The Pentacon 28mm f/2.8 was a wide-angle prime made by VEB Pentacon in Dresden for the Praktica SLR system. It descended from Meyer-Optik Gorlitz's retrofocus wide-angle work and stayed in the lineup from the mid-1970s through reunification, a budget wide option alongside the 50mm standard and 35-70mm zoom.
Built as a retrofocus design with automatic diaphragm, it came in a chrome-nose single-coated 'auto' form and later a black multi-coated 'MC' version. It mounts natively in M42 screw thread, fitting Praktica L- and LTL-series bodies, with a manual aperture ring and compact Dresden-made build.
Wide open it shows softer corners and lower contrast than contemporary Japanese wide-angles, sharpening from around f/5.6. The MC coating curbs flare versus the earlier single-coated auto version, though color neutrality still trails Zeiss Jena's Flektogon line from the same factories.
These sell cheaply on the used market alongside other Praktica-mount glass, generally undervalued next to their Flektogon cousins. Check the aperture blades for oil contamination, common on Pentacon automatics, and confirm the M42 threads are not cross-threaded from years of adapter use.