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I recently bought a Promaster off camera flash cord for my Canon 7D and Canon 580EX II. I noticed with the flash directly mounted to the camera, the flash can fire several times before it needs to recycle. However, with the off camera flash cord, my flash can only fire once and wait for about 3 to 5 secs before it can fire again. I'm wondering is that normal? Would a flash external battery pack reduce the wait time (perhaps flash recycling)?
Thanks,
Raymond
Doesn't sound normal and makes no sense to me. Flash recycle time should only be dependent on how much a given flash burst drains the capacitor and how fast the flash batteries can recharge it. I'm guessing that you were somehow pumping out a higher power flash burst (longer duration) when you had it connected with the cord. Try doing a more controlled test with both the camera and the flash set to manual mode and use the same camera settings and the exact same flash power setting in both cases. You should not see a difference. One other thing to check is to make sure that the 580EXII is firmly seated in the hot shoe in both cases. I have found that the weather seal seems to sometimes somehow loosen the flash connection and can cause the flash to act flaky which often results in it firing at full power, which, of course, would make it take longer to recycle than it would at a lower power setting.
In any case, adding an external battery pack would indeed reduce the recycle time as you would then have more battery power available for recharging the capacitor.
I normally mount my flash on the camera directly and use ETTL and at -1 to -2. Under the same settings with the flash mounted on the camera, the flash can fire a few burst (Canon 7D, 8 fps). However, with the same settings and the flash mounted on a off-camera cord, the flash could only fire once then I had to wait for a few seconds before it could fire again. So I was wondering is it the cord or will more batteries (8 AAs instead of 4) help speed up the flash. I will experiment with manual settings to see if it helps.
Thanks,
Raymond
