Such a symptom may occur because alkaline battery has a charactristic that reduces the capacity sharply during use.
DiMAGE 7 is designed to have a margin before itself shuts down even if the battery is exhausted while saving the capture image data to a CompactFlash. The data will not be lost.
Becauase it consumes more power than other CompactFlash cards for operation and data storage, users of IBM Microdrive must use Nickel Halide cells.