Find duplicates "between" two folders / directories?

Is it possible to find duplicates through "cross-comparison" of two folders / directories?

For example: I have a folder that contains many scanned PDFs and I would like to find all files in this folder that already exist in my documents directory structure (including subfolders). I have a tool (Duplicate Cleaner Pro) that does this job very well, I just would like to know, if DirOpus can do this, too. Could be much quicker and more convenient in many cases.

Bearbeiten - Weitere markieren - Quelle-Ziel-Dateien markieren usw. + Flatview.
oder mit mehr Optionen
Extras - Duplikatsuche (Strg+U)

Edit - Select Other - Select Source Selection to Destination etc. + Flatview.
or with more options
Tools - Find Duplicate (Ctrl+U)

Deutscher/German Support: Directory Opus - Directory Opus-Forum

The Duplicate Finder tool in Opus can be told to search across multiple directories. Just keep in mind that it will not really care where the duplicates are. They could all be in one folder or the other, or both.

You can select "all but one" of each duplicate group (e.g. to move or delete the others). The one that is kept is the first one in each group. So you can sort by location to influence which thing is kept, but if there are two duplicates below that folder then one will still be selected.

You can also use more advanced filters to include/exclude all files under a certain folder. Just be careful not to delete everything in situations where the duplicates are only in one of the folders.

(We have plans to add more advances selection controls for this kind of thing in the future.)

Please add a lock option for the find location; when I add multiple directories then I want to lock one or more directories; no files will be select for delete in the locked directories.

What is the basis for comparison? I would like to have MD5 comparison so that (slightly) different names or dates would not hinder finding duplicates.

MD5 is one of the options in the duplicate finder.