I have several Canon cameras, two with CHDK, two without, and they all use the same naming convention for files - IMG_####. Unfortunately, all 4 cameras are used pretty equally, so the file names are very close in range. Is there anyway using CHDK that I can change the default image filename prefix to something other than IMG? For example, CM1_#### for camera 1, CM2_#### for camera 2, etc? The two I use with CHDK are identical models, and other than having duplicate file names when compiling projects, this would also let me know exactly which of the cameras the image came from.
I'm aware that I can change the naming options from continuous to Auto Reset, but that would just guarantee that all my images are within 100 or so of each other the file names. Right now, they vary by as much as 1 to several hundred depending on the week.
Is this option already available and I missed it?
Cameras running CHDK are A720IS.