I've come to the conclusion that it's pretty much impossible to keep them away forever. My method is to spray around the camera thoroughly with Home Defense spray. I'm sure there are many other brands, but this has more or less worked for me. Forget the 3 month coverage that they promise on the container. Use it often and liberally...
I've read that applying a strong scented essential oil around the camera can be quite effective and acts as a harmless deterrent rather than a toxic poison.
I plan to try this in the next few days by putting some peppermint oil (apparently spiders really don't like that one) on to a small cloth which I will then attach to the camera.