The older of these two systems, from an evolutionary point of view, is the one consisting of rods. The special attributes of this system include high light-sensitivity and a great capacity for perceiving movement over the entire field of vision. On the other hand, rods do not allow us to perceive color; contours are not sharp and it is not possible to concentrate on objects, i.e. to study items clearly even if they are in the center of our field of vision. The rod system is extremely sensitive and is activated when the illuminance level is less than 1 lux. Our night vision features, particularly the fact that color is not evident, contors are blurred and poorly lit items in our peripheral field of vision are more visible – can be explained by the properties of the rod system.