2002.03.11 02:07 "Re: reading EXIF data from a TIFF", by Chris Losinger
i've written a parser that works on the EXIF data in JPEG_APP1 markers from JPG files, and i'm hoping i can use it to parse the data in TIFF files. bt, i can't find out where or how to get the EXIF data block out of a TIFF.
You're probably looking at it the wrong way 'round. EXIF's JPEG marker contains a mini-TIFF file, which I'd always supposed meant that they thought the world revolves around TIFF ;-) More than likely, the equivalent info appears as TIFF tags interspersed with the regular TIFF tags when you look at an EXIF-compliant TIFF. In other words, point your EXIF parser at the whole darn TIFF file...
I tried this - sortof.
i tried to read one of the EXIF tags from a TIFF that is purported to have EXIF info. LibTiff doesn't show anything but the usual stuff in TIFFPrintDirectory, and TIFFGetField failed when i tried reading the tag with the ID number of a specific EXIF tag (0x8822 - exposure program).
any other ideas?