Umbrella and 420EX

[rayzorb]

Hi All,
I have got a 580EX on my 20D and a 420EX slaved
attached to a stand and Unbrella.

My question is which way should the red beam (AF assistant beam)
be pointing? Either in torwards the umbrella (as I first had set up)
or out towards the subject and have the flash head rotated back towards the umbrella?

With the flash all pointing in to the umbrella I seem to get underexposed shot. With the other way around the exposure seems to be fine. I am using ETTL mode and in <P> mode.
Regards
Ray

[scottbergerphoto]

Since you are using it as a slave, you need the red plastic pointing in the direction of the Master flash to receive its instructions. The flash head of course is pointed at the umbrella.

[rayzorb]

Thanks Scott,
Does the red beam the slave sends out from the red plastic thing do anything in Slave mode?

[scottbergerphoto]

As a Slave, I don't believe that the 420EX is emitting an AF assist beam. It flashes a red light to let you know it is on and ready.