Taking the professional photographer to the next level, the Canon EOS-1N RS is a specially-developed camera designed to meet the demands photojournalism, sports and scientific photography where precision and high speed are essential. Containing almost all of the features of Canon's flagship EOS-1N, this model features a pellicle mirror which eliminates the flipping of the mirror as the shutter is released. This results in several dramatic differences for the professional photographer. In addition, unlike the EOS-1N, which permits increased film advance speeds by adding on the optional Power Drive Booster E1, the EOS-1N RS features a built-in motor drive which can provide three different modes: RS, Continuous, and single frame film advance.