You are outside with a friend on a cold day when something happens and you want to take a picture. You run into the warm house to get you camera but your friend says, "It's no use, the lens will fog up when you bring the camera out here in the cold."
Is your friend right? Explain.

Question

You are outside with a friend on a cold day when something happens and you want to take a picture. You run into the warm house to get you camera but your friend says, "It's no use, the lens will fog up when you bring the camera out here in the cold." 
Is your friend right? Explain.

anonymous · Answer

No. I actually think it's the other way around.... In the sense that, the lens is only likely to fog up if it is brought from a very cold room to a warm one.I speak from experience because I wear glasses and sometimes when I pop it in the freezer for a while & then remove it, it gets fogged up.
 I think is is because the water vapor present in the warm air will easily condense onto the cold surface of the lens

anonymous · Answer

rajathsbhat is true ı think.. there must be cold surface and warm air for the formation of advection fog.