20d/580ex

[mercphoto]

I want to try to figure out what types of batteries work best in my flash. To do this, what I want to do is fire the flash at full power continuously for 20 flashes in a row, timing how long it takes to do so. What I can't figure out is how to fire the flash as soon as, and only when, the flash has recharged.

Any ideas?

[Mongrel]

I don't know if this will work as I don't have a 580EX (yet...), but have you tried hitting the 'test' button?

You may be able to cycle the flash manually that way. It wouldn't even have to be mounted on the camera I don't think.

[wmsnyder]

I want to try to figure out what types of batteries work best in my flash. To do this, what I want to do is fire the flash at full power continuously for 20 flashes in a row, timing how long it takes to do so. What I can't figure out is how to fire the flash as soon as, and only when, the flash has recharged.

Any ideas?Usually lithium batteries work best unless you are wanting to go with rechargeables. You can fire the flash manually by pushing the pilot light.

[mercphoto]

Usually lithium batteries work best unless you are wanting to go with rechargeables. You can fire the flash manually by pushing the pilot light.

Aha! Push the pilot light. I knew there wasn't a Test button. What I ended up doing instead last night was putting the flash in manual mode at 1/1, putting the camera in manual mode, and when I saw the pilot light go active I fired the camera. Did twenty shots that way.

Duracell: 2 minutes
Duracell Ultra: 1:40
Energizer 2200 mAh NiMH: 1:04

Wow! Big difference. My last remaining question, possibly to be answered tonight, is how the rechargeables last compared to the alkalines.

[pathfinder]

Aha! Push the pilot light. I knew there wasn't a Test button. What I ended up doing instead last night was putting the flash in manual mode at 1/1, putting the camera in manual mode, and when I saw the pilot light go active I fired the camera. Did twenty shots that way.

Duracell: 2 minutes
Duracell Ultra: 1:40
Energizer 2200 mAh NiMH: 1:04

Wow! Big difference. My last remaining question, possibly to be answered tonight, is how the rechargeables last compared to the alkalines.
I routinely are using the NiMh in my 580EX. They usually last longer than I need them - never counted the frames, but with a better beemer they are usually used a significant number of shots in a session. Much better than alkalines. But when they die, they don't give much warning - just here one minute and gone the next. Keep some spares handy if you are on a paying gig.

[Mongrel]

Aha! Push the pilot light. I knew there wasn't a Test button.
Well, I did say "I don't have a 580EX" and on my Sigma EF500 DG Super there is a "test button", which obviously is the same as the "Pilot light" on the Canon.

Anyway...

You're welcome...

Anthony