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has anyone every tried keeping an activated hand warmer (or two) in with the binos during late season to keep them from fogging when you look through them?
The reason they fog is that your body heats them up and then you bring them out into the cold. If you used a handwarmer, same thing.
Quote from: pianoman9701 on August 07, 2017, 12:44:42 PMThe reason they fog is that your body heats them up and then you bring them out into the cold. If you used a handwarmer, same thing. You've got this backward. Cool surfaces, not warm ones, fog in damp environments. That's why your back window has a heating element on it, and you de-fog your windshield by blowing warm air on it. Binoculars fog because the environment near your body (especially your face) is always damp. When that damp, warm(er) air comes in contact with the cool glass of your bino lenses, the warm air cools below the dew point and the moisture condenses onto the lens, i.e., you get fog. No idea if handwarmers would prevent this or not, but it's certainly true that warm lenses wouldn't fog as much.
I think that going either from hot to cold or cold to hot will fog binos and glasses. In NH, we kept our rifles outside at night so the glass wouldn't fog when we came out of the cabin in the AM.
It doesn't matter. When it's cold, they fog up without some kind of defogger. That work?