The easiest way to answer your question, SillyRabbit, is this:

"It varies, just like real life does."

Think about waking life. When you first wake up in the morning, sometimes, you are groggy. Your mind is hazy, you're not quite in tune with your surroundings and you barely even care enough to notice anything.
On the other side, when you are full of adrenaline - when you've just climbed a mountain and are taking in the air, when you're running a football down the field with 7 guys chasing after you, trying to take you down, when you've riding the biggest, wildest, fastest rollercoaster at a theme park - you feel alive. You're noticing more sounds. Your vision has increased. You are more aware.

Such is the nature of how hazy or vivid lucid dreams can be. It all depends on your frame of mind, while having the dream.