HoudahSpot uses the macOS Spotlight index for ultra-fast file searches. By building upon Spotlight, HoudahSpot can find files by name, text content, as well a wide variety of file properties and metadata.
Spotlight in turn relies on importer plug-ins to read all kinds of files. When indexing a file, Spotlight calls upon the plug-in that specializes in the file type at hand to extract text and metadata. Such importers are installed with the system and with applications that introduce new file formats.
The Info pane in HoudahSpot shows the information available for a given file. This is the metadata that the importer plug-in has shared with the Spotlight index.

Info Pane
The top sections of the Info pane show a summary of the most relevant metadata for the files currently selected in search results.
The bottom section lists all metadata available for the current file. For the photo file in the screenshot, this includes information on the camera and lens used.
It is safe to assume that the same information is available on other files of the same type. You can see the information for all files in search results by adding columns to the list of results. The same metadata properties shown in the Info pane can also be used as search criteria. For example, you can run a search to find all photos taken with the Panasonic DC-G9 camera. Likewise, you can filter search results to show only images taken using the same lens.
Info Window
HoudahSpot can also show file information in a floating window. This is found from the Window > File Info menu item.
Just like the Info pane, the Info window shows file information for the currently selected search result.
Inspect a File
You can also use the Info window to view properties and metadata for any Spotlight-indexed file. Drag the file you want to inspect from HoudahSpot or Finder and drop it onto the Info window.
This technique also works to learn what kind of information is available for a particular file type. Inspect a few sample files. You can assume that other files of the same type share the same set of metadata attributes.
Add Columns to Search Results
The Info pane and window show file information that helps you assess the pertinence of a search result.
Often there are key pieces of information you want to check or compare so as to find the best match in your search results. When searching for images, you may, for example, look at pixel counts.
In order to see such key information for all files at a glance, you can add columns to the list of search results: list camera model and pixel counts for all photos in your search results.

Right-click or control-click an entry in the list of metadata properties to reveal the context menu. From the menu select Show Column to add to the list of search results.
Filter Search Results – Find Similar Files
Filters let you view only a subset of the current search results. You can use this to pare down search results or to browse results in manageable chunks.
The filter options in the Info pane let you focus on files that share common property. Tick the box next to the Modified date to see only files that were modified on the same day as the currently selected file.
You can also use the context menu to set or remove filters.

Refine a Search – Zero in on Files You Need
Often times a first search returns more results than you care to peruse. You then refine your search criteria until only relevant files are found.
To refine a search, you add more specific search criteria. In effect, you tell HoudahSpot more about the files you are looking for. You may for example remember which camera you used to shoot the photo that you want to find.
Examining file properties can spark a memory or idea. The camera information may catch your eye and prompt you to use that information for further refining your search.
Right-click or control-click an entry in the list of metadata properties to reveal the context menu. From the menu select the Refine Search option to add to the search criteria.
Alternatively, you can also drag an entry from the Info pane and drop it into the Refine pane. Using this technique you can add the new criterion to a specific group in your search criteria.
The Any group will match photos taken using an Apple, Ricoh, or Panasonic camera.