ETTL working with manual flash?

There are couple of recent discussions on combining ETTL with manual flashes. I have not used this combo before and wonder how it work in real practice. So here go the test.

First the trigger setup: stick the ebay trigger on the side of the 580EX, plug in the sync cord. The ebay trigger is smaller and lighter than the PW, so there is an advantage

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I do a lot of drag race photography and I have been toying with using studio lights as fill for the sides of the cars and and a 580EX as the main light for the front. I was going to try my ebay radio unit plugged into the PC socket and the 580 on the hot shoe. Placement of the studio light would be an issue since I need to have the studio light more or less the same intensity within a range of where the car is at the time of the shot. Things don't always happen at the same spot even in a drag racing starting line photo. I haven't done it yet because I've been a little concerned about being more of a distraction to the drivers than I already am, but one of these days, I'm going for it. I'm glad to see someone playing with the idea.

Lotto, yes the result you got looks fine; it assumes the off-camera flash contributes no light on your subject, but only on the background.

If your manual off-camera light casts its output onto the main subject, you end up with very different results!

I double light weddings, and my off-camera unit is not on Manual, but on Auto (on-flash photosensor control). My on-camera flash functions as fill light, my off-camera flash functions as key light.

Wilt wrote in post #3274808
I double light weddings, and my off-camera unit is not on Manual, but on Auto (on-flash photosensor control). My on-camera flash functions as fill light, my off-camera flash functions as key light.

Do you trigger the off-camera light with an optical slave? .. I'd like to do the same and retain ETT-L Oon the on camera flash) but the pre-flash prohibits.
Mike

Jim, I would agree that it could be a distraction. I know the race drives and their crews are anal about all the little details

Wilt, I normally would not use auto mix with manual anyway. This is more like for testing purpose. But since you mentioned adding the slave to main's exposure, I went ahead and did another test. ETTL and thyristor metering are bit different. In ETTL, flash metering and required power are sent to EXs before the camera tripping the manual flash. My Sunpak firing has no effect on camera's flash metering, though it will add its own flashing on top of what the camera/EX think is the proper exposure. With thyristor flashes, if they are pointing to the same subject, the master/salve will affect each other because they meter and fire at the same time.

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mmahoney wrote in post #3275433
Do you trigger the off-camera light with an optical slave? .. I'd like to do the same and retain ETT-L Oon the on camera flash) but the pre-flash prohibits.
Mike

Radio slave. No way I would ever depend upon optical trigger at a wedding, where every Uncle Bob and Aunt Maggie with a camera would be triggering my slave!

Lotto wrote in post #3278249
But since you mentioned adding the slave to main's exposure, I went ahead and did another test. ETTL and thyristor metering are bit different. In ETTL, flash metering and required power are sent to EXs before the camera tripping the manual flash. My Sunpak firing has no effect on camera's flash metering, though it will add its own flashing on top of what the camera/EX think is the proper exposure. With thyristor flashes, if they are pointing to the same subject, the master/salve will affect each other because they meter and fire at the same time.

Seems to me that the shot with both flashes is brighter by about 0.25 EV

ETTL on camera with a wireless transmitter works fine. The flash doesn't fire until the pre flash has finished. Therefore the wireless transmitter doesn't fire until the preflash is done - second curtain Or first curtain doesn't matter. Once the preflash is quenched all flash circuits will fire.

On a body that has a sync port and a non 580II flash it does the same thing.

I've done this lots. You have to fiddle a bit but it works just fine.

cosworth wrote in post #3279863
ETTL on camera with a wireless transmitter works fine. The flash doesn't fire until the pre flash has finished. Therefore the wireless transmitter doesn't fire until the preflash is done -second curtain Or first curtain doesn't matter. Once the preflash is quenched all flash circuits will fire.

On a body that has a sync port and a non 580II flash it does the same thing.

I've done this lots. You have to fiddle a bit but it works just fine.

If you have a setup like in Lotto's previous example (with the stuffed dog), having the non-ETTL flash in auto mode fire on the 1st curtain and the ETTL flash fire on the 2nd curtain would ensure that the exposure of non-ETTL flash is not influenced by the ETTL flash. Also, dialing in some - EC on either or both flashes to attain the proper lighting ratio would be a good idea, too.