Making a camera is difficult. But making a camera from scratch, without the help of a laboratory, a whole team of engineers, and needing to source all of the raw elements yourself is nearly impossible.
How to Make Everything is a YouTube channel where the host attempts to make everything simple, from swords up to, in this video, a camera lens. While this video isn't quite a tutorial, per se, it is a fascinating look into the amount of work that goes into creating a (rather simple) camera lens; From making glass from rocks and sand (with elements sourced from around North America), to grinding it down, to making a copper housing (sourced from pennies), and more grinding. It's eye opening to see just how much work can go into building a lens, and why they can be so expensive. All of this is without things like coatings, optical image stabilization, aperture, shutter control, or even a lens cap.
While the video, sadly, does not show us a fully completed image at the end as the host, Andy George, still has to make his own film, a mount, repair his camera, as well as fix the lens that he dropped, I find these videos incredibly eye opening and brings the complexity of our tools into focus.