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[tmodes <2064625@xxxxxxxxxxxxxxxxxx>]

> Is it safe to assume the Focal Length in 35mm already incorporates the
digital zoom factor correction?

No, as already written the EXIF standard says clearly: Digital zoom
ratio is not taken into account.

Just your examples and the files in the mentioned other bug report (Samsung phone):
exiftool -make -model -focallength* -digitalzoom* -e -ext jpg .
======== ./IMG_7964.JPG (non zoomed)
Make                            : Apple
Camera Model Name               : iPhone SE (3rd generation)
Focal Length                    : 4.0 mm
Focal Length In 35mm Format     : 28 mm


======== ./IMG_8093.JPG (zoomed)
Make                            : Apple
Camera Model Name               : iPhone SE (3rd generation)
Focal Length                    : 4.0 mm
Focal Length In 35mm Format     : 55 mm
Digital Zoom Ratio              : 1.950967742

======== ./PXL_20221219_230755050.jpg (non zoomed)
Make                            : samsung
Camera Model Name               : SM-A528B (a52sxq)
Focal Length                    : 5.2 mm
Focal Length In 35mm Format     : 39 mm
Digital Zoom Ratio              : 0

======== ./PXL_20221219_230800590.jpg (zoomed)
Make                            : samsung
Camera Model Name               : SM-A528B (a52sxq)
Focal Length                    : 5.2 mm
Focal Length In 35mm Format     : 39 mm
Digital Zoom Ratio              : 2.55

So the Samsung test images matches the EXIF standard, but the Apple
iPhone images don't follow the standard. And I don't know which models
are affected and which one not. This would mean to maintain a list of
phones which don't follow the standard (and this may change with each
software update).

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https://bugs.launchpad.net/bugs/2064625

Title:
  35mm focal length on iPhone SE3 2nd generation over corrercted

Status in Hugin:
  Incomplete

Bug description:
  This is for an iPhone SE 3rd generation. Looking at the exif data for
  a zoomed picture I can see:

  Lens Specification  |3.990000, 3.990000, 1.8, 1.8
  Lens Make           |Apple
  Lens Model          |iPhone SE (3rd generation) back camera 3.99mm f/1.8
  Digital Zoom Ratio  |1.951
  Focal Length in 35mm|55

  For a normal picture:

  Focal Length in 35mm|28
  Scene Capture Type  |Standard
  Lens Specification  |3.990000, 3.990000, 1.8, 1.8
  Lens Make           |Apple
  Lens Model          |iPhone SE (3rd generation) back camera 3.99mm f/1.8

  Turns out the reported focal length for a zoomed picture is already
  corrected for the digital zoom factor so
  src/hugin_base/panodata/SrcPanoImage.cpp:542 over corrects by
  multiplying again with the digital zoom factor ending up with an hFOV
  too small. I just commented out line 542 and now when I add the zoomed
  picture I get an hFOV of 34.9 (which is what I would expect) instead
  of 18.3 (wrong).

  --- a/src/hugin_base/panodata/SrcPanoImage.cpp  Wed May 01 19:41:11 2024 +0200
  +++ b/src/hugin_base/panodata/SrcPanoImage.cpp  Thu May 02 15:18:02 2024 +0200
  @@ -539,7 +539,7 @@
       const float digitalZoom = Exiv2Helper::getExiv2ValueDouble(exifData, "Exif.Photo.DigitalZoomRatio");
       if (eFocalLength35 > 0 && digitalZoom > 1)
       {
  -        eFocalLength35 *= digitalZoom;
  +    //    eFocalLength35 *= digitalZoom;
       };
       float focalLength=0;
       //The various methods to detmine crop factor

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