Certainly the trick works, but when you fiddle with cameras and ziplock bags with freezing fingers, all kinds of improvements come to mind. Hence the question: do I really need a separate plastic bag, or could I simply use my camera bag?
Not all camera bags are sufficiently tight to prevent condensation. But which bags are good enough? Are there any "winter bags" that work (almost) as well as the combination of a normal camera bag + a ziplock bag?
For example, Lowepro has some waterproof camera bags – are such bags sufficiently air-tight for winter use? Are there cheaper options? How far one can go with a normal camera bag + some silica gel?