I use a Sony a900 and a77 and need some cold weather advice. When going from a warm environment like my car out into the cold my lens fogs up. How do I prevent that and can the fogging damage my lens? I usually use a Tokina 11-16/2.8 or Tamron 28-75/2.8 depending on what camera I'm using. And what about the opposite? Getting in my car after being out in the cold, that also fogs up the lens.