<p>I use Exif Editor, with many different setups for camera and lenses.<br>
But I also discovered a powerful iPhone/Mac application to both register photo data, and embed the data into the files later.<br>
The name is PhotoExif on Apple AppStore, and after purchase you can download the Mac version for your desktop. It basically works like this: when you take a picture you register the data on the mobile app. When you have all the files (from the scanner in my case), you connect the iPhone with the desktop Mac via wifi, open the destop application (PhotoExifDesktop) and transfer all the data inside the metadata file: camera, lens, film, time, aperture, notes, GPS (!), date and time.<br>
There is also a plugin for Lightroom able to change some metadata, it's called LensTagger, but in my opinion it has a narrower scope.</p>