580EXII AF Assist beam without Firing Flash

Hey guys; I've read that it's possible to set my 5dMKII camera settings so that my 580EXII when on camera will not fire the flash but still use the AF Assist beam; my question is, if I have a Pockey Wizard on my camera to fire OCF, will THAT still work? Seems like it would but I don't want to find out the hard way it won't. Thanks!

It depends on which PocketWizard you have on there, but the basic units that don't do TTL will not trigger the AF assist beam. If you have the flex units that support TTL, then AF assist should work.

I have the PW PLUSIIs

How do you have the PW Plus II's connected? Through the camera's PC port?

klr.b wrote in post #15730404
How do you have the PW Plus II's connected? Through the camera's PC port?

Yes.

I doubt the PC port will get the flashes to trigger the Assist beam. The PC port just has a "Flash fire now!" signal.

That's correct. You can't activate the AF Assist light with the PC socket, even if the flash was connected to it directly. The flash needs to be on the hotshoe, or connected to the hotshoe via TTL cord with all six conductors.

To answer the first part of your question - Some Canon bodies have a custom function to make the flash not fire. However, I don't see that option on the 5D Mk II.

Maybe I'm misunderstanding, but I have my flash in the hotshoe, set to not fire, with the PW connected to the camera's PC socket.

With the flash in the hotshoe, the AF Assist beam will illuminate when needed, if you're using One Shot AF mode (not AI Servo). However, as far as I can tell you can't prevent said flash from firing when you take a shot with the 5D Mk II (The option to prevent the flash from firing is available on some other Canon bodies).

The PC socket, and whatever you have plugged into it, has no bearing on the above paragraph. You will activate whatever is plugged into the PC socket when you take a shot.

Curtis N wrote in post #15732698
With the flash in the hotshoe, the AF Assist beam will illuminate when needed, if you're using One Shot AF mode (not AI Servo). However, as far as I can tell you can't prevent said flash from firing when you take a shot with the 5D Mk II (The option to prevent the flash from firing is available on some other Canon bodies).

The PC socket, and whatever you have plugged into it, has no bearing on the above paragraph. You will activate whatever is plugged into the PC socket when you take a shot.

Ok Thanks! {btw, just upgraded to the MKIII! Her name is Roxy }

Ok so now that we have established the technical limitations, here is a practical solution: Turn the flash head around backwards and set it at 1/128 power. The AF Assist will work fine that way, without adding light to your shot.

Curtis,

If the option isn't available via the 5D MKII menu, can't you just disable the master from firing via the back of the flash?

A la, top of page 2 here: http://www.learn.usa.c​anon.com …LC_580EXII_Quic​kGuide.pdf

Or page 39 of the 580EX II manual: http://gdlp01.c-wss.com …dlite580exii-en-es-fr.pdf

FWIW, the option is available via camera menu on my 50D.

I had not considered the Master mode/Master Off option. I would point out that it still fires a command flash during the exposure, so she might still want to turn the head around backwards.

Curtis N wrote in post #15731343
<snip>

To answer the first part of your question - Some Canon bodies have a custom function to make the flash not fire. However, I don't see that option on the 5D Mk II.

I had no idea the 5DII couldn't disable flash firing. Both of my cameras could disable firing so I could just use AF assist.

I dug around in the 5DII's manual and on page 105, the second footnote at the bottom says:

Why would a 580ex have an option for Flash Firing, but not a 580exII?

Of course it can, and so can the 5D Mark II. Curtis was looking among the custom functions for this, but more and more flash related functions have moved into the flash control menu, something which started with the 1D Mark III, and has become more elaborate since then.

So the setting for disabling the flash, but keeping the AF assist beam, is under the flash control menu. Controlling the AF assist beam itself may still be in a custom function in the 5D Mark II, though.