Speedlite 430ex Problems

[ROCKNSWIFT]

Hello, all! Please pardon my lack of knowledge on the Speedlite 430ex for I am a novice.

Recently when I set my camera (40D) in automatic with the flash attached, my photos turn out to be very dark to nearly no exposure; but when set on any manual setting, it doesn't have problems attaining the sufficient light I need. I'm not sure if I set something on the flash that I shouldn't have.

Has anyone come across this problem? I hope I've explained myself well enough for someone to diagnose this problem.

If anyone has a clue as to what I did, and also know how to get me out of this dilemma, please let me know.

Thank you kindly!

[SmartWombat]

It's pretty hard to tell without some sample photos.
If you add them as attachments, and when you resize them to 800x600 please don't take out the EXIF information, then we have something to go on.

[CaraRose]

Is the flash actually firing in auto?

[Loupey]

I have two 430EXII's and both had the same problem (at different times). What happened in my case is that when the preflash fires for E-TTL, it does so at full power. Therefore, no flash is produced during the actual exposure - can't recycle fast enough.

You can test this by simply shooting into a mirror. If the flash did not trigger in the reflection, this is the problem.

I don't know why the 430 does this. My first one was repaired under warranty but my second one is SOL. My 580EXII never did this.