The Lens details of a series of images taken by Steve Cushing on mirrorless camera.

Fitting has no mount and has a 42mm Flange Distance - this lens will fit and achieve focus to infinity mirrorless cameras but not on DSLRs.

Lens History

Rollei Projar was made by Isco. Isco was founded in 1936. It is a maker of lenses and high precision optical systems. Its specialty is cinema projection lenses. In the heyday of the German camera industry it delivered lenses for several types and brands of cameras. The company is based in Göttingen.

Most projector lenses are of Petzval format. The Petzval lens was invented by Austrian mathematician/physicist Joseph Petzval, in 1840 for Voigtländer. The design is much simpler than modern lenses and the layout of a typical Petzval lens is shown above, it has two positive colour correction doublets and a large air space between.

The one I used here is a slide projector lens. I purchased 5 lenses for less than €3 as a job lot. I then glued it to a cheap m42 step up ring. It was then mounted using a m42 hélicoïdal adapter.

Lens in Use

With no aperture this lens takes some getting used to. Exposure is controlled by ISO and shutter speed. Focus via a helicoid. It does have a built in sun shade. The lens is very plastic and looks strange on a camera, but it works and is actually very sharp.

Remember this lens was designed for projecting flat slides onto a flat screen. It has a very narrow focus plane which creates the unusual images.

Summary

I would describe this lens as the Swirly Bokeh King, as can be seen in the sample images, the painterly bokeh is just wonderful. The lens even works into direct sunlight (see example)


For general information on lens design and lens elements go to the homepage HERE