Problem: unable to turn 550EX flash off when master..

[hotrod10d]

Hi,

I have 10D + 550EX and 420EX flashes.
The 550EX manual describes how it is possible to turn off the 550EX flash and use it only to trigger 420EX slave.. (so that 550EX would only flash the "signal" for the 420EX but not provide any light to the actual photo). Basically this way the 550EX should work just like ST-E2 remote trigger.

My problem is that I have done everything exactly like described in the manual on page 104 but still my 550 provides "full flash" together with the 420.. All test photos are identical no matter if I have set the falsh "on" or "off"

I have browsed through pretty much the whole internet and there seems to be many people with the same problem but no working solution.

Has anyone any ideas to this matter, or has anyone been able to use those flashes like that?

Best regards,
-Jarmo

[scottbergerphoto]

The Master Flash set to off, should show the flash icon flashing in the LCD. The 550EX will still emit the pulses required to control the slave flashes. Those occur prior to the actual flash. Have you tried turning the 420 away from the subject to see if the 550 is producing all that much light? It isn't the amount of light you should be looking at but where it is coming from. ETTL will try to maintain the amount of light the same whether you use one flash or two.

[hotrod10d]

Thanks a lot Scott for your reply, it encouraged me to give still one more try, and suddenly it worked!!

I repeated the test I had already done 10+ times today but this time everything worked fine for the first time..
(I placed the 420EX behind the subject facing away from the subject and me, and this time the front side of the subject was dark and the save triggered (in my previous tests my 550EX had provided light to the subject from the front..) All the settings were 100% identical to the previous tests, that incon blinking and all..

This is guite weird, maybe there is something wrong with my 550EX.. anyway I am glad to know it is possible :D

Br,
-Jarmo

[scottbergerphoto]

Thanks a lot Scott for your reply, it encouraged me to give still one more try, and suddenly it worked!!

I repeated the test I had already done 10+ times today but this time everything worked fine for the first time..
(I placed the 420EX behind the subject facing away from the subject and me, and this time the front side of the subject was dark and the save triggered (in my previous tests my 550EX had provided light to the subject from the front..) All the settings were 100% identical to the previous tests, that incon blinking and all..

This is guite weird, maybe there is something wrong with my 550EX.. anyway I am glad to know it is possible :D

Br,
-Jarmo
I hope you don't mind, but I spoke to your Master flash. It has a whole new attitude now. This ones on the house. ;)

[GyRob]

lol can you speak to my car Scot it needs a good talking to ;)
Rob.

[tim]

And maybe you can speak to my girlfriend while you're at it ;)

Most electronics have a keen self preservation instinct. When they sense you're about to get pissed off and smash them to bits they suddenly start working. It's a new form of AI.