Until "XMP Specification Part 2 - Additional Properties" revision of 2008, aux:Lens, aux:SerialNumber existed in the aux namespace, see the following excerpt:
Possibly they may have been replaced by exifEX:LensModel and exifEX:LensSerialNumber in CIPA DC-010-2012 (the separated document specifying all of the Exif properties since XMP Specification Part 2 of 2016), however this is not documented either in the current specification pdf document or the Markdown rendition.
I believe the two properties should be either fully reinstated in "XMP Specification Part 2" or reinstated as deprecated.
This issue has been first created in the pdf-issues repository but moved to this one after the PDF TWG discussion.
Until "XMP Specification Part 2 - Additional Properties" revision of 2008,
aux:Lens,aux:SerialNumberexisted in theauxnamespace, see the following excerpt:Possibly they may have been replaced by
exifEX:LensModelandexifEX:LensSerialNumberin CIPA DC-010-2012 (the separated document specifying all of the Exif properties since XMP Specification Part 2 of 2016), however this is not documented either in the current specification pdf document or the Markdown rendition.I believe the two properties should be either fully reinstated in "XMP Specification Part 2" or reinstated as deprecated.
This issue has been first created in the pdf-issues repository but moved to this one after the PDF TWG discussion.