Private Tags/MakerNoteSafety

TIFF Tag MakerNoteSafety

Code50741 (hex 0xC635)


Used in IFD 0 of DNG files.

MakerNoteSafety lets the DNG reader know whether the EXIF MakerNote tag is safe to preserve along with the rest of the EXIF data.

A MakerNote is safe to preserve if it follows these rules:

- The MakerNote data must be self-contained. All offsets within the MakerNote must be offsets relative to the start of the MakerNote, and must not point to bytes outside the MakerNote. (This is actually a rule that applies to all TIFF data blocks, and is necessary to enable data relocation and thus TIFF editing and transcribing and such, without corrupting your data. It is explicitly mentioned here, seeing that some MakerNote tag writers violate this rule.)

- The MakerNote data must be byte-order independent. Moving the data to a file with a different byte order must not invalidate it.

- The MakerNote data must not contain any thumbnail images. Image editors may change the image, and any embedded thumbnails would become stale.

See also