When a picture is taken, the camera names the file by adding one to the last file number used. This option controls whether file numbering continues from the last number used when a new folder is created, the memory card is formatted, or a new memory card is inserted in the camera.

Option Description
On File numbering continues from the last number used. This simplifies file management by minimizing the occurrence of duplicate file names.
Off File numbering restarts from 0001 or from the largest file number in the current folder (if you turn sequential file numbering off and then on again, file numbering will resume from the last number used).
Reset As for On, except that the next picture taken after Reset is selected is assigned a file number by adding one to the largest file number in the current folder. If the folder is empty, file numbering is reset to 0001.

File Number Sequence

If a picture is taken when the current folder contains 5000 pictures or a picture numbered 9999, a new folder will be created and file numbering will restart from 0001. The new folder is assigned a number one higher than current folder number or, if a folder with that number already exists, the lowest available folder number. If the current folder is numbered 999, the camera will not be able to create a new folder and the shutter release will be disabled (in addition, movie recording may be disabled if the camera calculates that the number of files needed to record a movie of the maximum length would result in the folder containing over 5000 files or a file with a number over 9999). To resume shooting, choose Reset for Custom Setting d6 (File number sequence) and then either format the current memory card or insert a new memory card.