Petter Stahre
New member
I wan't to only use the AF-assist function from the 580EX, but without the flash firing ...
... so I set the 580EX as a master and turn the flash off (using the 580EX menue, pressing the zoom button a couple of times and then the wheel (not powering down the flash unit itself of course)). But when shoot with my 1DsII in the Av-mode, I can see that I get different shutter speeds depending on if the flash unit is on or off. From what I understand this shouldn't happen when I've disabled the flash, or?
I know that the 580EX always tries to transmit data to a second flash, using a pre flash, when it's in the master mode (which it needs to be for me to disable the flash).
Apparently this pre flash affects the lightning in the image - which it shouldnt, or? This is evident both by the different shutter speeds (depending on the flash unit being on or off) and I can also see shadows created by the flash firing.
What am I doing wrong? Or can it really be the case that you can't totally turn the flash off - meaning that for "normal" dark scenes the preflash will (almost) not be seen but for very dark scenes the preflash will affect the lightning quite much?
Anyone?
(I also have the ST-E2 but I would like to use the 580EX instead.)
// Petter
... so I set the 580EX as a master and turn the flash off (using the 580EX menue, pressing the zoom button a couple of times and then the wheel (not powering down the flash unit itself of course)). But when shoot with my 1DsII in the Av-mode, I can see that I get different shutter speeds depending on if the flash unit is on or off. From what I understand this shouldn't happen when I've disabled the flash, or?
I know that the 580EX always tries to transmit data to a second flash, using a pre flash, when it's in the master mode (which it needs to be for me to disable the flash).
Apparently this pre flash affects the lightning in the image - which it shouldnt, or? This is evident both by the different shutter speeds (depending on the flash unit being on or off) and I can also see shadows created by the flash firing.
What am I doing wrong? Or can it really be the case that you can't totally turn the flash off - meaning that for "normal" dark scenes the preflash will (almost) not be seen but for very dark scenes the preflash will affect the lightning quite much?
Anyone?
(I also have the ST-E2 but I would like to use the 580EX instead.)
// Petter