Cannot update the Lightroom Filter for 'Lens' for Samyang 8mm

[David Eagle]

Hi, am using Exiftool via Lenstagger to attempt to update the Exif data for my brand new Samyang 8mm fisheye.
I can get all the details changed with the exception of the 'Lens' tag that Lightroom uses to filter lenses on.

So instead of getting anything related to the 8mm lens, I get "21mm".

Commands are as follows:
/usr/local/bin/exiftool  -Lens="Samyang 8mm f/2.8 UMC Fisheye II" -LensModel="Samyang 8mm f/2.8 UMC Fisheye II" -LensType="Samyang 8mm f/2.8 UMC Fisheye II" -FocalLength="8" -MaxApertureValue="2.8" -FocalLengthIn35mmFormat="12" -m -overwrite_original_in_place -P "-UserComment<LensTaggerVer:1.7.6" -Keywords+="LensTagger" "/Volumes/EX2_Pictures/My Pictures/2017/2017-12/2017-12-25 - Christmas Fisheye/XT1S5237.RAF" -v0 > /tmp/excmd

Looking at the Lightroom XMP file in TextEdit, there is an aux: tag which carries the 21mm, edit that to 8mm and then (for some reason) the full Samyang description appears.... is there anyway to avoid manually having to do this every time?

All help appreciated

[Phil Harvey]

All of the XMP aux tags should be writable by ExifTool.

- Phil

[David Eagle]

Hi, thanks for the swift reply, have done some more digging....

The Lenstagger/ExifTool script line references the following tags
exif:FocalLength
exif:Focallengthin35mmFormat
aux:Lens

Looking at the metadata tags as displayed in Lightroom, 'Lens' is NOT updated, and looking at the XMP file, the following tags do not seem to be getting updated, aux: LensInfo; aux: Lens

Checking in Mac Photos, the lens model IS picked up from the image file, so obviously is getting updated.

Its evident that not all the metadata tags are written to the XMP files by Lightroom, even when 'write metadata to file' is executed, so my assumption is that Lenstagger/ExifTool may update the aux tags in the image file (but not the XMP file), and Lightroom is not transcribing/reading those values to/from the XMP file when write metadata to file is selected.

So....using the Lenstagger/Exiftool option to write to the XMP file, the details ARE updated in lightroom, but the XMP file is rather bloated, however
aux:Lens  IS updated
aux:Lensinfo is NOT updated

In short,  this fixes the Lightroom display/filtering problem, but it would be nice if the XMP file didnt get bloated

I note that the Lenstagger screen shows 'Write to XMP sidecar' as 'Experimental', are there any other risks associated with this option?

[Phil Harvey]

In short,  this fixes the Lightroom display/filtering problem, but it would be nice if the XMP file didnt get bloated

Bloated how?  By what?

I note that the Lenstagger screen shows 'Write to XMP sidecar' as 'Experimental', are there any other risks associated with this option?

You'd have to ask the LensTagger people about this.

- Phil

[David Eagle]

Apologies for the lack of an explanation, its the XML tags.
In the XMP update version each individual element has its own start/end tag, whereas in the non-XMP update (i.e. the option where the changes are written to the RAW file), there is a more of a nested construct used. I have attached a couple of files, XT1S5226 which is the Lightroom XMP sidecar which has had the changes written to the image file, and XT1S5277 which is the XMP sidecar file that has had the changes written into the XMP ( and which is the one that gets the changes visible in the Lightroom filter settings).

Again, apologies if I have inadvertently caused offence, and I'll post the 'experiment' question to the Lentagger folks.

Many thanks.

[Phil Harvey]

OK.  Yes.  Adobe has moved to using the short form of XMP.  ExifTool has always used the long form.  No way around that currently I'm afraid.

- Phil

[David Eagle]

OK, many thanks for persevering with this thread! I have a way forward that works for me, so happy chap.

Thanks again

Dave Eagle

[Phil Harvey]

When released, ExifTool 10.76 will write the short-form XMP when the -z option is used.

- Phil