Photographer Mathieu Stern of the Weird Lenses Museum has published another video showcasing an old projector lens used with a 3D-printed adapter to shoot a video featuring beautiful, crazy -- and in this case, swirly -- bokeh.

As with the projector lens video Stern published earlier this year, the latest project involves an old projector lens designed for cinema projectors. Stern explains on YouTube that he paid €2 for the lens at a flea market, later determining that it is an 'extremely rare' Cinestar 75mm F1.9 model.

Stern used a 3D-printed adapter to insert the lens into a helicoid ring, enabling him to focus the lens. The ring was then used with an M42 to E-mount adapter for use with a Sony A7III camera. The result, Stern says, 'Is the most amazing swirly bokeh I [have ever] seen.'

Stern showcases a number of unusual lenses on his website, including one that he made using ice from an iceberg.