So I bought a 580 ex a while ago thinking hey this will go perfect for getting some fill flash in my skate sequences (30D 5FPS) WRONG. It's worked great for lighting indoor situations with its little built in white card, but I finally got some skate shots in yesterday and was sadly disappointed to find that with high speed sync it fires on the first shot and then quits for the entire 12 picture sequence (at least in RAW). Is this what I should have expected or is there something I am doing wrong?
Your flash can't recycle fast enough to keep firing while you mash down the shutter at 5 fps. If your aperture, distance, and ISO are such that the flash only needs minimal power for each frame, you can probably get off a few shots. But under normal conditions, even without high speed sync, the recycle time is longer than the frame rate.
That is what you should have expected. There are a number of external battery packs that will decrease the recycle time, but even then the best you will probably get is two or three frames. Not only that, but in high speed light will not get out there very far.
I doubt you'd find many (if any!) flash units that can cope with such high firing rate. Even if you could find a way to force it, you'd end up destroying them by burning them or have them melt!!!
Suparman Widja wrote:
Hmm. Why not use 2nd-curtain in this case? You can also bump up the ISO so the flash does not have to consume that much power (and recycle faster).
2nd curtain has nothing to do with the OP issue. You can't 2nd curtain with high speed flash, anyway
Reducing the amount of power the flash needs, (higher ISO) will help, but not solve the issue. Banging off a dozen flashes at full speed - I doubt any camera mounted flash can do this - and especially at hi-speed sync.
You might try shooting at the synch speed and give your flash a better chance of catching up. PRobably will give you toomuch motion blur.
High speed sync vastly reduces power as it's a rapid pulsing of the flash. If it actually fired at fully output, you need 6 seconds to recycle, even with fresh batteries.
If the flash is the main light (weak ambient), try a long shutter speed with the flash in strobe mode. I used to do this with film and would get half a dozen sharp images on a frame.
By using the Cannon battery pack, I found the 580EX can do fairly good keeping up when shooting a burst with the lower fps rate of the 40D but not too well at the faster fps.
