EOS cameras number files sequentially from 1 to 9999. Some photographers use the file number as a record of how many shutter operations they have made, other more prolific ones need to take care of the number every week!
With the advent of high capacity storage cards it is possible for a camera to store more than 9999 pictures on a single card. The camera neatly avoids a file name confusion by creating a new folder on the storage card when IMG_9999.JPG or IMG_9999.CR2 is saved.
I’m getting duplicate file names from my cameras!
I have a 50D and a 5D Mark II. Both are numbering the same on the CF cards so when I go to download it asks if I want to replace the new files I just downloaded from the previous camera’s card.
I attempted to use the “manual” numbering on the camera but it will not allow me to use it?
I recently received themessage above from one of the site visitors asking about file numbering. Specifically they asked why their cameras seemed to be often creating duplicating file numbers as it was causing them problems with downloading pictures to their computer. I have already replied and they were most thankful, but it’s worth a blog post here too.
EOS camera file numbering explained
EOS cameras keep a track of the file numbers in their internal memory. This number is one more than the last numbered file the camera created. If the camera just wrote IMG_0108.CR2 then the number stored by the camera is 0109.hold this thought in your memory a second or two
EOS file numbering options, (grabbed from EOS 7D Mark II)
EOS cameras have three settings for file numbering;continuous, auto reset and manual reset
Continuous – the default
If a card is inserted and it already has files on it that are numbered higher than the camera’s memorised count then the camera will update it’s internal count to be one greater than the highest numbered file on a card. However if the card is blank or the highest numbered file is less than the camera’s internal count then the next file will be based on the camera internal count.
For example if you put a card with IMG_3451.JPG in to then the camera counter is moved to 3452, unless the camera internal count was already greater than 3452.
Auto reset
In this case the camera counter is reset automatically to the lowest number of the camera or the card. So if you format a card in the camera the camera will start counting from 1 again. Put another blank card in the camera or format it and the number starts from 1. If the card has files on it, then the camera resets it’s count to be one more than the lowest number of the files on the card.
Manual reset
If this option is chosen the camera internal count is either set to 1 if no card or a blank card is in the camera, or reset to 1 more than the highest numbered file on the card. Once the reset is completed the camera will return to the last used of Continuous or auto reset automatically.
Solution for photographer with two cameras…
In the specific case of the photographer with two cameras, then the best approach is as follows…
- Manual reset both cameras with formatted cards in them. This will reset each camera counter to 0001.
- Then take a picture with one camera to create the IMG_0001.JPG file
- Put this card in the computer and rename the file to IMG_5000.JPG
- Then return the card to the camera and it will update it’s internal counter to 5001
But and there’s a BIG BUT, if you mix the cards form the cameras up then you will mess up the system.
It is for this reason that I suggest that when you import the pictures to your computer you do so in a structured way that automatically renames the files to prevent duplicate filenames. You can use EOS Utility, Lightroom, Photo Mechanic or many other software tools to manage the renumbering on import.
Personally my files get the two digit year, two digit month pre-pended to the original filename and then a sequential 5 digit number added to the end.
So IMG_0001.JPG would become 1512IMG_0001_19345.JPG and later on the next card would be 1512IMG_0001_20101.JPG so it’s unique.
