Rollei V/S Heidosmat 90mm f2.4 Slide Projector Lens
When i found this weird projector lens in a Yard sale for only 5 euros i was not sure it would be great for photography, but after my first test i was blown away.
It produces an elegant bokeh that is perfect for close up portraits.
you can use this to adapt this lens to your camera :
M52 to M42 adapter :https://amzn.to/2WbPEzh
m42 adapter :https://amzn.to/2DrDQ4U