Above: One of the tabbed menu screens on a Canon Rebel T2i / EOS 550D / Kiss X4 DSLR with “File numbering” highlighted and “Continuous” selected as the file numbering option. Photo (c) Andrew Darlow

Post by Andrew Darlow

(I’ve chosen the “Open Letter” approach for this article because I believe it’s an ideal way to publicly make a few recommendations to all camera manufacturers regarding simple but effective ways in which files can be named as they are written to a camera’s internal hard drive or removable media card.)

To All Manufacturers of Digital Cameras:

As many others have done for years, I’ve been renaming my digital camera files after downloading them to a computer. The primary reason for this is to avoid having files on my computer with exactly the same file names. Without going into all the potential problems related to having multiple files with the same file names, the main issue that arises is that it is much easier to accidentally overwrite files with the same names on a computer or network compared with having files with unique file names.

Currently, most digital cameras offer just two basic options: continuous file numbering, in which the camera names files sequentially from 0001 to 9999 (for example, IMG_9898.CR2, then IMG_9899.CR2), even if a card is formatted in the camera; and auto reset, in which the camera resets the file names to 0001 every time a card is formatted in the camera (and in some other cases, depending on the camera). An example of the first file name a camera might create when using the auto reset option is DSC_0001.JPG.

A number of cameras (generally higher-end DSLRs) allow you to set a custom 3 or 4 alpha-numeric prefix (for example, A6T_0001.NEF), which is a step in the right direction because it can reduce or avoid the need for file renaming. Examples of cameras with this functionality include the Nikon D200 and the Canon EOS 1D Mark III. The downside to this system is that you must constantly remember to change the prefix before 9999 images are shot (or each time a card is formatted if auto reset mode is chosen with a specific prefix).

Some cameras assign a random prefix each time a card is formatted, such as XTPFY_IMG_0001.JPG), which in some ways is better than the 3 or 4 character custom prefix because as long as the camera generates unique prefix characters, there should never be two files generated with the same file name. Other cameras assign a random but constant 4 character prefix, which solves the issue of multiple cameras owned by the same person having the same file names, but it does not solve the problem of having files with the same names once the first 9999 exposures are shot on any one camera.

Now that I’ve reviewed some of the digital camera file naming systems currently in use, I’d like to outline what I believe is a better alternative. I propose the following to all camera manufacturers, including manufacturers of video cameras, cell phones and smartphones so that renaming files will no longer be required in order to have unique camera file names:

The default file naming protocol should include the capture date in this format (YYYYMMDD), followed by a 4-digit number created sequentially from 0001 to 9999. For example, if I format a card in my camera and choose continuous file numbering, the first image on the card that I capture (if my camera is in JPEG mode, and if I take the photo on 9/13/2010) will be 20100913_0001.JPG. If I take the next photo on 9/14/2010, the file name will be 20100914_0002.JPG. It’s important to use continuous file numbering with this approach, or the system will not work when a new card is formatted on the same day as another card. This is the renaming procedure I currently use, and virtually all file renaming software currently provides this renaming functionality.

For all DSLRs (and potentially all other digital cameras), I recommend giving users the ability to designate one or two letters after the YYYYMMDD in case a photographer has multiple cameras, or if the photographer is part of a team of shooters who submits cards for post-processing on a computer that handles multiple photographers’ cards. As long as each camera has a unique letter or letters following the YYYYMMDD, this system will go one step further toward avoiding any duplicate file names (unless more than 26 cameras are involved!). An example of the file name in this case would be 20100913A_0001.JPG, or 20100913AD_0001.JPG.

Main benefits of this system:

1. The camera will always generate unique file names, avoiding the need to rename files after downloading to a computer or other device;

2. Users will immediately know the date on which their photos were shot just by looking at the file names; and

3. Files can quickly be backed up without having to be concerned about having multiple file backups with different file names. Many photographers currently back up their RAW files before changing the file names due to concerns about making any changes to RAW files prior to backing them up to one or multiple locations. Many photographers then back up the same files again, but with their new file names. In these cases, the potential savings in time and disk space are substantial.

Potential issues and suggestions to camera manufacturers related to this system:

1. The camera must have an internal clock that is working, set correctly, and able to be accessed by the camera. Virtually all digital cameras have internal clocks, and most cameras record EXIF data that includes the time and date of capture, so this should not be a problem for the vast majority of cameras;

2. If more than 9999 photos or video clips are taken on a single day, duplicate file names will result. Few people take more than 9999 photos or video clips on a single day, but it is still important to note this.

3. Certain countries use YYYYMMDD and others use YYYYDDMM for indicating a specific date. I recommended adding a menu option for either format. Other date formats are commonly used, but I recommend this one because it is compact, easy to read and allows for easy viewing when sorted by file name on a computer or other device. Many cameras already have the ability to choose a specific date and time format.

I am truly amazed at the many innovations that have taken place in the field of digital photography, and I hope that this open letter starts a conversation that leads to improvements in the area of file naming.


Andrew Darlow

Sponsored by PMA
– It’s not too early to mark your calendar because this is big. For the first time in the USA, the PMA tradeshow and conference will be open to the general public – September 6-11, 2011 in Las Vegas. See you there – http://bit.ly/9yaL2I