[GrahamS]

Jane, if you are taking night shots using "B" or a fairly long shutter speed and you have the camera's auto noise reduction set to "on", the camera will process each image for noise reduction before saving it to the card, and the LCD will display the message "Busy." This can slow things down considerably. I suggest that you switch the noise reduction off, and do your noise reduction later in post processing, if it is necessary.