Paul C. Buff, Inc. Technical Forum

Going to try and do a shoot underwater. I'll be about 3 feet deep max shooting down, at a angle, onto a model about 4-8 feet deep. I have 4 Einsteins. I plan on using a cybersync to fire them. Camera is in a case that has room for the cybersync. I know light fall off will go quick. Any other input from anyone?

Thanks

I'll be curious if the CST signal makes it out thru 3 feet of water. I'm guessing no, but I'm just guessing.

Yeah me too. I have the cyber commander but don't think it would do much better. I could probably work with the sync above water and just have the lens under if I can get the angle. I have just about everything Paul sells so looking at grid and attachment advice. Of course any advice is welcome.

Keep in mind light duration. The slight wave action will bend the light and the image will have a different look at full power (with a longer duration) than at fractional powers (motion stopping duration). So try both and see.
Also, if range is a concern as others think, line of sight is best for radio signals. With you maybe even below the Einsteins, consider hanging them upside down if that is a more unobstructed path.

The problem is not so much of range, but attenuation. Water will attenuate radio signals rather effectively. Line of sight issues as far as what side of the light the reciever is on pales in comparison. 6-12" is about as much as you can hope for, and is certainly not guaranteed.

A hypothertical solution: If your camera can set the pop up to manual, do that and set it as low as possible. You can then attach an optical slave to the CST and place it in a clear water tight case (WalMart, <$10 in the fishing and camping section). You can float the case over the camera. If you tether the case to your camera housing with a string, it will not float off.

I'm shooting with Nikon D3S so it doesn't have a popup but I do have room for the SB-900. I'll try to find a optical and try what you suggest. But I'm in El Paso TX and they have nothing here...lol. Worse case I think I'll be able to leave the CST exposed above water and have most of the camera and lens underwater....I'm thinking that should help as the signal will only have to make it through the plastic of the housing and the flash will only be a couple of feet away.

Do you have any other speedlites? If so, put one on "M" on the camera. Put the SB900 (SB800 and some other Nikons will also work) in SU4 mode and connect the CST to the SB. The SB will act as the optical trigger.

If you can do the shoot without submerging the CST, then the case will not be an issue.

Ok thanks. Let me make sure I understand. I have 6 SB-900s. So put a SB-900 on the D3S on manual inside the case (I can do that). Put a second SB-900 in SU4 and connected to the CST above water either in a clear case or on the side of the pool. This will trigger the optical on the Einsteins. Do I have it right? I would think it would be the other way around. I put the SB-900 on the camera in SU4 mode (I also have a SU-800 which is a dedicated SU4 basically) and a SB-900 in a clear case (floating on the surface) to fire at max power to fire the optical on the Einsteins.

Appreciate the help. Also any ideas on how grids etc. I have just about everything to include a couple of PLMs, boxes, grids, laser, beauty dish...etc.

The SU4 acts as a basic optical tripper. I guess you can go with the fancier CLS if you wish, but I do not know for sure it will work (probably will). But you will not be optically triggering the Einsteins, that is why the CST is connected to the remote SB900. When the 900 gets triggered, the signal is passed through the PC terminal and to the CST, which then triggers the Einsteins via radio. The SU800 should work, but may be more limited in rotation to trip the slaved flash.

I have done that. Water swallows radio waves pretty good, so any radio trigger I tried did not work. I ended up using the pop up flash of the camera. I modified it so it would aim up rather than forward. It worked OK as long as the ambient light outside was low.