Citation :12 CONFIGURATION FILE
exiv2 can read an optional configuration file, which allows additional lens definitions to be added to translated output. On Unix-based systems (including Cygwin), this file is called .exiv2 and on Windows (including MinGW), exiv2.ini. The file is searched for first in the current directory, then in the home directory ($HOME on Unix-based systems, and %USERPROFILE% on Windows).
You can determine the name of the file and where it is searched for, with the command:

Code :

$ exiv2 --verbose --version --grep config_path
exiv2 1.0.0.9
config_path=/Users/rmills/.exiv2

The configuration file uses the Windows INI format (see https://en.wikipedia.org/wiki/INI_file) and has sections for each of the major camera manufactures: Canon, Minolta, Nikon, Olympus, Pentax and Sony. The configuration file definitions override any existing values.
For example, to add a new lens definition, first obtain the lensID for your camera:

Code :

$ curl --silent -O https://www.exiv2.org/Stonehenge.jpg
$ exiv2 --print v --grep lens/i Stonehenge.jpg
0x0083 Nikon3       LensType           Byte       1  14
0x0084 Nikon3       Lens               Rational   4  180/10 2500/10 35/10 63/10
0x008b Nikon3       LensFStops         Undefined  4  55 1 12 0
0x000c NikonLd3     LensIDNumber       Byte       1  146
0x000d NikonLd3     LensFStops         Byte       1  55

Then using the 'LensIDNumber' value (i.e., 146), add the following text to the configuration file:

Code :

[nikon]
146=Robin's Sigma Lens

The text will now appear when the translated print option is used:

Code :

$ exiv2 --print t --grep lens/i Stonehenge.jpg
Exif.Nikon3.LensType                         Byte        1  D G VR
Exif.Nikon3.Lens                             Rational    4  18-250mm F3.5-6.3
Exif.Nikon3.LensFStops                       Undefined   4  4.58333
Exif.NikonLd3.LensIDNumber                   Byte        1  Robin's Sigma Lens
Exif.NikonLd3.LensFStops                     Byte        1  F4.6