backscatter when using internal flash to trigger a slave flash?

[Dee]

Here's what my rig looks like, with a different camera.

Sealife Camera

The black plastic in front of the main flash has a reflective sticker on it, which triggers the strobe.

Not sure what you mean by "preflash". The camera has an external strobe setting, which fires the main flash a couple times before the strobe fires.

If your strobe is postioned straight ahead like the one in the photo, that's your backscatter problem.

The pre-flash on some cameras is just that....the first quick flash is what the camera uses to record the scene to set the automatic settings, the second flash a micro-second behind the first is what kights the scene. There are several pre-flash compatible strobes that are designed to ignore the pre-flash and use the second flash as the trigger for the slave.

 

[whitedragon13]

so based on the pic of my rig, do I need to rig some sort of tube/optic between the flashes or should I be good to go?

 

[marpacifica]

Ah, the trusty Mellow Yellow (the name for my old Sealife camera/strobe). I can't speak about the flexible plastic tubing or duct tape, but I did have lots of fun with my Sealife using just the black reflector with the external strobe. You'll notice two sensors which look like large scallop eyes on the bottom of the external strobe. These are what record the flash, so you'll have to figure out a way to get your internal flash to trigger them. I'm pretty sure the Sea & Sea fiber optic cable (about $65 on the web if you run a search; check out http://www.seaandsea.jp/products/accessory/acce/digital.html and scroll down to YS-25 fiber optic cable for a pic) will work, but you'll have to custom fit it for your system. It comes with black velcro. The "hook" fabric has adhesive on the back which you attach to the top and front of your camera, and the fuzzy fabric sticks to the hooky fabric and blocks the internal flash. You'll have to custom cut the fuzzy fabric b/c the kit comes with templates for cameras but I'm pretty sure there's not one for yours. With the fibre optic cable, one end attaches to the fuzzy fabric over the int. strobe, but you'll have to figure out how to attach the other end to one of the sensors on the external strobe. Duct tape might work.

The problem with the Sealife ext. strobe is that it's a slave strobe, meaning that it will fire whenever properly charged and whenever it senses a flash -- other divers' strobes will fire your strobe and you may miss a shot if somebody else is taking a shot in your vicinity. So if you cover up the extra sensors with duct tape and attach the fiber optic cable to one, you'll get rid of the nasty unwanted flashes from other divers and just get the light from your int. strobe to fire your ext. strobe.

Good luck. If you could take a pic of your rig after you've figured out a good system, please post it on this board for others to try.

 

[Dee]

so based on the pic of my rig, do I need to rig some sort of tube/optic between the flashes or should I be good to go?

I defer to marpacifica's information...I know nothing about the inner workings of SeaLife cameras!

 

[JohnW48]

I'm using a Canon G10 in a WP-DC28 which comes with a flash diffuser, the strobe trigger I have has a thread end. I drilled and tapped a hole for the trigger and spray painted the diffuser black to eliminate back scatter.