A quick search turned up a C# free (downloadable, source code available) MakerNote reader for Canon: [
^]. My first impression, from a quick scan of the code, is that writing a parser is not trivial.
As you may know, that tag is reserved for manufacturers, and its format is left up to the camera manufacturer; the link you provide has no information about that tag:
TIFF Tag MakerNote
IFD Exif
Code 37500 (hex 0x927C)
Name MakerNote
Type UNDEFINED
Count N
Default None
Description
Manufacturer specific information.
A tag for manufacturers of Exif writers to record any desired information. The contents are up to the manufacturer, but this tag should not be used for any other than its intended purpose.
You can find information on Canon's MakerNote format here:[
^], and here: [
^].
Note this caution on manipulating Exif information in TIFF format: [
^
"Most vendors write the makernote in TIFF format, i.e., in the same format as the rest of the Exif information is encoded. This appears to be a sensible thing at first glance. Unfortunately, in general it means that any change of an Exif tag, which moves the makernote field, will corrupt it. It is an inherent problem of the TIFF format that a writer must know the format and all extensions used, in order to be able to write changes correctly; unknown tags are potentially corrupted when they are moved (rearranged). But since makernotes are usually proprietary, Exif writers often don't know these details. The reason to write to the Exif data could be as simple as to add copyright information, an Exif comment, etc. Some camera manufacturers seem to have recognized this problem and now use a modified TIFF format with offsets relative to somewhere at the beginning of the makernote field for the makernote IFD to address the issue."