The Meyer-Optik Görlitz Diaplan 100mm f2.8 is projection lens for 35mm Slide Projectors.
No filter mount, no aperture and no helicoid. It was used in 35mm slide projectors with 42,5mm and 52,5mm mounts.
Its optical design is the same as the Meyer-Optik Görlitz Trioplan 100 mm f/ 2.8 (http://allphotolenses.com/lenses/item/c_409.html) and also the soup bubble Bokeh is the same.
The first version of this lens was the Diaplan in all metal. The later Pentacon has a plastic barrel.
Links to online resources:
Posted by: Andreas Lindemann Date of publication: 08.05.2016