The canon EOS 1Ds is a digital SLR 11 megapixel camera. It has a NiMh battery. However it can also run off a/c. I tested it in this a/c mode.
Just on and not doing anything it uses 1-2 watts.
Holding down the shutter release and shooting continuously it uses 18 watts of power.
The power consumption of writing to the compact flash card or shooting slowly is around 8 watts.