Manipulating EXIF Info

The Leica M9 has no means of determining foreign or old lenses. The newer Leica lenses have a 6-bit (visual) coding mechanism for determining the lens. Problem is that this is only for (relatively new) Leica lenses. There is the possibility to manually select the lens in the menu of the M9, but that's only limited to the Leica brand lenses. No option for Carl Zeiss lenses.

For certain characteristics, and in-camera processing of the RAW image it's handy to manually select a Leica lens even though you've attached a Zeiss lens. This can be automated by coding the lenses yourself (or have Zeiss do it for €100 a lens).

All this is nice, but it still generates photos with faulty EXIF information, because you shot the photo with a CZ C-Sonnar 1.5/50mm and not with a Leica 1.4/50mm Summilux ASPH....

The solution for this is to manipulable the written EXIF information in the image file. Unfortunately, this cannot be done with most image/photo manipulating software. Those software packages are mostly limited to editing the IPTC information (like location, GPS, copyright info etc.).

Hardcore EXIF editing is done through he use of a command-line tool EXIFTool.
This tool is available for both Windows and OS X. There are also several GUI's available, mostly for the Windows platform.

To get an idea what values can be manipulated just type the following:

exiftool -a <filename>

Remove the spaces from the parameters in the left column, and those values can be set using the exiftool. In my case the following EXIF parameters need to be changed (in most cases) for the Zeiss lenses:

• ApertureValue
• FNumber
• Lens
• FocalLength

The parameters LensType, Lens, LensID are fairly static;

exiftool -Lens="Carl Zeiss C Sonnar T* 1.5/50 ZM" <filename>

exiftool -Lens="Carl Zeiss Biogon T* 2.8/28 ZM" <filename>

exiftool -Lens="Leica Summicron-M 35mm f/2 ASPH." <filename>

 The <filename> parameter can contain a wildcard like *, *.* or *.DNG. You can even put multiple filenames behind each other. E.g. you can select multiple files in Finder, and drag those to the Terminal window and the files (its textual reference) will be placed at the end of the line (containing the exiftool command with all the parameters).

E.g. if you shot an entire day with the 1.5/50mm lens and only with an aperture of f/1.5 than the processing of the (RAW)files would be:

exiftool -Lens="Carl Zeiss C Sonnar T* 1.5/50 ZM" -FocalLength=50mm -FNumber=1.5 -ApertureValue=1.5 *.DNG

This can also be used to create an image shot by a non-existing (at the moment) Nikon D5x and a Nikon AF-S 200-600mm f/4G N ED VRIII. Even with the authenticity stuff enabled, since that has already been compromised.....