ExifTool Forum

ExifTool => The "exiftool" Application => Topic started by: linuxuser on December 11, 2017, 02:10:30 PM

Title: Scale Factor To 35 mm Equivalent
Post by: linuxuser on December 11, 2017, 02:10:30 PM
With a Pentax K-1 you can deside if you use fullformat or APS-C.

There is a composite value:

APS-C:
[EXIF]          0xc61e Default Scale                   : 1 1
[Composite]          - Scale Factor To 35 mm Equivalent: 1.5

FF:
[EXIF]          0xc61e Default Scale                   : 1 1
[Composite]          - Scale Factor To 35 mm Equivalent: 1.0

How is this "Scale Factor To 35 mm Equivalent" calculated? By some metadata? Is there an EXIF or XMP-field where this info can be written, except comment or similar text fields.

Title: Re: Scale Factor To 35 mm Equivalent
Post by: linuxuser on December 11, 2017, 02:23:54 PM
What does this field mean:

[EXIF]          0x00fe Subfile Type                    : Reduced-resolution image

It says with fullformat also reduced.
Title: Re: Scale Factor To 35 mm Equivalent
Post by: Phil Harvey on December 11, 2017, 09:27:06 PM
The Composite tags and the tags they are derived from are listed here (https://exiftool.org/TagNames/Composite.html).  ScaleFactor35efl is particularly complex, but the simplest way to set this is to write both FocalLength and FocalLengthIn35mmFormat.

The SubfileType gives the type of image in the given IFD.  Use -G1 to see which IFD.

- Phil
Title: Re: Scale Factor To 35 mm Equivalent
Post by: linuxuser on December 12, 2017, 03:24:51 PM
Thanks, I am testing, where I can write a crop-factor (the composite value) so that f-stop can read it. Any idea for a field? I assume an EXIF-tag could work, which I would try first before xmp.
Title: Re: Scale Factor To 35 mm Equivalent
Post by: linuxuser on December 12, 2017, 07:47:09 PM
I found something, -EXIF:CameraLabel is displayed as unknown tag and -XMP:Label works fine with f-spot.