I am trying to use my 420EX mounted on my 1Ds camera. The camera triggers the flash but the pictures are dark or the flash has no effect on the exposure. I used normal and high speed sync but nothing helps. The flash works fine with other cameras, namely 40D, 50D and 60D. Is something wrong with my 1Ds or is there a camera/flash setting I'm overlooking. This is a big problem because the camera does not have a built in flash like the others mentioned.
I've had a similar problem and in my case the flash wasn't all the way forward into the hot shoe. However it might be a loose hot shoe. Read the story here.
Thank you for posting. I am inclined to agree with cicopo on this one. Please make sure the flash is all the way onto the hotshoe and it is secure. If it is loose, then there may be a connection issue between the flash and the camera. You can also try cleaning the contacts on both the flash and the hotshoe with a soft microfiber cleaning cloth. This will also help to improve the connection between them.
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