Different focusing distance tags in one category

[gverhoev]

Dear all,

For some of my academic work, the focusing distance recorded by Nikon is used for selecting certain mages. However, Nikon writes this in different "lensdata groups" (see screenshot). I can use one tag to drive a category, but can I also use multiple tags? Or should I make a category for every instance of FocusDistance and then use a category formula to combine them?

Any help on this is greatly appreciated! Cheers, Geert

[Mario]

That's one of the problems with undocumented and ever-changing metadata values.
ExifTool tries to make some sense of it, ending up with different "made up" tag names.

If this is important to you, you could handle this with a data-driven category based on variables. They offer a tremendous amount of flexibility, but are comparatively slow compared to using tags directly.

The general idea is to probe several tags via a File.MD* variable. And using the default function to fall back to another tag if the first tested tag is empty. This can be nested in the form of {File.Tag.<Name>...|default:{File.MD.<Other Tag Name>| |default:{File.MD.<Yet Anther Tag Name>| ...} to check multiple tags and use the first non-empty tag.

Tip: You can try this out in the VarToy app and then create a data-driven category based on the variable when you're satisfied.
Let us know if you need more details about using default

If your database is large, set the data-driven category to manual to update it only when needed.

If your database is really huge, consider creating a per-file Attribute Set, with a "lens data" attribute. Fill this attribute using the Attribute Importer and your variable. This way you can create the data-driven category based on the Attribute, without relying on an expensive variable.
I've used that trick in several projects where a complex variable was required to cluster files and filling an Attribute once and using it to drive a data-driven category was 100 times faster that calculating the complex variable every time for each file in the database.