CARL ZEISS JENA SONNAR 50mm f/1.5

US 1,975,678 — ZEISS IKON / LUDWIG BERTELE (1932)

7 ELEMENTS / 3 GROUPS
f ≈ 50.2 mm
F/1.5
2ω ≈ 46.8°
ALL SPHERICAL

Focus Mechanism

Unit focus — entire lens translates forward. BFD changes from 35.2 mm (∞) to 38.2 mm (0.9 m). Typical of 1930s Contax rangefinder mount lenses.

Optical Elements (7)

ElementTypeGlass
L1Positive MeniscusUnmatched (vintage Schott/Jena dense crown, patent nd=1.6375, νd=56.1)
L2Positive MeniscusUnmatched (vintage Schott/Jena BaF10-class barium flint, patent nd=1.6727, νd=47.3)
L3Biconvex PositiveUnmatched (patent ultra-low-index crown, nd=1.4075, νd=65.7; no practical catalog glass)
L4Biconcave NegativeN-SF8 / SF8 equivalent (Schott, patent nd=1.6890, νd=31.0)
L5Negative MeniscusUnmatched (vintage Schott/Jena light flint, patent nd=1.5481, νd=45.9)
L6Biconvex PositiveUnmatched (SSK51-class very dense crown, near N-SSK5; patent nd=1.6578, νd=51.2)
L7Negative MeniscusUnmatched (vintage Schott/Jena crown, patent nd=1.5488, νd=63.0)

Analysis

Detailed analysis available in the interactive viewer above.