Farlens tech
I ran into the Library and started scaling the stairs up. As I reached the third floor, the Librarian herself passed me, going the opposite direction. As everyone was panicking, she didn't pay me any attention. I reached the 4th floor and opened one of the windows there, the one leading towards the docks. From my pocket, I took out a small monocle and put it on. The view got magnified and I could take a closer look at what happened there. And what I saw was...The first farlenses were created around midway through the Age of War as an easier to carry alternative to spyglass and binoculars. Compared to those tools, farlenses give their user the ability to change the magnifying power of the lens simply by focusing on it.
Construction
The construction of a farlens at the same time seems simple and yet needs a few different specialists First, a convex lens with a hollowed-out center needs to be made. Next, one needs to create a solution out of the Blue Pigment at the right concentration. Said solution is poured into the center where it forms into the pupil surrounded by a ring.Lenses are usually framed in some way and turned into monocles, spectacles, spyglasses, or binoculars.
Access & Availability
After the Age of War, the farlenses became a pretty commonly seen item. While they aren't produced in the same quantity as before, many of them managed to survive to today. Though one needs to watch out when buying the older models, as often with age, the Blue Pigment contained within them either partially evaporates or gets "muddied up" with other Colors and loses its magnifying properties.
A secret version
Right now, only The Witchhunt knows it, but if one dissolves a drop of Green Pigment in the standard Blue solution at the right ratio, the lenses gain another property. With the help of the Color of voice, they "magnify" the sound of whatever the user is looking at, letting them listen in on and spy. Whether Witches know about it already or not is unknown.
Nice little touches here with the blue muddying, or the green boosting audio!