Backscatter

[aquakiwi]

In the weekend I managed a couple of dives at the Poor Knights Islands, on my second dive (didn't take camera on first) I took several shots in a similar vein to the above.
I know that flash angle probably contributes to most of the backscatter in the right of the pictures and I use dual flashes angled outward. It seems to me tho that all the pictures I took in cavens and or archways had backscatter and shots taken in open water seemed fine. I never moved the strobes around as my drysuit leaked and I wasn't feeling much in the experimental mode and indeed cut my dive short.

[DDT uk]

I am sure that someone more knowledgable than me that will come along in a minute but until then here's my 2p.

The first thing that strikes you is the shadow of the left hand side of the diver. As you are using two strobes this suggests that either the left one hasn't fired or that it is pointing too far out and so has not lit the diver. The right hand strobe appears to be lighting the whole scene which suggests that it is pointing too far inwards. This would explain why there is so much backscatter. I don't suppose the you had a buddy with a camera to show you where the strobes were pointing?

I would assume that the reason for the backscatter in caverns is because the reflected light is illuminating the water column between you and the subject (if you are close to the side).

Daniel

[KenByrne]

It does appear that the left hand strobe has not lit the subject, maybe pointing the wrong way or maybe blocked by the cavern wall.

The divers face looks overexposed so you could have turned the strobe down a bit, or if using TTL use spot metering so the strobe isn't trying to light the background as well.

If you're using TTL it could be that less strobe light is needed outside the cavern so you get less backscatter, also backscatter will show up less against a lighter background. Could also be your subject has kicked up more silt in the enclosed environment of the cavern

Final possibility I can think of is that you've bumped your strobe in the cavern and altered the aim slightly.