Ah, you want specialized instead of general.
Well, then is a couple of books enough to train your LLM? How many books are there on wavelengths your first doublet filters for?
Seems like you might want a forum full of topic specific comments too to feed into the model. A photography textbook with a section on lenses is good, real questions and answers from actual photographers with real scenarios would be better for most people.
Ha, two people I tagged so far in this thread. One for being a self-described and proud redpiller type (I don't remember the specifics on that one) and one for conversing in bad faith; that person kept arguing with well-sourced fact. Think flat-earther type stubbornness to acknowledge reality for the sake of being funny or edgy. There's a time and a place for that, but it was on a serious topic where everyone else was taking it seriously and trying to be genuinely helpful.
I haven't tagged you, OP. Yet.