In comparison with out human ability to see, a dog's sense of sight is less well- developed. Its vision is not as detailed as ours, and it recognizes objects by shape and form rather than detail and texture.
Dogs are not colour-blind, but they see colour less well than humans. It is more difficult for them to distinguish between certian colours; for example, a red ball on green grass will blend in, whereas a white one will stand out.
Dogs can see better at night and in dim conditions than we can, because they have a reflective layer at the back of their eyes that traps and light entering and allows them to make more use of it. This is why they can run off at top speed into the darkness on winter walks without crashing into trees and fences ( and why their eyes shine when caught in the beam of a car's headlights).
Dogs are also much more sensitive to movement than we are, especially when it occurs at ground level. We are able to see stationary and moving objects equally well, whereas dogs are much more likely to see objects that are moving and ignore stationary ones. This means that they can detect the slightest movement of our bodies and allows them to anticipate our actions before we have deliberately moved.