safe sync adapter

I have been taking pictures of babies in homes using a simple set up which is not working. Usually I set them up very close to a window, place one Fotudiox L-120 strobe on the other side and then use my 430ex flash to trigger the strobe. 45% of my pictures are overexposed and 45% are underexposed. Now I turn off the strobe and just use the modeling light. I am not sure what I am doing wrong. So I am thinking if I connect my camera to the strobe I will have better luck, but I have heard that my Rebel XT can't handle the voltage. Any suggestions?

If the positioning of the lighting is what you want with the Speedlite on the camera and the other strobe elsewhere, you can get them to fire properly. You need to have BOTH the camera and the Speedlite in fully manual mode. No automation will function properly for the exposure - period.

The reason is fairly simple.

One scenario is that the remote strobe is triggering off the pre-flash from the Speedlite and not recycling fast enough to trigger with the main flash. Thus the remote flash would not contribute to the exposure.

The other possibility for problems is a little more complex. The camera and Speedlite work in concert with each other to determine how to fire the Speedlite for a proper exposure. The Speedlite emits a pre-flash which the camera analyses. The camera then tells the Speedlite how long a burst to emit as well as controlling its own aperture and shutter speed. If you got a remote flash to pop at the same time as the main flash, you would definitely have an overexposure situation unless the remote flash is merely illuminating otherwise dark background or something like that. The reason is that when analysing the pre-flash, the camera knew nothing about the extra flash source and could not possibly adjust things for it.

Does this make sense?

I think I do understand. So actually connecting the camera to the strobe will not help. What is your opinion about a safe sync adapter. My strobe only uses 5v. Thanks for your reply

Audra wrote in post #2812636
I think I do understand. So actually connecting the camera to the strobe will not help. What is your opinion about a safe sync adapter. My strobe only uses 5v. Thanks for your reply

If your flash sync voltage is measured at less than 6 volts, then for sure you can use a common hotshoe-to-PC adapter to connect the flash unit to the camera. This will eliminate the ability to use the Speedlite, of course, as the adapter will be in the hotshoe that is required by the Speedlite.

There is the slight possibility that the adapter you get will have female hotshoe (similar to the one on the camera) with a feed-through for the center pin (and common) that could fire the Speedlite. The Speedlite would fire at full power all the time unless you use its manual control to turn it down.