Why does LR Classic not set Exif orientation tag, even removes it?

[Miwist2]

I've taken photos with a Fujifilm X-T3 camera using its raw format RAF, both landscape and portrait orientation. Checking the Exif metadata of the RAF files I see Orientation tags showing the correct orientation.

Then I import the RAF files into LR Classic, add my rights metadata and export them as JPEG files. What a surprise: the Exif metadata of JPEG have have no Orientation tag at all.

The technical problem is that Exif defines a default orientation for each image, it applies even if there is no Orientation tag: it is the landscape orientation of the image sensor in the camera. But this is wrong for the portrait shots and such shots may not be shown correctly.

[Lumigraphics]

Are you stripping the XMP metadata on export?

[Miwist2]

No I don't strip any metadata.

And: the Exif Orientation Tag does not reside in the XMP packet but in the Exif metadata header.

[johnrellis · Accepted solution]

"Then I import the RAF files into LR Classic, add my rights metadata and export them as JPEG files. What a surprise: the Exif metadata of JPEG have have no Orientation tag at all."

In normal operation, when LR exports a JPEG, it rotates the original photos' pixels stored in the JPEG to match the current orientation as displayed in LR, omitting the Orientation tag from the JPEG (which defaults to value 1).

For example, consider an original photo taken with the camera rotated counter-clockwise 90 degreees. The camera records the pixels from the sensor in landscape mode and includes EXIF Orientation = 8. When the photo is imported into LR, it is displayed rotated counter-clockwise 90 degrees. When LR exports that image as a JPEG, it rotates the pixels in the JPEG to match what is displayed visually, and it omits Orientation (which defaults to 1).

When you open the exported JPEG in an external viewer, it should appear rotated just as it was shown in LR at the time of export.

If your exported JPEGs as viewed in an external viewer don't match how the raw originals are displayed in LR, that is a bug (either in the viewer or LR) that we should investigate.

"The technical problem is that Exif defines a default orientation for each image, it applies even if there is no Orientation tag: it is the landscape orientation of the image sensor in the camera."

This isn't quite right. The EXIF Orientation tag merely specifies how the rows and columns of pixels stored in the JPEG should be displayed visually. For example, the standard says that with Orientation = 1, "The 0th row is at the visual top of the image, and the 0th column is the visual left-hand side."  And with Orientation = 8, "The 0th row is the visual left-hand side of the image, and the 0th colum is the visual bottom.".

Nothing in the standard requires that Orientation = 1 corresponds to the camera sensor in landscape mode.  Most cameras do that (all that I know of), but nothing in the standard prevents a conforming camera from rotating the pixels stored in the raw or JPEG to match the orientation of the camera at the time of capture, recording Orientation = 1 in the EXIF (or, equivalently, omitting Orientation).

See the Exif 2.32 spec for details.

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[Miwist2]

This explanation makes sense, I'm familiar with the Exif standard (also available on the official CIPA site). A wide assumption of the workflow of an image is: it is taken by the sensor of a camera in the landscape mode, after that it stays stable, rotations for the viewer's eye are done by the Orientation tag.

As I didn't find a documentation or a hint that LR really reorganizes the rows and columns of pixels when exporting an image I was following this basic assumption.