1. A system for converting a film camera into a digital camera, comprising: an image sensing array; a read-out circuit coupled to the image sensing array; a memory coupled to the read-out circuit for storing a digital picture derived from an image read-out from the image sensing array; an audio sensor for detecting sounds within the camera; an acoustic pattern recognizer that compares signals received from said audio sensor to determine if the signals correspond with acoustic patterns associated with shutter operation, said acoustic pattern recognizer having a training mode that can be used to develop a set of acoustic patterns associated with shutter operation based on signals from said audio sensor during said training mode; and an image processor associated with said image sensing array and said read-out circuit, said image processor being operable to end an image capturing process, wherein said image sensing array has a low power listening mode and an image capture mode and is configured to switch from said listening mode into said image capture mode when the pattern recognizer recognizes an acoustic pattern associated with shutter operation.