Chris Ross

I must disagree with this statement, if you are looking at Nauticam housings for example the price of the housing for a full frame Z8 is near enough double that of an OM-1 (m43). Domes are generally smaller cheaper and easier to travel with and the lenses can be around half the price depending on the model and are significantly smaller. If you are shooting wide angle because you are shooting at f8 on m43 rather than f11-16 on FF you can use less powerful strobes which can be lighter and cheaper as well. Plus wit h APS-C you can use a Tokina 10-17 and m43 the Canon 8-15 for a very flexible zoom setup that just is not available on FF unless you go with the very expensive FCP port.

The colour temperature or WB in camera only impacts the starting point for the the RAW file and impacts how it looks when you first open the file as I understand things and in theory you can adjust the WB in post to get to any of the settings. As I understand things in lightroom, adobe standard, landscape etc are presets which apply a standard adjustment to the file and again are a starting point. Colour space such as AdobeRGB or sRGB when set in camera is also a starting point it sets the range of colours the raw converter can map to from your RAW data. The other thing all these in camera settings are used for is to make the in camera JPEG which is used to display the image. RAW processing can get around all of this, however it does help if you are trying to check for clipping in your file for example. With the wrong settings the 8 bit in camera JPG will clip before the RAW file clips and give you misleading information when adjusting your settings.

Here's an actual example, this shot was taken in PNG at Walindi resort. First I have the as taken shot, only sharpening has been done, here it is in Adobe RGB profile - it should look fine as long as you use a colour profile aware browser: Unprocessed in Adobe RGB and here it is sRGB with blues tweaked a little you can see the cyans are suffering: Unprocessed in sRGB You can see in the unprocessed image that the subject is rendered quite warm as it is illuminated by 4500K light while the frame is balanced at about 5900K. Next is global adjustments to colour balance and contrast , first in AdobeRGB then in sRGB, I quite like the blue in Adobe RGB but not so keen on the sRGB version.: Processed in Adobe RGB Processed in sRGB I've linked them from Google drive as any image posted here is processed further and for some reason when I upload them the colours go way off. Should be able to open them in tabs to flip between.

This is true, but the same strobe light is illuminating both the subject and the backscatter, so if the backscatter doesn't move the pixels where it is recorded receive the same relative amount of light as the subject portion that is occupying the same slice of the image where the shutter is open. If the subject is the same brightness in the final image the backscatter must also be the same brightness. The only way it can be less bright is if it is recorded again on a different pixel or group of pixels on the sensor. Another way to think of it is that the very high frequency pulsing on and off approximates continuous lighting so the result is similar to increasing the natural light coming in albeit from different directions and coverage. To take the astro photo stacking analogy, if you get a satellite trail through one frame of a 20 frame stack it's only 1/20th as bright in that stack as it was only recorded on those pixels in that frame. But you don't get that in backscatter unless the particle moves enough to not be recorded again on those pixels in the next frame.

You are likely correct for a lot of the shots in my IG, but I would also suggest being cautious with images on IG. I process my images in Adobe RGB and get reasonable blues but converting to sRGB they go off and I haven't discovered a magic formula to bringing them back. In addition Facebook I know and I assume IG strips the colour profile for the image and converts it to uRGB, which is their own profile - they do this to reduce the size of the profile attached to the image, with the millions of images uploaded it saves significant bandwidth. If I am honest I think a lot of images I'm not close enough so they don't get enough flash light - I can compensate for that but the blues probably suffer a little as a result. I shoot RAW, (no JPG) out of camera, autoWB, using two Z240 with the 4600K diffusers for some of the images - mostly the tropical ones, I have a huge number of images from Sydney using the standard diffusers. Don't use lightroom, I use Capture One feeding into photoshop. in camera it's Adobe RGB profile. If you are shooting Raw the colour profile in camera is somewhat irrelevant, it just sets the starting point when you open in your Raw processor. Of course shooting JPEGs are a different story and profile in camera is important. The only way to remove greens though is through the tint adjustment on WB - the starting point you get will certainly vary with the camera you are using and the colour profile you set but changing the shutter speed only makes it lighter or darker. The point of the images I posted previously was to show that the water colour does not change with shutter speed only the brightness. Certainly increasing your shutter speed can improve the look of your image by darkening the background providing more contrast. A lot of this is going to vary with how your camera deals with WB. Some cameras if they know a flash is attached will set to a constant value others will adjust WB based upon the pre-flash, my OM-1 seems to produce images with around 5900-6100 K WB setting at least in Sydney waters. I have found my best shots seem to come from ones that are minimally processed. Just a quick tweak of levels/curves and WB adjustment.

