High Resolution Stereo Camera (HRSC) is a camera experiment on Mars Express. A version for Earth called HRSC-AX was also developed, as was a version for Mars 96. It has four main parts: camera head, super resolution channel, instrument frame, and digital unit. At an altitude of 250 km from Mars, SRC can produce images with a resolution of 2.3 meters/pixel of 2.35 km square Mars terrain. It has 9 other channels and can produce digital terrain models. A typical image from HRSC of Mars has a resolution ranging from 12.5 for nadir (directly down) to 25 m/pixel for the farthest off-nadir shots, which can be up to 18.9 degrees.
By 2012, about 61.5% of the surface of Mars was mapped at a resolution of at least 20 meters per pixel by the Mars Express mission using this camera. Another area of study is repeat imaging, to allow the study of dynamic processes on Mars. Another trick is to make short videos of the Mars surface by taking advantage of the pushbroom nature of the detector, each section is slightly offset for a different color, but when combined each view be used to make a short animation.
Here is Orcus Patera, imaged by the HRSC: