How to Prevent It Camera Lens Fog

How to Prevent It Camera Lens Fog
Shooting winter/snow scene, being outdoor on a chilly day for many hours. If you plan on doing outdoor photography the next day, think ahead. Put your camera and lens inside a large Zip Lock bag.Zip it tight and leave it in the trunk of your car (I would only do this if my car is parked in my garage and can be locked up of course). This will mean the lens should be at about the same temperature as the outside temperature when you pull it out to use the next morning. Also if you are stepping out of a warm car into the chilly air to take a snapshot when you are driving and your camera is coming right out of your backpack in the warm and toasty car, keep your camera close to your body inside your fleece jacket until you are ready to use it and do so quickly. Have a Zip Lock bag handy, put the camera in the Zip Lock bag and zip it tight before you get back into the car.

If you wipe a cloth with a couple of drops of citrus juice or acid from the peel, it will keep the lens from fogging. It's a scuba trick to keep the mask from fogging. Spit works too, but it's a bit gross.
They make a anti fog for diving masks, and sell it at dive shops. I think that it is just dilute citric acid.
If you don't want to put anything on the lens, use it on a UV filter.
You could try heating the camera a little before going to the pool area. If it has been in A/C, it will be cooler than the air at the pool, and will condense moisture.