Flash on Slave not shooting at the same time!

Hello all! first post! I hope you guys have the answer:
I have a Canon XTi and found in my uncle's old stuff an external Vivitar V-160 and a Metz Mecalux 10 slave.
I have the slave with the flash on top on a tripod, when I shoot my camera's flash in order to triger the slave, it appears that the slave shoots FASTER?
I can't get the flash light in the picture. I've tried slower speed to see if the slave was slower than my camera, and it looks the other way.
Any way to fix this?

The built in flash on the XTi always produces a preflash before the actual exposure flash.

The off camera flash is triggering on the preflash, so is not recycled and ready to fire when the camera actually open the shutter.

Enjoy! Lon

Thanks! but nop!
I knew about the pre-flash focusing thing, and I did it on manual focus... same thing.

bluetorch wrote in post #5951622
Thanks! but nop!
I knew about the pre-flash focusing thing, and I did it on manual focus... same thing.

manual focus doesn't cause the preflash. it's the flash mode you are using. are you sure you are doing it right? I mean... optical flash slave triggering has been around for a very long time now.. It has to be user mistake.

You can't use the built in flash to trigger optical slave flashes, you have to use an external flash in manual mode. A manual workaround is to hit the * button on the camera, wait 10 seconds for the slaves to recharge, then shoot, but that wastes time and batteries. You can get a wein product that has an optical slave trigger that knows about the preflash and only fires strobes on the 2nd flash, but they're not cheap.

Be careful putting old flashes on the camera hotshoe, the voltage can fry them. The Wein Safesync can protect against that, but again, not particularly cheap.

As Tim said above, you can press "*" to set off the pre-flash (which will trigger the slave flash) and then press the shutter button to set off both flashes at the same time. So effectively you will be triggering the slave flash twice for each shot. However, you may not need to wait for 10 secs depending on how fast the slave flash recycles. On my one (model YinYan :rolleyes it recylces within about 1-2 secs if I got some fresh batteries on. So I trigger the preflash with "*" and then take the shot with the shutter button as soon as the ready red light comes back on the slave flash.

You should also try shooting in manual mode (NOT manual focus mode but the "M" mode instead of "Av" or "Tv" modes). I beleive this disables the preflash so that you just need to press the shutter button to take the shot with both flashes firing. Needless to say if you put your camera flash on manual mode or take off the option of preflash it would work as well.

I'm fairly sure the preflash can be disabled on the internal flashes of eos cameras, no matter what mode you're in. Even in M the camera needs the preflash to figure out the required flash power.

^^^ That's what I thought as I was looking at doing the same thing after some research I found that you cant disable the preflash .

tim wrote in post #5952361
I'm fairly sure the preflash can be disabled on the internal flashes of eos cameras, no matter what mode you're in. Even in M the camera needs the preflash to figure out the required flash power.

No, the preflash cannot be disabled for the internal flash because there's no way to set the internal flash to manual mode.

I have the same problem. I am using the XTi and a 430EX flash monted on the camera, as a second flash I am using an old Vivitar 283 flash with a Vivtar slave. The Vivitar 283 does fire, but it is not in sync with the 430EX. I can see both flashes go off as I look thru the viewfinder, but when you look at the finished rusults there is no evidence of the 283 flash ever firing. So how do I get the Vivitar flash to sync with the camera and 430EX?

Thanks; Speedy

speedygonzo wrote in post #5955643
I have the same problem. I am using the XTi and a 430EX flash monted on the camera, as a second flash I am using an old Vivitar 283 flash with a Vivtar slave. The Vivitar 283 does fire, but it is not in sync with the 430EX. I can see both flashes go off as I look thru the viewfinder, but when you look at the finished rusults there is no evidence of the 283 flash ever firing. So how do I get the Vivitar flash to sync with the camera and 430EX?

Thanks; Speedy

Put the 430EX into manual mode.

Thanks, that worked....