This is not the typical what am I doing wrong question but I have a Sigma 600mm mirror lens with a problem. The black paint on entire surface of the body is sticky. It feels like the paint is wet and if I hold the lens I leave finger prints in the paint, the lens functions properly. Has anyone encountered this problem and what can be done to fix it. All my lenses are in a dry climate controled place and non of the other lenses are having this problem.