The exposures from my flashgun seem to be erratic.

Ensure you are using the correct fitting flashgun, ie. a Canon fit gun on a Canon camera. Ensure the flash / camera is not on Manual mode. Ensure the 17mm Wide Panel is not covering the flash head. If using a digital camera, ensure the model is compatible See our compatibility chart for details. We suggest using spot metering for more accurate results. If the problem persists, please contact us for further information.