Carl Zeiss Jena's four-element M42 standard prime — the Tessar 50mm f/2.8 with 0.35m close focus.
The Carl Zeiss Jena Tessar 50mm f/2.8 was the East German maker's budget standard prime for M42 screw-mount SLRs, sitting below the faster Pancolar in the Jena line-up. The Tessar formula itself dates back to 1902, and post-war Jena kept it in production for decades through preset, semi-automatic and automatic aperture versions, with late examples engraved 'Carl Zeiss Jena DDR'. Earlier variants were also made in Exakta and Altix fittings.
It is a manual-focus M42 screw-mount lens with a 50mm focal length and an f/2.8 maximum aperture, stopping down to f/22. The optical construction is the classic Tessar arrangement of 4 elements in 3 groups. The automatic DDR-era version focuses down to a close 0.35 metres, takes 49mm filters, and uses a 5-blade diaphragm in a compact barrel around 45mm long, sold in both zebra and later all-black finishes.
The Tessar draws with moderate contrast and a slightly soft, glowing centre at f/2.8, sharpening well across the frame from f/4 to f/8 in the way that earned the design its 'eagle eye' marketing. The 35cm close-focus limit makes it more flexible than most vintage 50s for tabletop and detail work, and its light weight and plain, low-drama rendering suit general, street and documentary shooting.
These are among the cheapest routes into Jena glass and survive in large numbers, so be picky: common faults are haze on inner surfaces, fungus, separation in the cemented rear group, and oily or slow aperture blades on the automatic versions — test that the auto/manual pin snaps the diaphragm shut promptly. Zebra-ring examples are collected slightly above black ones. A simple M42 adapter, ideally flanged to press the pin, mounts it on mirrorless bodies.