A Few Images From Saturday Evening 6/26

how many trials did you make for each of these subjects? Initially, and perhaps forever, you want to make multiple attempts when the subjects allow. As you get common approaches dialed in, then it may take fewer to get the needed shot. And if you're shooting sensitive subjects like pygmy seahorses, limit the number. But eggs on a cone snail - go to town.   Spend 5 minutes trying out different approaches.   Make sure the camera playback isn't equalizing exposure levels, or have it display the levels so you know if you're over or under exposing.   Blowouts should be highlighted in playback.

First thing - move to F/8. You're shooting most of these as F/4 1/250 and they would be sharper and better exposed as F/8 1/125. Your strobe's contribution would also become more dominant over ambient light. For non moving subjects, 1/60 or even 1/30 would be fine, though I believe with the M43 we probably want to stick around the F/8 range due to defraction concerns.

Shot 1 - I think your strobes may be too pointed directly at the sanddabs, whereas you want to use more of the edge of the strobe.   I was a bit surprised that Backscatter doesn't list the angles of coverage for their mini strobe, with and without the diffusion covers.    But I'd be trying it with the strobes pointed more outward, and also seeing if I could sneak a bit closer.   Sand is our biggest enemy, exposes to the smallest amounts of strobe.    So this could be one where snooting to just the sanddab while lowering the overall exposure could also diminish the brightness of the sand.

Shot 2 - overexposed-  I think this would benefit from moving to F/8, and also increase depth of field.   Maybe go even tighter for that.  (though must say, it's difficult to review focus/dof concerns on the little screen)   And I suspect the right strobe needed to be pulled further away or reduced in power compared to the left one so the viewer is drawn to the in focus head on the left.   Sea hares represent a focus challenge unless you shoot at 90 degrees.   Same problem as nudis but the size of a football rather than a thumb.

Shot 3 - I think you were closer to the subject, while your strobes were still positioned the same as before.  Hence the background was highlighted over the subject.     This is a situation where it's often best to push the strobes in front of the lens plane, but then aim backwards to you.   The level of light that hit the subject itself looked good to me.   You just want the background to be dimmer than the subject.

Shot 4 - I thought your intent was to capture the two cones, so the miss was the underside of the left is too dark.   This would be a case of trying a few different ways to get it all covered.   The backscatter may be unavoidable, though in your image it's safely contained above the subject.

But your title points to the eggs instead.   Unfortunately a case of not having the right lens for the job.   Too small for the 8mm unless you get right on top of it.   Now I think you can do this, with the reversed strobe placement, but I would have continued trying to get the two larger objects with the eggs as a point of interest.

I also think you should swap out those 3" arms for 6s.   I use a combo of an 8s and 12s myself.   If the first one is too short, it limits your ability to shoot inward and backwards.

https://www.uwphotographyguide.com/underwater-photography-strobe-positioning