Hi Bogdan,

I understand. Yes, the unknown tags are presented without any translation (in raw numerical form).

The -a only supresses tags which would be extracted with the same tag name. Internally, exiftool ignores some tags which have a zero value, but this can't be changed by a user setting. I assume you are talking about the FocusDistanceUpper tag, where the 0 value conveniently is replaced by the CameraInfo for the 450D. This would be replaced without -a regardless of the value of the first tag. By default, the last value is the one you see without -a, but I play with the priorities for many tags to cause the most reliable and/or expected value to be displayed by default.

- Phil