Went on a journey trying to figure out what valid exif tag types are, in both JPEG and TIFF files. In summary:
| TYPE # | Name | Exif 2.32 | Tiff 6.0 | Adobe TN[1] |
|---|---|---|---|---|
| 1 | BYTE | X |
X | |
| 2 | ASCII | X | X | |
| 3 | SHORT | X | X | |
| 4 | LONG |
X | X | |
| 5 | RATIONAL | X | X | |
| 6 | SBYTE | X |
||
| 7 | UNDEFINED | X | X | |
| 8 | SSHORT | X | ||
| 9 | SLONG | X | X | |
| 10 | SRATIONAL | X | X | |
| 11 | FLOAT | X | ||
| 12 | DOUBLE | X | ||
| 13 | IFD | X |
The last 3 columns indicate where the tag type is specified. e.g. Type #9-SLONG, is documented in both Exif 2.32 and Tiff 6.0, whereas type #11-FLOAT is only defined in Tiff 6.0.
[1] Adobe TN refers to "Adobe PageMaker® 6.0 TIFF Technical Notes".