I do not generally shoot portraits. The enclosed photograph was shot with a Df and the new 300mm f4 lens. studying various forums on photnet tells me that for portraits like this one I should focus on the eyes which I attempted to do. However, the nose and mouth seem to be out of focus. The photograph was taken at f4. Would I be correct in assuming that if I shot with a different f stop, the complete face may have been more sharp??