I know there is another post re using external battery packs and I know the benefits of using one, however, this question is aimed at just AA batteries inside the flash unit.

I have noticed at the last couple of weddings that my batteries (I use 2500mh rechargables) don't last that long. I sometimes get through three sets in a day. When I used the 580 EX one set would last most of the day, normally.
I am using the 5D camera. My wife uses a 30D with my older 580EX and only uses 1 set of batteries all day.

Has anyone else noticed the 580EX 11 using more battery power than the 580 EX?
I'm pretty confident the batteries are still okay. I appreciate that some replies may say "it depends how much you use your flash" but I am basing my comparisons on previous weddings shooting in a similar style.

...and yes, one of my purchases for this year will be a Quantum, but in the meantime it's running on AA's.

Carl

no idea what the big difference would be here, besides the fact that the flashes are different. however, canon claims that the 580EX II is supposed to be more efficient... so wouldn't it perform better with the same batteries? Hmmm...

other than that, i cant be of much help... since you're already getting a quantum i don't have to open up that can 'o worms again. let me know what you find out!

The 580 / 580 II on the 30D is going to zoom in a bit tighter because of the "sensor crop", while on the 5D it will not.

That might be part of the reason maybe?

(if you're not familiar, the 580 line of flashes set the head zoom to match the "calculated" sensor size, so a 50mm on the 30D works out to about 80mm, so it would set the flash zoom for 70mm, while the same lens / flash on the 5D will still be set for 50mm - using more light to cover that wider area).

That's the only possibility I can think of. Try swapping flashes to see if it's camera or flash related.

Shan

Have you checked the batteries, I was getting lousy battery life sometimes until I found that I had one battery that wasn't charging fully - new batteries and brilliant battery life.