Photographer Mathieu Stern is passionate about finding and even making unusual lenses. This time, he hit a flea market and found a $6 treasure: Rollei 90mm f/2.4 MC. It’s a slide projector lens, but Mathieu adapted it to his Sony mirrorless camera and found out that it’s also great for portraits.

The Rollei 90mm f/2.4 MC has no diaphragm. However, Mathieu found out that it fits perfectly in an M52 helicoid tube, which gave him a possibility to adjust focus. Finally, he added an M42 to Sony E adapter, and went out to try out his new lens. As it turned out, this cheap lens can produce awesome portraits, considering that it’s pretty sharp and creates a gorgeous bokeh. Check out some of the photos Mathieu took with this lens mounted to his Sony A7III:

Along with the M52 helicoid tube and the M42 to Sony E adapter, the whole build costs around $50, which is still pretty affordable for a lens. So, next time you’re at a yard sale or a flea market, watch carefully. You might find a super-cheap yet valuable lens like this, too. [Using a cheap Slide Projector Lens for Portraits (Amazing bokeh) | Mathieu Stern]