580EX II is still flashing when I turn flash off trying to slave.

[capturedexpressions]

After attending the Imaging conference, I learned that the Canon Speedlite 580 EX II has the ability to work as a transceiver to a slave without the flash actually going off. When I read the manual, I set it up that way but the flash is still going off. Is it a different camera setting or slave setting needed for that to properly work?

Know of any good tutorials on showing this?

[RLipp69]

After attending the Imaging conference, I learned that the Canon Speedlite 580 EX II has the ability to work as a transceiver to a slave without the flash actually going off. When I read the manual, I set it up that way but the flash is still going off. Is it a different camera setting or slave setting needed for that to properly work?

Know of any good tutorials on showing this?
are you actually takeing the picture or are you useing the pilot button in back of the flash to fire the flash?

[CliveyBoy]

If you have the display show the flash icon but no flashhead rays, and Master, and above it a large OFF, then you have it set correctly.

However, the preflash is still required, and may be what you are seeing. Try watching in the viewfinder while you take a shot. The preflash will be visible, until the mirror goes up before the shutter opens. That's how the flash communication works.

It causes great problems for any optical triggers around, but takes no part in lighting the subject.

[capturedexpressions]

If you have the display show the flash icon but no flashhead rays, and Master, and above it a large OFF, then you have it set correctly.

However, the preflash is still required, and may be what you are seeing. Try watching in the viewfinder while you take a shot. The preflash will be visible, until the mirror goes up before the shutter opens. That's how the flash communication works.

It causes great problems for any optical triggers around, but takes no part in lighting the subject.

That might of been it, I just seen the flash and thought it couldn't be working. So it will flash every time but it's just a preflash, I didn't see that in the book. I had the master on with the beams off. Thanks for the info!

[capturedexpressions]

are you actually takeing the picture or are you useing the pilot button in back of the flash to fire the flash?

I tried it both ways. I was actually just watching the flash and not through the viewfinder to make sure it didn't flash and it did.

[Big Mike]

The 580 uses light pulses from the flash for communication with it's slaves (not IR). You could also call this 'preflash'.

[PacAce]

After attending the Imaging conference, I learned that the Canon Speedlite 580 EX II has the ability to work as a transceiver to a slave without the flash actually going off. When I read the manual, I set it up that way but the flash is still going off. Is it a different camera setting or slave setting needed for that to properly work?

Know of any good tutorials on showing this?
There is a note in the 580EX II manual at the bottom of page 39 that says that the master flash will still fire even when it's disabled.

Since the master is disabled, there is no reason for it to fire a preflash to determine exposure (because it's not contributing light to the exposure) but it still does need to fire the command signals to the slaves and that is what you are seeing. This really isn't a preflash per se because it not only fires before the shutter opens but it also fires when the shutter is open (this will be evident in the picture if there is no ambient light in the scene, especially when using higher ISO values).

Anyway, what you are seeing is normal. :)

[capturedexpressions]

There is a note in the 580EX II manual at the bottom of page 39 that says that the master flash will still fire even when it's disabled.

Since the master is disabled, there is no reason for it to fire a preflash to determine exposure (because it's not contributing light to the exposure) but it still does need to fire the command signals to the slaves and that is what you are seeing. This really isn't a preflash per se because it not only fires before the shutter opens but it also fires when the shutter is open (this will be evident in the picture if there is no ambient light in the scene, especially when using higher ISO values).
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Anyway, what you are seeing is normal. :)

Thanks!

[Mike Fulton]

The 580 uses light pulses from the flash for communication with it's slaves (not IR). You could also call this 'preflash'.
Yep this is correct, many people, including myself in the past called this the preflash. The Master has to communicate with the wireless units by light pulses and the flash you are seeing is just that. As already stated unless you shoot into a mirror or reflected surface bouncing this light back into the field of view you should not see this flash in the image captured when on this setting.

You will notice on your LCD screen the 3 lines coming out of the little flash icon is not there when in this mode, its a nice visual alert letting you know which mode your in since both have flash coming out when you click the shutter.

[CliveyBoy]

This really isn't a preflash per se...
Canon calls it a pre-flash, but without defining the term.
"Even if you disable the master unit's flash firing, it will still fire a preflash to transmit wireless signals"

[PacAce]

Canon calls it a pre-flash, but without defining the term.
"Even if you disable the master unit's flash firing, it will still fire a preflash to transmit wireless signals"

Yes, they did but they qualified it with "preflash to transmite wireless signals" to differentiate it from the exposure preflash which is what most people think of when they use the term "preflash". I also wanted to point out that the command flash is made up of a preflash which fires before the shutter opens and another flash (coflash?) which fires after the shutter opens.

[gooble]

PacAce has come to the rescue twice in two days. I had the a similar question in this thread: http://photography-on-the.net/forum/showthread.php?t=664451