Working with 2 580EX's

I have 2 580EX's and I need instructions on how to set them to work as follows:

1. Flash on camera fires / flash off camera fires.

2. Flash on camera does not fire / flash off camera fires.

I think I know the answer to number 1:
You set your on camera flash to master and the other one to slave. (look at the manual for the options. you can choose A:A, A:B and such ... I forgot). Leave your flash at ETTL mode. Then when the flash on the camera fire, it will also trigger the off camera to fire.

For number two, try setting the custom function to not fire and see if it work. But I think it won't work though because as far as I know, canon flash works on the basis of light triggering, not radio signal (?? someone please correct me if I'm wrong). Therefore, if the master does not fire, the slave won't fire either.
Hope this helps (even if just a little )

jerrybsmith wrote in post #3622013
I have 2 580EX's and I need instructions on how to set them to work as follows:

1. Flash on camera fires / flash off camera fires.

2. Flash on camera does not fire / flash off camera fires.

I see you have an ST-E2.

I don't know if you can make the flash on camera 'not' fire... but you could use your ST-E2 to fire the remote flash only. you probably figured that

You are right Wakko. I use the ST-E2 all the time but would like to explore the capabilities of working with two 580EX's.

jerrybsmith wrote in post #3626203
You are right Wakko. I use the ST-E2 all the time but would like to explore the capabilities of working with two 580EX's.

You can't work with two flashes, firing one only, if the one on camera is supposed to trigger the other one, off camera, unfortunately.

So either you'll have to use the ST-E2, to trigger a remote flash, trigger only a single flash with the ST-E2, or use a very long extension cord .

For two flashes, you can use both as remote flashes with the ST-E2, use one connected to the camera to trigger the other, or use a divider to connect more than 1 flash to the camera.

In short, it means that with

1. Flash on camera fires / flash off camera fires
you can use the on camera flash to trigger the other one set to slave

2. Flash on camera does not fire / flash off camera fires
can only be done by removing the flash on camera, substituting it for the ST-E2, or connecting the off camera flash by a long flash extension cable.

Kind regards, Wim

Mmmm...I'm sure I've got my 580 to trigger my 430 without the 580 flashing.

...let me check.

Here's a pic of my 430 being trigged from my 580.

Byte size: ZERO | Content warning: NOT AN IMAGE

How do you prevent the 580 from firing COMPLETELY though. Isn't it set to always fire a preflash or comm. flash or something?

I did some product photography today with two 580's, one on camera and one in a home made soft box, and it's impossible to only have the slave fire. I've tried every setting and if the main flash on camera doesn't fire, neither does the slave.

crackaonrice wrote in post #3626432
How do you prevent the 580 from firing COMPLETELY though. Isn't it set to always fire a preflash or comm. flash or something?

Ahhh....in that case. No, the 580 will always pre-flash.

Ephemeral wrote in post #3626715
Ahhh....in that case. No, the 580 will always pre-flash.

Phew! Good!...well, not good for us in general...but good for me because i spent like 2 hours trying to get that to work and didn't get the results you claimed earlier.