The real power of these connections is that you don't have to open the housing, I got one for my OM-1 housing and on my last trip I charged the camera each evening and downloaded all the images for review without opening the housing. Very handy for that setup as I had an adapted 8-15 which I would need to pull the port and remove the lens to get the camera out. One thing to note is that charging through the camera seems a bit slower than using a dedicated charger, may or may not be the case for other brands. If you get one from Nauticam, be sure to get the specific 28mm bulkhead designed for the USB-C connection, the Nauticam cable doesn't fit through the other one.

Sorry, but that is not how it works, changing the shutter speed changes the amount of every wavelength of light the same amount, it doesn't preferentially cut off certain wavelengths. What can happen is on Auto WB the camera might shift the WB around on each frame or shooting a different subject might provide a bigger shift in auto WB. I was out diving this morning in greenish water and took a series of shots of just the water, then copied a square out of the centre of each frame and pasted into a single file. I did this first as shot, you can see I didn't get the same aim in each frame so exposure wasn't equal. I then equalised exposures on all frames and pasted another set of squares. YOu can see the equalised brightness squares are all pretty much the same. The water was under exposed a little so I then increased exposure of each frame by 1.3 stops and also pasted them into the file. You can see that the colour doesn't really vary among the frames. I also noted the colour temperature and tint from each frame and it moved a little bit, but undoing this I could see no change in frame colour. The way to shift greenish water to blue is increase tint which adds magenta. This may or may not be feasible depending on how the the subject reacts when you do a global tint adjustment. Not saying that darkening the background water doesn't improve things, it just doesn't change colour. Shooting with warming filters does however shift the colour of the water towards blue/cyan, removing yellow and red.

One option is to break them down into clip lengths, have some short and sweet and others longer, maybe keep them in separate folders? As for me a short sharp clip is nice, and if it has exceptional content etc I'll watch for longer.

Hopefully we'll see something official soon, wonder if he'll also go to Boot dive show in Düsseldorf?

I've already factored that in by calculating the the amount a particle would need to move at 0.3x magnification to move one pixel width on the sensor which is 3.3 microns/0.3 x = 11 microns.

I would check how easy the focus peaking is to use in practice. I know it can be problematic on my Olympus, it will depend on how it's implemented in camera or on the monitor. I have a an Atomos Shinobi and find the monitor is more optimistic about what is in focus compared to the camera when using on land. You could probably try all of this on land before committing to a housing for the monitor.

Sounds like the claim is that each pulse of HSS light is very short and if the particle moves between pulses it will receive less light. The problem is that HSS pulses are at very high frequency in the kHz range and likely the particle won't move very far between pulses. A quick analysis, assume a 20MP m43 sensor shooting at 0.3x . Pixel pitch is 3.3 microns and the backscatter particle needs to move one full pixel which is 3.3/0.3 = 11 microns to not appear on the same pixel at the next pulse. Assume the HSS is operating at 20 kHz so each flash is 1/20000 = 0.00005 sec. To move 11 micron in this time particle needs to move at 0.000011m/0.00005 sec = 0.22 m/s. Not particularly fast, that is 0.42 knots. However the particle is probably bigger than 11 micron to be conspicuous, lets say it's 1mm across so it needs to move 1/2 a mm so it doesn't cover any of the same pixels in the next pulse, so that's 0.0005mm/0.00005 sec, so that's 10 m/sec which is 20 knots. Any slower and it leaves a short trail as it is illuminated each time the flash pulses. This analysis is not exact of course and only gives you an idea of how quickly things need to move to be not be recorded by more than one flash pulse. In a HSS image at 1/250 shutter speed and HSS at 20 kHz, the total time the shutter is open is 0.004 sec and at 20 kHz that's 80 flashes. You do get a moving window of the focal plane shutter and that means each bit of image receives only some of these pulses, but the total light must be the same if the subject is to be exposed correctly.

