[boxcam78]

I am having a problem with this combination recently. Not having used the flashgun for some time I yesterday got it out because I wanted to use it at an event that I wanted to photograph. However I encountered a rather funny problem when I came to use it. The ready light lit just after switch on but when I pressed the the shutter button to focus, the light went out and the flash did not fire and the shot was way underexposed. Occasionally it did fire. The flash will fire OK off camera when the 'ready' light is pressed and will recharge Ok after a few seconds. The flash is set to P-TTL and Auto Flash and mounted on the camera. Am I missing something or is the Flashgun faulty or the Camera.

[clawhammer]

have you tried cleaning the contacts on the bottom of the flash/top of the camera? It sounds like there is a connection problem between the camera and flash.