'm prepared for the weight and travel issues. However to fair again, shooting at f2.8 is not something everyone can do with the lenses they have and to get the best out of fisheyes behind domes and wide rectilinears requires stopping down to at least f11 for many people's tastes. For me I occasionally run into trouble with sunbursts with Olympus, often due to laziness on my part setting things up but overall I'm happy with what it puts out. I should add this applies to the latest 20MP sensors, the earlier 16MP sensors seem to me to be a step behind.

OK so a bit out of the way then. I'm likely going on Saturday, I've got a ticket so should be there.

yes, but apart from sunbursts, dynamic range I don't think is that useful under water, most shots I take I'm increasing contrast. Don't disagree there are certain situations where it will help. If you look at noise it seems to me the performance is closer than most people think. Here is one example comparing an EM-1 MkII with a Sony A7RV from DXO mark : You'll see the noise when the EM-1 is set to ISO200 is about the same as when the Sony is set ISO400. Effectively one stop better and shooting wide you may well want to have the Sony at 400 due to stopping down to f11-13, while the Olympus is happy at ISO200 at f8, but either way it's not a huge advantage. of course if you compare true ISO it's about a stop and half difference. The point is m43 can claw back quality by shooting at wider apertures and due to the smaller sensor they are less constrained by dome size. Here's a link to have a play with if you like: DXOMARKOlympus OM-D E-M1 Mark II vs Canon EOS R8 vs Sony A7R V |... The dynamic range curve is similar. In fact if you throw the Nikon Z8 or the Canon R8 into the pot they all very closely mimic the Sony curve. In fact DXO's most recent test results are from a camera released in 2023, it's like the curves are all so close there is little separate them and other shooting factors come into play like computational photography, AF, high frames/second etc. etc. to differentiate cameras today, making this sort of testing somewhat obsolete. Now I'm the first to admit these curves don't tell the whole story and certainly you shoot a bit higher ISO without noticeable penalty with full frame and there are other advantages for specific cases, but for general reef shooting and macro where you are shooting within a stop of base ISO it's close to a wash. I've linked in the past a shot taken on an OM-1 at ISO10,000 - it is surprisingly good. on the topic of large prints it seems to me we are talking A2 and above. If you look at physical prints in the big photo comps, I haven't looked lately but it seems they are mostly in A3 size range or the old 16x20.

Pure manual triggers I believe rely upon the X-sync contacts within the shutter closing the circuit between the centre pin and the common edge contact, so to work they need the shutter to operate. E-Shutter needs the trigger to talk to the flash and establish communications so the sensor can trigger the flash. So a pure manual trigger doesn't tell the camera flash is even connected - this for example is how the Nauticam manual trigger can sync at 1/400 with the OM-1, the camera doesn't lock out the higher shutter speeds and the flash still fires regardless. Electronic shutter needs to co-ordinate with the sensor reading to fire the flash at the right time to fully illuminate the frame - on most camaeras unless they have very fast readout this means the sync speed for electronic shutter is lower. Out of interest why do you want to use e-shutter? Seems like it would be simpler to take advantage of the high mechanical sync speed in most circumstances?

Digi direct, DCW, Camera Pro among others have bricks and mortar stores, Digi has 4 in greater Sydney. What town are you in? If you come to the Go diving show ingreater Sydney there's quite a few stores still that you can visit. Apparently OM system is an exhibitor at Go Diving.

You have to remember that while some of these testing and review websites might be useful, and well tell you various things about noise measurements and which combination has the best noise characteristics. They are however run by people who measure photographs rather than make photographs in many cases. the differences are often only visible when viewing the image at 100% on Photoshop and even then you need to look at them sideways multiple times to pick the differences. If you look at the images as a whole image it can be hard to pick the difference between well exposed images taken on m43 and full frame unless you are talking about extremely large images or very high ISO, but even then m43 can produce some amazing images in low light. You have to go down to a compact like a TG-7 with a tiny sensor and not expose it that well to produce an image that is obviously not as nice. Back in the day when digital first started there were big differences, these days things are much closer and gains are very much incremental. It's not that FF doesn't have it lace but for me and many others the gains aren't enough to offset the downsides of ownership.

Digi Direct used to be a go to, these days they sometimes don't have stuff in stock and don't always tell you till after you order. They used to be cheapest but not always these days. Avoid grey market importers - you often won't get warranty service locally as the warranty is through the retailer not the official importer. Digital camera warehouse is another to checkout, they have been around a long time. Another is Camera Pro. I've bought from Camera pro, digital camera warehouse and digi direct, sometimes Ted's George's or diamond have the model you are after at a good price. Best bet is to go to google and type in the model you want, then "price australia" and a bunch of options will pop up. you can look at online reviews but looking recently they all seem similar. Best to physically call them to check for stock prior to ordering.