Understand that Canon is manufactured in Japan but Nikon is mainly done in Thailand. For the older film cameras, Nikon was ahead of Canon as pro equipment, but for digital cameras, Canon seems to be slightly earlier in the introduction of new technologies. Both brands are supposed to be very good for low light exposure, with relatively better chroma noise suppression. Sony, on the other hand, has higher noise suppression but concentrated mainly in the luminance signal I.e. green noise is well suppressed but the other colours are less well controlled. The results are less good for dark scenes.