I have just started using flash in my photography and decided to purchase a Jessops 280 AFC Flash Gun (canon dedicated) to use with my EOS 30. The problem is that the flash is coursing the shutter to not work. I can be taking pictures with the flash and then all of a sudden nothing. I press the shutter button fully and the shutter and flash do not work . The camera is still metering fine and focus is still working fine. The flash ready light is on and I have only used it in manual mode with manual focus. I know to fix this problem would be to get a canon flash but does anyone know what could be happening. It�s starting to happen right when I need to take a critical short! Any input is welcome. Thanks in advance.