I have just purchased a second hand Fuji x100s after reading so many excellent reviews. I have noticed that I seem to be missing focus from time to time. I presume it's me and not the camera. I have, however, read that there are software updates for this camera. Can anyone advise how I find out which version of software I have in the camera and how I go about updating it if necessary. Also is there any advice from users on the best way to get good focus. Any help appreciated.