Chris Ross

It's not going to be first vs second curtain sync, that just moves the timing of the pulse from the beginning to the end of the exposure. I don't know of any explanation apart from shooting at higher than the maximum sync speed. Shooting macro you would notice any other issues like dark background water as the exposure is entirely from the strobe. Look at the EXIF data in your original files, what ever you use to process the images will report the shutter speed used. More than likely you could review the images in camera and get it to report the aperture/shutter/ISO used.

This is clearly something else, on minimum power they should allow for rapid firing, something is preventing this. The suggestions I posted above are test for potential issues. My first inclination is a problem with the trigger, online I see various issues reported with the Z8 and trying to sync with manual flashes.

It's been discussed here and also I think on old Wetpixel forum, here's one link I found: There are probably other posts as well.

It seems like you might be reaching the natural limit for your batteries if this is the case, potentially it's not so much the exposures taken but the time the camera is on, presumably it doesn't go off to sleep at any point in the 4-6 hours. I also see Canon has a new battery out the LP-E6P, this video claims greater run time for a cinema camera using it: Totally Awesome - Canon - What Have You Done - LP-E6P vs...I just watched a great video on youtube by Josh Sattin. In it he compares video runtime performance between the new LP-E6P and the now older LP-E6NH. Since I shoot in 4K 24p most often, this was hug Might be worthwhile getting one of these to try it out and see if you get an improvement?

There's something going on there, at minimum power it should fire off a few bursts before needing to recharge, regardless of aperture you are using. The aperture is a separate problem as it won't burst on min power . A couple of things to try: Try progressively reducing frames/sec See if the camera will allow setting second curtain sync, then do a test shot in a darkened room with the shutter speed around 1 second. This is a handy way to check if a pre-flash is firing, the pre-flash fires first and the main flash at the end of the exposure. It just allows you to see both pulses. I know it "shouldn't" but worth checking. What batteries are you using - eneloop or eneloop pro is generally recommended. How old is your flash trigger - it may have some issues with the Z8 as it has no mechanical shutter?? Try triggering you strobes with a Nikon speedlight as trigger if you have one, test shooting into a mirror so you can see if the strobe fired easily If you still have your OM-1 see if burst shooting works there

Need more details of what you are doing, what trigger, manual or TTL, are you using the booster, how many frames/sec you are trying etc?

Thanks for the update on the strobes, I also upgraded recently, however I got a set of Retra Pures before they were discontinued, which were lower powered but significantly cheaper. The biggest change I noticed was significantly less backscatter when using them with reduction rings for macro shots. By no means backscatter proof but immediately noticable compared to my old INON Z240s. Haven't done much wide angle with them as yet, but been pleased with light quality on what I've done so far.

So is this only when you started using it in very cold water or is it was working for a while in the very cold water but suddenly started dying? This may indicate a new battery could do better? Other than that you could try keeping the housing in a cooler with a hot water bottle until you hop in the river perhaps?

Your best bet is probably the newer battery, it could be you've lost a bit of capacity of your existing battery as well if it's a few years old. The USB bulkhead only helps if the camera allows battery charging in the camera, the 5D MkIV does have this option it seems?

I found a reference that states that a dome port gives increased depth of field in water compared to what you would get from the same lens in air. This is due to the object being compressed into a virtual image close to the dome. Whether the Ivanoff optics work from a virtual image I don't know, but I expect that it quite possibly could. They give an example of a 24mm lens at f8 imaging an object at 1m distance having 563mm DOF UW and 424mm in air. Here is the reference, scroll down to section 4. https://pmc.ncbi.nlm.nih.gov/articles/PMC4732081/ Without doing a detailed analysis, it's basically guesswork as to what is going on as the Ivanoff optic is neither a dome or a flat port. A flat port is limited to a field of 96° by Snell's law, but a 16mm lens has a field of view of about 106°. Odd things can happen with some optics UW, the Nauticam FCP for example seems to suffer from reduced depth of field based upon posts from users when it was first introduced.

Welcome aboard, I recall we have a few free diving photographers on the site. Type freediving into the search box and it brings up a lot of posts.

Not on a APS-C camera but I reported on using it with the Olympus 60mm macro (2x crop) recently: If it works well on m43 and full frame it stands to reason that it will work fine on APS-C. The 100 mm macro is 160 mm equivalent on the R7 while the 60mm macro on m43 is 120mm equivalent, so I would suggest even more of a case to use it on APS-C. The specs for the field of view and working distance /magnification on Canon APS-C is on the MFO-3 port chart: Google DocsMFO-3 2025-08-27.pdf

Great images captured must have been quite the experience.

I have no doubt it would work well in a dome, I would say though using it as macro lens is different to use in a dome where you are out in the 0.3x magnification and less with a working distance up near 70mm due to the dome where the AF of macro lenses generally picks up. I know what you mean about focusing on skinny things - transparent things give similar problems, seems like there are some things that the AF gets confused with. I encounter occasional things the AF doesn't play well with on my m43 setup.

I have the original Nauticam 45° which I used with the EM-1 MkII before moving it to my OM-1. The attachment is different between the MIL and DSLR versions, but the mounting can be swapped over to suit either a mirrorless or DSLR housing. As I recall the corners of the viewfinder were a little soft in the EM-1 MkII, while in the OM-1 they are softer still. The centre of the image is fine but reading to info in the corners is a little harder. The new versions are reported to be better in the corners. this approximates the view through the 45° on the OM-1 , ignore the vignetting as that's due to alignment issues with the lens and viewfinders. The blur in the corners is halfway between the far left and right side of the info bar at the bottom of the viewfinder image. It's difficult to get everything lined up using a camera lens compared to just placing your at the viewfinder. The EM-1 MkII viewfinder view is a bit better than this but the corners are still a little blurry.