Help with off-camera flash

[Ovidius]

Hi all,

I'm using a 5D mk2, with a non-canon flash.

When I use the flash in the camera hot-shoe, I have no issues.

However, when I take the flash off-camera and use a remote trigger, the picture consistently turns out dark.

I'm shooting in Manual mode - I've been experimenting with ISO 320, f7.1, and various shutter speeds, all of them slower than 1/200 (even as slow as 1 second).

I suspect that the flash is not in sync with the shutter, how do I resolve this???

Thank you very much for any help you can offer!

[TCampbell]

This sounds like your trigger is trying to do E-TTL flash and your off-camera flash is trying to do manual flash.

In E-TTL mode there is a pre-flash that the camera uses to determine how much light it should use for the shot, then the shutter opens and the flash fires a 2nd time, but at the power level calculated by using the pre-flash test.   

This is all happens so fast that most people don't realize the flash fired twice.

But if the off camera flash is in manual mode, it will fire it's one and only pulse of light during the pre-flash and when the shutter opens to take the shot, the flash has already gone dark.   Again, this all happens so fast that you don't realize it's done this.

If any components use E-TTL then everything in their system h to support E-TTL and be in that mode.  If any component is manual-only, then everything has to be set to manual flash. 

If if you have a basic 3rd party flash then it likely cannot support E-TTL mode.

[ebiggs1]

... or your flash is not powerful enough.  Off camera flash requires you calculate the distance carefully.