Interaction between 500D and flash

Has anyone had problems with T1i/500D and Speedlite flash?

I occasionally get into a mode where the camera and flash aren't fully communicating. Normal behavior with the 580 in ETTL mode is that the flash displays the zoom of my lens, the aperture, and a bar display along the bottom for how far out the flash will likely be effective.

When it gets in the strange state, it shows ETTL, with a zoom of 24mm (which is the minimum it ever shows for my 17-55 lens) no matter how I zoom the lens, it doesn't display the aperture, and it gives no bar chart. When I take a shot, the flash seems to fire maximum: everything is overexposed.

I've discovered (by messing up, and by reading the manual) how and when it's normal for the flash not to zoom, by putting it into bounce, or by not having the wide panel fully retracted. I know now how to see on the display when I've done this, and this isn't what's happening.

I'm guessing that what's happening is that one of the pins on the hot shoe not connecting sometimes. Anyone have any experience with this? Incidentally, I had a 430EX until this past Christmas, and I had a similar experience, so it's probably the camera.

Cheers;
Rick

Hi Rick,

It's a fairly well know phenomina (sp?) - caused by (as you say) a mis-communication between camera and flash. Best solution is to switch off both - reseat the flash (making sure it's screwed down firmly) - switch on flash first, and then the camera.

Traditionally it can do it most if you're shooting vertically oriented shots (as the orientation puts more loading on the mount). Also, make sure that the mount isn't coming loose on the camera, and clean the contacts. Only small thing I picked up on is that usually when it does it it'll say TTL, not ETTL.

Hope this helps :)

Excellent, thanks, Colin!!

I cleaned the contacts with contact cleaner. The mount seems solid. I'll get in the habit of powering up flash, then camera, and do a reseat if it's not behaving.

Cheers!
Rick

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Originally Posted by rick55

Excellent, thanks, Colin!!

I cleaned the contacts with contact cleaner. The mount seems solid. I'll get in the habit of powering up flash, then camera, and do a reseat if it's not behaving.

Cheers!
Rick

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No worries Rick. In theory it shouldn't matter which you power up first but experience tells me that a 20D / 580EX combination gave less of the problems you describe if done "flash first".

You could also try torquing the flash a bit by hand to see if you can reproduce the problem.

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Originally Posted by Colin Southern

You could also try torquing the flash a bit by hand to see if you can reproduce the problem.

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When I had the problem last, I tried wiggling the flash on the mount, and unlocked and relocked it, with no effect. Then I powered everything down and removed and replaced the flash, and it was okay. I'm not sure which I powered up first, though.

I just tried moving it, without inducing the problem, but I did clean the contacts before, so perhaps it was a combination of a dirty contact and the torque. It does seem a small physical mounting for a moderately hefty device. I can certainly see why turning the camera vertical causes more trouble.

Cheers!
Rick

Quote:

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Originally Posted by rick55

It does seem a small physical mounting for a moderately hefty device.

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Agreed, the 'hot shoe' is one of those interfaces, mechanically at least, where the organic development over time and standardisation, combined with ever bigger and more top heavy flashes, means if they started the design again 'today', it probably wouldn't be anything like what it is.