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Im creating an app that uses "FocalLenIn35mmFilm" to calculate feild of view(FOV). unfortunately not all photographs contain this property in their meta data, the Motorola Nexus 6 is an example. The crop factor is missing too, which could be used multiply it by the focal length. Here is a screen shot of the data i have:

enter image description here

Any help would be greatly appreciated?

Many Thanks

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1 Answer 1

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The sensor (SONY IMX214) diagonal is 5.867 mm (~1/3").

crop factor = diagonal of the 35mm frame / diagonal of the sensor = 43.3 mm / 5.867 mm = 7.38
FocalLenIn35mmFilm = focal length * crop factor = 3.82 mm * 7.38 = 28mm
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  • \$\begingroup\$ While I agree this is correct, is there any way to work this information out solely from the metadata? \$\endgroup\$
    – Philip Kendall
    Jul 14, 2015 at 17:13
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    \$\begingroup\$ @Philip Kendall : I have not seen full metadata for this file (source, not through Picasa) - I have to have the source file to know. However for our own programs we keep sensor (size) database in case some necessary data is missing in metadata. \$\endgroup\$
    – Iliah Borg
    Jul 14, 2015 at 17:25
  • \$\begingroup\$ source file. so without knowing the image sensor information(not in metadata) theres no way to work out the FocalLenIn35mmFilm? \$\endgroup\$
    – edward
    Jul 14, 2015 at 17:43
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    \$\begingroup\$ @edward : Thank you, looked at the file - no useful data for calculation of effective focal length from actual focal length. However, the exif mentions Picasa. Are you sure the file is straight out of camera, not modified in any way? \$\endgroup\$
    – Iliah Borg
    Jul 14, 2015 at 17:52
  • \$\begingroup\$ @lliah does Picasa typically strip metadata? This is what the user gave us. getting originals requires them to transfer to desktop manually, so difficult. Is the sensor size database open source? If so we have a work-around \$\endgroup\$
    – edward
    Jul 14, 2015 at 19:51

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