Concerning the deer's sight, they are extremely good at detecting movement, but not so good at making out and object. That's why I think all the debate about different camos is pretty much BS. I've had deer look straight at me many times when they heard a sound, but couldn't make out what I was. If you are on the ground, though, and they spot your movement, they will freeze on you and you are usually busted.

However, if a deer smells you, it doesn't need to see or hear you and it knows which direction the smell came from most of the time.