Each of the two robot rovers -- Spirit and Opportunity -- is equipped with two color and seven black-and-white digital cameras. Cutting edge technology when the project was developed about 10 years ago, the Pancam cameras now seem a little outdated. They are 1 megapixel cameras with approximately 100 dpi resolution at a distance of one meter (a calculation Bell carried out while we chatted on the phone). They have a fixed focus and are set at f/20 for a wide depth of field. For each color photograph the Pancam produces, three identical photos must be taken, one each in red, yellow, and blue, which are reassembled back on earth, a process that is done instantaneously by off-the-shelf digital cameras.