From Isis Workshop
 Instrument Overview
HiRISE has acquired more than 20,000 images of the martian surface in unprecedented detail.
HiRISE operates in visible wavelengths with a telescope that will produce images at resolutions never before possible in planetary exploration. These high resolution images will enable scientists to resolve 1-meter (about 3-foot) sized objects on Mars and to study the morphology (surface structure) in a much more comprehensive manner than ever before.
From an altitude of approximately 300 kilometers above Mars, HiRISE will return surface images comprised of pixels representing 30 centimeters of the martian surface.
These high-resolution images provide unprecedented views of layered materials, gullies, channels, and other science targets, as well as possible future landing sites.
 Technical Details
This telescopic camera has a primary mirror diameter of 50 centimeters and a field of view of 1.15°. At its focal plane, the instrument holds an array of 14 electronic detectors, each covered by a filter in one of three wavelength bands: 400 to 600 nanometers (blue-green), 550 to 850 nanometers (red), or 800 to 1000 nanometers (near-infrared). Ten red detectors are positioned in a line totaling 20,028 pixels across to cover the whole width of the field of view. Typical red images are 20,000 pixels wide by 40,000 lines high. Two each of the blue-green and near-infrared detectors lie across the central 20% of the field. Pixel size in images taken from an altitude of 300 kilometers will be 30 centimeters across, about a factor of two better than the highest-resolution down-track imaging possible from any earlier Mars orbiter and a factor of five better than any extended imaging to date. As a rule of thumb, at least three pixels are needed to show the shape of a feature, so the smallest resolvable features in the images will be about a meter across for an object with reasonable contrast to its surroundings. The instrument uses a technology called time delay integration to accomplish a high signal-to-noise ratio for unprecedented image quality.