> Specifically,I carry my FA,FE-2 and lens in a Haliburton case. My van(no > trunk) has AC, I stayed in an AC motel. My camera case is either with me > in the car on in the room at all times. Of course, the humidity is high > on the coast. When ever I took one of the cameras out of the case and > attempted to take a picture, my lens would instantly fog and put me out > of business for at least five minutes. Jim, 1) We measure the moisture content of air is by relative humidity. When we say it is 80% humid, it means the air contains 80% of the moisture it can possibly hold. 100% humidy is fully saturated air. Beyond that, the extra moisture comes out of the air in the form of rain, fog or condensation. 2) Warm air can hold more moisture than cold air. This means that air at 30 deg C and 80% humidity holds more moisture than air at 20 deg C and 80% humidity. When we put 1) and 2) together we see that when warm air is cooled (such as coast air coming in contact with your cool air-conditioned camera), the relative humidity increases. If the air cools to the point where humidity reaches 100%, condensation forms. Fogging can happen any time you move the camera from a cool place to a warm place. Another common situaton is when you are shooting in cold conditions and take the camera inside to a warm room. To stop your camera from fogging up, you need to bring it up to the outside air temperature before exposing it to the himid air. You can do this by placing the camera in an air-tight plastic bag when you go out. After a few minutes, when the camera has warmed up to air temperature, you can take it out of the bag without fear of it fogging up. Roland.
