Second curtain flash sync

[notmentat]

I was inspired by the capture motion blur article the other day and discovered the technique of using the second curtain flash.

I have a Canon EOS350D and a Sigma EF 530 DG SUPER flash.
I was playing around with my camera last night and had trouble with it working correctly.
I set the both the camera and flash to enable second curtain sync, but when I took a photo, the flash fired both at the beginning and end of the exposure.

I think the initial flash was considerably less powerful than the final one. Having never done this before I'm a bit confused as to why the flash is firing twice.

Any ideas why this might be happening? Perhaps there's something else I should have set before trying it?

[ARKreations]

The initial flash is the camera's pre-flash for TTL metering and exposure. It occurs before the shutter opens and does not contribute to the exposed image.

[notmentat]

Hmm. I did wonder if it was something like that, but it did sound like it was at the same time as the shutter opening. I'll investigate more tonight.
Thanks for the response!

[Gonzo13]

I thought the same thing with my camera when I was first playing with 2nd curtain flash. I was photographing a roll of tape that I had pushed so I could see the results though.

[RustySterling]

I've been doing a lot of second curtain flash lately. What I do is set up the second curtain for my 580EX II in the camera. Then I set the flash to manual -- I've found for the latest situations 1/16 power worked just fine. By using the flash in manual mode I don't get the first flash. I only get the flash when the shutter is closing.

Here's one I took recently during our Waikiki vacation. I took my exposure reading from the background, set the flash to second shutter, flash was 1/16th power on manual mode, flash was also off-camera with a small softbox aimed at us. We just stood there for the time it took for the flash to fire. Result is capturing the lights in the background and we are clearly seen.



Here's another that I took of me, again using second shutter flash. But in this case I stood on one side for a 20 seconds of a 25-second exposure and moved to the other side just before the flash fired. I had no idea what I'd get but I like the result and played with it a lot more. I call it Ghosts of Waikiki:



Again, in both situations I had the flash set in manual mode. Because of that I didn't get the first flash which is, as someone said, for the ETTL to get a proper reading.

[notmentat]

Interesting stuff, thanks.
I love the second photo!

[RustySterling]

Originally Posted by notmentat

Interesting stuff, thanks.
I love the second photo!

I love it too. I was just playing around with long exposures and second curtain. I love how the background bleeds through. It really is a ghostly effect to me.

[axfircu]

looks good and congrats. hope you enjoy the car like many of us