I am looking for some input on strobe choices for my SP-350.  I currently am using a slave strobe from my last (flooded unit) Sea-Life SL 96010. Which doesnt really work that well with the Olympus underwater housing.  Has anyone used the UFL-1 Olympus slave? Im am also considering Sea & Sea DS-51?  Suggestions/help please. 

Here is pic from last trip to Coz with my new SP-350 1st practice shots

I have used Sea & Sea strobes (YS-90DX) via fiber optic connection with a Olympus P&S;and enjoyed using it.  I have used a DS-50 with a cord on another housing and I also like the strobe size and its ability to use standard batteries.  The DS-51 is more flexible with its adjustments on output but you will need an adapter to shoot off the strobe (you can also use TTL with the Ikelite housing if you want another housing.)

On your photos/EXIF you may want to adjust your settings a bit (shutter of 1/1000 is probably too high) and maybe bring the ISO up a bit.  How close were you to the tutrle and angel fish?  Were these crops or full?  If you were shooting at 24mm and these are not cropped looks like the strobe is not firing or positioned correctly (or the strobe is very limited output.) You may want the shutter to be more in the range of 1/100 of a second.

Did you set up the camera in manual and force flash on to fire?  Looking at the pictures the flash probably should have fired from the camera and trigger the external flash.  Also keep in mind that the external flash may be reading the pre-flash and you may need to shut the pre-flash off on the camera or set the pre-flash cancellation on the strobe differently (it may be dumping on the pre-flash of the camera and not firing on the actual flash itself.)

Hi Ao Diver and welcome to DIGIDEEP!

Looks like your current flash does not cope well with pre-flash.

Also Drew is right on the shutter thing.
Maximum value allowed is 1/200 sec. to sync the strobe.
If you go faster the picture sometimes is half-black.

However I do not see any internal flash in your pictures either.
Maybe you just get closer to solve that?

Pics are not cropped - I was very up close.  Strange thing is the strobe is in sync out of water, I have tested this over 100 times. In the water it seems to be random.  For the shutter speed - I had camera set on Auto - underwater settings. As these were my first shots with this set up.  I am really looking for options for new lighting for my next trip to Bonaire in December.  I may just rent a strobe to play with options down there until I can see what will work. Thanks all for the critique’ I have had only 4 dives with this unit due to weather issues on last trip - 2 weeks of daily diving will I hope fine tune things.

Looks like the internal strobe is not firing then I would guess.  If you are that close some light should hit from the internal strobe (24mm means you are darn close there).  Make sure you are setting the camera to force flash, if it is automatically setting ISO to 50 with a shutter speed of 1/1000 it looks like the camera thought there was too much light to fire.  Same for the other shot.  You are very close to both subjects (good job on that) and if I had to guess the lack of the internal strobe firing is the issue, there should have been some flash hitting even if not very strong or even. (I have used the internal flash on an Olympus 3040 and not as close to subjects as you are and it will throw off more light than I am seeing in your pictures which is why this seems to be the issue.  If I forgot to set the camera to force flash I would get the same results.)

Try setting it to Manual and force flash either by the camera setting (you can set the camera to force a flash no matter what) or dialing the f/stop up (larger number f/stops than 4.9) and/or adjust the ISO.  I would just set the camera to force flash. The shutter should be in the range of 1/80 - 1/125 as a start.

PS: The SP-350 has an 8-24mm zoom lens so it looks like you were fully zoomed in, you actually also may need to get closer to the image, I was a bit twisted around when looking at the EXIF data.  Sorry.  Best thing to do is leave the camera at Wide Angle to start and when the frame is filled there then you should be close enough.