only one strobe TTL?

i have not applied this but i expect to get a third flash and want to anticipate what my options will be.

i have two manual flashes: a vivitar 285 and a canon 540ez. i trigger them using cactus v2.

i intend to get a third flash, canon 580ex ii.
will i be able to mount the 580ex onto my camera and use the TTL function while still firing my other two flashes manually via my wireless trigger? or does using TTL on my main flash not allow me to wirelessly fire my other two flashes using the cactus triggers that i have?

i know i could fire all three wirelessly using the cactus triggers, but wondering if i will be able to accomplish the above.

thanks.

As long as your canon flash is in the hotshoe, you keep your ettl. I'm guessing your wireless v2 will be triggered with a cord...if this is the case, you should have no problem.
One thing..be careful where your "dumb" strobes are pointing. Your camera does not know they exist, and will not know that they will fire. If you use these lights as any kind of a mainlight, your ettl will be confused and you will get very inconsistent results from your 580.
I do what you are saying all the time, with pocketwizard plusII's, and it works great. You can use them for backlighting, rim lighting, environment lighting, etc, but just be aware that if things don't seem right it's probably because these lights are confusing your camera.

Mixing manual and eTTL flash is not that great of an idea unless the manual flashes are for the background only. The camera is going to meter the eTTL flash with the pre-flash and set the exposure for that and then the picture is going to overexpose when the unexpected additional light appears from the manual flashes.
You can do what you want to do by connecting the Cactus trigger to your PC port is your camera has one.

There is an art to using manual and TTL flash together.
The TTL flash is being metered by the camera so that it can deliver the proper exposure.
If you want the manual flash to be the main then it has to be configured to deliver the primary exposure.
That means that the TTL flash will have to be backed off to provide fill. That is accomplished with FEC. Dial in -1/2 or -1 or whatever you want.

Similarily, if TTL flash is going to be main light then manual flash has to be set to provide less light. That will require some metering or chimping to get right.

TTl means the flash is being adjusted on a shot by shot basis. So there are likely to be variations. But the principle holds.

ok.
i understand.


thanks all