rwbowman Posted September 30, 2004 Share Posted September 30, 2004 I'm using a Canon EOS 10D camera and Photoshop CS with the latest RAW plugin (2.3). In Photoshop's display of Camera Data (Exif) information, the item "Lens" is shown, and beside it the focal length of the lens used, for example, "28.0-70.0mm." Does anyone know the correct exif property name for this item, and its correct EXIF tag? (Note, I'm not referring to the exif items F-Stop, Aperture Value, or Max Aperture Value.) Many thanks! Link to comment Share on other sites More sharing options...
mark u Posted September 30, 2004 Share Posted September 30, 2004 Read all about it here: http://www.exif.org/Exif2-2.PDF Link to comment Share on other sites More sharing options...
rwbowman Posted October 1, 2004 Author Share Posted October 1, 2004 Mark, thanks for your response. I've read the EXIF specifications document, but I don't believe the information I'm seeking can be found there. Link to comment Share on other sites More sharing options...
malcolmdwyer Posted October 1, 2004 Share Posted October 1, 2004 If you have access to perl with Image::Info installed, you can try this: perl "-e" 'use Data::Dumper; use Image::Info qw(image_info); print Dumper(image_info(shift));' filename.jpg (Obviously, replace 'filename.jpg' with the appropriate filename). Image::Info grabs all the EXIF data out of the jpeg, and data dumper prints a list of all key:value pairs for you. You should be able to match up the value given by Photoshop with one of the keys. I don't have access to such a system right now, but if no one else gives an answer, I'll try it when I get home tonight where it should work, and I'll post again. (I've got the 10D, so I should be able to give you the exact key). Malcolm Link to comment Share on other sites More sharing options...
malcolmdwyer Posted October 1, 2004 Share Posted October 1, 2004 Well... There's no one tag in there identifying the lens... but I found these tags in a picture taken with the 17-40. 'Canon-ShortFocalLengthOfLensInFocalUnits' => 17, 'Canon-LongFocalLengthOfLensInFocalUnits' => 40, And then there's this one identifying how big a FocalUnit is... 'Canon-FocalUnitsPerMM' => 1, Hope this helps. Let me know if you want more info... I've got a script I use for my personal webpage photo gallery that extracts a bunch of these tags. Malcolm Link to comment Share on other sites More sharing options...
malcolmdwyer Posted October 1, 2004 Share Posted October 1, 2004 And for future reference to anyone coming across this thread... drop the double quotes around the -e in the command line I gave above. It should be: perl -e 'use Data::Dumper; use Image::Info qw(image_info); print Dumper(image_info(shift));' filename.jpg Malcolm Link to comment Share on other sites More sharing options...
rwbowman Posted October 2, 2004 Author Share Posted October 2, 2004 Malcolm, Thanks very much for your help. I've learned since my original posting that the two items you extracted "CanonShortFocalLengthOfLensInFocalUnits" and "CanonLongFocalLengthOfLensInFocalUnits" are "Canon MakerNote data in IFD format" a reference to which is here: http://www.burren.cx/david/canon.html Unfortunately, this doesn't get me any closer to extracting the data for my use, as I'm far from expert in understanding the world of metadata, perl, etc. If there were some way you could extract the tag without going to too much trouble, I'd be most grateful. Cheers and best regards, Rob Link to comment Share on other sites More sharing options...
mike_morgan1 Posted October 3, 2004 Share Posted October 3, 2004 Look for a program called exifer Link to comment Share on other sites More sharing options...
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