[Originally posted by wobaa666 on 2008-04-09 19:14:25-07]Hello,
Ive tried several images from Dpreview with exiftool and saw a stange behaviour with several images, here its ISO value.
Sample Image:
Link to ImageWhen using
exiftool(-k -ISO).exe the output is ISO: 200 (correct)
but when using
exiftool(-k -n -ISO).exe the output is: ISO: 9 (wrong)
All ohter Images I've tried have correct value with -n.
I'm wondering how the values where calculated using the -n parameter?
My concern ist, that I can't rely the correctness of the conversion done by -n.
Exiftool 7.23 used on windows
Jan
[Originally posted by exiftool on 2008-04-09 20:12:06-07]For tags based on lookup tables, using
-n will
give you the value on the left hand side of the lookup.
The specific Pentax ISO tag you mentioned is decoded with a
table. See the ISO tag in
this
table to see the lookup table.
For some tags I have buried the lookup at a deeper level
so the user doesn't have to worry about it. This avoids
this problem, but reduces the control that the user has
to set a specific value in cases like this where different
values convert to the same ISO for different models.
However I am always open to opinions, and perhaps
I should be doing this differently.
- Phil
[Originally posted by wobaa666 on 2008-04-10 07:35:52-07]
Thanks, didn't even thought about that.
I use exiftool to fill a database with exif information. So the "original" value received with -n is in most cases what I intentionally want. Integer or Float values can be stored more efficiently than interpreted as string (e.g. MeteringMode).
So I don't know if it makes sense to look up values like ISO while don't look up other values (e.g. Flash). Who will decide which values to look up?
Perhaps a combination like -n -lookup ISO to explicit specify values to lookup can help. I'm not sure if it makes sense to give this option.
Anyway, thanks alot! Whenever strange values occur I will take a look at these lookup tables and check if it is the value I need. If not, I will handle this as special case using the lookup tables.
Regards, Jan