Hi members of the forum,
I just thought I'd go straight to the point with the title and the post. I'm planning to go on a rather big field trip with my 4x5 Large Format and shoot some Kodak Ektar film, as well as some black and white. I only have two film holders, which means 4 shots at a time, and I will most likely need to use a changing bag to swap films so I can take more.

So my question is:
How can I make sure when I take them out to take the shot, or to swap the film in the changing bag, that I don't get condensation on the film from the drastic change of temperature from inside the bag to outside in the cold snowy weather?

I'm thinking firstly to use sandwich zip-bags to store the holders in when not using them, but is that going to make a difference when quickly taking them from considerably warm to cold, to warm again?

Thanks again!
-Constantin

PS: Hope this is the right section of the forum to post this kind of question.