The Pentacon Prakticar 50 mm f/1.8 MC is a standard fast prime lens for 35 mm Praktica B-System SLR cameras.
This is an Oreston 1.8/50 modification designed for the PB bayonet mount. The first version had been manufactured under the brand name Meyer Oreston (since 1970). The first version featured a metal frame, the second featured plastic elements. The second version was marked 'Carl Zeiss Jena P'. Its minimum focusing distance had changed from 0.33 m to 0.45 m.