need help with umbrella flashes

[FilmaTroy]

so i just bought 2 umbrella flashes off ebay for $70. they said that the flashes would be triggered off of my on cam flash (or another off cam flash)
well they fire but my camera doesnt have any result from them, its like they go off before my shutter catches the image. they cam with what i think are pc cords, but i have a canon rebel xsi which doesnt have a pc port!
anybody know what i could do about getting the flashes to work properly or if they have a pc adapter or something?

Thanks!

 

[SpeedTrap]

You would need to shut off the pre flash on your camera,
Most of the pop up flashed hace a very quick metering flash just before the main. The Pre-Flash will trigger the flashes.

 

[FilmaTroy]

You would need to shut off the pre flash on your camera,
Most of the pop up flashed hace a very quick metering flash just before the main. The Pre-Flash will trigger the flashes.

forgot to mention im not using pop up flash, i am using a 430 ex i

 

[Derrel]

This comes up very frequently; Last week, it was a nice lady with two umbrella flashes and a 430 EX...same scenario...her 430 was NOT synchronizing the flashes with the shutter. Both flashes fired, she said, but there was no effect. I looked at the EXIF of two of her samples--she was using two,different automatic modes. One was Normal Program, the other mode was Aperture Value auto...when set to those modes, the normal 430 EX behavior is to fire in an E-TTL mode, if I am not mistaken.

What you need to do is to set the camera to Manual exposure mode. Set the shutter speed to 1/125 second, and pick an f/stop like f/8 at ISO 200. Set the flash to MANUAL mode, and try 1/4 power to see i that will trigger the umbrellas flash units through their built-in slaves.

The slaves in the flashes also must be turned to "on". The pre-flash the 430 EX emits gives the camera an idea of the reflectivity/return rate of the flash, in mere milliseconds, then the 430 EX is commanded by the camera to out put the correct amount of flash for a good exposure. The pre-flash triggers the umbrella flashes, which fire immediately, but the ACTUAL SHUTTER exposure comes a few milliseconds later, after the umbrella flashes have already dumped their capacitors.

 

[FilmaTroy]

This comes up very frequently; Last week, it was a nice lady with two umbrella flashes and a 430 EX...same scenario...her 430 was NOT synchronizing the flashes with the shutter. Both flashes fired, she said, but there was no effect. I looked at the EXIF of two of her samples--she was using two,different automatic modes. One was Normal Program, the other mode was Aperture Value auto...when set to those modes, the normal 430 EX behavior is to fire in an E-TTL mode, if I am not mistaken.

What you need to do is to set the camera to Manual exposure mode. Set the shutter speed to 1/125 second, and pick an f/stop like f/8 at ISO 200. Set the flash to MANUAL mode, and try 1/4 power to see i that will trigger the umbrellas flash units through their built-in slaves.

The slaves in the flashes also must be turned to "on". The pre-flash the 430 EX emits gives the camera an idea of the reflectivity/return rate of the flash, in mere milliseconds, then the 430 EX is commanded by the camera to out put the correct amount of flash for a good exposure. The pre-flash triggers the umbrella flashes, which fire immediately, but the ACTUAL SHUTTER exposure comes a few milliseconds later, after the umbrella flashes have already dumped their capacitors.

Thanks for the tip, ill try this when i get home saterday to see if it works, im out of town on business right now. but i ALWAYS shoot manual but ill try changing my apature and iso as well and setting to 1/4 and 1/125, ill see what happens this weekend and post

 

[FilmaTroy]

thank you darrel! it worked!! you just saved me some money , now that i dont have to buy a hot shoe pc adapter!!

 

[jonahr]

this should not be in the film forum.