Vision is composed of many simultaneous functions. If vision is normal, seeing is so effortless that we do not notice the different visual functions.

The different components of the visual image are:

forms
colours
movement.

Thus we have form perception, colour perception and motion perception.
We see both during the day light and during very dim light. In day light, photopic vision, we perceive colours because of function of the cone cells; in very dim light, scotopic vision, we see only shades of gray, since rod cells respond only to luminance differences. In twilight, when both rod and cone cells function, we have mesopic vision.