Chris Ross

The example image I was referring to IMO had un-workably thin DOF. I don't know how extreme the magnification was on that shot but for me you would have to be picky about subjects the soft coral head had background and foreground out of focus and to me blurry foreground elements ruin a shot, background elements being soft is not an issue for me. The shot was taken at f13 so not much opportunity to get more DOF by stopping down either.

Walk into any camera store and buy the off brand caps - they however are very easily dislodged as is the genuine article, I think tight fitting neoprene cylinder like a stubby cooler and attaching a lanyard to it might in fact be a better option.

I don't know that I would say it's a CFWA solution seeing the soft coral posted by Sergio, the lens was zoomed to 29.5mm and the DOF in that image was remarkably narrow. The shot was out of focus both in front of and behind the plane of sharp focus at f13. Certainly expect to do better with a fisheye and dome.

It is often reported that the quality of light is better with the ring flash strobes, I haven't been in a position to experience this, only ever shooting with INON Z-240, but personally know a few people who swear by the light quality improvement. This is a very subjective improvement and not one you can demonstrate with testing so easily except perhaps to show that the light falloff is less. All reports seem to indicate that the Retra strobes are quite similar to the big guns in this regard. On the technical discussion versus end results, some people can look at graphs and plots and understand what the impact on results is, others it doesn't help. Publishing an image really only shows that in the hands of the photographer in question that strobe produces a good looking image. It's very hard to look at a pair of photographs of different scenes and say you like one strobe better than the other. Ideally the same scene on the same day with two different strobes might help but it's hard to tell if the differences are due to the strobe or small position changes of camera and strobes by the photographer. Both the technical and artistic approaches have value and ideally using a balanced approach to selecting gear surely must be the ideal situation.

Hi John, yes I'm using it now in a new Nauticam housing. It's quite nice to use UW, though probably not any super compelling reason to upgrade. The AF is better than the EM-1 MkII with the 60mm macro and I also bought the USB-C bulkhead so I could download images and charge the camera without removing from the housing. Can't do the charging with the EM-1 MkII. It means I don't need to remove the front port, Zoom gear and 8-15 lens every day just to change battery and get my images, I could leave it sealed for an entire trip if I don't want to change lenses. I basically changed as my EM-1 mkII which was 6 years had a couple of times when it stopped responding and needed to pull the battery to get going again. I could get it repaired but it only does it occasionally so finding the cause might be hard and getting stuck with the camera in the housing not responding didn't sound great. I could also get another EM-1 II but it's a 7 yr old camera now and thought it better to put the repair cost towards the new housing.

This is an older housing and I expect probably different arrangement to newer ones. Typically there is a metal insert that remains in the acrylic window and they should be standard sizes. I assume the standard viewfinder is the one that came with housing as original equipment or did you you purchase it to use with your housing? Normally you remove the viewfinder by removing an o-ring inside the housing and slide it out of the metal insert. You should be able to do this on your housing. Typically you don't unscrew anything to remove the viewfinder. Now that you have unscrewed the insert you would need to install it back into the window and also make sure the seal to keep water out is sound. First check the view finder you should see an o-ring in a grove that you can remove to allow you to pull out the viewfinder. Carefully remove this o-ring and try pull out the viewfinder. Next check the insert to determine how it is sealed - probably an o-ring - check this carefully and re-assemble. I would suggest maybe talking to a store like backscatter who services housings and tell that what you've done and ask if there are special arrangements to ensure it seals between the rear window and the insert. this instruction manual for viewfinders might help: 32201 32203 32204 32205 Instruction manual for viewfinders (nauticam.cn)

Comparing rectilinear and wide lenses on the diagonal field of view is a bit misleading. The field of view on the horizontal axis of the WWL/WACP is actually about the same a 14mm rectilinear lens due to the barrel distortion. The view is stretched most in the corners. I prefer to use the horizontal axis to compare as when you are framing a subject like a shark for example you don't usually place it along the diagonal. Due to the barrel distortion the zoom ratios are not totally comparable as you are zooming into centre section which looks enlarged with a fisheye. I use a Canon 8-15 on my OM-1 which on first glance is a 2x zoom. However if you use the horizontal field of the lens to compare you find the framing is similar a 5.8mm zooming to 28mm rectilinear lens so this is like a 4.8x zoom lens. I have done the calculations to show how the horizontal field changes when you zoom and then taken images with the 8-15 at 15mm and my 7-14 lens at 14mm (m43 camera) and apart from the barrel distortion the field that is framed is remarkably similar. The WWL behaves more like a fisheye zoomed into a 130 deg diagonal field than a 10mm rectilinear lens and I've done the calculations to show this and the 10mm takes in a wider horizontal view. The increase in zoom ratio is not as much as the 8-15 lens shows as the distortion is a lot lower. This is the technical view - it somewhat ignores the end result. The barrel distortion pulls the subject forward to be more prominent in the frame and places it firmly front and centre - this is the fisheye look and you can't replicate it with a rectilinear. That not to say there is no place for rectilinear lenses - there certainly is whether it is shooting video, the need to have straight lines remain straight in a wreck or needing more reach for smaller shy subjects. Recognize what the difference is and then make your choices to suit your application and the look you prefer.

