doc:appunti:hardware:canon_s120
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Canon PowerShot S120
Exif Tags
Using the exiv2 command linee tool (should be packaged into every GNU/Linux distribution), you can view all the Exif metadata contained in each photo:
exiv2 print -p a IMG_1858.JPG
There are several proprietary Canon tags stored for each photo, as far I know, there is not a comprensive guide to that tags. An useful resource can be the Metadata reference tables, an index of the names of all tags recognized by Exiv2 library.
Here are some of the more interesting ones:
Exif.CanonSi.SubjectDistance | Subject distance, as per manual focus or Auto-Focus. The number seems to be the distance in cm, where infinity is reported as 6553. |
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ISO Speed | |
Exif.CanonCs.ISOSpeed | ISO speed mode. Version 0.24 of Exiv2 library is missing some values, see issue #1217. |
Exif.Photo.ISOSpeedRatings | The actual ISO speed used for the shot. |
Exif.CanonSi.ISOSpeed | Manual selection of ISO speed? This value is equal or very close to Exif.Photo.ISOSpeedRatings , sometimes it has decimals. This value seems to be always 200 when ISO speed is in auto mode. |
Aperture | |
Exif.Photo.FNumber | F-number: the ratio of the lens's focal length to the diameter of the entrance pupil. |
Exif.Photo.ApertureValue | The lens aperture in APEX value. Practically it is always the same value as Exif.Photo.FNumber . |
Exif.CanonSi.TargetAperture | Its value is always close to the Exif.Photo.FNumber , sometimes it differs for few decimal points. |
Exif.CanonSi.ApertureValue | Sometimes it differs for few decimal points from Exif.CanonSi.TargetAperture . |
Exposure | |
Exif.Photo.ExposureTime | The exposure time in seconds or fractions. |
Exif.Photo.ShutterSpeedValue | The shutter speed in the APEX units. It differs slightly from Exif.Photo.ExposureTime . |
Exif.CanonSi.TargetShutterSpeed | Always equal to Exif.Photo.ShutterSpeedValue . |
Exif.CanonSi.ShutterSpeedValue | It differs sligthly from Exif.Photo.ExposureTime and Exif.CanonSi.TargetShutterSpeed . |
Ligth Value | |
Exif.CanonSi.MeasuredEV | May be it is the calculated light value for a proper exposure. See here. |
Exif.CanonSi.MeasuredEV2 | Unused? Seems to be always -6.0 |
doc/appunti/hardware/canon_s120.1472545035.txt.gz · Last modified: 2016/08/30 08:17 by niccolo