YouTuber Mathieu Stern is a weird lens expert, but even he didn’t realize the gem he’d uncovered when someone sold him an old cinema projector lens for 2 Euros at a flea market. It turns out this rare 75mm f/1.9 lens produces some of the most intense swirly bokeh Stern has ever seen. Since this lens wasn’t made for any camera that Stern had ever used, he actually had to 3D print a solution in order to attach it to…