Good to see, their behavior has been really bad. For example they held off from providing a fix to the running the program on high resolution monitors in CS6 blaming Microsoft for not updating their APIs and didn't fix it till the subscription model came out. Turns out a simple registry fix made the software usable on such monitors. I still use CS6, though on my latest laptop with Win11 getting the software to activate has proved a challenge, so I'm trying affinity photo.

This is correct, a strobe is 100 CRI. The light is produced by heating the Xenon in the tube to around 5000 kelvin and the radiation approximates black body radiation - a continuous spectrum. Better quality LEDs can produce a more complete range of wavelengths that get close to the strobe but you pay $$$ for this.

WACOM tablet all the way absolutely indispensable for editing IMO. for example re-touching images just touch the stylus to the tablet with the cloning tools on each bit of backscatter and it's gone, no clicking the mouse constantly, refining masks by drawing is a lot easier with a pen. I do all my editing pulling curves etc with the stylus as well. I have a roller bar mouse and a tablet to control my system, never use a regular mouse these days. Once you get used to it it's hard to do without. I use it in PS and Capture One, never had lightroom, my understanding is the smart healing brush is more efficient for this sort of work compared to how lightroom does it

Actually depth of field is down to magnification and aperture and to me this is the best way to think of it. Focal length changes DOF due to a change in magnification. The problem with focal length is it is not constant in most macro lenses - it reduces as you focus closer. For pretty much all normal lenses DOF is constant at a given magnification and aperture. There are of course special cases such as it appears the the new FCP which does some funky stuff with the image to feed it into a macro lens where it appears the DOF is thinner than equivalent magnification in a fisheye lens. On the original question about shallow DOF yes diopters reduce DOF because they increase magnification. In this sort of photography getting the right angle of approach and picking exactly what bits you want in focus is a large part of getting a pleasing image. YOu have to think about how you will approach the critter to get the focal plane where you want it. THis is the curse and challenge of macro photography. I've recently started focus stacking on land and it rapidly teaches you how thin the DOF is at high magnification and how many shots you need to take to get a 3D object all in focus - it's a lot and I'm using a m43 sensor which has more DOF as you need less magnification to fill the frame.

Typically domes are sealed with o-rings - like any type of rubber they won't last forever, but it seems they have quite a long lifetime. Many dome ports you buy spare acrylic elements for and they are user replaceable. You could always inquire if spare o-rings are available for your dome.

For those who don't want to download the zip file here is a centre crop, quite sharp where it's in focus. 1/100 @ f13 ISO100 and 29.5mm So quite shallow depth of field from being in so close - do you recall the approximate size of this soft coral?

On the question of the A1 as I understand it - it has a mechanical sync speed of 1/400 and with electronic shutter it is 1/200. The 1/400 is a limitation of the speed of the shutter curtains and the 1/200 with electronic shutter is a limitation of the read out speed of the sensor. On the question of HSS - yes in theory you can run you shutter speed all the way up to the maximum shutter speed for the camera, but you are in a diminishing returns situation. HSS works by rapidly pulsing so the flash is illuminating the scene the whole time the shutter is open which is often faster than the flash duration. Effectively however the flash now has fixed output and you can't get as much light as you can at maximum power. Flashes work at constant power output and control power by duration. During HSS the only way to control power is by changing the percentage of time the flash is on, but it needs to pulse very rapidly to avoid flicker and other artifacts. It can't normally stay on the whole exposure so it has to pulse as it would run out of power. At high shutter speed you have a narrow window crossing the frame during the exposure this means that each part of the sensor can receive light for a very short time frame - exactly the same as if you turned to power down. This leaves you with two scenarios: First is the sunburst wide angle shot: you are shooting at f11-16 of full frame so strobes are near full power. You want high shutter speed to control ambient light to tame the sunburst. In this situation something like 1/320-1/500 is your limit as you straight up run out of flash power and you need the most powerful strobes available and they need to capable of delivering this power relatively quickly. Second is the wide open aperture shallow depth of field macro shot. Here everything works in your favour, the aperture is wide so you don't need much flash power. Shooting macro your strobes are close in so need less power. You can extend the shutter speed quite a bit more as the demands for flash light are much less. You can probably use most HSS capable strobes in this case.

