Adding External Strobe Slaved to On-Camera Flash

I hope I'm placing this question in the right place.

My wife uses a small pocket camera (Konica Minolta Dimage Xg) in a nice small housing for underwater photograpy. It actuall takes pretty good pix except for the abundant backscatter caused by the on-camera flash.

So we're thinking of getting an not real expensive external strobe, and the one I'm thinking about presently "slaves" to the internal flash, no sync chord required.

So, I'm just wondering, if the external strobe requires the light from the internal flash to fire, isn't there still going to be backscatter from the internal flash? Would it do any good to put tape over the internal flash, would there still be enough light seeping out the sides to trigger the external strobe.

I recognize that we're taking short cuts here, so be kind when you answer.

Thanks,

-PS

Driver,

Some digital strobes have an optical cord which "covers" the internal flash and pipes the light up to the strobe to fire it. That would be the ideal way to fire your external flash and minimize backscatter. The method that you're describing with tape might also work if it manages to fire your external strobe. Some point and shoot housings have a removable diffuser plate which you can place in front of the internal strobe. If your housing has one you can always cut a piece of dark plastic film to slide into this slot made for the diffuser (a few strobe manufacturers actually take advantage of this when designing the fiber optic cord going to the slave strobe) this will be a little cleaner and more durable than tape.

Gary,

Do NOT put tape directly over the internal flash. Your internal flash might be strong enough to burn the tape into the plastic of the flash. Ask me how I know...

<_<

Driver,

I have just gone through this same conundrum with my Sony point and shoot. The housing that is made for this camera doesn't provide a diffuser or any other way to deflect the camera's on board flash. I'm not sure what your housing for the Minolta has to offer in this respect. I did a lot of searching and asking questions. If you purchase a strobe that just senses your deflected flash (with no cable of any kind), the strobe may go off on its own by sensing another photographer's flash or even the sun if it hits the sensor just right. There are a couple of options however that get around this. Ikelite, Inon, and Sea & Sea all have ways to sense specifically your camera's flash. I chose an Inon strobe and their AD mount base with the Optical D Cable/Cap set made for my housing. The cap set completely covers the strobe's sensor and is attached to a small fiber optic cable that runs to the AD mount base which blocks the camera's flash. When the camera flashes, the optical cable pickes up the light and tells the strobe to flash simutaneously. This system works very well on a camera/housing that was never really meant to take an external strobe.

To answer your questions: The only way to get rid of backscatter is to use an external strobe (or get really good with Photoshop). Yes, the external strobe is fired using the camera's native flash in your set up. You must set the camera to "force flash". The Inon system I mentioned (Clear Photo System) uses a UV filter to cover your camera's flash and blocks it to prevent backscatter.

Hi,

I recently bought a Sea & Sea 8000G and YS-90 external strobe.

The external stobe is fired by a fibre optic link which senses the

camera's internal flash.

The camera flash is set to 'flash on every shot' mode. There is a difuser

within the housing that cranks up in front of the internal flash but

it's not the perfect solution.

The fibre optic link plugs into a recepticle on top of the housing over the

internal flash. A piece of black adhesive velcro has been placed directly

in front of the internal flash but on the OUTSIDE of the housing.

This prevents the issue of backscatter caused by the internal flash

and the internal flash also goes upwards by reflection inside the housing

and fires the fibre optic cable which in turn, triggers the strobe.

In addition, there is a sensor on the strobe that determines the

strobe intensity required to illuminate the subject so it's important

to angle the strobe correctly.

The results, even in green water, are quite impresive.

Make sure any strobe you buy can handle cameras that pre-flash

(set your camera off in a dark room facing a miror if you are not sure).

Some stobes relying on optical fibre pick up can get very confused

by pre-flash.

Hope this helps

Steve

"I have just gone through this same conundrum with my Sony point and shoot. The housing that is made for this camera doesn't provide a diffuser or any other way to deflect the camera's on board flash."

The Sony red filter kit comes with a difuser that can be used in most of their housings.

Thanks, masguy. I have never seen/looked into the red filter kit because I never felt I needed one. I have heard arguments on both sides. So, Sony does make a diffuser? I'll check it out more closely. Thanks!