Added by Sergey Salnikov over 10 years ago
Hello.
As far as I know Canon cameras don't write tag Exif.Photo.FocalLengthIn35mmFilm. Is there another way to extract information about crop-factor or focal length in 35mm equivalent from Canon's EXIF?
For example, exiftool provides a tag called "Scale Factor To 35 mm Equivalent". However, I can't find something similar in exiv2.
I believe the Exiftool tag is a composite tag which it calculates from other tags. Exiv2 could of course also do that calculation but it has no mechanism for composite tags at present.