I would argue that all this talk about HSS and even flash sync speed doesn't have a great deal of relevance for macro shooting, you are mostly using flash as your main light source and the flash duration which is quite short especially at low powers is what freezes motion for you. The one exception is in shallow bright tropical waters where the ambient light is strong, however the OP is using f18 -25 which with 1/200 sync speed excludes a great deal of ambient light for shooting shallow depth of field. To be clear shutter speed has no impact on flash exposure for normal flash shots, this is controlled by the combination of flash power and aperture alone. In HSS, the flash pulses rapidly for the whole exposure to get around mechanical flash sync limitations, this is what allows you to use faster shutter speeds, but it sucks the life out of the flash to keep it pulsing for so long, so as shutter speeds get shorter the available flash power reduces. Likewise flash power is set by duration HSS is really only relevant UW for wide angle shots with sunbursts or if you are trying out shallow depth of field and you want to exclude ambient light. The higher shutter speeds I would argue are mostly unnecessary for freezing motion, in most cases 1/200 should be adequate particularly in combination with image stabilisation in modern cameras to freeze motion from a diver holding a camera. The main use is to control exposure at wide apertures or in bright ambient light. On the concept of using high shutter speeds to deal with blurriness due to camera motion, yes this can assist, however for shooting macro UW the camera/diver moves in 3 dimensions and in 5 axes - up/down side-side, roll and also back and forth which adds another problem, that of keeping the shallow depth of field on the subject so it remains in focus. There is really no substitute for remaining stable while shooting. To the OP I think there's probably other factors to consider besides sync speed to make your choice of camera. Look at the whole package. You don't mention wide angle, do you shoot wide angle, CFWA etc. ? If you are a mostly macro shooter - I think the first consideration is the macro lens that has the best AF is it the Sony 90mm, Nikon 105mm, Canon 100mm?

I don't believe that's what's happening here. Yes you likely need more strobe light to balance against the brighter ambient light. There's various things you can do in processing to assist First pull highlights down to deal with the bright water, then boost shadows to get your subject right. You can do a lot with this, otherwise you need to boost strobe power some more. On the question of WB, I believe that technically your photo is close to white balanced, just needed some tint adjustment. If you look at the Red/Green/Blue histograms they are all even and run all the way from 0 to 256. This is a sign the image is properly white balanced. The Hue adjustment is restricted to the cyans and made them bluer this is outside of a global WB. One thing you could try is to process for the water and boost shadows in post but don't draw on images to make a mask though! too easy to detect. If you have full PS the luminosity masks from Tony Kupyer are great, the free one works fine. Otherwise copy the image and invert it and use that as your mask. Increase the contrast of the mask so that the brightest highlights go white and it's a perfect mask. Here is the shadow mask from your image, D3 from the Tony Kupyer action panel, D4 would basically exclude water all together from the adjustment: With this method you don't have to deal with feathering and trying to hide the transition. Use it on curves layer with an "S" curve pin the bottom of the curve very low down before pulling up shadows:

The Leak detectors are reliable but they do need some liquid water to reach them to activate them, a drop or two may not set them off. I agree it's very likely water from opening the housing. You can get your self a hand held blower bulb (I use the Giotto rocket blower) and use that to blow away excess water drops along the seam and in the latch mechanism. It gets water that a towel won't reach. A microfibre cloth (lint free) is useful to wipe down the o-ring to remove any remaining droplets. I keep one in a clean ziplock to stop it picking up grit and hair for this purpose. On a side note water droplets like this are likely the source of the myth that leaving the housing in the sun causes condensation. The root cause is actually the water that vapourises and then re-condenses on the glass port.

you don't actually need a cotton bud, a damp finger does just fine. One less piece of plastic waste in the waste stream each month.

