removed photos from DSLR and moved back - Canon DSLR can't recognize photos

haring

I have removed card/RAW photos from Canon DSLR, renamed photos and without changing them moved back to card and inserted camera. Canon DSLR can't recognize photos...It can't play them. Why? Anybody can explain this? Thanks!

ziggy53

@haring said:
I have removed card/RAW photos from Canon DSLR, renamed photos and without changing them moved back to card and inserted camera. Canon DSLR can't recognize photos...It can't play them. Why? Anybody can explain this? Thanks!

Obviously, you did change them, at least enough to cause the camera to no longer recognize the files.

Please explain, in detail, your process for getting the files onto your computer, what you did to change the file name (software, operating system and process), and how you copied the files back to the card. Please be explicit and complete with your details and what you did.

Please provide an example file name that you used.

Please also explain what you were trying to accomplish, i.e. why you decided to change the file names.

kdog

Canon cameras write and expect filenames on memory cards to conform to the following pattern. Anything else is ignored by the camera.

XXXXDDDD.ext

Where:
X = alphanumeric character or _
D = digit
ext = file extension, ie, CR2, JPG, MOV, etc

How do I know this? I just experimented with it. Doesn't seem to be documented anywhere.

ziggy53

@kdog said:
Canon cameras write and expect filenames on memory cards to conform to the following pattern. Anything else is ignored by the camera.

XXXXDDDD.ext

Where:
X = alphanumeric character or _
D = digit
ext = file extension, ie, CR2, JPG, MOV, etc

How do I know this? I just experimented with it. Doesn't seem to be documented anywhere.

Yes, this is a potential issue. Just the naming structure itself, as well as overall name length.

---

Additionally the file needs to contain certain header information and closing information, and sometimes even the byte-count can matter (depending upon what file type the camera expects.)

---

Bottom line is that the original *.CR2 (or CRW for older Canon cameras) really needs not to be tampered with in order to maintain full camera body compatibility.

---

First, remember that all digital camera manufacturers use the DCF (Design Rule for Camera Filing Systems) standard, which includes a root directory/folder "DCIM", and then sub-directories/sub-folders with the form: 3-number prefix from 100 to 999, followed by a 5-digit alphanumeric. If you format the card in the camera first, that should at least produce the necessary basic directory/folder structure.

For anyone who wishes to create a flash memory card of image samples, I recommend going through a normal post-processing session first, culminating with high-resolution JPG file output. Make sure that any files to run on the camera contain similar to the specifications here: sRGB, filename prefix "IMG_" followed by a 4 digit number. This should conform with the widest number of Canon cameras, both older and newer, and both entry-level bodies through professional bodies. Be sure that EXIF information is omitted for greatest compatibility.

To make this easy I use IrfanView (Windows freeware), which has a simple method both for file renaming plus an ability to eliminate all of the makernote data, inclusive of EXIF.

---

For more Canon specific information about this I recommend the following pages:

http://www.learn.usa.canon.com/resources/blogs/2014/20140708_winston_filenames_blog.shtml

http://cpn.canon-europe.com/content/education/infobank/storage_and_archiving/file_numbering_and_naming.do
http://cpn.canon-europe.com/content/education/infobank/storage_and_archiving/file_numbering_and_naming.do?page=2