To be fully accurate, changing shutter speed doesn't change the colour of the water, it makes it brighter or darker. Changing the colour temperature means there is more or less yellows in the blues. The tint can also have a big impact on how the blues appear, adding magenta makes them appear deeper in colour. Making the water darker however can improve the look of the water, providing higher contrast with the subject. I agree masks can be a problem - it's always better IMO to get it right in camera. It's so easy to get carried away when processing and produce something you want to throw out when you see it the next day with fresh eyes, so keeping your processing simple is always a good thing.

The issue with the 180mm dome is it is not a fisheye dome and it only covers the field of a 16mm lens with the entrance pupil at the dome centre of curvature. This means you have to place this lens well forward in the dome to avoid vignetting and it will not be as sharp as it would be if properly placed and the filed of view will change somewhat. Fisheyes are more tolerant of incorrect placement compared to rectilinear lenses, there will be some image degradation but without actually testing it hard to predict how much and if it's acceptable. You see vendors like Ikelite offering shallower 8"domes than the 180mm for use with the 8-15 for CFWA work and it still works and produce fairly decent images. I would expect the 180mm dome to be close to this in performance. THis link has some test shots which will give you some idea: https://www.ikelite.com/blogs/buying-guides/when-to-use-a-compact-8-dome-port-underwater?srsltid=AfmBOoq7cYAIaQzEIVTEl0zBJ5dC71nshLjTj2nHBSLCxy_wFBWMEuqy

Wondering what specifically you might concerned about with your vision and how you think a monitor might solve that? For myself my closeup vision is not so good so struggle to details up close a little. I use a separate monitor on land for judging sharpness when the camera is low to the ground and for it to be a all helpful I need my reading glasses on. So my take on that is you need good closeup vision to take advantage of the monitor or supplementary lenses on your mask, because by it's nature the monitor will be quite close in. UW is use a Nauticam 45° viewfinder and it provides a full bright image and it has diopter adjustment to allow me to see the details sharply and it's my preferred way of shooting. Admittedly I don't shoot video, but the distance vision problems are the same.

Welcome on board, assume your hesitation is the cost, it's a fairly big step to house a full frame camera and everything is more expensive with larger sensors - housings, potentially domes, lenses etc. You may want to look at all the components you will need and also compare them to other brands to see what makes the best deal facially. Yu can of course ask questions of the members here to help you with decisions.

The point of warming diffusers is that only the flash light is warmed, the light from the strobe has zero impact on the water. To get the right balance on your subject, generally 4500K light would look too warm and you need to cool the colour temperature a little in post, this means the water will be cooled down as well if you do a global colour temperature adjustment. You end up with deeper blues in the water as a result. As far as the original question goes in Raw files it doesn't really matter if you use a preset 4500K WB in manual or an auto WB. The correct WB for the subject remains the same regardless and you can adjust this very easily as a global adjustment in post. I tend to use AUTO WB and find that it works just fine, use the one that ends up closest to correct when you open it in Raw. The whole point of the warming diffusers is it takes advantage of the fact that the subject is flash lit and the water is not. This way a global WB adjustment ends up cooling the temperature of the water. Yes you could do this with masks but my preference is to minimise post processing if possible.

While masks are very good, my view is it is always better to not mask, it's less work in post processing for a start and unless you adjustments are limited getting transition between masked can be an issue.

The Tokina if it's a Canon mount can be used on m43, Canon EF and R series APS-C and Sony APS-C and the dome would come along with it. Unfortunately the hazard of going with a very good but lower volume camera brand is the ability to keep it housed. THe 10-17 is as future proof as anything in the sub full frame sector.

No problems, regarding the Tokina 10-17 the process is to check the Metabones website to see if they have tested it. You will see here that they haven't but they have tested the Canon 8-15mm: https://www.metabones.com/products/details/MB_EF-X-BT1 The fact that it is established using the tokina 10-17 on mounts such as Sony E mount, m43 among others where the Canon 8-15 and Tokina 10-16 also work is documented so I'd be surprised in the 10-17 didn't work. You could always use the Canon 8-15 which has a zoom limiter for APS-C and is documented to work on Fuji. Then check with Nauticam on their recommendation for using adapted EF lenses with Sony x- mount. Typically with adapted lenses Nauticam used to have a line on the port charts that included a port adapter to use N120 ports using a zoom knob on the adapter in combo with the Canon EF zoom gear. I can't recall if Nauticam ever had this for the Fuji port chart. It has been done before with adapted EF lenses on Fuji, this article from the old wetpixels site has details: https://wetpixel.com/articles/compatibility-report-fuji-x-t3-by-tino-brandt

