In photos of my camera (CANON PowerShot A620)
in section EXIF "Image" there is no data "<ISO value>". But they are in section EXIF "Makernotes" 
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Whether It is possible to support both variants in tags "<ISO value>" and "<ISO value CANON>" for a choice necessary at information display
Example of my exported EXIF in attachment..
P.S. In later models of CANON this lack have eliminated, having involved standard position <ISO value> in EXIF data...