I agree never leave a camera alone in a rinse tank, bad things can happen. However the vacuum doesn't hurt you in this situation it helps. Typically you have a 200 mbar vacuum in a housing like Nauticam and this is exactly equivalent to being 2m under water. What is important is the pressure difference. 200 mBar is 0.2 kgf/cm2. On a small compact housing measuring say 14 x 10 cm this means the closing force is 0.2 x 14 x 10 = 28 kg. This means the housing back will be very difficult to open, particularly the clamshell style where you can't push the back sideways at all. All that matters is the air pressure outside is greater than the air pressure inside. One of the big benefits of the vacuum systems is that it pre-loads the o-rings and that means it's much less likely to leak in shallow water.

I commonly see various aquas/greens in bright shallow water in my shots. It seems to me the cause is the reds, yellows have not scattered away and there is always some algae in the water which shows up under these conditions. Easier to fix on the Raw file perhaps. Basically you need to add some magenta, the browns in the corals to my eye contain some green so move tint towards magenta some more. I had a look at the image in PS (I don't use lightroom) and added some magenta in levels, however any global adjustments don't really do the full job as they will send off the subject colours. SO I then used a Hue/saturation layer and went to the cyan channel and pushed the Hue towards Blue: Here is what I got you can adjust the hue to your taste if you work on your original image I left a little of the aqua/green in the brightest bits and also boosted shadows as adding magenta makes the blues darker:

Good to sea this, after all charging Li-ion is said to the cause of some liveaboard fires. If you really want a USB-C battery charger you could always upgrade to an OM-1 it has a twin USB-charger🤣. But seriously I really don't see the attraction to power everything off USB-C. I'm quite happy with my 8-cell MAHA charger and the little camera battery charger. Though last trip I installed a USB-C bulkhead on my OM-1 housing and could download images with the camera in the housing, then switch over and charge the battery in there as well. The Nauticam bulkhead is vacuum tight. The download speed is a touch slow compared to a card reader and battery charge is a little slow too. But it means I don't need to pull off the front port, remove the Canon 8-15 to pull the camera body to charge/download and then put it all back together again every night Not an option for the EM-1 II as it won't charge over USB-C though.

Resize the files to 1200-1600 pixels on the long side and then save them as jpeg and adjust quality, to get the file size down, you should achieve 300-400 kB easily this way. As to your question , in shallow water green light is still coming through and has not scattered out as yet, if you are shooting into the sun, then it will be bright and may even have some red in the mix. However post your examples, there are different ways to approach this depending on your starting point.

In general round tube flashes are slower. The old YS-250 had a duration of 1/50 second or so at full power, quickly got faster of course as it was turned down. There was a post on Wetpixel some time back where someone quoted flash duration times. Mostly not a problem till you get into 1/400 plus flash sync speed. I think some flashes might be an issue with for example a manual flash trigger and an Olympus camera which can do 1/400 to 1/500 sync if I recall correctly. One post is here but there are more I'm sure: https://wetpixel.com/forums/index.php?/topic/60459-flash-duration/

Did you open the housing to change the battery prior to this? Water will cling to the o-ring and when you close a clamshell style housing it can push some of this water inside. If it was the first dive it could just be water drops dislodging as you open the housing. Do you have a vacuum system on the housing? I would suggest to pull the o-ring and dry underneath it in the groove, shake the o-ring dry, clean and grease it and re -install. For drying the housing, do you have access to a fan, a hair dryer or perhaps the dive operator can provide an air gun attached to a scuba tank to blow out the housing, use the airflow to dry out the inside of the housing. Take care when you open the housing and watch for water drops. Dry off the o-ring before you close the housing . Have a lint free cloth ready to wipe up any drops that are clinging to the o-ring when you open the housing. As to where the water came from, I checked current weather in Marsa alam and it said 37° and 26% humidity, so it's quite unlikely to be condensation.

The Canon 8-15 is adapted more often I believe is due to the fact that Canon lenses are easier to adapt compared to Nikon F mount. There are so many flavours of Nikon F mount as well which no doubt complicates things. this link has some explanations: https://briansmith.com/where-are-the-nikon-af-lens-adapters/ As far as fisheye goes it comes down to what you shoot and what effect you like, for me fisheye is unbeatable for reef scenics and CFWA. I now use the Canon 8-15 on OM-1 which gives amazing versatility and effectively combines a full frame fisheye with a 7-14 (14-28mm full frame equivalent) lens. Of course in full frame to get the same versatility you would be looking at adding a 1.4x to the 8-15 which doesn't have as much range or venturing into FCP which has it's own set of issues, cost possibly not the least of them?