Hello all, Just acquired this lens and apart from a tiny amount of fungus behind the fornt element (anyone know if it's easy to remove the element?) I have a big problem with the focusing mechanism. The ring moves way past infinity and fails to let the lens focus to its stated minimum distance. Does someone know whether this is a DIY job to correct or am I looking at a professional repair? And with fungus present, I understand some repairers won't accept such lenses... Thanks for any advice.