It is ok to take your camera from warm inside temperatures to cold outside temperatures. It is also ok for your camera and lenses to be out in the cold (you will need spare batteries is you are out for any length of time).
The danger is in taking a cold camera (and lens) from cold temperatures into warm temperatures. That is when condensation can occur both outside and inside your equipment.
After taking pictures outside in the cold, put you gear in a zip lock bag or zip it in a camera bag before bringing it inside. Let your equipment warm up gradually before opening the camera bag or zip lock bag. It is a good idea to carry a few large zip lock bags in the bottom of your camera bag for this and other uses. Wadded up in the bottom of you bag, zip-locks make for a little extra padding until you need them.
Your car may be just enough warmer than the outside air to cause condensation. Pack your gear away before turning on the heater.
A few words about batteries. When your camera tells you the batteries are about shot, don't throw them away. Put your them in a warm pocket and put spare batteries in your camera. When they get too cold and tired, take the batteries out of your warm pocket and put them back in uyour camera, they should be ready to go again (unless they were almost dead before you went out into the cold). In cold temperatures, good batteries will look like they are almost dead when they are only partly discharged and just need to warm up.
Added January 20, 2000
