I am going to start experimenting with some time-lapsing with my t3i and I had a question about weather. I am wanting to try a sunrise and I'll have it set up for 3 hours or so. If the temp is around 20 degrees F, is that OK to leave my camera outside that long? I've heard after shooting in the cold for a long time, condensation can build up when you bring the camera inside. Any tips on how to avoid this? Thanks!