When you edit the properties of a photo to add metadata in Windows Vista or Windows XP, the third-party software that is included with the digital camera may no longer recognize some proprietary metadata that the digital camera automatically adds to the photo. This metadata is specific to the manufacturer of the camera.
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This issue occurs because some camera manufacturers include an EXIF Maker Note tag in an image.
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If you use a third-party program that reads Maker Note tags, and it is important that you can access the tags, do not use the Photo Acquisition Wizard to download the photos to the hard disk. Also, do not use Windows Photo Gallery, Windows Live Photo Gallery or Windows Explorer to edit the properties of the image. These properties include the following:
| • | Title |
| • | Subject |
| • | Rating |
| • | Tags |
| • | Comments |
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The Maker Note tag contains information that is not included in the standard EXIF specification, such as proprietary camera setting information.
Neithere Windows Vista nor Windows XP directly reads the Maker Note tag information. The data structure for the Maker Note tag is proprietary. The data structure for the Maker Note tag is different for manufacturers. The Maker Note tag typically contains absolute references to other data within the image stream.
When the metadata in an image is changed, for example, by adding keywords or captions, the Maker Note tag may be relocated in the image stream. In the past, this would cause the Maker Note tag to become damaged. However, the Windows Imaging Component (WIC) that is used by Windows Vista or Windows XP keeps track of the number of bytes that the Maker Note tag has been moved. Windows Vista and Windows XP write this information to a public offset tag. Programs that can read the public offset tag can recover most of the Maker Note tag information.
Microsoft is currently working to inform hardware developers and software developers about this new feature. Microsoft is working to encourage hardware developers and software developers to update their tools. Programs must also be updated to adjust for the offset. Therefore, existing programs that read Maker Note tags cannot read the Maker Note tag information in files that are edited by Windows Vista Photo Gallery or Windows Live Photo Gallery.
For more information about the software for a digital camera, contact the manufacturer of the digital camera.
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More information for software developers
When the Maker Note tag is relocated by Windows Vista or Windows XP, the EXIF Maker Note tag (37500) is automatically updated to reference the new location. Also, Windows Vista and Windows XP record the offset between the old location and the new location in the EXIF OffsetSchema tag (59933). If the Maker Note tag contains relative references, the developer can add the value in the OffsetSchema tag to the original references to find the correct information.
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