Are you taking about fog on the front element, or inside the lens?
If its the front element, you need to keep it dry. I like to use a chunk of cardboard (wrapped in plastic if need be) and hold it over the camera and lens for the shot; or the easier alternative of just shooing from some sort of shelter.
If it is in the lens, it is often the result of condensation as the lens cools to the ambient temperature. Give the lens time to cool off from the warmth of your camera bag/ car/ house before you start shooting. On cool nights it is a good idea to keep the camera bag in the trunk rather than the heated passenger compartment to speed up that process.
One other cause of fogging on long night shots is light seeping in the viewfinder. on long shots you need to cover it up before you hit the shutter. |
