Read metadata from file

Here is some more information on what I am trying to do:

I have a G1 camera and an adapter to use an old manual Minolta AF lens with it. The pair produces nice pictures, however, since the adapter is mechanically only, the camera isn't able to write the Lens, ApertureValue and FocalLength values into the EXIF info of the photo.

That's where LR comes into the picture. I have all my pictures in LR and want to add the Lens info manually to the raw files. Since LR doesn't allow it (only IPTC data), I was looking for a different way to do this. I ended up with writing a plugin for that task. What the plugin does, is simply present a dialog to the user to let him enter the lens info, retrieves the list of selected photos and executes ExifTool for each picture. This works fine, but the newly written EXIF info does not show up in LR sidebar in the EXIF view. It, of course, only comes up as soon as you click on 'Reload Metadata from Files'.

What I was looking for, is a method to to the last step automatically by the plugin. This, however, seems to be a problem. You told me that there is no API functionality for it and even HotKey scripting is not a solution, since this menu entry has no hotkey assigned to it. :-(

Any other suggestions?

(but thanks so far!)

---

local function updateExif()

     -- get the path of the selected photo

     catalog = LrApplication.activeCatalog()

     photos = catalog:getTargetPhotos()

     -- invoke ExifTool for each picture

     for loop, photo in ipairs(photos) do

          pathName = photo:getRawMetadata('path')

          LrTasks.execute('exiftool -overwrite_original -Lens=\"' .. properties.lens .. '\" -FocalLength=\"' .. properties.focalLength .. '\" -ApertureValue=\"' .. properties.aperture .. '\" ' .. pathName)

     end

     LrDialogs.message( "EXIF Complete", "Done processing " .. #photos .. " pictures. You have to reload the metadata from the files now.", "info" );