In Lightroom 2015.5 and Lightroom 6.5, the EXIF Lens metadata field is hidden for some cameras.

Note: The metadata is still in the file, it's just hidden from display.

Solution: Update Lightroom and adjust settings for affected camera models

Use these steps to display the hidden lens metadata.

1. Update Lightroom to 2015.5.1 or 6.5.1.
2. Open your Lightroom 6.5 catalog with Lightroom 6.5.1.
3. Select any file from an affected camera model that you had imported into Lightroom 6.5.
4. Choose Metadata > Save Metadata to File (Cmd/Ctrl + S), to ensure that any Develop settings made to the file will be maintained.
5. Choose Metadata > Read Metadata from File.

To verify that the Lens metadata is being displayed, expand the Metadata panel in Lightroom’s Library Module, choose EXIF from the panel header’s pop-up menu, and look for the Lens field, which will be populated with the correct Lens information for the selected file.

Correct any virtual copies impacted by this issue

If you created virtual copies from files that were missing Lens metadata, use these steps to correct them, after you perform the above steps: 

1. In the Develop module, create a new virtual copy from the repaired master photo.
2. Select the old virtual copy, and choose Settings > Copy Settings.
3. Select the new virtual copy and choose Settings > Paste Settings. 
4. Delete the old virtual copy.