Thanks for the added info, I might get it eventually and get a trial first to see that it works or not. The 48 hr trial period though means I have to find a slot where I have time to play with it. Seems like it would be beneficial to provide at least some of the tutorial pages pre-trial download, it may convince some people to give a trial a go. I would think that seeing as how it can create a layer with the processed results it shouldn't matter when you do it as long as the layer is at the bottom of the stack - that way the layers above apply to the combined layers below. If you make mask adjustments you just need to be sure the mask is based upon the combined backscatter free image - you don't want the masks to include any of the backscatter. This would happen for example with luminosity masks that use the image to create the mask.

The issue is that the Nauticam wet optics don't necessarily work with any 28mm full frame equivalent lens, something about entrance pupil size, so they mostly work with slower kit lenses. The 16-50 lens you reference seems like it probably should work due to the small 58mm filter size and internal zoom, but it's a gamble. The fact that that Nauticam only list the 15-45 lens with MWL/WWL/WACP may be due to the fact that's all that works or that they haven't tested the 16-50 with the other ports yet. The WACP-C is basically the same as the WWL optics as I understand things from previous posts so if the 16-50 works with the WACP-C it should also work with a WWL, bt again until someone tests it...... I see a few options: Buy the 16-50 and take both it and the 15-45 with you and use with MWL. If you have issues with the 16-50 you could revert to the 15-45 lens. You might need a different flat port to house it though as it is about 6.5mm longer. You could message Nauticam and ask them, I recall others have done this and they have responded. You could consider other options, perhaps an adapted Tokina 10-17mm with a 100mm dome?

It seems it is a Photoshop plug-in - at least the Astro version of it is, though some here are calling it an action which it could well be if it feeds a seperate app which does the processing. If you can access plug-ins or actions within ACR then I guess you might be able to use it that way. I use Photoshop quite a bit but it's CS6, so likely BXT won't work for me. Though I see the Star exterminator on the RC astro site will work for CS4 or later as a plugin. IT might be worthwhile my trying it out. As for where it's best to use I expect it should also work on a completed image as long as your processing doesn't do anything strange to the backscatter. Probably be best to download the trial version to see if it works OK or not with your workflow.

The 180mm dome will use a different extension as it's not a full hemisphere so I would expect it to need a bit less extension as the centre of curvature is further behind the dome. Both the 140mm and 230mm dome are closer to a full hemisphere and it appears they have the centre of curvature the same distance behind the dome mounting flange. You would want to use the same extension on the 140mm dome/14-35 as you do with the 230mm dome. If you did the test shots with 30mm extension the entrance pupil was likely well forward of the optimum point. I would expect the 14-35 to perform better at 14mm with the right extension. I thought you had used the 60mm extension for the tests. I'd suggest trying it dry first to check it doesn't vignette, it shouldn't based on the port chart but you might just catch the corner of the shade which could be solved by zooming in a little. You can check for vignetting dry as it's purely down to geometry, test shots of course should be UW.

Reading all these replies, I can see how subjective this is. I've seen what Dave Hicks does and can see why he's less concerned with even light with the dramatic lighting used to create shadows. I can also see the point of view of those who shoot big reef scenes exploding with colour from soft corals, Alex Mustard comes to mind, talking of the benefits he sees from the even lighting coverage. It using a different means to create drama in the image. I see some people saying that once they went to premium strobe they stopped having problems with light "missing"in the centre of frame- I'm guessing that's because the Retras in that case have a wider beam with more light at the edge of the cone so are less demanding of positioning and as I recall testing showed that indeed the Retra has more light out in the edges of the light cone. You could argue you could do the same with the INONs - but they obviously haven’t managed to work that out previously. Some people are perhaps not so rigorous when positioning their strobes. If the strobe helps them overcome this it seems like it's well worth it. The Blue water colour is certainly a real advantage of warmer strobes - you can get it with coloured diffusers at a cost of loss of light. I'm wondering also if upgrading strobes to higher power or even just pushing that power to the edge to the light cone away from the centre hot spot just puts more strobe light on the scene? I often find I need to tweak subject colour a little shooting my Z-240s as they are not putting out enough power or conversely I'm not close enough. More power will certainly help a bit with this, if you don't need to warm up the subject you won't impact the water colour adversely with your adjustments.