Camera bags for winter

Question

Many people recommend putting cameras in sealed plastic bags when coming from winter conditions back to normal room temperature – see, e.g., here and here.

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?

Answer 1

For what it's worth, my laptop and photography equipment comes into room and warms up in a regular laptop backpack with its zipper closed. Winter temperatures were around -20°C (-4°F). I think the necessary part is to keep your equipment from contacting huge volume of room air from which a noticeable amount of humidity could be gathered on cold metal surfaces, but absolute airtightness is not necessary - small amounts of warm air oozing in over long time do not contain enough water to cause trouble.

So, I would trust a tight (closed with zipper or similar) camera bag. Throwing in a small pack of silica gel just to feel sure sounds like a good idea.

Answer 2

You only need to protect your camera when coming in from the cold. If you seal up your camera perfectly airtight all the time you are outside, and then come in and open up the bag, you will still get condensation on it. If you like, carry a ziplock bag around with you, seal up the camera just before you come inside, and wait until it warms up. You should see no condensation.

EDIT:As far as I can work out the amount of condensation is proportional to how much high-humidity air gets in contact with the camera before it heats up. Putting it in any bag before coming indoors will reduce that - a tightly zipped bag with little airspace will be better than a loosely closed one with lot of airspace; a watertight bag will reduce it more, and an airtight bag all but eliminate it. But only the period while the camera is warming is important.