It would be really useful to have the "name" of the optical train in the FITS metadata.
At the moment in the metadata the fields that come out of ekos I can see (exiftool) appear to be :
Instrument : The camera / sensor name
Telescope : The mount driver name
Focallen : focal length from the optical train (lens / telescope modified by the barlow factor)
Aptdia : aperture from the optical train
I currently use a Canon 400 F5.6 prime lens and an Orion 8" reflector with an 800mm focal length. I also use a 1.4 extender and a 2.0 extender.
For the various combinations I use, I have setup 5 optical trains. It would make things much easier when searching through metadata if the optical train name was in the metadata as well.