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Thread: Weird Flash Triggering Problem. Help?

  1. #1

    Default Weird Flash Triggering Problem. Help?

    I was trying to do a cross-flash shoot for my friends last night, and I seem to have problem with the Canon 7D not being able to trigger my other flash.
    Here's the list of equipment:
    - Canon EOS 7D
    - Canon EOS 450D
    - 580EXII Speedlight
    - Emoblitz ds328az flash

    (The Emoblitz flash is just a normal flash, operating SOLELY on it's own light sensor. I covered the light sensor with a black piece of tape to push it to full power. Thereby acheiving a "manual mode". It has 3 modes. Normal (N), Slave 1 (S1), Slave 2 (S2). Slave 2 is supposed to work with ETTL systems to ignore the initial flash burst so that it can sync with the 2nd main flash)

    Our first shot was indoor. I set up my 450D and popped up the internal flash. The two flashes were pointing from left and right to the rest of my friends. We set the Emoblitz to S2 mode, and the 580EXII to slave mode (not sure which slave mode it was). I took a shot, and the Emoblitz flash fired, but the 580EXII didn't fire. Because we forgot how to fully operate the 580EX II, we decided, better use the 7D to do the triggering, since that'll fire the 580EXII, and as long as there's a flash, the Emoblitz will fire as well. So we switched over to the 7D and fired (without adjusting any other settings). All went as planned. We packed up to move to another venue, which was outside.

    There, again, we set up the two flashes, but this time, our friends were standing in a line instead against a railing, and we were shooting at an angle. One flash was pointing at them perpendicular to the line, and the other was shooting across them to give some highlight. Without adjusting any other settings except flash exposure compensation on the 580EXII, we fired again (also using the 7D) But this time, although my Emoblitz flash fired, it didn't appear on the shot. It was still in S2 mode. This was extremely puzzling, so I brought down my flash from the stand and aimed it directly in front of the camera. When my friend took a shot, we clearly saw the Emoblitz fire, but again, the camera didn't register the flash firing. I even got him to drop the shutter speed down to 1/50, but it was no use, his 7D couldn't catch my Emoblitz flash.

    So, just to be sure the flash didn't malfunction, I took out my 450D, popped up the internal flash as well, and took a shot at the Emoblitz. It caught the flash firing!

    So why is this so weird? Is there a significant difference between the ETTL systems in the 450D and 7D such that the pre-flashes from the cameras are sooo different that one can't capture my Emoblitz flash, and the other can? What's worse is that they all worked PERFECTLY indoors! No problems whatsoever!

    The only reason I can think of at this moment is that the 7D fires it's own internal flash more than twice during firing, and "tricked" my Emoblitz into firing early. While indoor, I do note that the sensor of my Emoblitz was pointing at the 580EXII, to trigger from there, rather than directly from the 7D as well, and the S2 mode is supposed to fire upon the brightest flash, which is the 580EXII, so that might have been it. Even then, it still feels weird really....

    But I've never used a 580EXII before, so what do you guys think?
    (Just to note again, all these were at night. First shot was indoor, on a staircase. Second was outdoor, against a railing, behind was the river.)

  2. #2

    Default Re: Weird Flash Triggering Problem. Help?

    450D not triggering the 580EXII is perfectly normal. 580EXII slave is not just optical triggered.

    So now what's the 7D flash control settings? Set to external only or both external and buildin flash fire?
    Last edited by GRbenji; 6th December 2011 at 01:53 PM.

  3. #3

    Default Re: Weird Flash Triggering Problem. Help?

    I am aware of the 450D not triggering the 580EXII cos the 7D can transmit some info or something to the 580EXII but the 450D cannot.

    Erm, 7D flash control settings are default I think. We didn't tinker with that one. But both the camera's onboard flash fired, and the 580EXII fired (as well as my Emoblitz, but only the emoblitz didn't show up on the image)

    Any idea why? My Emoblitz flash works perfectly with my 450D.

  4. #4

    Default Re: Weird Flash Triggering Problem. Help?

    By default 7D won't trigger a 580EX slave flash. Flash Control has to set Wireless function to on, and here you select whether buildin flash fire too.





    The above images are taken from here.
    Last edited by GRbenji; 6th December 2011 at 01:11 PM.

  5. #5

    Default Re: Weird Flash Triggering Problem. Help?

    Ic. So how should I set them so that my Emoblitz flash also fires correctly? And why doesn't it fire correctly in the first place?

  6. #6

    Default Re: Weird Flash Triggering Problem. Help?

    Quote Originally Posted by Wizongod View Post
    Ic. So how should I set them so that my Emoblitz flash also fires correctly? And why doesn't it fire correctly in the first place?
    I couldn't tell you exactly as I don't have the flash, and neither can I find any info online. Only based on your mentioned that it is triggered optically, hence advised you to check 7D flash control settings.

  7. #7

    Default Re: Weird Flash Triggering Problem. Help?

    hmm... i c. Looks Like I gotta do some rigourous testing in this case to fully understand the 580EXII pairing up with the 7D....
    Thanks for the help!

  8. #8

    Default Re: Weird Flash Triggering Problem. Help?

    Quote Originally Posted by Wizongod View Post
    hmm... i c. Looks Like I gotta do some rigourous testing in this case to fully understand the 580EXII pairing up with the 7D....
    Thanks for the help!

    the onboard flash of the 7D triggers off to triggers the 580EXII, the emoblitz is catching the onboard flash (preflash) so when the shutter goes down only the exposure from the 580EXII is caught as the emoblitz already went off. it's too fast for your eyes to see, looks like it's going off same time.

  9. #9

    Default Re: Weird Flash Triggering Problem. Help?

    Well, the thing is, the Slave 2 mode (S2) is suppose to ignore the first flash, i.e. ignore the pre-flash. It works well with my 450D, which also does ETTL, and hence has a pre-flash. It just didn't work with the 7D.
    Not only that, but the set-up (as you may read above) worked indoors perfectly, and only failed outdoors. Very strange.

  10. #10

    Default Re: Weird Flash Triggering Problem. Help?

    Try using the flash from 580EXII to trigger the other flash.

  11. #11

    Default Re: Weird Flash Triggering Problem. Help?

    Ah yes, that's a good way, but how do you shield the other flash from the 7D's onboard flash so that it "sees" only the 580EXII? some sort of snoot?

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