How to renumber files on a CF card (Canon)

Every now and then strange things can happen with the numbering of image filenames on media cards. (This can particularly happen if you move cards between two cameras.) I first ran across this when I sent a camera in for repair and it came back with a sequence number thousands higher than when I had sent it in!

After some searching, I ran across the following procedure for resetting things.

Assumes you have a computer card reader.

1. Set the camera to numbering auto reset
2. Format card in camera
3. Take photo should be IMG_0001 (100-0001)
4. Set camera to continuous numbering
5. Switch off camera
6. Remove CF card from camera and into card reader. In computer rename the folder 100CANON to 104CANON and rename the files to IMG_0472.CR2 (or jpg) or whatever the current number of shots taken should be. Note folder number should match image number. 104 = 401-500 105= 501-600 etc.
7. Place CF card back in camera and take a shot, number should be the next one you want in this case IMG_0473 (104-0473).

Jan (Vasek)
26 Sept 2004

dpf
October 21, 2007

Other dpf notes (May 2017):

• Just use a four-digit file number. (E.g., if file number is 12345 or 22345 just use 2345.)
• Take that number and do DIV 100 on it (E.g., 2345 becomes "23").
• Then add that number to 100 to get the folder number (E.g., 23 + 100 = 123, so "123CANON")
• The exception is shot "00", so 2300 is part of 122CANON, not 123CANON.
  (The mnemonic to remember this is that the first shot ever is 0001, not 0000.
• So rename the folder to "123CANON" and the single test image to IMG_2342.CR2 (or whatever, giving a few numbers below where you want to end up, as advised above).