User Setting - Canon EOS 5Ds Instruction Manual

3 Changing the File Name
The first character cannot be an underscore "_".

User setting2

When you select the "*** + image size" registered with User setting2 and
take pictures, the image-recording quality character will be automatically
appended as the file name's fourth character from the left. The meaning of
the image-recording quality characters is as follows:
"***L" = 73 / 83 / 1
"***N" = 75 / 85
"***T" = b
When the image is transferred to a computer, the automatically appended
fourth character will be included. You can then see the image size without
having to open the image. RAW or JPEG images can be distinguished with
the extension.
The extension will be ".JPG" for JPEG images, ".CR2" for RAW images,
and ".MOV" for movies.
When you shoot a movie with User setting2, the file name's fourth
character will be an underscore "_".
198
"***M" = 7 / 8
K
"***S" = 7a / 8a / 61
"***U" = c
/
1
K 4