The Digital Camera Battery

The NP-E3 battery for the Canon 1Ds is very expensive, at $US125 each.   If I'd followed the same route as the D60 and bought 3 spare batteries, this would have been a very expensive proposition.

The solution I ended up taking was to buy something called the "digital camera battery", an external NiMH battery pack which has two outputs and uses different cables to provide appropriate power levels to different devices.   Not only was a cable available for the 1Ds, but I was also able to get a cable for my Mindstor PSS-1720 digital wallet, which contains a 20 gigabyte hard drive into which I download compact flash cards in the field.