I've attached a file which I downloaded today. I was not surprised that it had little Exif data recorded, but I was surprised when the EXIF_FocalLengthIn35mmFilm reported the lens was 2147483647mm. I thought you might want to inspect and see how this happened and consider whether to error trap your code to prevent reporting such large numbers. My program gave a range error which led me to discover this situation. I confirmed it with your EXIF demo program by adding the ability to report EXIF_FocalLengthIn35mmFilm.
EXIF_FocalLengthIn35mmFilm (exif tag 0xa405) should be a SHORT (16 bit unsigned integer) according to the TIFF specs, but this image stores the tag as RATIONAL (a floating point value).
We have updated ImageEn to truncate floating point values to integer, when an integer is expected but a rational is found.
So now IO.Params.EXIF_FocalLengthIn35mmFilm returns 3 for this image (truncated from 3.882).
Thanks for addressing this. Now if I only had time to install and use all of your recent updates! Apparently the 35mm focal length for this image is just plain wrong since 3mm would be quite a fish eye view.
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Possible error in EXIF_FocalLengthIn35mmFilm
Posted - Sep 29 2016 : 21:06:16
