Hi, I am experiencing a problem with my FX-3 Super 2000. I cannot seem to get stuff in focus, especially at large apertures (1.4-4). My subject is always out of focus. I am very sure this is not user error, or slow shutter speeds that cause it not to be sharp. The minimum shutter speed i use 125. I've read in another forum that these cameras tend to have their mirror become loose, how do I fix this?