Just from yesterday I've start getting a message on my 50D that my 24-105 lens and camera's conection must be clean. I've done it on the camera and lens, test other lenses on the camera and found that the problem is with my lens. Cleaned the connections again but still the same error message. When turning on the camera the lens try to get focus by itself -with out me puching the shutter button- and cannot focus as well. Then the error message. Any advice please let me know. Oh yes, I'm in South Africa and the nearest Canon service centre is about an hours drive from my town. With thanks.