Hi for reasons which escape me I like to use my 4x5 camera outside when its cold, I seem to find my best subject matter that way. Among the challenges this brings is the problem of focusing without fogging up the screen. This is my (home made) dark cloth. Its light weight, dark, water proof and the silver side really helps keep it tolerable in the heat (when I'm home in Australia). Here in Finland I have other problems ... When its less than -10°C I have trouble with the glass fogging up (and then freezing fogged). Presently I hold my breath, but I'm thinking of using a snorkel to see if this works ... anyone have any tips?