Shooting in the Arctic zone requires both the photographer and his equipment to be protected from the cold and the wind. A temperature of -35.6°F (-2°C) with a 9.3mi/h (15km/h) wind is equivalent to a cold of -44.6°F (-7°C), this is called the 'wind chill factor'. If the wind does not lower the temperature, it accelerates the cooling of bodies and objects, hence the need for a last layer of windproof clothing for the men and appropriate protections for the equipment.