Why? It has to do with taking your gear from inside a dry air-conditioned place to a hot and humid environment. When this happens condensation builds up instantly and it cannot be removed UNTIL….
How do we fix this issue? There is pretty much one way to fix this problem. Your gear has to warm up to the ambient temperature before the condensation goes away. The best way that I have found is to take your gear bag with all the equipment and place it out side while still closed. In about 20 to 30min. you should be fine. This allows the temperature inside the bag to slowly rise to the ambient. Using this method will ensure that you can take shots when you are ready without the worry of condensation. However, this does take some additional planning (make sure to show up early!!).