Flash misfiring

[Stacylouwho]

I have a t3i and just got an external flash. I found that I can use my on camera flash as a trigger. but I have had a lot of issues with the external flash firing right before the flash goes off and I don't catch the light? Is this common when using the on camera flash..?

 

[runnah]

It helps if you fire the flash right before you plan on using it. Get the easy flash out of the way first, that way you can last much longer.

 

[cptkid]

Your camera flash is firing in TTL mode, which means that it actually flashes twice. once to meter the scene, and once to actually light the scene, in very quick sucession. i.e so fast you cannot see it.

The external flash that you are using as a slave is then firing when first flash goes off, not the second. You need to change the slave mode to fire when the second flash goes off not the first.