I'll soon be converting hundreds of rolls of film to digital scans. I'll be dealing with minor sharpening for the scans but I notice I also have some excellent images taken at night of parades and stage shows where the lens was slightly out of focus. So the question is, where can I learn sharpening techniques in detail so I know what to use where, and also, do specialist sharpening plug-ins do a better job? Anyone one use these extensively?