I was recently using OpenDroneMaps to generate orthomosaic photos from my aerial shots. The software libaries used relies on the "Focal length" EXIF tag to be populated with data, and I found that none of the images shot with my Phantom 4 have this data. Images from my P3P provide the "Focal length" tag and data FWIW. For now I'm working around this limitation by using exiftool to add the correct focal length (3.5mm) before the pictures are processed.

Any chance a firmware update could add this functionality?

P.S. I sent a patch to the OpenDroneMap project to enable the DJI FC330 sensor used in the Phantom 4.

Thanks for your suggestion! the focal length of phantom 4 is 20 mm ( 35 mm format equivalent )