I am very, very pleased with the high ISO quality of the Canon EOS-1D X. This was taken in the reduced resolution MRAW mode (forgot to set it back to full res after a tradeshow) at ISO 3200, at sunset, when most of the canyon was already in shadow. Between the image stabilization of the 24-105mm f/4L IS lens and the 1D X's low noise, I was able to shoot this handheld in very poor lighting conditions.